Deregulation of mouse antibody-forming cells by streptococcal pyrogenic exotoxin. II. Modification of spleen T-cell-complemented nude mouse PFC responses

Effects of carrier ampholyte contamination on the biological and biochemical properties of streptococcal pyrogenic exotoxin type C

Three streptococcal pyrogenic exotoxins (SPEs), designated as SPE A, B, and C, have been purified and characterized. Routine purification of the SPEs includes the technique of isoelectric focusing. An earlier study showed that the removal of commercial carrier ampholytes (Ampholines) from SPE was difficult. The physiochemical properties of SPE C were previously reported; however, the SPE C preparation used in those experiments was contaminated with Ampholines. As an alternative to Ampholines, we used simple buffers to generate the isoelectric focusing pH gradient and used this SPE C in a comparative study to evaluate the effects of Ampholine contamination on the biological and biochemical properties of this toxin. We found that Ampholine contamination overestimates protein concentration; consequently, the biological activity of SPE C was actually greater than reported. The most serious effect of Ampholines in SPE C was on amino acid analysis. The presence of Ampholines causes an apparent increase in neutral amino acids and a decrease in basic amino acids.

Complementation of the plaque-forming cell responses of T-cell-deficient nude mice by a T-cell hybridoma

Spleen cells from NFR/N mice primed with carrier rabbit erythrocytes were passed through nylon wool and fused with cells from the AKR T-cell lymphoma BW5147 in order to construct functional T-cell hybridomas. Several hybrids have been obtained. One of the cloned hybrids possesses a marked capacity to functionally complement the T-cell-dependent hapten-specific plaque-forming cell responses of NFR/N nude mice to the trinitrophenyl group. The hybrids carry the Thy 1 marker of the immune parent, express the Lyt 1 surface marker, possess Fc receptors at their surface, and express an Ig heavy-chain variable region determinant at their surfaces as detected by anti-VH MOPC 315 antiserum.

Inhibition of ribonucleic acid synthesis by group A streptococcal pyrogenic exotoxin

Group A streptococcal pyrogenic exotoxins (SPEs) A, B, and C and alpha-amanitin enhance host susceptibility to lethal endotoxin shock. The capacity of SPE C and alpha-amanitin to prepare rabbits for the enhancement phenomenon required pretreatment of the animals 1 to 2 h before giving endotoxin. Endotoxin clearance from the circulation of rabbits pretreated with either SPE C or alpha-amanitin was reduced. Even at the time of death, significant amounts of endotoxin remained in the circulation. It is proposed that the SPE and alpha-amanitin inhibit ribonucleic acid synthesis in Kupffer cells with concomitant alteration in reticuloendothelial clearnace function, allowing endotoxin to persist in the circulation and produce host injury. All three SPE types and alpha-amanitin inhibited ribonucleic acid synthesis by 50% or greater in whole liver cells. Kupffer cells, liver cell nuclei, and liver nuclear extracts; inhibition was observed liver cells from both mice and rabbits. The inhibitory effect by SPEs was dose dependent and was observed after as little as 15 min of preincubation with liver cells. The content of ribonucleic acid in liver nuclei of mice pretreated with either SPE C or alpha-amanitan was reduced, whereas total deoxyribonucleic acid and protein content remained unaltered.

Ganglioside and monosaccharide inhibition of nonspecific lymphocyte mitogenicity by group A streptococcal pyrogenic exotoxins

Group A streptococcal pyrogenic exotoxins (SPE) types A, B, and C are potent nonspecific lymphocyte mitogens. The mitogenicity of these exotoxins was inhibited by gangliosides and sialic acid, whereas concanavalin A was unaffected. The capacity of both concanavalin A and SPE-A to stimulate lymphocytes was suppressed by alpha-methyl-D-mannopyranoside. Galactose reduced the activity of SPE-C. The sugars, glucose, N-acetylglucosamine, alpha-methyl-D-glucopyranoside, and fucose, did not affect SPE mitogenicity.