Human-porcine MHC-I homology allows for antibody cross-reactivity

Pigs are especially useful large animal models, however, limited availability of commercially available antibodies for immunoblotting presents a significant obstacle facing preclinical xenotransplantation research. Major histocompatibility complex class I (MHC-I) molecule expression enhancement by nucleotide-binding oligomerization domain (NOD)-like receptor family with a caspase recruitment domain (CARD) containing caspase 5 (NLRC5) is fundamental to understanding porcine xenoantigen presentation. Swine Leukocyte Antigens (SLAs) are the porcine MHC homologs for human leukocyte antigens. SLA-I is a known xenoantigen that causes T cell activation. NLRC5, SLA-I, and B2M are all targets of immune modulation in genetically engineered pigs in xenotransplantation research with the goal to reduce SLA-I expression. In the present study, the human anti-NLRC5 (ab105411), anti-NLRC5 (ab117624), anti-NLRC5 N-terminal (ab178767), anti-HLA E (ab203082), anti-HLA E (ab135826), anti-HLA E (ab2216) and anti-β₂ M (ab75853) antibodies were examined using immunoblots for porcine cross-reactivity. The anti-human antibodies ab117624, ab105411, ab178767, ab2216, and ab75853 cross reacted with cognate proteins in porcine cell lysates. Antibody reagents from this study will allow for validation of NLRC5, B2M, MHC-I expression in future research studies. In addition, following the methodology described in this study for other xenotransplantation targets may provide an alternative to custom antibody development.