Cutting edge: CD1d deficiency impairs murine host defense against the spirochete, Borrelia burgdorferi

CD1 molecules can present microbial lipid Ag to T cells, suggesting that th ey participate in host defense against pathogens. hi this study, we examine d the role of CD1d in resistance to infection with the Lyme disease spiroch ete, Borrelia burgdorferi (Bb), an organism with proinflammatory lipid Ag, Ph infection of CD1d-deficient (CD1d(-/-)) mouse strains normally resistant to this pathogen resulted in arthritis. Pathology correlated with an incre ased prevalence of spirochete DNA in tissues and enhanced production of Bb- specific IgG, including IgG to I-ig rapidly down-modulated on spirochetes i n vivo. CD1d(-/-) Inice exhibited high-titer Bb-specific IgG2a, an isotype commonly induced in disease-susceptible mice but not in the disease-resista nt control mice in this study. These results show that CD1d deficiency impa irs host resistance to a spirochete pathogen, and are the first example of a mutation that imparts Ph-resistant mice with the Ab and disease profile o f a susceptible mouse strain.