Role of Human Lymphocytes Bearing αβ and γδ T-Cell Receptor in Malaria Infection

Objective: To investigate the role of γδ T cells in the regulation of immune response in Plasmodium falciparum infection. Methods: γδ and αβ T cells were purified from peripheral mononuclear blood cells (PMBC) by positive selection method using monoclonal antibodies. The PMBC were obtained from normal healthy donors. The role of various T cell subsets was investigated by observing their capacity to inhibit the growth of P. falciparum parasites. Results: By positive selection using monoclonal antibodies we were able to obtain a relatively pure fraction (>95%) of γδ T cells from PMBC. The parasite growth inhibitory capacity of activated γδ T cells ranged between 6 and 55%, however, activated αβ T cells failed to inhibit the growth. It was also observed that the inhibitory capacity of γδ T cells was dose-dependent and required physical contact with the organism. Conclusion: Activated γδ T cells have the capacity to inhibit the growth of P. falciparum parasites and thus may act as a first line of defense in controlling the blood stage infection. The significance of γδ T cells in influencing various bacterial infections is discussed.