MLR-stimulating properties of five homozygous typing cells found in an outbred population.

In the characterization of stimulating properties of five HTC's two features were taken into consideration, the reproducibility of stimulation results and the individual cut-off level at which reactions positive for Dw antigen are separated from negative reactions. The reproducibility was characterized by the number of repetitions necessary to diminish the standard error to 10 DNV. Depending on HTC 2-8 repetitions were found to be necessary. The individual cut-off levels were determined with the help of maximal correlation between Dw and DR antigen typing. For different HTC's the levels varied from 22 to 57 DNV.