Correlation of in vivo and in vitro expression of cell-mediated immunity to mumps skin test antigen.

The simplest functional assay of cell mediated immunity, skin testing, is not always possible to do in every patient. A variety of in vitro assays, including lymphocyte transformation (LT), have been developed as possible alternatives to skin testing. In this report studies were undertaken to determine whether LT induced by mumps skin test antigen (MSTA) correlated with skin test sensitivity. LT stimulated by MSTA was performed with cells obtained from 43 normal subjects. Each subject was subsequently skin-tested with up to four concentrations of MSTA. LT results correlated well with skin test reactions. Lymphocytes from all subjects were responsive in LT assays. A less pronounced correlation was observed between the concentration of MSTA used for skin testing and LT. The results of these experiments suggest that LT assays with MSTA provide an adequate substitute for MSTA skin tests.