Early and late heat-induced proteins during Leishmania mexicana transformation.

During in vitro transformation of L. mexicana from promastigotes to amastigotes at 37 degrees C, a higher growing temperature, transforming parasites showed two different sets of polypeptides. One set of proteins was synthesized at the beginning of temperature-shift and corresponded to the so called "heat shock proteins" (hsp) being expressed by promastigotes mostly. The second set was expressed later on was specifically associated with the amastigotes stages and was strongly similar to the pattern of polypeptides synthesized by amastigotes from infected peritoneal macrophages. These results suggest hsp may play a function at a defined time in the transformation of the parasite.