Advantages of cryopreserved lymphocytes for sequential evaluation of human immune competence. II. Mixed lymphocyte cultures and mononuclear cell subpopulations.

Peripheral blood lymphocytes were obtained from normal volunteer donors over a 2-week period. One-way or two-way mixed lymphocyte reactions, percentages of T-cells and B-cells, and percentages of monocytes were quantitated on both fresh and cryopreserved lymphocytes. These comparisons revealed that the measurement of mixed leukocyte reactions, fractions of E-rosettes and EA rosettes, and the fraction of esterase-staining cells were not altered by cryopreservation and storage at -196 degrees C up to 1 year. Cryopreserved reference lymphocytes provided a stable standard for use as stimulating cells in mixed lymphocyte cultures and could be irradiated or treated with mitomycin C prior to being frozen, without alteration of their function as stimulator cells. Cryopreserved cells thus appeared to be utilizable in the sequential measurement of the immune competence of humans.