CHARACTERISTICS OF ANTI-A AND ANTI-B IN BLACK ZIMBABWEANS

Sera from young, black, group O Zimbabwean blood donors were screened for anti-A and anti-B haemolysins. Nearly one fifth of the sera were f ound to be strongly haemolytic for either A or B cells or both. Some o f the sera were titrated for agglutination in saline before and after treatment with dithiothreitol. Serum dilutions beyond the endpoint of agglutination were further tested by the indirect antiglobulin techniq ue using specific anti-IgM and anti-IgG sera. More than 60% of the str ongly lytic sera had high titres of IgG (greater than or equal to 64). The IgM and IgG concentrations both of anti-A and anti-B were correla ted and these levels were in turn correlated with haemolytic activity.