Normal Immunological Parameters Among Healthy Volunteers in Kambila, Mali

Overview

This study will determine the immune response to malaria infection in healthy volunteers compared with malaria patients. Malaria affects millions of people in Mali and Africa. It can cause fever, headaches, body aches, and weakness. Without treatment, the disease can be very serious in children. Developing an effective vaccine against the parasite that causes malaria is a crucial step toward controlling the disease; however, vaccines tested so far have provided very short-lived protection. A better understanding of the natural immunity to malaria may provide insight that can be applied to developing a more effective vaccine. People 18 years of age or older who live in Kambila, Tieneguebougou or Kalifabougou, Mali, and are in good health may be eligible for this study. Participants undergo a complete physical examination at the start of the study and then once a year for the 4-year duration of the study. They have a maximum of nine clinic visits a year to collect blood samples for research. The visits last about one hour, including a 30-minute observation time after the blood draw.

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.