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Presentation Number: 796
OBJECTIVE: The staphylococcal enterotoxin B (SEB)-reactive T cell, rendered anergic after x2 priming with SEB, can be reactivated from anergy to proliferate and secrete IL-2 by further repeated priming (x8) with SEB in normal H-2d BALB/c mice. This was accompanied by the induction of autoantibodies including rheumatoid factor (RF) in sera and the reappearance of V(D)J recombinase complex including RAG 1/2, skewing of T cell receptor (TCR) repertoire and TCR chain revision in the spleen of the mice (Nakashima T, et al. Arthritis Rheum. 48(9): Suppl: S550). RF was induced in 100% of naïve mice by T cell transfer. We show that once-anergized T cell in autoimmune-prone MRL/lpr mice cannot be reactivated from anergy and unable to generate autoantibodies even after repeated x16 priming with SEB, whereas the T cell of control MRL/n mice or H-2 compatible BALB/c mice is easily recovered from anergy and generated autoantibodies including RF faithful to the protocol.
METHODS: BALB/c (8 weeks old), MRL/n (8 weeks old) and MRL/lpr (5 weeks old) female mice were repeatedly primed with SEB by means of i.p. injection every 5 day. RF, anti-Sm antibody (Ab) and anti-ss and anti-ds DNA Ab in sera were determined by ELISA 9 days after last priming of SEB. Spleen cells of mice repeatedly primed with SEB were isolated and stimulated with SEB in vitro, and IL-2 production was measured by ELISA. Proteinuria and the weight of organs were measured after priming.
RESULTS: The T cell of genetically compatible control MRL/n and BALB/c mice were reactivated from anergy after x8 priming with SEB and produced IL-2 and autoantibodies including RF and anti-Sm Ab. However, the once-anergized T cell of MRL/lpr mice did not recover from anergy nor produce IL-2 or autoantibodies after x8 priming with SEB. Even after x16 priming with SEB, the levels of autoantibodies remained comparable to those of untreated MRL/lpr mice, indicating that autoantibody production of autoimmune-prone MRL/lpr mice is independent of exogeneous stimulation with antigen. In the MRL/lpr mice primed with x16 SEB, however, proteinuria was significantly reduced (p<0.05) and the weight of thymus and cervical lymph nodes was decreased (p<0.05), which were likely due to T cell suppression, i.e., decreased proliferation and low IL-2 because of anergy.
CONCLUSIONS: Autoantibody production in MRL/lpr mice is not antigen-induced, and must be genetically programmed. The study highlights an important difference between genetically programmed autoimmunity and antigen-induced autoantibody generation.
METHODS: BALB/c (8 weeks old), MRL/n (8 weeks old) and MRL/lpr (5 weeks old) female mice were repeatedly primed with SEB by means of i.p. injection every 5 day. RF, anti-Sm antibody (Ab) and anti-ss and anti-ds DNA Ab in sera were determined by ELISA 9 days after last priming of SEB. Spleen cells of mice repeatedly primed with SEB were isolated and stimulated with SEB in vitro, and IL-2 production was measured by ELISA. Proteinuria and the weight of organs were measured after priming.
RESULTS: The T cell of genetically compatible control MRL/n and BALB/c mice were reactivated from anergy after x8 priming with SEB and produced IL-2 and autoantibodies including RF and anti-Sm Ab. However, the once-anergized T cell of MRL/lpr mice did not recover from anergy nor produce IL-2 or autoantibodies after x8 priming with SEB. Even after x16 priming with SEB, the levels of autoantibodies remained comparable to those of untreated MRL/lpr mice, indicating that autoantibody production of autoimmune-prone MRL/lpr mice is independent of exogeneous stimulation with antigen. In the MRL/lpr mice primed with x16 SEB, however, proteinuria was significantly reduced (p<0.05) and the weight of thymus and cervical lymph nodes was decreased (p<0.05), which were likely due to T cell suppression, i.e., decreased proliferation and low IL-2 because of anergy.
CONCLUSIONS: Autoantibody production in MRL/lpr mice is not antigen-induced, and must be genetically programmed. The study highlights an important difference between genetically programmed autoimmunity and antigen-induced autoantibody generation.
K. Tsumiyama, None.