This substudy will enroll volunteers from participants of ATN 024 and ATN 025. Participants in ATN 024 are HIV-infected youths aged 12-24 years while participants in ATN 025 are HIV-uninfected youths aged 12-17 years. These youths must also be negative for HBV core antibody, HBV surface antigen, and HBV surface antibody to be eligible.
Blood will be drawn from study participants prior to immunization, 1 month after completion of primary immunization and at study exit (week 72 for ATN 024 and week 76 for ATN 025) for cytokine assays and enumeration of antibody-secreting cells. In addition, the antibody to HBV surface antigen will be determined 2 and 4 weeks after supplemental immunization in nonresponders to the primary series and at study exit.
This laboratory substudy is designed to evaluate some aspects of cellular immune response to hepatitis B vaccination that are directly related to the generation and durability of antibody response to HBV surface antigen in HIV-infected and HIV-uninfected adolescents. Cytokine production by peripheral mononuclear cells will be determined following in-vitro stimulation, and antibody-secreting cells will be enumerated.
