Immunologic Memory (Supp. of ATN 024)

This is an exploratory, laboratory-based evaluation of cellular immune response to immunization with hepatitis B surface antigen in HIV-infected and HIV-uninfected adolescents. This is a substudy of ATN 024 and ATN 025. This substudy will compare cellular immune response in responders and nonresponders to immunization and also evaluate the relationship of these factors to the persistence of known correlates of serologic protection for the hepatitis B virus.

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.