Lymphoproliferative responses to a merozoite surface antigen of Plasmodium falciparum: preliminary evidence for seasonal activation of CD8+/HLA-DQ-restricted suppressor cells.
We have investigated the phenotype of human lymphocytes responding to a defined Plasmodium falciparum malaria antigen in vitro. Cells were obtained from the peripheral blood of malaria-immune donors from an endemic area of West Africa and were tested for proliferation in response to cloned fragments of a merozoite surface protein (PfMSP1). Depletion and inhibition studies indicated that the majority of proliferating cells were CD4+ and restricted by HLA-DR or -DQ. A proportion of responding cells appeared to be CD8+, but their response was dependent on help from CD4+ cells. In two donors there was evidence that low responses could be enhanced by removal of CD8+ cells and/or blocking of antigen presentation by anti-HLA-DQ antibodies. This phenomenon was observed in cells collected during the wet (malaria transmission) season but not in cells collected from the same individual during the dry season.
Riley
E M
EM
Institute of Cell, Animal and Population Biology, University of Edinburgh, UK.
Morris-Jones
S
S
Taylor-Robinson
A W
AW
Holder
A A
AA
D000293:Adolescent; D000328:Adult; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D016827:CD8 Antigens / Q000032:analysis; D005260:Female; D006683:HLA-DQ Antigens / Q000502:physiology*; D006684:HLA-DR Antigens / Q000502:physiology; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D020066:Merozoite Surface Protein 1; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000276:immunology*; D011498:Protein Precursors / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D012621:Seasons; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D000953:Antigens, Protozoan; D000954:Antigens, Surface; D016827:CD8 Antigens; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D020066:Merozoite Surface Protein 1; D011498:Protein Precursors; D015800:Protozoan Proteins