Biomaterials direct functional B cell response in a material specific manner

B cells are an adaptive immune target of biomaterials development in vaccine research but despite their role in wound healing have not been studied tissue engineering and regenerative medicine. We evaluated the B cell response to biomaterial scaffold materials implanted in a muscle wound; a biological extracellular matrix (ECM) and synthetic polyester polycaprolactone. In the local muscle tissue, small numbers of B cells are recruited in response to tissue injury and biomaterial implantation. ECM materials induced plasmablasts in lymph nodes and antigen presentation in the spleen while the synthetic PCL implants delayed B cell migration and induced an antigen presenting phenotype. In muMt- mice lacking B cells, the fibrotic response to the synthetic biomaterials decreased. Immunofluorescence confirmed antigen presenting B cells in fibrotic tissue surrounding silicone breast implants. In sum, the adaptive B cell immune response to biomaterial depends on composition and induces local, regional and systemic immunological changes. Murine tissue samples (quadriceps femoris muscle and inguinal lymph nodes) were obtained for single cell flow cytometry and/or fluorescence activated cell-sorting. Quad tissue samples were finely diced and digested with 1.67 Wünsch U/mL Liberase TL (Roche Diagnostics) and deoxyribonuclease I (0.2 mg/ml; Roche Diagnostics) in RPMI-1640 medium (Gibco) for 45 min at 37°C. The digested quad tissues were ground through 70-µm cell strainers (Thermo Fisher Scientific), rinsed with RPMI-1640 + 5% fetal bovine serum. Percoll (GE Healthcare) density gradient centrifugation was used to remove debris from quad digestions and enrich the leukocyte fraction. Inguinal lymph node samples were ground through 70-µm cell strainers with excess RPMI-1640 + 10 mM HEPES buffer solution. The enriched single-cell suspensions were washed and stained following antibody panels, respective to the intended application. No differences in single-cell isolation from different material environments were observed.