Cloning of Leishmania donovani genes encoding antigens recognized during human visceral leishmaniasis.

In this report we describe the construction and analysis of a genomic library of Leishmania donovani gene segments in the bacteriophage vector lambda gt11. This cloning vector permits the expression of parasite polypeptides as fusion products with Escherichia coli beta-galactosidase. A group of 90 clones which express L. donovani antigens have been isolated from this library using various polyvalent antisera. Many of these clones appear to encode parasite membrane antigens some of which are recognized by sera from patients with visceral leishmaniasis (kala azar). Some clones reacted with specific subsets of kala azar sera while others reacted with all kala azar sera tested. In addition, some of the clones appear to encode conserved antigens that are recognized by sera from mice immunized with L. major. Preliminary characterization of five clones indicated that each one contains a distinct genetic element and that at least four encode different fusion peptides.