COMPLEMENT-MEDIATED ENHANCEMENT OF HIV-1 INFECTION IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS

We investigated if complement-mediated enhancement of HIV infection oc curs in peripheral blood mononuclear cells (PBMC). In 7 experiments, m e evaluated the effect of human complement on HIVIIIB infection in vit ro. We measured HIV antigen production on day 4 and found that pre-inc ubation of HIV with complement led to enhanced production of antigen w ith a median enhancement of 2.5-fold (range 1.1-6.8). This complement- mediated increase in antigen production was statistically significant (p < 0.02). Complement-mediated enhancement of HIV infection was also tested in CD4 cells enriched from PBMC, and CD4 cells persistently gav e higher levels of infection enhancement than PBMC, Thus, CD4 cells ap pear to be sufficient for complement-mediated enhancement of HIV infec tion to occur, In addition, me tested if it mas possible to detect com plement-mediated enhancement of primary HIV isolates in PBMC. We teste d 3 isolates and found only a minor effect on antigen production (medi an enhancement 1.2-fold, range 0.6-1.5). Furthermore, addition of HIV- specific antibodies in combination with complement resulted in enhance d antigen production in 2/3 sera tested. However, the combination of c omplement and antibodies resulted in only a minor increase in enhancem ent of HIV infection compared to that obtained with complement alone. Finally, me found evidence of complement-mediated enhancement of HIV i nfection in resting PBMC. In conclusion, me demonstrated that compleme nt-mediated enhancement of HIV infection does occur in vitro in PBMC.