So, where do you go without relying on natural infection?
What we have to do is develop immunogens and find out the fundamental, basic questions: Why is it so difficult for the body to develop a neutralizing antibody response? And given that, what can we do to present an immunogen to the body to allow it to develop a neutralizing antibody response readily—not in a very difficult situation, but readily in the vast majority, if not all, of the people that get vaccinated? Those are fundamental questions, the answers to which we don't have.
Do you think we got this far without very basic questions being answered because the HIV vaccine is such a desperately sought after goal—that the world is truly hungry for one to exist?
Obviously the world is very hungry, as you put it, for an HIV vaccine. But following the classical vaccine paradigm, what we were doing was not unusual. It was only when we had the full realization that, "Wait a minute. There's something very very different about this virus, so therefore the classic paradigms might not hold so strictly." So, I don't think the only motivation to move ahead was that we were "hungry for a vaccine." Our motivation was that that approach had been imminently successful with other viruses.
But, these moments of realization, have they come in nuggets over the past 20 years or are they big signs like the failure of Merck's STEP vaccine last year?
There were suggestions and hints of it very early on when we found out that antibodies that were elicited in people generally neutralized lab-adapted strains [of HIV], but did not neutralize the wild type strains from the body. This indicated that antibodies that were elicited weren't particularly effective against the kinds of viruses that were circulating in the community. That was a hint, but most of the people felt, "Well, let's just give it an empiric shot and vaccinate people with the envelope [the antigen, or protein on HIV's surface] and see if we can elicit a really good neutralizing antibody response.
It was only as the science moved along in parallel with those empiric attempts that we realized that the part of the envelope that neutralizing antibodies bind to is very cryptic in its conformation and doesn't reveal itself to the immune system very well or for a significantly long period of time. It's hidden. It has a confirmational component to it that doesn't allow the immune system to see it very well, much less elicit an antibody. We didn't really know that until we'd already launched some trials way back years ago using the empiric approach of what we would do with any other virus: get the outer coating, that is, the envelope, and use it as an immunogen. We didn't appreciate that the part of that immunogen that you would need to show to the immune system didn't readily reveal itself.
So, how does the STEP trial factor in? Its failure seems to be one of the primary triggers for the HIV vaccine reassessment.
The STEP trial was another interesting thing because as the antibody component failed, and we needed to go back to the basics to figure out how to elicit an antibody response, there were studies in an animal model that suggested that perhaps you couldn't block acquisition of infection. But, perhaps you could get the lowering of the viral set point so low that the person who was vaccinated would benefit because their disease would not progress. They would almost be like a long-term nonprogressor, and the other herd immunity-type benefit would be that if their viral load was low, then perhaps they would not readily transmit the virus to someone with whom they come into contact.
So, that's when the STEP trial approach of a T cell immune response was done. But, the correlates of immunity that were measured in the early part of the trial and in the animal were assumed to be correlates that would be therapeutic. As it turned out, when you vaccinated people in the STEP trial, it neither blocked acquisition—which we didn't expect it to do anyway—but it had virtually no effect on the viral set point. So, the question was, "Well maybe we can look at the immunological response and get some information from a subset of people in the trial who seem to have responded well?" That's a fallacious approach. If the vaccine doesn't work, doing immunological correlates, in my mind, and the minds of many many of my colleagues, is not worth doing.
That's really the fundamental reason why I elected to not accept the proposal for a moderately sized—or big-sized—PAVE 100 trial. I said, "I reject that." The reason I reject that is we really need to know that if the product is interesting and different enough from the STEP product. It's a DNA–DNA–DNA followed by an adeno and it also contains envelope, in addition to the other viral genes. I think it's worth pursuing, but not in such a large trial that it will allow you to get all the immunological correlates you want.
I first want to find out if it has a beneficial effect. If it does, then we'd be willing to invest more resources, more people, more specimens. If it doesn't succeed in lowering the viral set point, then I don't think it's worth going and pursuing these elusive immunological correlates. You don't even know what they are correlated with.
See what we're tweeting about
5 Comments
Add CommentAmiable readers, to maintain the fidelity we published the article in the original language.
