Mice that are heterozygous or homozygous for the "Nalp1b129S1" transgene are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. Protein products from both the native and transgenic alleles of the gene are detected by RT-PCR analysis of macrophage-derived mRNA. Bone marrow-derived macrophages from these transgenic mice are highly susceptible to necrosis induced by anthrax lethal toxin, similar to macrophages isolated from inbred 129S1/SvImJ mice, and in contrast to macrophages from inbred C57BL/6J mice, which are resistant. This mouse strain may be useful in studies of inflammatory autoimmune and infectious diseases, and of anthrax in particular. The Jackson Laboratory 2024, used with permission.