Characterization of a congenitally LPS-resistant, athymic mouse strain

C57BL/10ScN (nu/nu) mice have B cells and macrophages unresponsive to a phenol-water extracted preparation of Escherichia coli K 235 LPS. This unresponsiveness was demonstrated in vitro by the inability of spleen cells to incorporate 3H-thymidine after a 48 hr incubation with LPS (Ph) and by the inability of LPS (Ph) to inhibit macrophage phagocytosis of 51 Cr-labeled, opsonized sheep erythrocytes. Furthermore, macrophage cultures stimulated with LPS (Ph) produced low levels of LAF and PGE2 when compared with macrophages from the LPS-sensitive C3H/HeN and C3H/HeN (nu/nu) strains. Therefore, the C57BL/10ScN (nu/nu) strain is similar in its LPS unresponsiveness to the well-characterized C3H/HeJ and C57BL/10ScCR strains. The combination of endotoxin unresponsiveness and the athymic nature of this mouse strain may provide a powerful new tool for studying the cellular events mediating endotoxicity.