A Plasmodium falciparum gene encoding a heat shock-like antigen related to the rat 78 Kd glucose-regulated protein.

We have cloned part of the genes encoding two antigens of 71 and 72 Kd froi P. falciparua (1,2). These polypeptides differ in their cellular location, expression during the parasite's erythrocytic cycle , isoeletric point in bi-dimensiona 1 gel electrophoresis and reaction with rabbit immune sera (1-3). The sequence of the 72 Kd gene identified it as a member of the P. falciparua heat-shock family (4-6, D. Mattel, unpublished data). Interestingly, the deduced anino acid sequence of the clone encoding the 71 kd antigen also shows 55% of horaology with that of a heat shock protein (Hsp70) of P. falciparua (6) and an even higher honology (72S) with the rat 78 kd glucose-regulated proteinGRP78 (Fig. 1) (7). The GRP78 (a Hsp70-like protein) has been shown to be identical to the immunog1obu1 in heavy chain binding protein (BiP) found in antibody secreting cells (8). The 71 kd antigen thus represents a second P. falciparua Hsp70-like protein.