I-A/I-E proteins are part of the Major Histocompatibility Complex (MHC) class II molecules, which are heterodimeric transmembrane glycoproteins expressed on antigen-presenting cells such as dendritic cells, macrophages, and B cells. These proteins are encoded by four genes located in the mouse MHC and are composed of 伪 and 尾 subunits. The I-A and I-E molecules are highly polymorphic and can form hybrid molecules in heterozygous individuals, contributing to the diversity of antigen presentation. They play a crucial role in presenting peptide antigens to CD4+ helper T cells, initiating adaptive immune responses. Additionally, MHC class II molecules can trigger intracellular signaling pathways in antigen-presenting cells, influencing their proliferation, maturation, and apoptosis.