In vitro studies of group E streptococci in swine leukocytes. 3. The migration inhibition test as an indication of delayed hypersensitivity in streptococcic lymphadenitis.

A procedure for conducting tests for leukocyte migration inhibition was developed for swine leukocytes. Leukocytes from normal swine were found to be inhibited by a factor of less than 20% in the presence of the whole cell antigen of group E Streptococci (GES). However, the migration of leukocytes from swine which had been exposed to GES was inhibited by more than 60% in the presence of the antigen. This was considered as significant and an indication for the presence of delayed hypersensitivity to GES in previously exposed swine.