Recombinant Protein from Trypanosoma Congolense a Good Diagnostic Antigen in Immunochromatographic Test

Abstract

Trypanosomes are hemo-flagellate protozoan parasites that cause disease in humans and livestock called sleeping sickness and nagana, respectively. So far, a vaccine has been elusive because of the immunodominant variant surface glycoprotein (VSG) in a phenomenon known as antigenic variation. According to amino acid domains structure, Tc38630 was assumed as a Trypanosoma congolense orthologue of the T. brucei invariant surface glycoprotein (ISG) therefore, a potential diagnostic antigen. Recombinant protein Tc38630 was successfully expressed, characterized and found to be antigenic. Among other serological tests, immunochromatographic test (ICT) has an advantage as a one-step rapid analysis, thus making it a convenient and sensitive diagnostic test .BALB/c mice were immunized with rTc38630 protein and serum was collected for IgG polyclonal antibodies purification for use as control line in ICT. The antigen-antibody reaction was detected by colloidal gold conjugated rTc38630 protein at the test line. The ICT result was found to be consistent with rTc38630 protein-based ELISA. For vaccine studies, five groups of BALB/c mice, were randomized and assigned as recombinant protein, recombinant GST, MCF homogenate, BSF homogenate and PBS andimmunized respectively. They were challenged with a lethal dose of T. congolense. The recombinant protein did not protect the mice (survival analysis, P=0.09)