7th International AIDS Conference Florence, Italy — June 16-21, 1991

Int Conf AIDS 1991 Jun 16-21; 7:96 (abstract no. M.A.1017)
Lu W, Ferreira N, Israel-Biet D, Andrieu JM; Laboratory of Tumor Immunology, Laennec Hospital, Universite de Paris V, Paris, France

OBJECTIVE: Given the importance of a precise knowledge of HIV tropism and growth characteristics for a better understanding of the HIV disease, we have undertaken a study of the infectivity, growth kinetics, and cytopathogenic effect of laboratory adapted HIV-1 strains, and compared them with those of fresh primary HIV-1 isolates recovered directly from patients' cells.

METHODS: The cell-free HIV-1 freshly isolated from PBL (n=4) or bronchoalveolar lymphocytes (n=3) of 7 seropositive patients, and 5 HIV-1 isolates maintained in laboratory T lymphocytic and monocytic cell lines (2 in CEM, 2 in HUT78, and 1 in H9), were studied. 10(6) PHA stimulated PBL from a normal HIV-negative donor were infected by a standardized inoculum (1 ng of HIV core p24 protein) of each single isolate. The growth rate of viral production in each case was assessed by serial measurements of the p24 content of supernatants (Abbott ELISA) during culture over 28 days. The cytopathic changes in infected cells were monitored by trypan blue exclusion dye test and flow cytometry.

RESULTS: All the primary isolates from each individual patient exhibited similar infectivity and growth kinetics. The peak of p24 level (day 7, 837+/-331ng/ml) was associated with 100% death of the CD4+ lymphocytes in the culture. In contrast, only 3 of the 5 laboratory strains productively infected PBL, with various infectivity and growth rates. HIV recovered from laboratory cell lines led to a very low viral production, always less than 10ng/ml, with a peak delayed after day 11. Strikingly, no cytopathic change was ever observed in these cases, nor CD4-receptor down regulation, as assessed by flow cytometry.

CONCLUSION: Unlike fresh primary isolates, the laboratory adapted HIV-1 strains infected PBL very poorly and lost their cytopathogenic potential in vitro. Therefore, results of studies using such laboratory cell-line maintained virus do not accurately reflect the situation in vivo and should be interpreted with caution.

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