Discovery and characterization of an antibody, anti-egressin, that is able to inhibit Trypanosoma cruzi egress in vitro.
Trypanosoma cruzi, a protozoan parasite, is the etiologic agent of Chagas disease. The disease is characterized by acute and chronic phases, with high and low parasitemia, respectively. A strong immune activation is necessary for the host to enter the chronic phase; however, immune mechanisms participating in the reduction of parasites between the acute and chronic phases of the disease have been very difficult to elucidate. We report here the discovery of anti-egressin, an antibody present in serum from chronically infected BALB/c mice that is able to inhibit parasite egress from infected BALB/c fibroblast cultures in vitro. The antibody is very concentrated in serum from these mice; chronic serum may be diluted 1:20 while still maintaining functional activity. Isotype analysis of anti-egressin has suggested it to be IgG2a. Further analysis revealed that anti-egressin was specific for a component expressed on the surface of infected host cells. The specificity of anti-egressin toward the extracellular portion of infected host cells was demonstrated both by using a quantitative assay measuring released trypomastigotes and through immunocytochemical staining. The novel role of anti-egressin in the inhibition of parasite egress from infected host cells has not been described in the literature to date. We believe that anti-egressin plays an important role in achieving the low parasitemia characteristic of chronic Chagas disease.
Molecular and Cellular Biology Program, Tropical Disease Institute, Ohio University College of Osteopathic Medicine, Athens, Ohio 45701, USA.
Deborah
D
Moore-Lai
Edwin
E
Rowland
D000818:Animals; D002460:Cell Line; D005591:Chemical Fractionation; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005347:Fibroblasts / Q000469:parasitology*; D007074:Immunoglobulin G / Q000097:blood* / Q000737:chemistry / Q000276:immunology; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D014349:Trypanosoma cruzi / Q000276:immunology*
D007074:Immunoglobulin G; C483178:antiegressin, Trypanosoma cruzi