ANTIBODY TO HIV-1 TAT PROTEIN INHIBITS THE REPLICATION OF VIRUS IN CULTURE

The HIV-1 transactivator protein Tat is essential for viral replication. Tat is released from infected cells and can be taken up and transactivate HIV-LTR in LTR-CAT transfected cell lines. The present study shows that the addition of monoclonal antibody to Tat in IIIB and MN-infected cultures reduces the HIV antigen production in a concentration dependent manner. These data suggest that external Tat might be important in the replication of HIV, exerting the effect in a paracrine fashion. Using 1 mu g/ml of anti-Tat antibody resulted in a decline of HIV antigen production to 33% and 45% of controls in IIIB and MN infected H9 cells, respectively. A time course experiment showed progressively increased inhibition of replication during 7 days of exposure to anti-Tat antibody, which could be due to increasing Tat concentration. The inhibitory effect of anti-Tat antibodies on the replication of HIV could play an important regulatory role during infection in vivo.