A prospective observational study to detect cellular immune function in gastro-intestinal mucosal tissues and peripheral blood

Primary Objective:  To detect and measure cellular immune function in lower gastro-intestinal mucosal tissues obtained via biopsies of the terminal ileum and colon and in the peripheral blood.

To compare cellular immune responses in the mucosa and peripheral blood of HIV seronegative volunteers with that of HIV-infected individuals.

To measure background reference levels of HIV-1 specific cellular immune function in an African population comparable to that of a previously sampled patient population in London