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Certain human Gp120-HIV antibodies react with anti-CD4 antibodies
K Lundin1, A Karlsson, A Nygren
1Department of Immunology, Karolinska Institute, Stockholm, Sweden.
Scandinavian Journal of Immunology
|January 1, 1988
Summary
Some HIV+ individuals produce antibodies mimicking CD4, blocking HIV's Gp120 binding. These unique antibodies, found in a long-term healthy HIV+ patient, do not affect CD4 cell function or neutralize the virus alone.
Area of Science:
- Immunology
- Virology
- HIV Research
Background:
- HIV-1 infection involves the envelope glycoprotein Gp120 binding to the CD4 receptor on host cells.
- Antibodies in HIV-positive (HIV+) human sera can target various HIV proteins, including Gp120.
- Some anti-HIV antibodies may possess epitopes that mimic the CD4 binding site on Gp120.
Purpose of the Study:
- To investigate the presence and characteristics of CD4-mimicking antibodies in HIV+ human sera.
- To analyze the functional impact of these antibodies on CD4+ cells and HIV interactions.
- To explore the potential role of such antibodies in long-term non-progression of HIV.
Main Methods:
- Screening of 58 HIV+ human sera for the ability to block anti-CD4 monoclonal antibody binding to CD4+ cells.
- Characterization of the blocking antibody from a high-capacity serum, including its binding properties.
- In vitro assessment of CD4-mimicking antibody effects on CD4-dependent cellular reactions and HIV neutralization.
Main Results:
- Three out of 58 HIV+ sera exhibited the capacity to block anti-CD4 monoclonal antibodies.
- The identified inhibitor was an antibody that binds to both HIV Gp120 and the anti-CD4 monoclonal antibody T4.2.
- These CD4-mimicking antibodies did not interfere with CD4-dependent reactions in vitro and showed no virus-neutralizing effect alone.
Conclusions:
- The study identified naturally occurring CD4-mimicking antibodies in HIV+ individuals.
- These antibodies bind to HIV Gp120 and mimic the CD4 binding site without impairing cellular function.
- The findings suggest a potential, albeit unproven, role for these antibodies in maintaining health in long-term HIV+ individuals, exemplified by a patient infected since 1983.