日韩av大片在线观看欧美成人不卡|午夜先锋看片|中国女人18毛片水多|免费xx高潮喷水|国产大片美女av|丰满老熟妇好大bbbbbbbbbbb|人妻上司四区|japanese人妻少妇乱中文|少妇做爰喷水高潮受不了|美女人妻被颜射的视频,亚洲国产精品久久艾草一,俄罗斯6一一11萝裸体自慰,午夜三级理论在线观看无码

The TCR γ/δ protein is a distinctive T-cell receptor （TCR） expressed on the surface of γδ T cells, composed of a γ chain and a δ chain linked by disulfide bonds to form a heterodimer, belonging to the immunoglobulin superfamily. Unlike the conventional αβ TCR, the γδ TCR can directly recognize a broad range of antigens （e.g., phosphorylated metabolites, lipids, stress proteins） without requiring MHC presentation, granting it broader antigen specificity. Its variable （V） region diversity arises from V, （D）, and J gene segment rearrangements, though it exhibits less diversity than the αβ TCR. γδ T cells are primarily found in mucosal tissues, skin, and the gut, playing crucial roles in early immune defense, tumor surveillance, and tissue repair. They can rapidly secrete cytokines （e.g., IFN-γ, IL-17） or exert cytotoxic effects, serving as key effector cells bridging innate and adaptive immunity.