FIG. 6.

Mitogenic activity of culture supernatants of M1T1 isolates. PBMCs from three healthy individuals were stimulated with sterile culture supernatants (1:100 dilution) prepared from 20 different M1T1 GAS strains (10 each from severe and nonsevere cases). Different symbols are used for each isolate; solid symbols are for severe and open symbols are for nonsevere isolates. Proliferative responses were assessed after 72 h of culture, after a 6-h [³H]thymidine pulse. The data are presented as percent relative response as defined in the text. Horizontal lines denote mean values for culture supernatants from severe and nonsevere cases.