Grouppe Kurosawa: HIV - Why Current HIV Vaccines Will Fail (print)

Why Current HIV Vaccines Will Fail

We have to admit that if the HIV virus wasn’t a plague against mankind, it would be considered beautiful by scientists. The HIV virus is an amazing assortment of dangerous proteins that subvert the immune response as soon as they are expressed. To some extent, all pathogens devise methods of evading the immune response, but the HIV virus has taken the art of immune evasion and elevated it into an art form.

It is Grouppe Kurosawa’s position that most of the current HIV vaccines in development will never completely block HIV from infecting the body. In fact, some vaccine protocols may actually end up promoting disease once subjects are exposed to the HIV virus. The following is a case in point.

In 1996, a study was published (McElrath, M. Juliana, et al. PNAS 93:3972, 1996. Human Immunodeficiency virus type 1 infection despite prior immunization with a recombinant envelope vaccine regimen) that carefully chronicled the immunization and anti-HIV immune responses of a volunteer that had been immunized with an experimental HIV vaccine. The subject was immunized over a period of four years—three times with a live recombinant vaccinia virus containing gp160 sequences, and three times with recombinant gp160 protein. Ten weeks after the last vaccinia virus booster immunization, the subject had unprotected sex with a new partner and became infected with the HIV virus. The subject had previously demonstrated the presence of both neutralizing antibody and strong T cell responses against the virus in in vitro assays. He became infected anyway. The most significant aspect of this study is the rapidity by which this subject became gravely ill. Within two years of infection, the subject’s CD4 T cell count fell to 250. This is an extremely rapid disease progression, and we believe it is entirely due to immunization with the gp160 protein. There is no such thing as a true neutralizing immune response against the HIV membrane protein gp160/gp120. It is a contradiction in terms, and an artifact of the testing procedure. Laboratory studies of HIV viral neutralization are meaningless predictors of vaccine efficacy. Any attempt to induce a vaccine-mediated humoral immune response to gp160/gp120 will invariably prove fatal to the recipient if they subsequently become infected with the virus. Studies in chimpanzees that purport to demonstrate the efficacy of anti-gp160/gp120 protein vaccines are all fatally flawed in design. The challenge stocks of virus used in these studies are almost always prepared with human cell lines. The chimpanzees respond vigorously to the human histocompatibility antigens on the membranes of the virus particles—not the presence of viral associated gp160. Our criticisms of current HIV vaccine designs and protocols can be summarized as follows.

