HIV infection is complicated by high rates of infections and cancers which are often the cause of death rather than the HIV/AIDS virus itself. Treatment of HIV with antiretroviral medications has decreased the frequency of many complications by over 90%, but bacterial pneumonia remains extremely high. Current vaccines are not very effective in preventing these infections in patients with HIV infection. The investigators are studying the cells (B cells) that make antibodies to fight infection by binding to and killing bacteria. The goal is to understand how HIV impairs the ability of B cells to make antibodies in sufficient quantity and of sufficient quality to protect patients with HIV to learn how to enhance protection against these infections. The investigators also seek to understand the role of the bacteria (specifically Streptococcus pneumoniae) that normally live in the nose and throat in the development of pneumonia and other infections.