Immunologic and virologic response after tetanus toxoid booster among HIV-1- and HIV-2-infected Senegalese individuals.

Twelve HIV-1-infected, nine HIV-2-infected patients and eight HIV-negative subjects were given a 40IU booster dose of tetanus toxoid (TT). Blood was collected on days 0, 7 and 30 after immunization. Changes in HIV-1 or HIV-2 RNA load were evaluated by nested PCR. TT-IgG antibody levels were quantified by ELISA. CD4 cell counts as well as activation, memory and maturation markers of T lymphocyte subsets were determined by flow cytometry. The induction of apoptosis was investigated using 7-aminoactinomycin D (AAD) and propidium iodide (PI) staining. Proliferative responses to TT and pokeweed mitogen (PWM) were determined by the level of [(3)H] thymidine incorporation. Seven and 30 days after immunization, there was no detectable increase in HIV-1 or HIV-2 plasma load. There were also no changes in CD4 cell counts, CD69, HLA-DR and memory CD45RO or naive CD45RA antigens. Immunization did not increase the spontaneous apoptosis of peripheral blood mononuclear cells (PBMCs), CD4+ and CD8+ T cells subsets neither in controls nor in HIV-infected patients. Similarly, apoptosis induced in vitro by PWM or by the specific TT recall antigen did not vary during the study period. The proliferative response to PWM and to the TT recall antigen was decreased both in HIV-1- and HIV-2-infected patients compared to HIV-negative controls. Immunization significantly increased the TT-IgG levels in healthy controls and in HIV-infected patients. However, the anti-TT-IgG response, as measured by the fold-increase index between days 0 and 30, was significantly higher in healthy controls than in HIV-1- (P=0.036) and HIV-2-infected patients (P=0.003). In conclusion, we found no deleterious immunologic or virologic effect was detected in healthy HIV-1- and HIV-2-infected individuals after antigenic challenge with a TT booster. However, the response to TT vaccination was lower in HIV-1- and in HIV-2-infected individuals than in healthy HIV-negative controls.