The Misguided Search for Neutralizing Antibodies Against HIV Envelope Proteins

1. There is a big difference between acute and chronic viruses. For example, influenza viral vaccines are made against killed viral proteins. This is the simplest of all vaccines. This type of vaccine stimulates the production of antibodies that bind the virus, fix complement (a series of 13 proteins in the blood that punch holes in pathogens) on the surface of the virus and destroy the virus before it has a chance to infect susceptible cells. These vaccines do not stimulate the production of a strong cell-mediated immune response against the virus. A cell-mediated immune response does not target the virus itself—it targets the cells producing the virus. Since acute viruses are in and out in a short period of time, this type of immune response doesn’t do much to protect against the virus (but it can help). In the case of HIV-1, a slow recurring virus that can assume latency in the body, a strong cell-mediated immune response is absolutely required in order to protect against chronic viral infection. HIV vaccines like AIDSVAX are recombinant or genetically engineered viral proteins that are administered by injection—much like influenza vaccines. They will not stimulate a cell-mediated immune response against the virus. Soluble proteins rarely do. Therefore, they will fail to protect. Virtually the entire scientific community agrees with this argument. VaxGen, the publicly owned corporation that developed the vaccine (as a spin-off from Genentech), argues that their vaccine protected chimpanzees against infection by a primary isolate of the HIV-1 virus. We believe it did not. More about this later.
2. The neutralization of viruses by antibodies is the Holy Grail for immunologists. The technique works great for viruses like influenza. As we said, influenza is an acute virus. But this isn’t the only issue. When people are immunized with a killed influenza virus, they make antibodies to it. Hopefully, the antibodies neutralize the virus in the sense that they prevent its uptake into human cells. The anti-influenza antibodies also “fix complement” or activate the complement cascade in the blood. This results in holes being punched into the viral membrane. The viral particle falls apart and is effectively dead before the macrophages or scavenger cells clear up the debris. This is an important issue so let us quickly review the process. When antibodies bind the virus, their butt end or FC domain undergoes a conformation change. Complement consists of an entire family of blood proteins, 13 of which work in sequence to form pores in the membranes of viruses, bacteria, etc. The first complement protein, C1, binds the antibody and begins the activation cascade. As the complement proteins are activated in the blood, they fall and stick to the surface of the pathogen. The latter complement proteins form a pore in the membrane of the virus and it falls apart. The entire process occurs within seconds. This doesn’t happen with the HIV-1 virus in humans. The viral envelope protein gp120/gp41 binds a complement control protein from the blood called Factor H that prevents the full activation of the complement cascade on the surface of the virus. All HIV viral particles in the blood are coated with antibodies targeting the envelope proteins, yet the virus continues to survive and infect new cells. Human Factor H recognizes the envelope gp120 and gp41 proteins as binding sites. This is an ABNORMAL binding reaction. Factor H should only bind the complement protein C3b in the blood. As a result of this abnormal preference for binding the gp120/gp41 proteins on the surface of the viral membrane, Factor H stops the activation of the anti-gp120/gp41-mediated complement cascade. Interestingly, if the HIV virus is incubated with anti-gp120 antibodies in the presence of fresh feline or rodent blood serum, the viruses are rapidly killed. Feline and rodent Factor H are genetically different from human Factor H and do not bind the viral gp120/gp41 proteins. Therefore, there is no interference with full complement activation and destruction of the virus particle. The story continues to get worse.
3. The immune complexes that form between the HIV virus and envelope-specific antibodies are highly infectious. It doesn’t make any difference if the antibodies binding the envelope proteins are “neutralizing” in a culture dish assay. When neutralizing monoclonal antibodies specific for gp120 were mixed with virus and injected into a mouse, the complexes concentrated in the germinal centers of lymph nodes and spleen. The complement proteins (called C3b) that bound the virus in the early phase of complement activation now act as ligands or docking proteins that allow the infectious immune complexes to bind the surface of dendritic cells and B lymphocytes. When T lymphocytes bind these cells during the course of their activation, the immune complexes are transferred to the T cells and they become infected. The immune complexes are also taken up by macrophages/monocytes where they establish a persistent, long-term infection. Macrophages and monocytes are natural reservoirs for the virus. If complement destroyed the HIV virus as it does the influenza virus, HIV infections would still exist, but they wouldn’t be fatal.
