796 - Once-Anergized T Cell in Autoimmune-Prone MRL/lpr Mice Cannot Be Reactivated from Anergy and Generate Autoantibodies After Repeated Priming with Exogenous Antigen

Ken Tsumiyama, Saeko Isaka, Akira Hashiramoto, Shunichi Shiozawa. Department of Rheumatology, Kobe University FHS School of Medicine, Kobe, Japan
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.

 K. Tsumiyama, None.