Re: Re: The predictions based upon the 'HIV/AIDS' hypothesis have been fulfilled 28 January 2005
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Nicholas Bennett,
Infectious Disease Postdoc/Clinician
Department of Pediatrics, University Hospital, Syracuse, NY

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Re: Re: Re: The predictions based upon the 'HIV/AIDS' hypothesis have been fulfilled

In response to Bruno Spagnoli:

It's true that I don't dispute the findings of Dr Giraldo. While I haven't seen his actual lab books or repeated the assays myself, what he finds makes biological sense and I have no reason to doubt the accuracy of his findings.

The "agent A" proposed is, probably, just low levels of cross- reacting antibodies. After all, the ELISA is only designed to detect human antibodies which remain bound to the substrate. If you add 400 times as many non-specific antibodies as you would normally expect, is it too surprising that if a few stick they will be detected?

The mammallian immune system is such that antibodies to almost every concievable antigen are created during the process of B cell maturation. The amplification of selected clones occurs once exposure to the antigen happens. Antibodies will cross-react if present in a high enough concentration (as anyone who has wrongly diluted an antibody in a Western Blot will testify). Whether they react in a detectable fashion at a low concentration is the real test for specific binding - dilution is the easiest method to remove low level cross-reactivity. For example, even monoclonal antibodies (those most "pure" and selected for their high activity) raised to a specific subunit of HIV-1 (p24) would react with p26 of HIV-2 in my hands, albeit at a much reduced level (conversely the p26- specific antibody would not react with HIV-1 p24). In support of this argument is the fact that non-specific addition of antibodies to a person can cause transient false-positive HIV ELISA results (e.g. intravenous immunoglobulin - IVIG -, or mononucleosis due to EBV). Such false positive ELISAs are easily detected by the fact that they do not confirm with the Western Blot and the reactivity disappears as the Ig levels normalise. The non-specific activity is partly why IVIG is given, to provide a background level of immunity in those either temporarily or permanently deficient in antibodies, or needing very rapid immune protection, such as in Kawasaki disease for preventing coronary artery inflammation. A fair number of papers were published reassuring the doctors that even though the concentrated antibodies in IVIG reacted with the HIV ELISA, it was not because the donors actually had HIV infection.

Western Blot tests are different from the ELISA in one large respect - they are qualitative, not quantitative. As an example, a positive screening ELISA may in fact only be due to a cross-reaction to a single protein. A Western Blot would show this and tell the investigator that the original ELISA was likely a false-positive. Experience has shown that HIV infection is associated with certain patterns of antibody reactivity.

The tests are also run using different proteins - as I stated before the antigens being presented may come from virus preps, recombinant expression systems, or just peptides. The UK diagnostic criteria employ multiple tests from multiple antigen sources. Similar criteria are employed with other virus tests (e.g. virus culture to back up initial negative ELISA results in flu, RSV etc).

In addition, there is considerable literature supporting the fact that HIV can only be cultured or detected by PCR from people with antibodies against HIV, as judged by these tests. If the cutoff truly is arbitrary, it's a remarkably fortuitous cutoff!

If an analogy helps (I find they usually do in biology!), picture antibodies as sharp shooters on a firing range. One sharpshooter trained to hit a particular target will do so again and again even if armed with only a 9mm rifle and permitted a single shot for each attempt. However, an untrained gunman will also hit the target if provided with a machine gun capable of firing hundreds of rounds per minute. Giving everyone machine guns and seeing the target hit every time is not a reason to conclude that the sharpshooter doesn't exist. Give everyone a single shot (dilute the sample) and then see what happens.

Nick Bennett njb35@cantab.net

Competing interests: None declared