4. It is our opinion that envelope-specific antibodies against the HIV virus substantially contribute to the development of AIDS. Since at least 75% of the 70 AIDS vaccines in development are attempting to develop neutralizing antibodies against gp120/gp41 or gp160 (gp120 and gp41 are derived from this larger envelope protein), anyone who is vaccinated with these vaccines might have a reduced ability to fight off an infection if exposed to the HIV virus. Antibodies to the envelope protein cannot kill the virus. All they can do is concentrate the live, infectious virus in the germinal centers of the lymph nodes and spleen and infect monocytes and macrophages. In the early days of AIDS research, scientists couldn’t find the virus in the blood. This lead to spurious theories that the virus didn’t cause AIDS. Finally, the virus, in the form of immune complexes, was found hiding in the germinal centers. In a tightly enclosed environment like germinal centers, the virus infects new T cells and systematically destroys the immune system. Remember, most viruses do not infect the immune cells that are responsible with their destruction. When immune complexes migrate to the germinal centers, which is natural, the viruses or bacteria that form the immune complexes are already dead. Complement activating antibodies rapidly destroyed the pathogens in the blood. The HIV virus is not dead. It isn’t even tired. A Texas company has a patent on cloning the gp120 protein into corn. They want to induce mucosal immunity to HIV by feeding people these edible vaccines. The edible vaccine idea is quite viable, but not with the gp120 protein. Any form of immunization that attempts to produce anti-envelope antibodies will promote disease progression—not stop it.
5. Antibodies against the gp120 and gp41 envelope proteins induce autoimmune reactions in humans (see the forthcoming essay on How the HIV Virus Takes Over the Immune System). These proteins share a number of amino sequences with normal proteins in the body, including the CD4 protein and Fas. There is a very large scientific literature on this subject. One scientist filed a patent on a technique he developed for removing some of these antibodies from the blood. Even if drug therapy stops viral production, the autoimmune antibodies are still going to exist and continue to do damage to the body. The immune complexes trapped in the lymph nodes and spleen will remain there for a long time. Autoimmune problems will continue to exist whether or not new virus is being produced. This is another reason to avoid using gp120, gp41 or gp160 as vaccines.
6. In addition to autoimmune phenomenon, anti-gp120/160 antibodies also induce programmed cell death in uninfected cells. This was very clearly demonstrated in a study conducted by the American Red Cross. Red Cross scientists constructed a transgenic mouse that expressed the human (as contrasted to the normal mouse) CD4 molecule on the membranes of its white blood cells. They immunized the mice with purified viral gp120 proteins, resulting in the production of anti-gp120 antibodies. When they immunized (boosted) the mice with another dose of gp120, the T cell population decreased 7 fold in 6 days, while the B cell population decreased 2-3 fold. The immune complexes, consisting of anti-gp120 antibodies and gp120, concentrated in the lymph nodes, and bound to CR1, CR2 and CR3 complement receptors on macrophages and dendritic cells. The gp120/gp160 in the immune complexes further bound and crosslinked the CD4 receptors on normal T cells and induced an inappropriate cell activation. The cells died from apoptosis or programmed cell death. The authors concluded that anti-gp120 antibodies not only sensitize T cells for apoptosis, but induce it per se. Anti-gp120/160 immune responses are fundamental to the T cell depletion that characterizes AIDS. Rather than target gp120/160 in a vaccine, we should clone gp160 into acceptable plants and attempt to induce immunological tolerance, or a permanent state of immunological non-reactivity. Since both p24 and p17 are partially expressed on the membrane of infected cells, these proteins should be vaccine targets rather than gp120/160. (see Yubin Kang, et al. An ongoing immune response to HIV envelope gp120 in human CD4-transgenic mice contributes to T cell decline upon intravenous administration of gp120. European J. Immunology 28:2253, 1998.). Other studies have reported similar results. This is a critically important study because it conclusively shows how an immune response to a viral protein—not necessarily the virus itself—can and does devastate both T and B cell populations in non-virally infected mice. In addition, this study explains why only 1 in 60,000 viral particles are infectious, yet the severity of the disease in AIDS is directly correlated with the amount of viral RNA in the blood. The HIV virus is the only virus ever studied that is as deadly dead as it is alive. The immune response against the gp120/160 protein cannot differentiate between infectious and dead viral particles. If protease inhibitors ONLY inhibited the viral protease, they would be therapeutically worthless. We now know that they also inhibit the proteasome complex of infected cells and this is how they decrease the titer of viral RNA in the blood. Please read the posted essay on Green Tea and its effects on proteasome activity for further details.

