ENHANCEMENT OF HIV-1 VIRAL PRODUCTION IN VITRO BY SUPERINFECTION.

P. N. FERNÁNDEZ LARROSA; A. CEBALLOS; R.D. RABINOVICH; S. MARQUINA; L. A. MARTÍNEZ PERALTA

Paris, France

Conferencia; 2st IAS Conference on HIV pathogenesis and treatment; 2003

Superinfection with HIV-1 occurs in vitro and in vivo, and is considered to be the main cause of the high frequency of circulating recombinant forms worldwide. Viral production is normally high in patients and different viral variants accumulate over time causing the necessary conditions for superinfection. Previous experiments in our laboratory suggested pseudotype production due to superinfection with different HIV-1 strains. However, no dynamic studies about viral production have been made in a superinfection system. In order to study the influence of superinfection on viral production, H9-HTLVIIIB cells, infected with HXB2 viral strain, were pretreated with 2.2 microg/ml polybrene for 30 min at 37$#176;C and centrifugated at 4$#176;C, before being superinfed with MN strain at moi=1. Viral production was quantified by syncytia production using MT2 cells by limiting dilution, and by a commercial ELISA for p24 antigen (HIVAGTM-1 Monoclonal Abbott, Abbott Laboratories). The virus produced by the superinfected cells was used to infect MT2 cells and characterization of proviral DNA in MT2 cells was made by amplification of the C2V3 region of env gene followed by digestion with an enzime (BsmA I) that differentiates both viral strains. Syncytia production revealed a 1.7 log increase at the first day post-superinfection (ps) as regard to a non superinfected H9HTLVIIIB control, while p24 antigen quantification suggested a 1.5 increase. Viral production during following days did not differ significantly from the control. Viral characterization showed both strains production at first day, while at following days, only the original strain (HXB2) was detected. Superinfection in vitro of H9HTLVIIIB cell line with HIVMN strain increased total viral production only at first day post-superinfection. The cytophatic effect observed since 24 h ps could probably explain why this enhancement was not observed later on. This viral mechanism could play an important role in vivo in the phisiophatology of HIV infection and persistence.