HIGH LEVEL OF CELL MORTALITY ASSOCIATED TO IN VITRO HIV-1 DIFFERENT STRAIN SUPERINFECTION

P. N. FERNÁNDEZ LARROSA; S. E. MERSICH; F. C. COULOMBIÉ; A. CEBALLOS; R.D. RABINOVICH; L. A. MARTÍNEZ PERALTA

Bangkok,

Conferencia; XV International AIDS Conference; 2004

Background: Viral production of HIV-1 is normally high in vivo and different viral variants accumulate over the time causing the necessary conditions for superinfection. Recently, several cases of superinfected patients have been reported and superinfection was suggested to be associated to a rapid AIDS progression. Other retrovirus cellular superinfections were associated to apoptosis and viral production increase. In our laboratory, in vitro superinfection with different HIV-1 strains was demonstrated to favor pseudotype production and viral reactivation. Material & Methods: H9HTLVIIIB cells, persistently infected with HXB2 viral strain, were pretreated with polybrene and superinfected with MN strain at different moi. H9 uninfected cell infection was also performed as a control for acute infection. Simultaneously, H9HTLVIIIB cells were treated only with polybrene or incubated with UV-inactivated HIVMN as controls. Cell mortality was quantified at different times post-superinfection (ps) by using Trypan-blue dye and percentage of dead cells was calculated by counting a minimum of 300 cells per sample. To detect the presence of apoptosis, Hoescht nuclear staining was performed. Results: Mortality of superinfected cells from day 1 ps was 46%, coincident with viral production peak, and increased up to 70% at day 4 ps (p<0,05). Acute infection showed significantly less mortality than superinfection, decreasing from 38% at day 1 up to 29% at day 4 ps. No cellular toxicity by UV-inactivated virus or polybrene per se treatment were observed. Hoescht methodology revealed 50-60% apoptotic cells at superinfected population at 6, 12, 24 and 48 hours ps, against 10-20% at non-superinfected population. Discussion: These results showed an increase of cell mortality associated to apoptosis after superinfection of persistently HIV infected cell. This phenomenon could be relevant in the physiopathology of HIV infection in vivo and the progression to AIDS.