Analysis of the Antigenic Composition of Trypanosoma brucei brucei Bloodstream and Culture Forms by the Quantitative Direct Fluorescent Antibody Methods*

Abstract

Quantitative direct fluorescent antibody (QDFA) methods were employed for the antigenic analysis of bloodstream forms and culture procyclics of 2 variants, TRUM (Trypanosome, Research University of Massachusetts [USA] 106 and TRUM 107, of T. brucei brucei [from mice]. Intact and trypsinized trypanosomes were studied. The specific variant antigens were localized in the surface coat of bloodstream trypomastigotes. In addition to the common antigens shared by bloodstrem forms and culture procyclics, there were also certain antigens unique to these latter stages. Still another group of antigens, not found in the culture procyclics, appears to be shared by the bloodstream forms, irrespective of their variant-specific antigens. These antigens may be present in part in the coat or on the cell membrane and in part within the cytoplasm. Irrespective of the bloodstream-form variant from which they are derived, the procyclics are antigenically the same. The QDFA results are analyzed statistically and discussed in the light of the available literature.