Studies in trypanosomiasis II.—Observations on the red cell adhesion test

Abstract

1. 1. We have shown that standard concentrations both of red cells and of trypanosomes are necessary in order to obtain constant results in the Red Cell Adhesion test. 2. 2. The character of adhesion obtained can be varied at will by altering the relative proportions of the various reagents or the time of incubation. 3. 3. Agglomeration and lysis of trypanosomes take place, in presence of homologous serum, when other conditions necessary for adhesion are not present, e.g., an unsuitable indicator (red cells or bacteria). 4. 4. The necessity for the presence of complement in this test has been confirmed and it is shown that the absence of any single component of complement inhibits the reaction. 5. 5. The end titre of an immune serum has shown only slight variations when repeatedly examined by the adhesion test. 6. 6. Certain human red cells will not adhere to sensitized trypanosomes. 7. 7. This condition is met with both in pathological conditions and in normal individuals. We have been unable to correlate it with any altered physical state of the red cell. 8. 8. In the same way certain bacteria adhere to be sensitized trypanosomes and others fail to do so. This is not correlated with rough and smooth states of the culture.