NFKB1 and infection: Even though HEK cells were inoculated with the equivalent of approximately 106 CFU of M. curtisii (multiplicity of infection [MOI] = 79) or 103 CFU of M. mulieris (MOI < 1), we consistently found that M. mulieris produced a TLR5-specific NF-κB inflammatory response, while M. curtisii did not (P = 0.002) (Fig. 4A).