Use of immunoplot analysis for the identification of immunodominant non-variant antigens of Trypanosoma brucei rhodesiense

Abstract The application of the ‘immunoplot’ technique to the analysis of a complex series of immunoblots is described. A number of isolates of Trypanosoma brucei rhodesiense blood forms from Uganda, Kenya and Zambia were separated by SDS-PAGE under reducing and non-reducing conditions and transferred by immunoblotting onto nitrocellulose paper. The separated antigens from each isolate were then probed with sera from European and endemic controls, and a large panel of sera from confirmed trypanosomiasis patients. The resulting series of immunoblots was examined by the ‘immunoplot’ technique, which involves comparing frequencies of recognition of each band by the sera of controls and patients. A number of antigens of possible diagnostic interest were identified; a bad of 37/38 kDa was found to be recognised with high frequency (> 55%) by the sera of patients and virtually not at all by control sera under both reducing and non-reducing conditions. When this band was combined with one of the other frequently recognised bands, recognition by patient sera was raised to 92% (reduced) and 76% (non-reduced). This did not appear to be isolate-specific. The ‘immunoplot’ technique has potential for further development and wider use in immunoepidemiology and immunodiagnostic research.