Lymphocyte transformation and macrophage migration inhibition by electrofocused and gel-filtered fractions of group A streptococcal filtrate

Biological effects of Pseudomonas aeruginosa exotoxin A: lymphoproliferation of T lymphocytes in athymic mice

Pseudomonas aeruginosa exotoxin A has been observed to exert modulatory effects on the immune response. The present study examines the ability of exotoxin A to induce proliferation of splenocytes from athymic nu/nu mice. We observed that exotoxin A induced the proliferation of athymic nude splenocytes which could be abrogated by heating the toxin at 70 degrees C or by preincubation of the toxin with rabbit anti-exotoxin A antiserum. Photoaffinity-labelled toxin significantly induced splenocyte proliferation although the relative activity was reduced. Maximum nude splenocyte proliferation was observed at a toxin dose of 100 ng. This same dose was shown previously for athymic splenocytes to induce an enhanced response to the thymus-dependent (TD) antigen, sheep red blood cells (SRBC). The increased [3H]-TdR uptake in athymic splenocytes stimulated by exotoxin A was initiated by 24 hours and continued to day 10. Nude splenocytes depleted of Ig+ and Ia+ cells were induced to proliferate by exotoxin A. Cyclosporin A addition abrogated the ability of exotoxin A to induce proliferation. These results suggest that Pseudomonas aeruginosa exotoxin A can stimulate the proliferation of splenic T lymphocytes in athymic nu/nu mice.

T-antigen does not induce cell mediated immunity in patients with breast cancer

A total of 80 subjects with benign and malignant breast disease and healthy controls were studied for reactivity to T-antigen, MN-antigens and phytohemagglutinin (PHA) using the lymphocyte blastogenesis assay. No differences were detected between controls and patients with benign or malignant breast disease in reactivity to T- and MN-antigens. Moreover, there was no differential response to T- and MN-antigens among patients with breast cancer. PHA reactivity, although similar between groups as a whole, was diminished in patients with advanced carcinoma. These findings indicate that T-antigen fails to induce cell mediated immunity in patients with breast cancer.

Mitogenicity of streptococcal extracellular products and antagonism with concanavalin A

Extracellular products have been purified from group A Streptococcus pyogenes culture supernatant fluids and their mitogenicities have been tested on rabbit and mouse lymphocytes. Two fractions were mitogenic: the kappa-fraction (pI = 4.8, mol. wt. = 30,000), a protein which was identified as the erythrogenic toxin, and the epsilon-fraction (pI = 10.3, mol. wt. = 17,000) a glycoprotein, both stimulated rabbit and CBA mouse spleen cells. The stimulation of rabbit thymocytes was weak unless macrophages or 2-mercaptoethanol were added. A third product, the gamma-fraction (a protein, pI = 4.2, mol. wt. = 72,000) was very weakly mitogenic and had the capacity to reduce the stimulation induced by a T-cell mitogen, such as Con A, but not by a B-cell mitogen such as Nocardia.

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.

Purification and characterization of streptococcal proliferative factor

Group A streptococcal infections are often associated with scarlet fever and flares of guttate psoriasis. Previous investigation has demonstrated the presence of a factor in streptococcal culture filtrates capable of stimulating proliferation of rabbit keratinocytes in vivo and human lymphocytes in vitro. This report outlines an in vivo method for the production of streptococcal proliferation factor, its purification, and characterization of its physical properties. We cultured Group A streptococci (Type 12, Strain NY5) in synthetic media by in vivo incubation within dialysis casing surgically implanted in rabbit peritoneum. Streptococcal exoproteins were isolated by centrifugation of the bacteria and millipore filtration. Purification of streptococcal proliferative factor was accomplished by differential solubility and molecular sieve was discovered in the resulting product. The relative by SDS gels and molecular sieve chromatography. The sedimentation coefficient determined by sucrose gradient ultracentrifugation is 2.7S. Isoelectric focusing showed minimal microheterogeneity with the pI of the major band being 5.0. Thus, streptococcal proliferative factor can be produced by in vivo incubation of streptococci in synthetic media. Purification entails a rapid 2-step process. The relative molecular weight, sedimentation coefficient and isoelectric points have been established.

Cellular responses of the mouse to the peptidoglycan of a gram-positive bacterium (Streptococcus pyogenes)

The cellular responses and the stimulation of the reticulo-macrophagic system induced in the mouse by a purified bacterial peptidoglycan (PGL) as previously described, were studied by the changes in the peritoneal cytology, the macrophage-migration-inhibition test and the clearance of colloidal carbon. PGL was submitted to chemical and immunochemical characterization and was shown to be substantially free of contamination by polysaccharides, phospholipids, teichoic acid and nucleic acids, but to contain a detectable amount of peptide contaminants; N-acetylglucosamine and the tetrapeptide (with terminal D-alanine) were shown to be the main antigenic determinants. This substance had no action on polymorphonuclear leucocytes but induced an inhibition of the migration of macrophages. This was due to an immunological reaction rather than to direct cytotoxicity, as shown by the negative cytotoxicity tests and the age and life-environment-dependence of the phenomenon. The reticulomacrophagic system was significantly stimulated after primary inoculation, and still more so after a booster. The possible mechanisms of these activities, which are therefore independent from toxic and/or inflammatory responses, are discussed.

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.

Studies of cellular sensitization to myelin antigens in multiple sclerosis. Dissociation of MIF and LBT production in response to a peptide encephalitogenic in rhesus monkeys

The macrophage migration inhibitory factor (MIF) assay and the lymphoblastic transformation (LBT) technique were utilized simultaneously to measure immune responses to peptide Y, the 17 amino acid C-terminal fragment of basic myelin protein, in patients with multiple sclerosis (MS). Ten normals and 67 MS patients from the Montreal Neurological Hospital and affiliated institutions were examined. A prospective attempt was made to correlate the measured responses with phasic clinical activity of the disease. The LBT results indicate some degree of cellular sensitization to peptide Y which parallels the clinical course of the illness, and resembles earlier positive findings obtained with the whole basic myelin protein molecule. These findings, however, are in contrast to a negative MIF response to the Y peptide used in the present study and further contrast the positive MIF results obtained earlier using the whole protein. It is not evident from the results of the present study whether sensitization may be of any pathogenetic significance, but the findings show that differing portions of the basic myelin protein molecule may selectively stimulate specific lymphokine elaboration by sensitized lymphocytes.