Impact of HIV Infection and Pregnancy on Humoral Responses to Pertussis Immunization

Despite the growing importance of maternal immunization in the control of infectious pathogens in early life, the impact of pregnancy on vaccine immunogenicity remains poorly understood. Evidence suggests that pregnancy may influence the quality of the antibody response to vaccines. Pregnancy is associated with modifications in the glycosylation profile of immunoglobulins G (IgG). Different patterns of glycosylation are associated with differential regulation of the effector functions of IgG such as antibody-dependent cell cytotoxicity, complement activation or antibody dependent phagocytosis. Whether similar modifications affect vaccine-induced IgG in pregnant women is unknown.

HIV infection is associated with important alterations in B cells and antibodies. Although antiretroviral therapy partly corrects the proportions of memory B cells (MBC) subsets, it does not restore B cell responses to vaccines, measured as seroconversion rates and antibody persistence. Reduced IgG responses to vaccines have been observed in HIV-infected pregnant women but the impact of HIV on the quality of vaccine-induced IgG has not been reported. On the other hand, HIV infection in pregnancy has a strong impact on the transfer of maternal IgG to the newborn, possibly as a consequence of hypergammaglobulinemia and immune activation.

The investigators will:

1. Assess the respective impact of pregnancy and HIV infection on the magnitude and quality of B cell and antibody responses to pertussis immunization with the TDaP vaccine.
2. Assess the impact of HIV infection and of the timing of maternal immunization on the transplacental transfer and on the quality of pertussis-specific IgG in the newborn.