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

Cytokine production by murine cells activated by erythrogenic toxin type A superantigen of Streptococcus pyogenes

The mode of pathogenic action of the Steptococcus pyogenes superantigen erythrogenic toxin type A (ETA) in causing toxic shock-like syndrome in humans is thought to be mediated by massive release of cytokines by patients immune cells. The cytokine-inducing capacity of ETA as an extracellular protein was compared with that of lipopolysaccharide (LPS), a component of cell wall of gram-negative bacteria. Peritoneal macrophages and splenocytes of BALB/c and C3H/HeJ mice were stimulated by ETA and LPS. Tumor necrosis factor (TNF), interleukin 3 (IL-3) and interleukin 6 (IL-6) activities in the supernatants of stimulated cells were evaluated. In contrast to LPS, ETA induced only low amounts of IL-6 and no detectable TNF activities in peritoneal macrophage supernatants. ETA-triggered BALB/c and C3H/HeJ splenocytes produced great amounts of IL-6. ETA triggered the production of IL-3 by both mice strains splenocytes in a dose dependent manner. The amounts of IL-3 in supernatants were comparable to those induced by concanavalin A. The simultaneous presence of ETA and LPS in macrophage and splenocyte cultures induced a slight enhancement above an additive value after 72-96 h. Challenge of BALB/c mice with ETA 6 h before the harvest of peritoneal macrophages led to an enhanced production of IL-6 upon stimulation with ETA as well as with LPS. Splenocytes of nude BALB/c mice did not produce IL-6 upon stimulation with ETA, whereas LPS-induced IL-6 production was similar in these mice and in their littermates. The pathogenic effect of ETA on host's immune cells could most likely be explained as a consequence of T cell activation. The results confirm also that LPS- and ETA-induced shock is mediated by different cell types.

Purification and characterization of streptococcal erythrogenic toxin type A produced by Streptococcus pyogenes strain NY-5 cultured in the synthetic medium NCTC-135. Comparison with the dialyzed medium (TP medium)-derived toxin

Streptococcal erythrogenic toxin type A (ET-A) was purified from culture filtrate of Streptococcus pyogenes strain NY-5 grown in a chemically defined synthetic medium NCTC-135. We succeeded in simplifying the purification procedure, and obtained a highly purified preparation of ET-A. The purification procedure was the combination of ultrafiltration with Amicon PM-10 and YM-10 membranes, chromatofocusing with PBE-94 exchanger (pH 4.0-6.0), and gel filtration through Sephacryl S-200. The purified toxin protein showed a single band with Mr 28,000 on SDS-PAGE and had pI 5.2 on agarose IEF. HPLC chromatography pattern of the toxin revealed one symmetric peak. The result of amino acid analysis of the toxin was in accordance with that of Gerlach et al and with Weeks and Ferretti who reported the nucleotide sequence of the spe A gene. Biological activities of the purified toxin were remarkably potent. The mitogenic activity for rabbit lymphocytes and one skin test dose in rabbit were found at the lower dose of 10 pg and 1 ng of the toxin, respectively.

High production of the acquired immunodeficiency syndrome virus (lymphadenopathy-associated virus) by human T lymphocytes stimulated by streptococcal mitogenic toxins

Purified streptococcal mitogens (SMs) including erythrogenic exotoxin were compared with phytohemagglutinin (PHA) for their ability to sustain lymphadenopathy-associated virus (LAV) replication after the stimulation of normal human peripheral blood mononuclear cells and purified CD4+ and CD8+ T cells infected with LAV. Both SM and PHA supported LAV production in peripheral blood mononuclear and CD4+ cells but not in CD8+ cells. LAV production assessed by the assay of reverse transcriptase in cell supernatants appeared earlier after stimulation with SM and was 6- to 10-fold greater than after stimulation by PHA.

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.

Differences in lymphoproliferative responses to the bacterium Actinomyces viscosus in various mammalian species

A water-soluble extract of Actinomyces viscosus (AVS) was tested for its capacity to induce DNA synthesis in lymphocytes from man, monkeys, mice and guinea pigs. The results indicated that the AVS induced an in-vitro lymphoproliferative response, as assessed by tritiated thymidine incorporation, in mouse-spleen cells, in the majority of human peripheral blood samples tested and in macaque monkey spleen cells. The AVS also elicited a blastogenic response from spleen, lymph node and peripheral blood lymphocytes from guinea pigs immunized with A. viscosus. The AVS did not elicit a lymphoproliferative response from human-cord blood cells, monkey peripheral blood lymphocytes, or peripheral blood and spleen lymphocytes from non-immunized guinea pigs. Thus there was a difference in the ability of A. viscosus to induce DNA synthesis in lymphocytes from the different animal species tested.