Lymphocyte-stimulating activity of scarlet fever toxin

Historical links between toxinology and immunology

Research on bacterial toxins is closely linked to the birth of immunology. Our understanding of the interaction of bacterial protein toxins with immune cells has helped to decipher immunopathology, develop preventive and curative treatments for infections, and propose anti-cancer immunotherapies. The link started when Behring and Kitasato demonstrated that serotherapy was effective against 'the strangling angel', namely diphtheria, and its dreadful toxin discovered by Roux and Yersin. The antitoxin treatment helped to save thousands of children. Glenny demonstrated the efficacy of the secondary immune response compared to the primary one. Ramon described anatoxins that allowed the elaboration of effective vaccines and discovered the use of adjuvant to boost the antibody response. Similar approaches were later made for the tetanus toxin. Studying antitoxin antibodies Ehrlich demonstrated, for the first time, the transfer of immunity from mother to newborns. In 1989 Marrack and Kappler coined the concept of 'superantigens' to characterize protein toxins that induce T-lymphocyte proliferation, and cytokine release by both T-lymphocytes and antigen presenting cells. More recently, immunotoxins have been designed to kill cancer cells targeted by either specific antibodies or cytokines. Finally, the action of IgE antibodies against toxins may explain their persistence through evolution despite their side effect in allergy.

Tissue cages for study of experimental streptococcal infection in rabbits. III. Influence of immunization with erythrogenic toxin type A (ET A) and its toxoid on subsequent infection with an ET A producing strain

Purified erythrogenic toxin type A (ET A) and the corresponding toxoid, prepared by formalin treatment, were used for the immunization of rabbits (200 micrograms per rabbit). The impact of anti-erythrogenic toxin and toxoid immunity was investigated under the conditions of experimental infection with the ET A-producing Streptococcus pyogenes strain SF 130 (type 1). Whereas non of the immunized rabbits (n = 14) died after infection, 40% of nonimmunized animals did not survive (Table 1). The increase of the spleen weight after infection was significantly smaller in the immunized groups (Table 2). The immunized rabbits responded after infection with a significantly lower increase of fever which did not exceed 0.8 degree C (2 degrees C in infected non-immunized animals). Humoral antibodies to ET A were detected after immunization by means of ELISA. The challenge infection acted as a booster leading to a further increase of antibodies. The antibodies were found to be neutralizing the nonspecific mitogenicity of ET A in vitro in relation to the antibody titer. Cell-mediated immunity was tested in the lymphocyte transformation reaction with peripheral lymphocytes. The nonspecific mitogenicity of ET A, ET B, ET C and Con A was pronounced after immunization, whereas the nonimmunized rabbits responded to these antigens to a lower degree. The toxoid was found to be nonmitogenic. The altogether higher lymphocyte stimulation was also observed using spleen lymphocytes of immunized animals after infection.

Purification and characterization of Streptococcus pyogenes erythrogenic toxin type A produced by a cloned gene in Streptococcus sanguis

The gene of Streptococcus pyogenes erythrogenic toxin type A (speA) has been previously cloned in Streptococcus sanguis (Challis) and produces extracellular erythrogenic toxin type A (ET A). The ET A produced and secreted by this heterologous host was purified to homogeneity and shown to have properties identical to ET A produced by S. pyogenes strain NY-5; i.e., serological identity in immunodiffusion, migration in SDS-polyacrylamide gel electrophoresis, mitogenic activity, inhibition of mitogenic activity by specific antibody, and precipitation by an international scarlatina antitoxin preparation. The cloned speA gene specified an ET A which had a molecular weight identical to that of ET A from S. pyogenes previously reported from this laboratory. NH2-terminal sequence determination of the purified protein showed the first nine residues to be gln gln asp pro asp pro ser gln leu; this is consistent with predictions made from the nucleotide sequence of the speA gene according to Weeks and Ferretti and different from the sequence published by Johnson et al.

