Cloning, Expression And Evolution Analysis Of The MHC Class Ⅱ In Mangrove Red Snapper (Lutjanus Argentimaculatus)

Major histocompatibility complex (MHC) is the antigen present molecule in theadaptive immune system, it’s also participate in immune recognition, disease resistance,autoimmune, sexual selection and mate choice. There are two mainly types of MHCmolecules, MHC class Ⅰ molecules present endogenously derived proteins to the CD8+T lymphocytes, while MHC class Ⅱ molecules present exogenous peptides to CD4+Tlymphocytes. Fish is a primitive vertebrate with adaptive immunity, the research on fishMHC class Ⅱ should help us to understand the evolution of adaptive immune system,and promote the vaccine effective in disease prevention, even important for selectionthe disease resistance species by molecular marker-assisted breeding. The MHC Ⅱgenes have been identified and characterized in various species of teleost resent years,and the expression of MHC Ⅱ also have been investigated.Here we identified the MHC class Ⅱα and Ⅱβ genes in mangrove red snapper(Lutjanus argentimaculatus), one of the important commercial marine fish. Thededuced MHC class Ⅱα and Ⅱβ proteins shared higher similarity with mammalian andpiscine MHC Ⅱα and MHC Ⅱβ chains in conserved sites and structures, respectively.The evolution analysis shown that the MHC I and MHC Ⅱ genes were probablelyevolved from a common ancestral gene.The MHC class Ⅱα and Ⅱβ polyclonal antiserums were produced, western blottingshown the molecular weight of MHC class Ⅱα and Ⅱβ chain both were about26kD,this identical with the theoretical molecular mass of MHC class Ⅱα24.21kD andMHC class Ⅱβ26.23kD, respectively. The high expression of MHC class Ⅱ in thymus,head kidney, spleen, gill, head kidney macrophages and spleen lymphocytes suggestedthat those organs and cells were the important APC organs and cells in mangrove redsnapper.