Variability of Sheep Red Cells in their Reaction to Agglutinins in Normal Human Sera

Summary The interaction (agglutination) of 25 normal sera against a panel of 10 different sheep red cells was studied. There were highly significant differences in the agglutinability of different sheep cells to any one normal serum, and the cells could be divided into ‘high reactors’and ‘low reactors’. Absorption studies confirmed these observations. The significance of these findings is discussed in the light of previous studies on anti‐sheep cell haemagglutinins in disease and the selection of sheep cells for all types of haemagglutinin immunoassays.