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

Int Conf AIDS 1991 Jun 16-21; 7:24 (abstract no. M.A.11)
Benedetto A, Di Caro A, Elia G, Garbuglia AR, Delfini C; Center Virology, S. Camillo Hosp; Rome

OBJECTIVE: Investigation of CD4 receptor, citopathic effect, viral expression, and integration in C8166 cells and in derived clones, surviving to HIV (HTLV-IIIB) infection. METHODS AND RESULTS: C8166 cells show maximal susceptibility to HIV, resulting in a near-synchronous infection cycle and cell death, within 4-5 days. Only in a few cases, we found rare cells escaping cell death; cell duplication recovered after at least 20 days. These expanded cultures showed low growth rate, normal morphology (no syncytia) and production of large amounts of infectious virus. After 30-35 days, cells were cloned in soft agar, with a very low cloning efficiency (10(-3)). The main characteristics of isolated clones were: i) absence of CD4 receptor (FACS analysis); ii) presence of soluble CD4 in medium (ELISA method); iii) absence of HIV provirus LTR, gag and env sequences (PCR). All clones could be reinfected by HIV, with the following features: a) inhibition of infection by anti-CD4 MAb; b) all cells produced low amounts of fully infectious virus; c) infected cells normally duplicated without syncytia formation. Such reinfected clones maintained for at least 2 months the virus production, even if progressively declining. One out of 3 persistently infected cultures stopped producing virus and resulted negative for proviral DNA. This non-producer line was still susceptible to HIV.

CONCLUSIONS: Recovery from HIV infection with provirus disappearance and maintenance of susceptibility to HIV reinfection suggest that, in these clones, the integration status of HIV could be reversible.

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