REACTION OF LYMPHOCYTES WITH PURIFIED PROTEIN DERIVATIVE CONJUGATED WITH FLUORESCEIN.

Busy coats from the peripheral bloods of persons known to give a positive reaction to purified protein derivative and of those known to be negative were treated with purified protein derivative conjugated with fluorescein isothiocyanate. Lymphocytes from positive reactors took up the labeled antigen in significantly greater numbers than did those from negative reactors. Leukocytes from newborns showed far less affinity for the antigen than leukocytes from adult negative reactors.