Cutaneous exposure to the superantigen staphylococcal enterotoxin B elicits a T-cell-dependent inflammatory response.
We analyzed the impact of superantigens secreted by skin-colonizing Staphylococci on the skin and the associated lymphoid tissue following epicutaneous application and intracutaneous injection of small amounts of staphylococcal enterotoxin B (SEB). A single intracutaneous injection of 50 ng of SEB elicited a strong inflammatory response in the skin of BALB/c mice. Three to 6 h later, we observed langerhans cell activation, mast cell degranulation, vasodilation, upregulation of ICAM-1, and induction of VCAM-1 on dermal blood vessels, with vascular adhesion of granulocytes. by 12 to 24 h, cell infiltration of the dermis increased, reaching the epidermis. Among the infiltrating leukocytes, a substantial number of eosinophils was found. After 48 h, the infiltrate was dominated by mononuclear cells. The response to SEB was dose-dependent, and signs of inflammation slowly disappeared over 5 to 7 days. Although the induction of VCAM-1 on dermal blood vessels suggested a role for interleukin-1/tumor necrosis factor-alpha in this reaction, the activation of monocytes/macrophages was not able to substitute for lymphocytes, as severe combined immunodeficiency (SCID) mice (which are lymphocyte-deficient) did not mount an inflammatory skin response to intradermal injection of SEB. The fact that nude mice (T-cell-deficient) also did not mount an inflammatory response to SEB indicated the T-cell dependency of the response. The V beta specificity of the SEB effect was demonstrated by the fact that SJL/J mice, which lack V beta 8+ T cells (the major SEB-reactive T cell population in mice), exhibited much weaker responses. Deletion or tolerization of SEB-reactive V beta T cells was not observed after a single intradermal injection of such minute amounts of SEB.
Saloga
J
J
Department of Pediatrics, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado, USA.
Leung
D Y
DY
Reardon
C
C
Giorno
R C
RC
Born
W
W
Gelfand
E W
EW
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003872:Dermatitis / Q000209:etiology*; D004768:Enterotoxins / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D013211:Staphylococcus aureus / Q000276:immunology*; D018089:Superantigens / Q000276:immunology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis
D004768:Enterotoxins; D018089:Superantigens; D019010:Vascular Cell Adhesion Molecule-1; C031818:enterotoxin B, staphylococcal