INTRODUCTION
The major histocompatibility complex (MHC) class II molecules are tightly linked and highly polymorphic cell surface glycoproteins, which preferentially recognize foreign antigen to T cells and subsequently, initiate specific immune responses against infectious disease (Kedrick and Kim, 2000; Patch et al., 2011). In swine, swine leukocyte antigen (SLA) class II antigens are heterodimeric proteins that are comprised of non-covalently linked α (34 kDa) and β (29 kDa) chains, with the α chain coded by the SL