Tissue cages for study of experimental streptococcal infection in rabbits. II. Humoral and cell-mediated immune response to erythrogenic toxins

Infection of rabbits with erythrogenic toxin producing streptococcal strains caused a marked increase of humoral antibodies, which was detected by immunoprecipitation and ELISA. An antibody response directed towards the erythrogenic toxin type A was demonstrated by fused rocket immunoelectrophoresis. All toxinogenic reference strains produced ET type A under in vivo conditions despite that this toxin was not always demonstrated under in vitro conditions. The infection resulted in an increase of mitogenic response of peripheral lymphocytes to the initial nonspecific mitogenic erythrogenic toxins, whereas the Con A stimulation was depressed starting 14 days after infection and lasting during a period of 90 days. Since a normal antibody response was evoked, it seems likely that the T helper cell function was not affected.

The gene for type A streptococcal exotoxin (erythrogenic toxin) is located in bacteriophage T12

The infection of Streptococcus pyogenes T25(3) with the temperate bacteriophage T12 results in the conversion of the nontoxigenic strain to type A streptococcal exotoxin (erythrogenic toxin) production. Although previous research has established that integration of the bacteriophage genome into the host chromosome is not essential for exotoxin production, the location of the gene on the bacteriophage or bacterial chromosome had not been determined. In the present investigation, recombinant DNA techniques were used to determine whether the gene specifying type A streptococcal exotoxin (speA) production is located on the bacteriophage chromosome. Bacteriophage T12 was obtained from S. pyogenes T25(3)(T12) by induction with mitomycin C, and after isolation of bacteriophage DNA by phenol-chloroform extraction, the DNA was digested with restriction enzymes and ligated with Escherichia coli plasmid pHP34 or the Streptococcus-E. coli shuttle vector pSA3. Transformation of E. coli HB101 with the recombinant molecules allowed selection of E. coli clones containing bacteriophage T12 genes. Immunological assays with specific antibody revealed the presence of type A streptococcal exotoxin in sonicates of E. coli transformants. Subcloning experiments localized the speA gene to a 1.7-kilobase segment of the bacteriophage T12 genome flanked by SalI and HindIII sites. Introduction of the pSA3 vector containing the speA gene into Streptococcus sanguis (Challis) resulted in transformants that secreted the type A exotoxin. Immunological analysis showed that the type A streptococcal exotoxin produced by E. coli and S. sanguis transformants was identical to the type A exotoxin produced by S. pyogenes T25(3)(T12). Southern blot hybridizations with the cloned fragment confirmed its presence in the bacteriophage T12 genome and its absence in the T25(3) nonlysogen. Therefore, the gene for type A streptococcal exotoxin is located in the bacteriophage genome, and conversion of S. pyogenes T25(3) to toxigenicity occurs in a manner similar to the conversion of Corynebacterium diphtheriae to toxigenicity by bacteriophage beta.

Tissue cages for study of experimental streptococcal infection in rabbits. I. Production of erythrogenic toxins in vivo

Tissue cages implanted subcutaneously were used to infect rabbits with erythrogenic toxin (ET) producing streptococci. The in-vivo production of ET was followed during the infection by immunoprecipitation analyses of the tissue cage fluid (TCF). ET types A and C were mainly detected during the first week of infection, but, as late as 4 weeks after the inoculation, ET was occasionally found in TCF. The nonspecific mitogenic activity of ET on human lymphocytes was also used as a biological marker to recognize ET in TCF. Mitogenic activity was detected in 90% of samples during the first week. In order to characterize the mitogenic material released by growing streptococci, TCF was electrofocused in polyacrylamide gel. The eluates of sliced gels were checked for mitogenic activity and compared with a purified ET preparation containing ET types A and C. It could be verified that ET type A was produced under in-vivo conditions by strains NY-5 and SF130, while ET type C was produced by strain T18. Differences between production of toxins in vitro and in vivo might be of significance for the understanding of the pathogenetic mechanisms in streptococcal infection.

