Malaria results in at least 2.7 million deaths per year, the majority among African children. The development of a vaccine against Plasmodium falciparum is regarded as a crucial step toward control of this disease. Unfortunately, vaccine candidates have resulted in short-lived protection at best. The ineffectiveness of current vaccines may reflect the kinetics of naturally acquired immunity to malaria in that multiple infections are required over years before partial protection is achieved and then immunity is lost, or becomes less effective, in the absence of recurrent infection. The mechanisms underlying the delayed acquisition and presumably rapid loss of humoral immunity are poorly understood. A more detailed understanding of these processes at the cellular level may be important for vaccine development. We are currently studying the cellular basis of humoral immunity to P. falciparum through research collaboration between the Malaria Research and Training Center (MRTC) in Bamako, Mali and the National Institutes of Health (NIH) in the United States. This protocol supports that research by ensuring a supply of blood samples from healthy Malian adults in order to establish normal immunologic parameters for this population and to optimize research assays performed at the MRTC.