Malaria specific human T cell clones: crossreactivity with various plasmodia species

Peripheral blood mononuclear cells (PBMC) from donors with or without previous exposure to malaria in vivo were cultivated for 4 to 7 days in the presence of different malaria antigen (M.Ag) preparations: Plasmodium falciparum (P.f.Ag), P. berghei (P.b.Ag) and P. gallinaceum (P.g.Ag). All preparations induced a proliferative response in PBMC from donors with or without previous exposure to malaria. PBMC from both groups of donors were then primed with each of the three M.Ag and cloned in presence of autologous irradiated PBMC and M.Ag. All 152 clones recovered had the T4+ phenotype and required autologous antigen presenting cells (APC) in addition to M.Ag for proliferation. Species specific and crossreactive T cell clones (T cell clones proliferating in the presence of the three M.Ag preparations) were recovered following priming with each of the three M.Ag. Species specific and crossreactive T cell clones were recovered in similar percentages (approximately 50%) using PBMC from donors with or without previous exposure to malaria. These data are discussed in the context of crossreactivity at the T cell level among various plasmodia species and in relation to epitope recognition of malaria native, synthetic and fusion polypeptides.