LEISHMANIA-MAJOR - EXCRETED FACTOR, CALCIUM-IONS, AND THE SURVIVAL OF AMASTIGOTES

Mouse macrophages infected with amastigotes of L. major contain about 40% more intracellular exchangeable Ca than control macrophages. Similar elevation of intracellular exchangeable Ca was observed in macrophages engulfing red blood cells coated with purified excreted factor from L. major. The rate of cytolysis of red blood cells coated with excreted factor was significantly lower than that of uncoated controls. Excreted factor strongly binds Ca; the possible role of a microenvironment rich in Ca bound to excreted factor within the phagolysosome in protecting the amastigotes may be considered.