获得免疫的特征是抗原特异性反

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