Delayed hypersensitivity to tetanus toxoid in man: in vivo and in vitro studies.

The frequency of positive delayed hypersensitivity skin test reactions to tetanus toxoid in 47 healthy volunteers was 80%. The frequency of immediate hypersensitivity was low (8%) and there was less discomfort than with streptokinase or PPD. There was good correlation between leukocyte migration inhibition and delayed hypersensitivity skin testing, and a quantitative relationship was demonstrated between diameter of cutaneous reaction and degree of leukocyte migration inhibition. No relationship was demonstrated between any measures of immune responsiveness and the interval from the last booster immunization. It was concluded that tetanus toxoid is a valuable antigen for assessment of delayed hypersensitivity in man.