Antigenic relationships amongTrypanosoma lewisi—complex cells

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Abstract
Cells of six isolates of Trypanosoma lewisi from the United States, England, Puerto Rico, Costa Rica, and Singapore were matched against antiserum to the ‘L’ isolate in microagglutinin chambers. Antisera were prepared in Sprague-Dawley rats. Serum protein determinations were made by the biuret reaction; electrophoretic fractionations of serum proteins were done with a semi-closed horizontal system (Evans & Stirewalt, 1947) at 4°C for 24 h, 120 V, and 8 mA with paper strips. Electrolyte was veronal buffer, pH 8·6 and μ 0·058. Agglutinin absorptions were carried out using inactivated anti-‘L’ sera.Total protein (mg/ml) values were higher in all infected animals (60 vs. 54). Albumin values (%) were higher in controls (47 vs. 40);α-1 fractions were essentially unchanged (15%) as were α-2 values (6%). β Fractions were elevated in infected groups (21 vs. 17%), as were the γ globulins (19 vs. 12%).Three protocols employing agglutinin reactions were completed. In two protocols 3+ agglutinin end-points were obtained with four isolates using 1·45–1·47 μg of immune γ globulin. Two of the isolates (Puerto Rico and Singapore) required 10 times this amount of immune globulin for the same end-point. In two other tests all isolates gave reaction end-points that required greater quantities (by a factor of ca. 500) of immune γ globulin than obtained in the first two tests, and there was further evidence that the Costa Rican isolate was quantitatively different from the others. These facts are interpreted to mean that all six geographic isolates show close qualitative relationships to each other, but that the relationships for the Puerto Rican, Singapore and Costa Rican isolates are quantitatively different. Agglutinins could not be absorbed from immune serum by any of the cells.