The Immunization of Intravenous Drug Abusers

VaxGen is presently testing one of its AIDSVAX gp120 vaccines in Thailand with the cooperation of the CDC. They have targeted heroin addicts, because these subjects have a high probability of becoming infected with HIV. Opiates are extremely immunosuppressive. Vaccines are difficult enough to develop without choosing a test population that has a chronically impaired immune system. How is the vaccination protocol supposed to be evaluated when the test population has a questionable immune system? The latest report in the literature about these clinical trials showed that two of the immunized subjects became infected with the HIV virus. We don’t know if the immunization enhanced the infection or if the immunization procedure was not complete. Heroin addicts should never be used in vaccine studies.

Alternative Vaccine Candidates

There are a few vaccine candidates that have real promise. One vaccine under development in Italy is attempting to control HIV infections by neutralizing the viral Tat protein. They have had promising results using SIV (a monkey virus very similar to HIV) models. Tat is one of the most immunosuppressive proteins every invented by God or man. Many of the immunosuppressive aspects of Tat are discussed in the essays How the HIV Virus Takes Over the Immune System and The Folly of Modeling HIV Vaccine Efficacy in Chimpanzees. Tat is considered an early viral protein. Shortly after a virus infects a new cell, it makes the Tat and Rev proteins. These proteins help the virus get established in the cell. Tat is readily released from infected cells. Soluble Tat doesn’t have to travel far to begin impairing the immune system. Remember that the HIV virus is highly concentrated in germinal centers of the lymph nodes and spleen. When Tat is released by infected cells, it binds normal immune cells and impairs their ability to mount an effective immune response against the virus (or any other pathogen). The virus uses Tat as a poison to protect itself from the immune system.

Immunizing against Tat rather than envelope proteins is intriguing because Tat is not expressed on the membranes of the viral particles. The rationale for controlling HIV in this manner is simple yet elegant. The immune system, if not impaired by outside factors such as Tat, Vpr, drug abuse or excessive stress, can fight off almost any pathogen. The Italians are trying to stop the immunosuppression that Tat induces. By doing so, they are allowing nature (the immune response to foreign pathogens) to takes its natural course. The antibodies against Tat do not bind the virus so there can be no inadvertent concentration of live virus in the lymph nodes/spleen. Long term non-progressors, people infected with the HIV virus for 10 years or so, virtually all have antibodies in their blood against viral Tat. Although the control of Tat is of paramount importance, a vaccine candidate that targets only Tat is probably not going to entirely protect. The Italian group found that their SIV anti-Tat vaccine protected 5 out of 7 monkeys against a real nasty SIV virus. This is good, but not good enough. The viral proteins Vpr, and p24, the most common viral protein, are also immunosuppressive and should be included in the design of a vaccine. It is particularly important that a vaccine neutralizes the ability of Vpr to enhance Tat activity and induce immunosuppression via action of the glucocorticoid receptor. In the absence of an HIV-induced immunosuppression, vaccine efficacy can be boosted tremendously.

The Use of Chimpanzees in Testing HIV Vaccines

Chimpanzees are 99% genetically identical to humans and can be naturally infected with the HIV virus. Chimps rarely develop AIDS. They appear to be quite resistant to the immunosuppressive effects of the HIV virus. When HIV vaccines undergo preclinical trials, they must be tested in chimpanzees. The chimps are immunized and boosted with the HIV vaccine candidates and challenged with live virus in order to demonstrate efficacy. The theory is that neutralizing antibodies will bind the virus and prevent it from entering susceptible cells. The ASSUMPTION is that the antibodies are also fixing complement and destroying the virus. We do not agree. There has never been a study proving that chimps can destroy the HIV virus by complement fixing anti-envelope antibodies. We propose a simple experiment. Select an anti-gp120 monoclonal antibody that is capable of activating complement. There must be hundreds available. Incubate the virus with the antibody and add either fresh, NON-heat inactivated human, chimp or feline blood serum. Compare the results. The HIV virus will not be killed by human serum (containing active complement), but it will be killed by the feline serum. What happens in the presence of chimp serum? This is an important question. If chimp complement can kill the HIV virus, it suggests that chimp Factor H is genetically different from human Factor H and cannot bind the gp120/41 proteins. Therefore, the complement cascade can proceed to completion, thereby destroying the virus. An active complement response to the HIV virus would certainly protect chimps from infection.

