Journal of Experimental Medicine, Vol 149, 1438-1449, Copyright © 1979 by Rockefeller University Press
Purification and properties of an extracellular blastogen produced by group A streptococci
ED Gray
An extracellular product of group A streptococci which induces lymphocyte
blastogenesis has been purified to homogeneity by DEAE- cellulose and
CM-cellulose chromatography. The protein, termed streptococcal blastogen A,
has a mol wt of approximately or equal to 17,500 and is inactivated by
protease treatment and by heating at 100 degrees C. The purified blastogen
gave rise to multiple protein bands on nondenaturing polyacrylamide gel
electrophoresis, only two of which possessed blastogenic activity.
Treatment of the protein with dithiothreitol before electrophoresis
resulted in the apparent conversion of the multiple forms to a single
active species. Blastogen A differs in electrophoretic mobility from the
streptococcal pyrogenic exotoxins and its lymphocyte stimulating activity
is not inhibited by rabbit antisera to the exotoxins. An enzyme immunoassay
has been developed to measure human antibodies against blastogen A. A
selection of sera with varying levels of anti-DNase B contained
antiblastogen A- IgG.