Enterotoxin type B Protein, S. aureus (P.pastoris, His)

Enterotoxin B (SEB) is an antigen derived from Staphylococcus aureus (S. aureus) that can be recognized and bound by MHC class II molecules on antigen-presenting cells. Enterotoxin B also interacts with T cell receptors (TCRs), triggering massive activation of CD4+ and CD8+ T cells, leading to the release of proinflammatory cytokines (TNF-α, IFN-γ) and Th2-type cytokines (IL-4, IL-5, IL-13), regulating inflammatory responses. Enterotoxin B also exerts anti-tumor potential in fibrosarcoma models, inducing tumor necrosis. Enterotoxin type B Protein, S. aureus (P.pastoris, His) is a recombinant Enterotoxin B protein expressed by P. pastoris yeast with N-6*His tag.

Enterotoxin type B, S. aureus is a superantigen of enterotoxin B (SEB) derived from Staphylococcus aureus (S. aureus), which belongs to the staphylococcal enterotoxin family. Enterotoxin B structurally binds to MHC class II molecules on antigen presenting cells and binds to the variable region of the β chain of the T cell receptor (TCR), activating T cells expressing a specific (Vβ)-TCR fragment. Enterotoxin B-TCR triggers massive activation of CD4+ and CD8+ T cells, leading to the release of proinflammatory cytokines (TNF-α, IFN-γ) and Th2-type cytokines (IL-4, IL-5, IL-13), and mediates the synthesis of nitric oxide (NO) through TNF and IFN-γ. The activity of enterotoxin B involves a regulatory loop in which NO downregulates cytokine production to prevent excessive inflammation. Enterotoxin B has been shown to induce T_H2-biased cytokine release in a nasal polyp model; in an endotoxin shock model, NO-mediated protection against lethal cytokine storm was observed. In addition, intravenous administration of Enterotoxin B enhanced IFN-γ production and CD4+/CD8+ T cell infiltration, demonstrated anti-tumor potential in a fibrosarcoma model, and induced tumor necrosis.

Enterotoxin type B Protein, S. aureus (100 μg; intraperitoneal injection; 1 time; single dose) can induce a large amount of NO synthesis in the mouse endotoxin shock model. The synthesis of NO is regulated by TNF and IFN-γ. At the same time, endogenous NO can downregulate the production of TNF and IFN-γ and play a protective role. Inhibition of NO synthesis will lead to the death of mice, while neutralization of IFN-γ and TNF can reduce the mortality of mice^[1].
Enterotoxin type B Protein, S. aureus (10 ng; intravenous injection; once every 3 days; 2 weeks) can significantly inhibit the tumor growth of the mouse fibrosarcoma model, increase the IFN-γ level and CD4+/CD8+ T cell infiltration rate, and induce tumor tissue necrosis, while intratumoral injection has no obvious tumor inhibition effect^[2].

Measured by its ability to induce IL-10 secretion by Raji cells. The ED₅₀ for this effect is 53.25 ng/mL, corresponding to a specific activity is 1.878×10^4 U/mg.

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  Measured by its ability to induce IL-10 secretion by Raji cells. The ED₅₀ for this effect is 53.25 ng/mL, corresponding to a specific activity is 1.878×10^4 U/mg.

Staphylococcus aureus

P. pastoris

N-6*His

P01552 (E28-K266)

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Full Length of Mature Protein

ESQPDPKPDELHKSSKFTGLMENMKVLYDDNHVSAINVKSIDQFLYFDLIYSIKDTKLGNYDNVRVEFKNKDLADKYKDKYVDVFGANYYYQCYFSKKTNDINSHQTDKRKTCMYGGVTEHNGNQLDKYRSITVRVFEDGKNLLSFDVQTNKKKVTAQELDYLTRHYLVKNKKLYEFNNSPYETGYIKFIENENSFWYDMMPAPGDKFDQSKYLMMYNDNKMVDSKDVKIEVYLTTKKK

Approximately 30.4 kDa

Greater than 90% as determined by reducing SDS-PAGE.

Lyophilized powder

Lyophilized after extensive dialysis against solution in 20 mM Tris-HC1, 0.5 M NaCl, 6% Trehalose, pH 8.0 or PBS, 6% Trehalose, pH 7.4.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O.

Stored at -20°C for 2 years from date of receipt. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.

• [1]. Patou J, et al. Staphylococcus aureus enterotoxin B, protein A, and lipoteichoic acid stimulations in nasal polyps. J Allergy Clin Immunol. 2008 Jan;121(1):110-5.  [Content Brief]

  [2]. Heidari M, et al. Staphylococcus aureus enterotoxin type B (SEB) and alpha-toxin induced apoptosis in KB cell line[J]. Journal of Medical Microbiology and Infectious Diseases, 2023, 11(2): 96-102.

  [3]. Florquin S, et al. The protective role of endogenously synthesized nitric oxide in staphylococcal enterotoxin B-induced shock in mice. J Exp Med. 1994 Sep 1;180(3):1153-8.  [Content Brief]

  [4]. Fooladi AA, et al. In vivo induction of necrosis in mice fibrosarcoma via intravenous injection of type B staphylococcal enterotoxin. Biotechnol Lett. 2008 Dec;30(12):2053-9.  [Content Brief]