Involvement of natural killer T cells in C57BL/6 mouse model of collagen-induced arthritis.

A subset of murine T lymphocytes sharing receptor structures with natural killer cells, named natural killer T cells, has characteristics distinct from conventional T cells and natural killer cells. The DBA/1 strain commonly used for collagen-induced arthritis induction does not express the natural killer 1.1 molecule, a marker for defining murine natural killer T cells. Therefore, collagen-induced arthritis was induced in the C57BL/6 strain carrying natural killer 1.1 marker and the role of natural killer T cells was examined in this model. The collagen-induced arthritis was induced successfully in the C57/BL6 strain with near 70% incidence. Lower percentages of natural killer T cells in lymphoid organs including spleen and lymph node and higher percentages of natural killer T cells in synovium were found in mice with severe inflamed joints as compared with those with mild inflamed joints. The results suggested an infiltration of natural killer 1.1+ CD3+ natural killer T cells into inflamed synovium in the model of collagen-induced arthritis. Although the preliminary results of natural killer 1.1 monoclonal antibody depletion experiments failed to alleviate the gravity of arthritis, such a C57BL/6 mouse model of collagen-induced arthritis may provide a tool in the study of therapeutic manipulation of natural killerT cells in human autoimmune diseases such as rheumatoid arthritis.