Recombinant Staphylococcus aureus exfoliative toxins are not bacterial superantigens

Abstract

Staphylococcal scalded-skin syndrome is an exfoliative dermatitis characterized by the separation of the epidermis at the stratum granulosum. This disruption is mediated by one of two Staphylococcus aureus exotoxins, exfoliative toxins A and B (ETA and ETB). Both ETA and ETB have been reported to be bacterial superantigens. A controversy exists, however, as other data indicate that these exotoxins are not superantigens. Here we demonstrate that recombinant exfoliative toxins produced in Escherichia coli do not act as T-cell mitogens and thus are not bacterial superantigens. These data fit the clinical profile of the disease, which is not associated with the classic symptoms of a superantigen-mediated syndrome.

FIG. 1

Histological examination of neonatal mouse skin exposed to rETA and PBS. Sections are from the bases of the tails of 2-day-old mice sacrificed at 24 h postinjection and were stained with hematoxylin and eosin. Magnification, ×40. (A) Control mouse injected with PBS showing intact skin; (B) mouse injected with 5 μg of rETA/g of body weight showing the characteristic splitting at the stratum granulosum.

FIG. 2

Mitogenic activities of rETA, rETB, rETA-S195A, staphylococcal V8 protease (V8), and rSpeA1. Shown are the results obtained from one representative experiment. All experiments had similar results.