Enzyme-linked immunosorbent assay for detection of type A streptococcal exotoxin: kinetics and regulation during growth of Streptococcus pyogenes

We describe the detection and quantitation of type A streptococcal exotoxin (erythrogenic toxin, streptococcal pyrogenic exotoxin) by an enzyme-linked immunosorbent assay. This sensitive and specific technique detected microgram amounts of type A exotoxin and was useful for studying the kinetics and regulation of type A exotoxin production during the growth of Streptococcus pyogenes NY5. Maximum production of type A exotoxin was observed during the mid-log phase of growth, similar to the production of other streptococcal extracellular products. When S. pyogenes NY5 was grown at 42 degrees C, decreases in both growth and type A exotoxin production were observed. The results obtained when we studied the influence of nutrient additives and metal ions on the production of type A exotoxin led to the conclusion that none of these factors significantly affected type A exotoxin synthesis and that regulation was constitutive.

Species-dependent response to streptococcal lymphocyte mitogens in rabbits, guinea pigs, and mice

Extracellular mitogen preparations from NY5 and S84 strains of streptococci induced different responses among rabbit, guinea pig, and mouse lymphocytes. Evidence of T-cell mitogenicity is presented.

Mitogenic and antigenic properties of group A streptococcal M protein preparations

The separation of a mitogenic substance in M protein preparations of Streptococcus pyogenes, type 1 and type 12, is described. The isolation was achieved by gel chromatography on Biogel A 0.5 m, and by immunochromatography on immobilized type specific antibodies. In the delayed cutaneous hypersensitivity test the immunochromatography purified M 1 protein caused erythema but no unspecific mitogenicity could be found by lymphocyte transformation test. In neutralization experiments the mitogenic activity of M protein preparations was specifically inhibited by anti-erythrogenic toxin antisera.

Effect of scarlet fever toxin on the phagocytic activity of the reticuloendothelial system

In normal rabbits and mice, one i.v. injection of scarlet fever toxin (ET) (30 000 STD per kg of rabbit weight or 20-g mouse) elicited a similar biphasic change in carbon clearance rate - early depression followed by a stimulating phase - as has been described for Gram-negative endotoxins. Prolonged depression without a subsequent stimulation phase was obtained in mice by raising the ET dose. The reasons of the discrepancy between these findings and those of Hanna and Watson (1965b) are discussed. Pyrogenic tolerance to ET is not accompanied by accelerated carbon clearance and is not impaired by RES blockade. A possible mechanism of ET tolerance is suggested.

Influence of antilymphocyte and antipolymorphonuclear sera on the pyrogenic effect of scarlet fever toxin

The role played by lymphocytes in the pyretic response to scarlet fever toxin (ET) was studied in vivo using antilymphocyte serum (ALS). Two i.v. injections of ALS inhibited the pyretic response to a subsequent ET injection in rabbits. The course of endotoxin fever remained uninfluenced by ALS. Antipolymorphonuclear serum had no effect on the pyretic response to either of the toxins. Pretreatment with ALS also inhibited the skin reaction after i.d. injection of ET. These findings are further evidence a mediating role of lymphocytes in the biological effects of ET, among other things in the release of endogenous pyrogen.

Further purification of group A streptococcal pyrogenic exotoxin and characterization of the purified toxin

Streptococcal pyrogenic exotoxin (SPE) isolated from culture filtrates of strain NY-5 (type 10), and separated from other extracellular by differential solubility in ethanol and acetate-buffered saline, has previously been shown to exhibit a wide range of biological activities including erythrogenic activity, pyrogenicity, enhancement of susceptibility to endotoxin shock, blockage of the reticuloendothelial system immmunosuppression, and lymphocyte mitogenicity. Toxin prepared in this way was found to consist of hyaluronic acid and several proteins which could be distinguished by thin-layer polyacrylamide isoelectric focusing (IEF), SPE has been further purified by ion exchange chromatography on QAE-Sephadex columns. One of the fractions isolated from QAE-Sephadex, and shown to be a homogenous protein by thin-layer IEF and Ouchterlony with hyperimmune serum, was highly active erythrogenically, pyrogenically, and in enhancing susceptibility to endotoxin. This fraction was identified as exotoxin A. A second, less active fraction identified as SPE B showed similar activities, but differed from the other fraction antigenically and in net charge and molecular weight. These findings indicate that a single highly purified protein can mediate at least three of the biological activities attributed to SPE and NY-5 produces pyrogenic exotoxins A and B in vitro as well as in vivo.