Mechanisms of Impaired HIV-associated B Cell and Pneumococcal Vaccine Responses

Inclusion Criteria: For HIV-infected subjects: * adults aged 18-55 years * \>200 CD4+ T-cells/microliter * no antiretroviral therapy (at the time of nasal swab/week 0) * receiving antiretroviral therapy for \>6 weeks (at the time of vaccination/week 12) For HIV-seronegative controls: * adults aged 18-55 years Exclusion Criteria: For all subjects: * age \<18 or \>55 years * history of prior pneumococcal vaccination * immunosuppressive therapy, defined as: prednisone \>15mg/day currently or \>14 days in the past 3 months, cytotoxic agents, anti-metabolites, cyclosporine, anti-tumor necrosis factor, B cell monoclonal antibodies * current or chronic pulmonary infection (bacterial, fungal, mycobacterial), pneumonia, or rhinosinusitis within 2 months * chronic lung disease * renal insufficiency, defined as serum creatinine \>1.6 * active liver disease, including hepatitis C virus infection * history of splenectomy * history of antibacterial therapy within 3 months of nasal swab (week 0) * current alcohol abuse * chronic heart disease * diabetes * current cigarette smoking