Chimps are also resistant to the immunosuppressive effects of the viral Tat protein. For some reason, Tat does virtually nothing in chimps. Since Vpr enhances the ability of Tat to induce HIV synthesis, viral Vpr may be unable to bind accessory proteins, such as the glucocorticoid receptor, in chimp T cells and monocytes. This would result in a reduced ability of Tat to induce programmed cell death. Again, this is a major reason why chimps can effectively fight off the HIV virus. Chimps respond vigorously to the presence of the HIV virus. Humans respond in a sluggish manner probably due to the secretion of Tat, Vpr, gp120 and p24. With this data in mind, why do scientists use chimps for testing anti-HIV human vaccines? The data is useless, because it cannot be interpreted with any degree of certainty.

The Problem with Laboratory Neutralization Assays

The basic HIV neutralization assay consists of incubating virus with antibodies to form immune complexes. If the antibodies are truly neutralizing, the virus will not be allowed to bind the CD4 viral receptor on the surface of a target cell population. If the cells do not become infected, the antibodies or anti-serum is considered neutralizing. We do not believe these assays predict the infectivity of the HIV virus in the body. When the neutralization assay is conducted, it is done in the presence of a nutrient solution. This consists of salts, amino acids, sugar, buffers, and 5-15% fetal calf serum. This serum contains a complex profile of additional nutrients, including hormones necessary for cell growth and viability. The serum is heat inactivated before use. This is done to destroy complement, a heat sensitive group of proteins. Everyone who uses serum of any kind heat inactivates it before use. No one wants complement destroying their cells by accident. In the real world—the body—virus can enter cells by different mechanisms. The virus can bind the CD4 receptor on T cells and macrophages and enter by this means. This is the so-called traditional route of entry. The virus can also enter via complement receptors present on T cells, B cells, dendritic cells and macrophages. The complement protein C3b, discussed previously, is covalently bound to the viral particle after activation by an anti-HIV antibody. Factor H is also bound and prevents further activation of the complement cascade. The live virus can now bind, via C3b and its cleavage products, and enter cells that do not necessary have CD4 molecules on their membranes. This is one of the mechanisms by which the virus spreads throughout the body. The neutralization assays used today do not, by definition, have complement in their nutrient solutions. It is an artificial system. An antibody may block viral binding to CD4 in a culture dish, but in the body the virus is going to spread unimpeded because it has C3b bound to it. The virus doesn’t care if it ever sees a CD4 molecule. True neutralizing antibodies against viral envelope proteins do not exist for the HIV virus. These assays accomplish nothing.

The Problem with Viral Preparation

Viruses are not like bacteria. They cannot grow outside a host cell. They are obligate intracellular parasites. The HIV virus, like most envelope viruses, is very unstable. It must be stored at –80C. We are talking cold. When virus is needed, it must be grown on host cells. Some laboratory viral strains have been “passaged” continuously for years in cell culture. HIV viruses passaged over a long period of time are easily “neutralized” when injected into animals. Primary isolates, on the other hand, are viral strains taken from an infected person or animal. These viruses are grown in the laboratory on fresh mononuclear cells. These host cells are not laboratory adapted cell lines. These viruses are much more difficult to neutralize when injected into animals.

