The Crohn's disease-associated bacterial protein I2 is a novel enteric t cell superantigen.
An aberrant T cell response to enteric bacteria is important in inflammatory bowel disease. However, the identity of relevant microbial antigens is unknown. Here, we report the presence of I2, a Crohn's disease-associated microbial gene, in the murine intestine. The I2 protein induced a proliferative and IL-10 response by CD4(+) T cells from unimmunized mice. The I2 response was dependent on MHC class II-mediated recognition but did not require antigen processing. Selective activation was observed for the TCR-Vbeta5 subpopulation. These findings indicate that the I2 protein is a new class of T cell superantigen and suggest that colonization by the I2 microorganism in susceptible hosts may provide a superantigenic stimulus pertinent to Crohn's disease pathogenesis.
Dalwadi
H
H
Department of Pathology and Laboratory Medicine, University of California, Los Angeles, School of Medicine, Los Angeles, CA 90095, USA.
Wei
B
B
Kronenberg
M
M
Sutton
C L
CL
Braun
J
J
D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D001426:Bacterial Proteins / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D003424:Crohn Disease / Q000209:etiology / Q000276:immunology*; D016753:Interleukin-10 / Q000378:metabolism; D007422:Intestines / Q000276:immunology*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D018089:Superantigens / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D001426:Bacterial Proteins; D018089:Superantigens; D016753:Interleukin-10