Cold lymphocytotoxin reactivity with lymphocytes from donors in various physiological conditions.

Sera containing cold lymphocytotoxins were studied in the presence of lymphocytes from neonates, pregnant women, blood donors and old people and the degree of positivity varied according to the lymphocyte population investigated: a strongly positive response to lymphocytes from neonates and pregnant women, a weaker response to lymphocytes from old people and a very weak response to chronic leukemic lymphocytes. Cold lymphocytotoxins seem to be a supplementary method of demonstrating a difference in lymphocytic behavior.