获得免疫的特征是抗原特异性反 应。当身体识别并有选择地对特 定抗原作出反应时就会发生。 Antigens 抗原 —> large molecules that stimulate an immune response. 能刺激免疫反应的大分子。 Involves lymphocytes 淋巴球 Antigen with its determinants Silverthorn, 2016, p. 769 antigen determinants (epitope)
Acquired Immunity - Intro Antigens determinants 抗原决定因 素： small parts of antigens that are recognized by and bind to lymphocytes 淋巴球 and antibodies 抗体 lock-and-key model (similar to enzymes) 锁钥结构 ( 类似于酶 ) Antigen with its determinants Silverthorn, 2016, p. 769 antigen determinants (epitope) works via the
3 major steps of the acquired immune system Antigen recognition 1, Major histocompatibility complex 主要组织相 容性复合体 (MHC) - Antigen determinant-lymphocyte binding Coactivation 共活化作用 - 2 , Lymphocyte activation 淋巴细胞激活 Cytokine secretion 细胞因子分泌 Cell proliferation 细胞增殖 Memory cells 记忆 3, Attack - Antibody secretion 抗体分泌 - Direct killing 直接杀死 leads to l eads to
antigen recognition activates helper T (CD4+) cells Acquired Immunity - Map 1.ANTIGEN RECOGNITION B cells cytotoxic T (CD8+) cells antibody-mediated immunity cell-mediated immunity activation & proliferation 2. LYMPHOCYTE ACTIVATION kill infected cells efficient against viruses (intracellular antigens) produce antibodies in plasma efficient against bacteria (extracellular antigens) main action main result 3.ATTACK
Acquired immunity has 2 branches Bacteria are cells Silverthorn, 2016, p. 755 Act and reproduce outside of our cells Need immune actions in the ECF Antibody -mediated immunity Viruses are not cells ≠ Act and reproduce inside of our cells Need immune actions in the ICF Cell -mediated immunity
Antigens get digested by cells (via phagocytosis) and only a small part, the antigen determinant , is ”seen” by the 淋巴球 cell-surface proteins to ”show” the antigen determinants major histocompatibility complex (MHC) 主要组织相容性复合体 so requires are called 1. Antigen Recognition 抗原识别 Full antigens are too big to react with immune cells 完全抗原 太大，无法与免疫细胞发生反应
1. Antigen Recognition: Major Histocompatibility Complex (MHC) receptors 可以连接到淋巴细胞受体 Def. Proteins found on the plasma membrane of most cells in the body 在大多数细胞膜上发现的蛋白质 function to Display antigen determinants that have been processed on the cell surface 显示在细胞表面处理的抗原决定 因素 results in The complex of MHC + antigen determinant can bind to lymphocyte OpenStax College, Anatomy & Physiology. OpenStax College. 25 April 2013. <;
MHC molecules OpenStax College, Anatomy & Physiology. OpenStax College. 25 April 2013. < col11496/latest/>
1. Antigen Recognition: MHC types Class I MHC molecules: - found on the surface of nucleated cells (i.e. almost all cells in the body) - present antigen determinants from intracellular pathogens (e.g. virus) - 现在的抗原的决定因素 - 细胞内病原体(如病毒) - signal to kill the cell 杀死细胞的信号 Class II MHC molecules - found on the surface of antigen-presenting cells (macrophages, B-cells and dendritic cells)- 在抗原呈递细胞的 表面发现（大噬细胞，b细胞和树突细胞) - present antigen determinants from extracellular pathogens (e.g. bacteria) 来自细胞外病原体 ( 如细菌 ) 的抗原决定因子 - signal to “rally round the flag 拥护国旗 ” —> stimulates 刺激 other immune system cells to respond to the antigen 其他免疫系统细胞对抗原做出反应
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