Anti-Interleukin 6 Receptor Antibodies Attenuate Antibody Recall Responses in a Mouse Model of Allosensitization

作者：Kim Irene; Wu Gordon^*; Chai Ning Ning; Klein Andrew S; Jordan Stanley

来源：Transplantation, 2014, 98(12): 1262-1270.

DOI：10.1097/TP.0000000000000437

• Alloantibody recall response
• Anti-IL-6R
• B cell
• ELISpot
• Flow cytometry
• Mice
• Plasma cell
• Tfh
• Th17
• Treg

Background. Interleukin (IL)-6 is a regulatory cytokine for T helper type 17 (Th17) and Treg cells and a potent stimulus for B/plasma cells. The current study evaluated the effect of IL-6 receptor (IL-6R) blockade with an anti-IL-6R monoclonal (mMR16-1) in alloantibody recall responses.
Methods. A mouse model of human leukocyte antigen (HLA). A2 sensitization was used for studies to evaluate the efficacy of anti-IL-6R on alloantibody recall responses and to examine the impact of IL-6R blockade on Th17, Treg, follicular T helper (Tfh) and plasma cells using multiparameter flow cytometry, flow antibody binding, and enzyme-linked immunospot (ELISpot) assay.
Results. Re-exposure of C57BL/6 mice to HLA. A2(+) skin allografts resulted in a surge of donor-specific (anti-HLA. A2) immunoglobulin (Ig) G antibodies. Anti-IL-6R treatment significantly decreased but did not eliminate alloantibody responses (IgG mean fluorescence intensity, 486 T 153 vs. control 792 +/- 193, P = 0.0076). Flow cytometry analysis showed that anti-IL-6R treatment resulted in reduction of IL-21(+)CD4(+) (Th17) cells (P = 0.006 vs. control) and CXCR5(+) CD4(+) Tfh cells (P = 0.04), but increased foxp3(+) CD4(+) (Treg) cells in the CD4(+) population (P = 0.04 vs. control). The IgG ELISpot experiments showed a significant reduction of IgG spots in the bone marrow and the spleen cells from the anti-IL-6R-treated mice. In vitro treatment of mouse hybridoma (PA2.1) cultures with anti-IL-6R decreased IgG spot formation but had limited effect on cell proliferation.
Conclusion. The data indicate that anti-IL-6R therapy attenuates alloantibody recall responses by modulating a number of immune regulatory and effector cells, including Th17, Tfh, Treg, and importantly, the long-lived plasma cells in the bone marrow.

• 出版日期2014-12-27