Abstract:

Studies on the host parasite relationship in experimental streptococcal infections have been greatly aided by fluorescent antibody techniques (1). By such methods it is possible to follow the localization and persistence of group A streptococcal antigen in cells and tissues of laboratory animals (2-6). To detect such antigens by fluorescent techniques, frozen sections are often employed and the antisera to streptococcal antigens must be repeatedly absorbed with organ powders to remove nonspecific staining. The present communication describes a simple method for applying a label of fluorescein isothiocyanate (FITC) to living group A streptococci, streptococcal cell-wall fragments,mucopeptides, and streptococcal Lforms. Such labeled streptococci and products were found to persist for long periods of time in inflammatory sites in the muscle and heart of mice and rabbits.