Purification and properties of an extracellular blastogen produced by group A streptococci.

Abstract

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.

In vivo andin vitro antiinflammatory and immunoregulating properties of streptococcal mitogen: Effects on adjuvant disease in the rat, on homograft rejection in the mouse, and on the appearance of Ia antigens on human T lymphocytes

“…Their products have been studied extensively [1,2]. A substance which they produce, the streptococcal mitogen (SM), stimulates both B and T cells [3]; induces Ia antigens on purified T lymphocytes [3]; and at a low concentration can distinguish normal lymphocytes from those of subjects with a history of RF [34].…”

Cellular Immune Responses to Extracellular Streptococcal Products in Rheumatic Heart Disease

“…containing 100 U/ml of penicillin, 100 ug/ml streptomycin, 50 ,g/ml of gentamycin, and 2 mmol/ml L-glutamine (MEM-PSG). The cell suspension was fractionated by centrifugation on a Ficoll-Hypaque gradient as previously described (15). The samples of blood were diluted with an equal volume of MEM-PSG and the monocyte population isolated in the same manner.…”

“…Streptococcal blastogen A and streptococcal nuclease B were purified from the crude extracellular products ofgroup A streptococcal strain C203S3 as previously described (15 blood agar plates. After overnight incubation at 370C, the streptococcal colonies were categorized as a-or f8-hemolytic and colonies exhibiting f8-hemolysis were isolated and serologically grouped (19).…”

“…Homogeneous preparations of two streptococcal extracellular products were used: streptococcal blastogen A (15), a product recently shown to have mitogenic properties, and streptococcal nuclease B,2 an antigen that specifically stimulates previously sensitized lymphocytes. Phytohemagglutinin (PHA) and a preparation of Candida albicans antigen were used respectively, as nonspecific mitogen and specific antigen controls.…”

Group A streptococcal pyrogenic exotoxin (scarlet fever toxin) type A and blastogen A are the same protein

“…Group A streptococci express a large number of extracellular factors that may contribute to pathogenicity. Among these are several nonspecific lymphocyte mitogens, and at least two of these have been shown to stimulate T-cell proliferation while not inducing B-cell division (1,6). Barsumian et al (1) and others (14) showed that streptococcal pyrogenic exotoxins (SPEs, also known as scarlet fever toxins and erythrogenic toxins) of types A, B, and C nonspecifically induce proliferation of rabbit splenocytes and human T cells while not stimulating murine spleen cells.…”