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.
Moore-Lai
Deborah
D
Molecular and Cellular Biology Program, Tropical Disease Institute, Ohio University College of Osteopathic Medicine, Athens, Ohio 45701, USA.
Rowland
Edwin
E
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