Neutralization and enhancement of HIV-1 infection by sera from HIV-1 infected individuals who progress to disease at different rates

We examined the neutralizing/enhancing activity in sera collected at an ear ly and a later time point postinfection from 13 HIV-positive nonprogressors , 13 moderate progressors, and 13 rapid progressors to determine the relati onship between neutralizing/enhancing activity and disease progression. Ear ly sera from each group reduced virus replication at low dilutions (10(-1) to 10(-2)) when compared with negative sera. The reduction was statisticall y significant for moderate and rapid progressors at 10(-1) dilution (P = 0. 02 and P = 0.02 respectively) but not for nonprogressors (P = 0.16). Late s era from nonprogressors and moderate progressors reduced virus replication at low dilution but late sera from rapid progressors lost neutralizing acti vity. These data suggest that an association exists between neutralizing ac tivity in sera and nonprogression or slower progression to disease and that loss of neutralizing activity is associated with disease progression. At h igher dilutions (10(-3) to 10(-6)), both early and late sera from each grou p increased virus replication over negative sera. The levels and frequency of enhancement were higher for sera from a subgroup of nonprogressors than a subgroup of rapid progressors who exhibited enhancement This suggests tha t enhancement is not associated with disease progression. The neutralizing/ enhancing activity observed in sera of these three groups of subjects sugge st that enhancement levels may reflect the overall level of antibody respon se to HIV. The replication patterns observed for early and late sera from i ndividuals in the different groups reflect changes in antibody activity tha t appear to be associated with protection or disease progression. (C) 2000 Academic Press.