The SIV virus is frequently used to test possible vaccine candidates. The virus is similar to HIV and readily infects lower monkeys. A number of excellent SIV vaccine candidates were reported in the literature about 8 years ago. They targeted the membrane gp120 protein and appeared to prove the efficacy of soluble gp120-based vaccines. Unfortunately, these studies were flawed by a common laboratory problem that persists today. The SIV virus, like the HIV virus, is grown in human cell lines and fresh mononuclear cells. These viruses bud from the membrane of infected host cells much like the influenza virus. In the process of budding, the viral particles accumulate host cell proteins in their membranes. This might not appear to be interesting or important, but it is. One of the host proteins accumulated on the viral membrane is the Class II histocompatibility antigen. This molecule is the natural ligand or binding protein for the CD4 molecule, the so-called HIV receptor. It is also an extremely immunogenic protein. Humans cannot freely donate organs to one another because they may not share the same histocompatibility antigens. This is why immunosuppressive drugs must always be taken by organ recipients, unless the organ or bone marrow was received from someone with a similar genetic profile. When viruses are collected from the nutrient broth that feeds the host cells, it is purified over sucrose gradients. The virus accumulates in a band based on its density and is collected. This is considered pure virus. It isn’t pure. White blood cells are usually considered round and smooth. Well, they are kind of round, but they definitely are not smooth. The surface of a lymphocyte is covered in surface protrusions. These protrusions often break off as “blebs”, a fine scientific term. These blebs are the same density as envelope viruses and co-purify with the viruses in the sucrose gradient. This wouldn’t be important if it wasn’t for the fact that the blebs contain a high concentration of surface Class II histocompatibility antigens. All envelope viruses contain these antigens on their surface, but the viruses grown in cell culture contain a very high concentration of this particular antigen. When viruses grow in cells, they activate the cells to express more histocompatibility antigens on their surface. When the viruses bud, they take these highly immunogenic proteins with them on their surface. When injected into animals, the animals mount a vigorous immune response against the viruses. What is the immunological target of this immune response? Herein lies the problem. The SIV viruses were grown in human cell lines, and injected into vaccinated animals. The immune response of the animals killed the virus. The assumption was that this was due to the presence of vaccine induced anti-gp120 antibodies in the blood. It wasn’t. When the same virus was grown in monkey cell lines—not human—the animals were not protected against infection. The virus killed the vaccinated animals. The monkey cell lines contain the same Class II histocompatibility antigens as the injected animals. The immune system of the animals did not recognize them as foreign proteins so it did not make antibodies against them. The anti-gp120 antibodies produced by the vaccine did not neutralize or kill the viruses. The anti-HUMAN Class II histocompatibility antibodies, made by the monkeys when challenged with the virus grown in human cells, actually killed the viruses. The vaccine antibodies did nothing. This is a very serious problem because it calls into question all the efficacy data accumulated in SIV and HIV vaccine protection studies.

We have already made it clear that we believe chimps are an inappropriate model in which to study the efficacy of HIV vaccines. Nevertheless, if an HIV virus is to be injected into a chimp, it should be passaged in chimpanzee cell lines first. Some scientists may have done this, but we are not aware of particular studies. Every time an HIV strain is passaged in human cell lines or fresh cells (it doesn’t make any difference), the viruses accumulate highly immunogenic human Class II histocompatibility antigens on their surface. The chimps respond vigorously to the presence of this foreign antigen. Remember, Factor H binds gp120/41 and protects the virus against complement destruction by anti-gp120/41 antibodies. Factor H does not bind Class II histocompatibility antigens. A chimp antibody that targets this molecule will fix complement, and destroy the HIV virus. This was proven in the SIV studies. This is a problem of biblical proportions because it suggests that the published protective ability of many, if not all, anti-envelope vaccines is an artifact of the method by which the scientists prepared the challenge stocks of virus. As a case in point, VaxGen, then a group at Genentech, tested their current anti-envelope vaccine in chimps. They used primary isolates of virus grown on fresh human mononuclear cells. The vaccine, it was claimed, protected the chimps against infection. These studies serve as the experimental basis for the current human clinical trials in both the US and Thailand. Interestingly, the serum from immunized animals did not neutralize the virus in a cell culture assay. If the antibodies in the blood of the chimps were anti-envelope specific and protected the chimps against infection, the same serum antibodies should neutralize virus in the laboratory. They didn’t. The scientists addressed this curious problem by questioning the efficacy of neutralization assays for primary isolates cultured in fresh cells. Maybe they are correct, but we have another interpretation.

