Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


NKT Cell Is Required for the Break of T Cell Anergy, Inducing Autoantibody, and Generation of Autoantibody-Inducing CD4 T Cell That Causes Systemic Autoimmunity.

Fujita1,  Yuko, Tsumiyama2,  Ken, Shiozawa3,  Shunichi

Depertment of Biophysics, Kobe University Graduate School of Health Science, Kobe, Japan
Depertment of Biophysics, Kobe University Graduate School of Health Science, Kobe, Japan
Depertment of Biophysics, Kobe University Graduate School of Health Science/Depertment of Medicine, Kobe University Graduate School of Medicine/The Center for Rheumatic Diseases, Kobe University Hospital, Kobe, Japan

Objective:

With regards to how autoantibody-inducing CD4+ T (aiCD4+ T) cell is induced, which is the key as the cause of systemic autoimmunity including SLE, we consider the recovery from anergy as the essential step in generating aiCD4+ T cell. Here, we studied the contribution of NKT cell to the break of anergy, induction of autoantibodies, and generation of aiCD4+ T cell.

Methods:

BALB/c mice were repeatedly immunized with staphylococcal enterotoxin B (SEB), staphylococcal enterotoxin A (SEA) and/or a-galactosylceramide (a-GC). SEB stimulates NKT cell and T cells, whereas SEA stimulates only T cells. Mice were also immunized 2x with SEB to induce T cell anergy, and then repeatedly immunized with a-GC. Further, spleen cells of naïve BALB/c mice were stimulated with a-GC in vitro, and supernatant from a-GC-activated NKT cells herein termed NKT-sup. This NKT-sup was repeatedly immunized in CD1d KO mice, following immunization 2x with SEB to induce T cell anergy. Spleen cells were stimulated in vitro with SEB, and IL-2 and mitotic events were measured. Autoantibodies, phoshorylation of ZAP70, LAT, Akt, the expression of Cbl-b and Ca2+ influx in T cell were examined.

Results:

The T cells of the mice immunized 2x with SEB were rendered into anergy. However, after further immunization 8x with SEB, this once-anergized T cells were re-activated from anergy to resume IL-2 production and proliferation. This re-activation was accompanied by induction of RF and anti-Sm antibody in 100% of mice, and this property can be transferred by CD4+ T cells into naïve recipients, thereby aiCD4+ T cells are generated. Phosphorylation of ZAP70, LAT and Akt and Ca2+ influx were inhibited in anergic T cells of the mice immunized 2x with SEB as compared with PBS-immunized control. However, this inhibition was released after immunization 8x with SEB. Further, expression of Cbl-b, an anergy-inducible protein, was increased in the T cell of mice immunized 2x with SEB. The Cbl-b was subsequently down-regulated after further immunization 8x with SEB. As to the contribution of NKT cell to the break of T cell anergy and the generation of aiCD4+ T cell, we found that spleen cells of mice immunized 8x with SEA neither induced RF nor secreted IL-2 because SEA did not activate NKT cell. When a-GC, a specific ligand for NKT cell, was co-immunized 8x with SEA, the once-anergized T cell was recovered from anergy and began to secrete IL-2 and RF and resume proliferation. Sole 2x immunization with SEB followed by 8x immunization with a-GC was also sufficient for the break of T cell anergy and induction of RF. Further, the once-anergized T cells of CD1d KO mice lacking NKT cells could be recovered from anergy after 2x immunization with SEB followed by 8x treatment with the NKT-sup, a supernatant of a-GC-activated NKT cells. These results indicate that the NKT cells and its effector molecule can break T cell anergy and induce autoantibodies, finally leading to the induction of aiCD4+ T cells.

Conclusion:

We show that the activation of NKT cell is indispensable for the re-activation of once-anergized T cell and the induction of autoantibodies, finally leading to the generation of aiCD4+ T cell that causes systemic autoimmunity.

To cite this abstract, please use the following information:
Fujita, Yuko, Tsumiyama, Ken, Shiozawa, Shunichi; NKT Cell Is Required for the Break of T Cell Anergy, Inducing Autoantibody, and Generation of Autoantibody-Inducing CD4 T Cell That Causes Systemic Autoimmunity. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1264
DOI: 10.1002/art.29030

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