Subject(s)
HIV Infections/virology , HIV-1/genetics , RNA, Viral/analysis , Gene Amplification , HumansABSTRACT
The aim of this study was to investigate the presence and the fine specificity of anti-CD4 autoantibodies in seronegative subjects sexually exposed to HIV-1. Anti-CD4 autoantibodies were previously detected in a fraction of HIV-1-seropositive individuals. Whole sera, purified IgG fractions, and supernatants of EBV-transformed lymphoblastoid cell lines were analyzed by means of ELISA, Western blot, and by competition assays using monoclonal antibodies with known fine specificities. Anti-CD4 antibodies were found in 6 of 18 individuals exposed to HIV-1 infection and who have been persistently seronegative. These antibodies inhibited HIV-1-driven syncytium formation, did not interfere with the CD4-gp120 interaction, and competed for CD4 binding with two of three anti-CD4 monoclonals with known fine specificities. Moreover, autoantibodies with the same fine specificities were found in the supernatants of oligoclonal EBV-transformed B cell lines derived from these individuals. At variance, in the HIV-1-positive patients included in our study, the anti-CD4 antibody response was directed to a broader panel of epitopes, including those involved in CD4-gp120 interactions. In conclusion, anti-CD4 antibodies specific for defined epitopes of the CD4 molecule are generated in the course of an early immune response to HIV-1 antigens in the absence of other signs of infection, as they can be detected by conventional methods. These autoantibodies may play a protective role either alone or in association with other cellular and humoral factors.
Subject(s)
Autoantibodies/blood , CD4 Antigens/immunology , HIV Seronegativity/immunology , HIV Seropositivity/immunology , Blotting, Western , Enzyme-Linked Immunosorbent Assay , HIV-1/immunology , Humans , Male , Risk FactorsABSTRACT
The performance and clinical relevance of a qualitative PCR-based assay for the detection of HIV-1 DNA sequences in peripheral blood mononuclear cells (PBMCs) was evaluated by two different laboratories. Four hundred and one samples were obtained from 397 individuals from different risk populations. All blood donors tested had negative results; positive signals were obtained from all infected patients. HIV-1 DNA was detected in 3 of 17 infants born to seropositive mothers; Western blot indeterminate blood donors and exposed health-care workers had negative results. Our results demonstrate that this PCR assay provides both sensitive and specific results and is suitable for testing large numbers of samples and for rapid identification of HIV-1 infection.