It is well known that attenuated viral strains, such as the one used by VaxGen to challenge their chimps after vaccination, grow well in cell culture (they do not kill their host cells), and can be relatively easily controlled in in vivo vaccine studies. Assume a company immunizes a chimp or monkey with a protein or DNA vaccine that contains viral gp120/gp160 proteins. After primary immunization, they continue giving the chimp booster immunizations for a lengthy period of time. When they finally challenge the chimp with live virus, they have to grow the virus in fresh cells first. Invariably, the cells of choice are fresh human peripheral blood mononuclear cells (PBMC), a mixture of T cells, B cells and monocytes. Before these “quiet” cells can be induced to produce virus, they must be activated with immunological agents, such as ConA, PHA, or anti-CD3 antibodies. Only activated T cells can be induced to take up (into the nucleus) viral DNA and produce virus. In the process of activation, PBMC cells activate the expression of large amounts of Class II histocompatibility antigens on their membranes. When the viral particles bud from the host cell membranes, they incorporate these highly immunogenic proteins into the viral membranes. When the virus, containing human proteins on its membrane, is injected into chimps or monkeys, it generates a vigorous humoral immune response against the Class II antigens. The anti-human MHC II chimp antibodies fix complement and destroy the virus. This reaction has NOTHING to do with the fact that the chimp was previously immunized with viral gp120/gp160 membrane proteins. The story continues.

All attenuated viral strains, such as the SF2 strain used by VaxGen and the IIIB strain used by many other scientists, have by definition a mutated Vpr gene. Viral strains with intact Vpr genes, such as NL4-3, are extremely virulent and destroy their host cells by inducing G2 cell arrest and apoptosis. Attenuated viral strains do not induce G2 arrest, which is why they can be readily grown in cell lines and PBMC cells. Vpr binds and activates the glucocorticoid receptor (GR). This binding is absolutely required for the G2 block and subsequent apoptosis. Cells that lack GR cannot be blocked in G2 by Vpr. When Vpr is fully active, it induces the activation and/or suppression of glucocorticoid responsive genes. MHC II expression on the membranes of PBMC is downregulated by natural anti-inflammatory hormones such as cortisol, and TGFb. This downregulation is but one of many methods by which these hormones inhibit inflammatory reactions and inappropriate immune activations. If an attenuated strain such as SF2 is grown in PBMC, it is likely that MHC II activation and expression on the membranes of these host cells will be maximal. Remember, these viral strains have mutant Vpr genes that DO NOT strongly activate the GR or glucocorticoid responsive genes. MHC II expression will not be downregulated as it would if the PBMC were infected with a virulent virus that contained an intact Vpr gene. In the case of the latter, the PBMC host cells would have a REDUCED amount of MHC II antigens on their membranes, and subsequently in the membranes of the viral particles that bud from their surfaces.

If an attenuated HIV strain with a defective Vpr gene is grown in PBMC and injected into a chimp or monkey, it will generate a strong anti-MHC II humoral immune response to the large amount of MHC II antigens on the viral membrane. However, the serum, after clotting for two hours or so at room temperature, will not be able to neutralize the virus in cell culture assays. The reason is straightforward. The neutralizing antibodies are anti-human MHC II—not anti-viral gp120/gp160. Complement is very sensitive to heat. The clotting process destroys the complement in the withdrawn blood samples and tissue culture media (fetal calf serum) is always heat inactivated before use. The anti-MHC II antibodies in the serum can bind the MHC II antigens on the PBMC cells and viral membranes, but they cannot block viral binding to their CD4 receptors nor can they kill the virus or host cells because there is no active complement proteins in the media. If a virulent strain with an intact Vpr gene is grown in PBMC, it will destroy most of the PBMC, but the released virus will also have a much lower concentration of MHC II antigens on the viral surface. This is due to two factors. First, the Vpr gene, like the GR, downregulates the expression of the MHC II antigens on the PBMC, and second the rapidity by which cell death occurs. These viruses, once injected into chimps and monkeys, will NOT generate a strong anti-human MHC II response, because the viral particles have few MHC II antigens on their membranes. Hence, the viral particles will not be as readily killed by the chimp humoral immune system. This allows the virus to not only propagate but to induce an increasingly serious glucocorticoid-mediated immunosuppression directly in the lymph nodes via the release of intact Vpr from viral particles.

