Anti-BAFF Treatment Interferes With Humoral Responses in a Model of Renal Transplantation in Rats

Abstract

Background. B-cell–activating factor (BAFF) is associated with donor-specific antibodies (DSA) and poorer outcomes after renal transplantation (RTx). We examined the effects of anti-BAFF treatment on B cells, expression of costimulatory molecules and cytokines, germinal centers (GCs), and DSA formation in an RTx model in rats. Methods. Anti-BAFF antibody was injected on days 3, 17, 31, and 45 after allogeneic RTx. Rats received reduced dose cyclosporine A for 28 or 56 days to allow chronic rejection and DSA formation. Leukocytes, B-cell subsets, and DSA were measured using flow cytometry; expression of cytokines and costimulatory molecules was measured by quantitative polymerase chain reaction, and GCs and T follicular helper were assessed using immunohistochemistry. Rejection was evaluated by a nephropathologist. Results. Anti-BAFF treatment reduced the frequency of B cells in allografts and spleen. Naive B cells were strongly reduced by anti-BAFF treatment in all compartments. Messenger RNA expression of interleukin-6 and the costimulatory molecules CD40 and inducible T cell costimulator ligand was significantly reduced in anti–BAFF-treated rats. GC area was smaller and plasmablasts/plasma cell numbers lower in anti–BAFF-treated rats, which was reflected by less DSA in certain IgG subclasses. Conclusions. Anti-BAFF treatment interferes with humoral responses at multiple levels in this model of allogeneic RTx.

Disruption of Tfh:B Cell Interactions Prevents Antibody-Mediated Rejection in a Kidney Transplant Model in Rats: Impact of Calcineurin Inhibitor Dose

“…Finally, we were interested in the involvement of the BAFF/ APRIL axis, which has been linked to pre-transplant sensitization, DSA occurrence and ABMR in Ktx patients and experimental Ktx (30,(50)(51)(52)(53). We found no change in BAFF, APRIL, BAFF-R or BCMA expression in SLO, but the expression of the BAFF/APRIL receptor TACI was significantly reduced in hiCNI.…”

“…Animal experiments were approved by local authorities (Regierung von Unterfranken) and performed according to animal protection laws. MHC-mismatched allogeneic Ktx was performed using Brown Norway rats (BN) as donors and Lewis rats (LEW) as recipients (Charles River Laboratories, Sulzfeld, Germany, 200-250 g), as previously described (28)(29)(30). In brief, BN kidneys were explanted, flushed with cold saline and transplanted orthotopically.…”

“…DSA were measured by flow crossmatch as previously described (30). Briefly, donor BN splenocytes were incubated with heat-inactivated recipient serum for 30 minutes at 4°C and then washed.…”

“…Rat spleens were macerated and spleen cell suspensions separated by ficoll gradient centrifugation, as described before (30). Cells were blocked using 10% BSA PBS and stained with mouse anti-rat CD45R-PE-Cy7 (ThermoFisher 25-0460), mouse anti-rat CD11b/c-PE (ThermoFisher 12-0110-82), mouse antirat CD3-APC (ThermoFisher 17-0030-82) and hamster antimouse CD27-biotin (Serotec/Biorad MCA-4701B, Puchheim, Germany) and Streptavidin-APC (BD, 554067).…”

B Cell Activating Factor (BAFF) Is Required for the Development of Intra-Renal Tertiary Lymphoid Organs in Experimental Kidney Transplantation in Rats

“…In Ktx patients, elevated serum BAFF levels have also been associated with pre-sensitization, anti-HLA antibody formation, ABMR, and reduced graft survival [20,21]. We have previously demonstrated expression of BAFF in experimental rat kidney allografts [22], and also showed that anti-BAFF treatment interfered with humoral responses in Ktx using the same model [23]. However, a necessity of BAFF for TLO development has not previously been shown.…”