TLR5 and systemic lupus erythematosus: Intriguingly, C57BL/6 mice with only the Yaa mutation do not develop clinical lupus, but the introduction of the Sle1 locus into B6.Yaa mice (B6.NZMSle1.Yaa strain) results in severe lupus symptoms similar to those exhibited by BXSB/Mp mice.