LETHALLY IRRADIATED NORMAL STRAINS OF MICE RADIOPROTECTED WITH SCID BONE-MARROW DEVELOP SENSITIVITY TO LOW-DOSES OF STAPHYLOCOCCAL-ENTEROTOXIN-E

Normal strains of mice are rendered sensitive to small amounts (3-10 m u g) of staphylococcal enterotoxin B (SEB) by transplanting bone marro w cells of SCID donor mice to lethally irradiated recipients. Four to 12 weeks post-transplantation, SEB induces 56-100% lethality. Transpla ntation of normal mouse bone marrow cells, either alone or with the SC ID mouse selected bone marrow cells, does not confer SEB sensitivity. These data imply that either irradiation ablates certain cell populati on(s), that confer resistance to SEB in normal mice (populations that are absent in the SCID donor mice) or that the donor cells selectively repopulate recipients with SEB-sensitive cells. This model will help elucidate the cells, cytokines and the SEB peptide fragments responsib le for SEB toxicity and will be useful in identifying promising vaccin e candidates and in developing preventive medicines to protect against this potent toxin.