CHARACTERIZATION OF A CIRCULATING ANTIGEN INVOLVED IN IMMUNE-COMPLEXES IN VISCERAL LEISHMANIASIS PATIENTS

Complications of visceral leishmaniasis are explained in part by immun e complex pathology, particularly nephritis. Using the polyethylene gl ycol precipitation method, we identified among these complexes a Leish mania infantum circulating antigen by, sodium dodecyl sulfate-polyacry lamide gel electrophoresis and immunoblotting. Monoclonal antibodies w ere produced to specifically detect this antigen. This protein (molecu lar weight 51 kD) is a cytoplasmic antigen of L. infantum and its synt hesis by promastigotes is related to stationary-phase culture. It was present in sera from dogs whose leishmaniasis was associated with neph ritis, and it was found in the sera of 30% of human patients with visc eral leishmaniasis. It was also detected in the sera of patients with cutaneous leishmaniasis, and it persists in the sera of clinically cur ed subjects.