CD8+ T cells from HIV-1-infected individuals inhibit acute infection by human and primate immunodeficiency viruses.

T lymphocytes expressing the CD8 surface antigen block HIV replication in CD4+ peripheral blood cells from HIV-infected individuals. We report here that CD4+ cells from HIV seronegative donors, when infected in vitro with HIV, also do not replicate virus when cocultured with CD8+ T cells from HIV-infected individuals. CD8+ cells from HIV-uninfected donors did not show this effect on virus replication. HLA-restriction of the antiviral response was not observed, and virus-containing cells were not eliminated from culture. The antiviral activity was broadly cross-reactive, as CD8+ cells from individuals infected only with HIV-1 suppressed the replication of diverse strains of HIV-1 and HIV-2, as well as the simian immunodeficiency virus. This ability of CD8+ cells to control HIV replication could play an important role in the maintenance of an asymptomatic state in HIV-infected individuals.

Antibody-dependent cellular cytotoxicity is directed against both the gp120 and gp41 envelope proteins of HIV.

To define the target antigens for antibody-dependent cellular cytotoxicity (ADCC), assays were performed using affinity-purified human immunoglobulin (Ig) or polyclonal rabbit sera directed against specific proteins of HIV. ADCC was not found using affinity-purified anti-core (p25) human Ig or sera obtained from rabbits hyper-immunized with recombinant p25. However, when affinity-purified human Ig or rabbit antisera specific for the envelope glycoproteins, gp120 or gp41, were used in ADCC assays, killing of HIV-infected cells was observed. These results indicate that antibodies in the infected individual that mediate ADCC are directed against both the gp120 and gp41 HIV envelope proteins and not against the viral core protein.

Simultaneous isolation of HIV-1 and HIV-2 from an AIDS patient.

Two distinct human immunodeficiency viruses, HIV-1SF480 and HIV-2UC2 were isolated simultaneously from the blood of an Ivory Coast patient with AIDS. The HIV subtypes were segregated by their differential ability to infect established human cell lines and by the cell surface expression of type-specific viral antigens. The viruses could be distinguished by both immunoblot and Southern blot analyses. The results indicate that an individual can be infected by both HIV subtypes.

PIP: 2 distinct human immunodeficiency viruses, HIV-1 and HIV-2 were isolated simultaneously from the blood of an Ivory Coast patient with AIDS. The HIV subtypes were segregated by their differential ability to infect established human cell lines and by the cell surface expression of type-specific viral antigens. The viruses could be distinguished by both immunoblot and Southern blot analyses. The results indicate that an individual can be infected by both HIV subtypes. The serum samples were from individuals who attended the Triechville Hospital in Abidjan, Ivory Coast. A 37-year-old woman presenting with recurrent vomiting and weight loss of 39 kg, prolonged fever, but no lymphadenopathy had both isolates. Necator americanus infection was diagnosed before she died. Altogether of 67 HIV antibody-positive samples tested to date, 23 (34%) had reactivity by both procedures to HIV-1 and HIV-2. PMC from 13 of these 23 individuals with dual reactivity were co-cultivated with PMC from normal seronegative donors. 15 of the other 22 individuals with dual antibody reactivity presented with parasitic bowel infections, chronic diarrhea and extreme weight loss; the remainder had pulmonary disease. There were no differences in clinical manifestations of individuals with dually reactive sera and of patients with antibodies specific to either HIV-1 or HIV-2 alone. However, it is not possible to assess the role of dual infection in the exacerbation of HIV associated illness as all patients in this study were selected on the basis of their clinical manifestations.

Detection of human immunodeficiency virus (HIV) in serum and body fluids by sequential competition ELISA.

A micro-ELISA based on competition with the biotin-labeled 25 kDa gag (p25gag) recombinant protein of the human immunodeficiency virus (HIV) was compared to commercial antigen capture ELISAs for the detection of viral antigens in a variety of body fluids including serum, cerebro-spinal fluid (CSF), sputum, saliva, milk, semen, vaginal and bronchial fluids, as well as earwash fluid. Two-thirds (24/30) of these specimens contained IgG and/or IgA antibodies to HIV. The results were correlated with the recovery of infectious HIV in culture. The competition ELISA detected the presence of HIV antigen in 4 out of 8 sera, 5 out of 6 CSF and 6 out of 15 other body fluids that were found to contain infectious virus. Comparatively, 5 of the 8 sera, 3 of the 6 CSF, and 2 of the 15 body fluids tested positive for HIV antigen by capture ELISA. The data suggest that the competition test is more effective than the capture method in detecting antigen in CSF and body secretions, which might be due to the presence of immune complexes. However, both ELISA methods showed similar susceptibility to antibody interference in spiked specimens. The results confirm that antigenemia status can be of value in assessing HIV infection when used in combination with other clinical and laboratory data.