Reply | Report Abuse | Link to thisLas vacunas son una preparación de antígenos que se inyectan en el cuerpo y generan una respuesta de ataque por medio de los anticuerpos que contribuyen a ponerle fin a algún virus o bacteria. Una vez que han sido suministradas en el organismo generan lo que se conoce por memoria inmunológica por lo que, en la mayoría de los casos, vuelven inmune a la persona a esa enfermedad determinada.La inoculación cuenta con antecedentes en China y Turquía, pero la primera vacuna como tal fue inventada, en 1796, por un médico rural inglés llamado Edward Jenner que dio con una forma para combatir la epidemia de la viruela. Jenner, observó que las mujeres que trabajaban ordeñando las vacas contraían una enfermedad que era conocida como la viruela de las vacas, sin embargo, ésta las hacía inmunes a la viruela humana. Así, sacó una muestra de leche de vaca de la mano de una de las granjeras y la inyectó en el brazo de un niño. Éste sufrió los síntomas de la viruela vacuna. Cuarenta y ocho días después, cuando ya no quedaban rastros de la enfermedad, le inyectó una muestra de la viruela humana y éste no padeció ningún síntoma del mal. Basados en esta observación, nosotros planteamos la siguiente hipótesis: las cucarachas son los insectos sobrevivientes más antiguos sobre la faz de la tierra, por su carga atómica que poseen han podido sobrevivir a grandes cataclismos y fenómenos atmosféricos, así también, las terribles bombas atómicas creadas por el hombre.
Existes miles de variedades de cucarachas, pero específicamente las cucarachas que viven en las alcantarillas y se alimentan de los residuos vaginales, el semen, las heces fecales y los excrementos. Estas han logrado sobrevivir, son inmunes y son portadoras del virus del sida. De igual manera como Edgard Jenner, hizo su investigación se hará es mismo procedimiento. Queremos decir hay que aumentar la capacidad inmune del cuerpo humano, aumentar los anticuerpos para poder resistir y convivir con el VIH/Sida. Cuando el cuerpo recibe esta dosis de virus o bacterias, el sistema inmunológico se pone en alerta y destruye a estos agentes que le son extraños al organismo. Así, cuando una dosis realmente dañina decide atacar, el cuerpo ya se encuentra preparado para reconocerla y atacarla rápidamente. Edward Jenner nació el 17 de mayo de 1749 en Berkeley, condado de Gloucester, Inglaterra y falleció un 26 de enero de 1823 en la propia localidad de Berkeley. Fue un afamado
investigador, médico y poeta.
Amiable Readers, the proteins of the cockroach are the solution for the vaccine of AIDS. The director of the NIAID, Dr. Anthony Fausi, must initiate the investigation.
Reply | Report Abuse | Link to thisThere are many natural ways to rid your body of HIV. In contrast with the traditional antiviral cocktails of medicine today, which cost thousands, have severe side effects, and comes with the double edged sword delema,meaning if the virus doesn’t kill you the cocktails will, this medicine is all natural.Please visit this site for the full information about this subject……http://pushgood-nomorehiv.blogspot.com/
Reply | Report Abuse | Link to thisI read a testimoney that coconut milk can stop AIDS; monolaurine can be purchased as the nutrient found in the coconut milk.
Reply | Report Abuse | Link to thisThere was a doctor from India that said he stopped the AIDS virus with a mixture of spices. I read the abstract about 7 years ago; it is on medline. I vaguely remember he called the mixture with a word that begins with "K". And what about Safi sold in East Indian grocery stores. There are so many foods that support the immune system, why do they not talk too much about them?
I read a testimoney that someone was healed of AIDS with coconut milk; monlaurine is a nutrient from that food that can be purchased from the health food stores.
Reply | Report Abuse | Link to thisAlso, I read an abstract of a study that a doctor from India stopped the sickness with some spice mixture that began with a "K" about 7 reads ago I read it. What about Safi? Can be purchased in an East Indian grocery store. So many foods support the immune system. Why is not diet mentioned more?