Immune responses to P-falciparum-MSP1 antigen: lack of correlation betweenantibody responses and the capacity of peripheral cellular immune effectors to respond to this antigen in vitro

Protective immunity to P. falciparum blood stage infection is thought to be dependent on IgG antibodies, although the mechanisms that underlie such im munity are not clearly understood. One of the antigens thought to be involv ed in this protective response is MSP1. The present study has examined the levels and distribution of IgG (and IgM) antibodies to the C-terminal 19 kD a fragment of MSP1 in plasma from P. falciparum immune adult Senegalese and the capacity of the peripheral blood mononuclear cells from these patients to either proliferate or secrete IFN-gamma, IL-10 or IL-4 in vitro in resp onse to this antigen. Specific antibodies were found in 74% of individuals' plasma; 44% of mononuclear cells proved capable of proliferating in vitro and IFN-gamma, IL-10 and IL-4 were detected in 37, 23 and 0% of culture sup ernatants, respectively. No significant association was found between the p resence of antibodies and immune cell reactivity under the culture conditio ns used. This study emphasizes the complexity of the mechanisms responsible for the sustained production of potentially protective antibodies in respo nse to proposed T-cell dependent P. falciparum blood stage antigens. (C) 19 99 Elsevier Science B.V. All rights reserved.