We believe this is a feasible explanation for the vaccine data reported by VaxGen. They used an attenuated viral strain grown in PBMC. The viral particles no doubt contained a large amount of highly immunogenic MHC II antigens on their membranes. If this scenario did not occur, it certainly cannot be discounted by their published data. The experiments that purported to demonstrate efficacy of the AIDSVAX vaccine in chimps are fatally flawed. This vaccine will not only fail; it will put in medical jeopardy the thousands of brave volunteers who agreed to be vaccinated a total of 7 times over 3-4 years if these people are ever exposed to the HIV virus. The anti-gp120 antibodies generated by the vaccine will form infectious immune complexes with the viral particles that are not destroyed by complement. The immune complexes will be subsequently concentrated in the lymph nodes, where they will destroy normal T and B cells via a process of Vpr (glucocorticoid) and CD4 crosslinking mediated apoptosis.

SUMMARY

The HIV virus has managed to escape a full frontal attack by the humoral or antibody-based branch of the immune response by blocking the activation of complement at its surface. To add insult to injury, the aborted effort to kill the viral particles by envelope-specific antibodies results in the deposit of highly infectious virus in the lymph nodes and spleen. This results in the eventual destruction of those organs. The viral immune complexes also readily infect monocytes, long term reservoirs for viral production.

The only vaccines that can protect against HIV are those that do not target the gp120/160 envelope proteins. The viral particles can still be destroyed by complement if the vaccine generates antibodies that recognize the p24 and p17 sequences that are exposed on the surface of the virion. Destroying the HIV virus also requires an indirect attack. Antibodies that neutralize Tat, Vpr and p24, all immunosuppressive proteins, will impair the ability of the HIV virus to suppress the immune response to its presence. Under most circumstances (except in the case of opiate users), an unimpaired immune system can handle the virus. This was clearly demonstrated in a study using an SIV viral mutant that only lacked the Vpr gene. When injected into monkeys, the virus grew, but did not cause disease. Two years later, a wild type virus containing an intact Vpr gene was used to challenge the monkey. There was no disease, nor could virus be recovered from lymphoid cells (Igarashi, T., et al. Protection of monkeys vaccinated with vpr- and/or nef-defective similan immunodeficiency virus strains. J. General Virology 78:985, 1997). Although multiple conclusions can be drawn from this data, we feel the most basic explanation for the lack of disease is that the Vpr protein was not available to induce an early glucocorticoid-mediated immunosuppression of the normal immune response against the viral proteins. In the absence of stress (high glucocorticoid levels in the blood caused by drug use, malnutrition, or psychological factors) and/or an intact Vpr gene, the immune system should be able to adapt to and control ANY strain of HIV virus to which it is exposed.

Scientists are good people. They try very hard and they usually aren’t too motivated by money. We are very worried that the public will blame the scientific profession for the lack of a viable HIV vaccine. It is simply no longer possible for the scientific community to hide behind the veil of official scientific ignorance, e.g. “we simply do not have enough data”. The scientific community doesn’t need anymore data in order to construct a viable vaccine. They simply have to assimilate the information that has already been published. Vaccine companies that target the envelope protein of the virus will absolutely cease to exist if the people they vaccinated are now “predisposed to HIV” rather than “protected from HIV”. The lawsuits will never end, and the biotech/pharmaceutical sector will be too afraid to develop new HIV vaccines without governmental liability protection.