Immunology Flashcards
Bcl-2
Anti-apoptotic protein
Decreased expression of Bcl-2 –> more susceptible to apoptosis
usually happens after inflammation
Where does B cells mature for birds
bursa of Fabricius 華氏囊
Compare small lymphocyte, lymphoblast and effector cell
Where do T and B lymphocyte mature for humans
T: thymus(but will regress with age)
B: bone marrow，bursa，Payer’s Patches
IL-1 / IL-6
IL-1: Promotes inflammatory response and fever
IL-6: promote innate immunity and elimination of pathogens
both secreted by activated macrophages
The 3 most important APC
Which one is the most potent?
Which one(s) need(s) to be activated in advance?
B-cell, Macrophage, Dentritic cell (most potent)
B-cell and Macrophage need activation. Dentritic cell doesn’t
MHC restriction and what cell
receptors on the surface of that cell could only recognize the antigen bound to MHC molecules.
T cells
IL-2
immunoglobin that can activate the T cells by binding to its surface receptor
Histamine
cause inflammation
receptors of it available on T cells
cell adhesion molecules
-確保T cells and APC 可以靠得很近+strengthen the bond between CD3/TCR on T cells and MHC on APC –> effective crosstalk
Increased expression of cell-adhesion molecules allows effective cytokines or cytotoxic substances transfer
- eg CD2 and LFA-1 on T cells
Which cell stimulate B lymphocyte by means of cytokines?
Th1? Th2? function of the other cell?
Th2
Th1: causing inflammation and activate macrophage
Cytoplasmic granules performed by NK cells
Perforin （穿孔素）：在細胞膜上穿孔。
Granzyme （顆粒酶—）：啟動細胞 apoptosis
ADCC
Antibody-dependent cell-mediated cytotoxicity
via FcγRIII（CD16）
NK cell上有 Fc receptor (FcγRIII/CD16) –> bind to Fc of antibody
- antibody in circulation detects antigen on a cell –> binding
- NK cell detect and bind to that antibody –> releasing cytokines 或 cytoplasmic granules，
- Cell lysis
ADCC除了NK以外中性球酸性球巨噬細胞也可以透過此機制消滅cell，癌細胞就是這樣消滅的
Macrophage in different Tissue (lung/CT/liver/bone/kidney/brain)
lung: alveolar macrophage
CT: histiocyte
liver: Kupffer cell
bone: osteoblast
kidney: mesangial cell
brain: microglial cell
Stages of Phagocytosis on macrophage
- psedopodia偽足：on the macrophage to 抓住 antigen –> 吞進去變成 phagosome
- fuse with lysosome –> phagolysosome
- Degradation of the antigen into smaller peptides of ~10 units
- if it is suitable –> sent to MHC II to express to T cells
Opsonization
Opsonization調理作用-透過antibody 幫忙
- After antigen coated with appropriate antibodyà the complex binds to antibody receptor on macrophage membrane
- More readily than antigen alone + enhance phagocytosis
- 若抗原被專一性抗體 coating，則其被吞噬的機率將提高 4000 倍。(ADCC)
- 不是所有抗體都有中和作用（僅少部分有中和作用的才叫中和抗體），但是所有抗體都可以進行調理作用。
Complement proteins
promote inflammatory response and elimination of pathogens
secreted by activated macrophages
Tumor necrosis factor(TNF)
secreted by activated macrophages
- to kill tumor cells
What are the granulocytes? Which one attacks parasite? Which one is not phagocytic? Which one causes allergy by histamine secretion?
Neutrophil, Eosinophil, Basophils
Eosinophils destroy the membrane of parasites by releasing eosinophilic substances
Basophil
polymorphonuclear leukocyte （PNL）
Neutrophils
What does cytoplamic granules of Mast cell contains?
肥大細胞
- histamine(組織胺)
- Pharmacologically active substance
- IgE-primed (IgE binding 在mast cell或basophil上能觸發histamine的分泌)，造成allergies。
Primary lymphatic organs
Bone marrow, thymus
Stomal cell network of thymus
- Epithelial cells, DCs, 和 macrophages
- 散佈在thymus 的cortex，對於cortex的T cell是訓練師的角色，上面有著各種MHC I&II用來訓練T cell
Nurse cell
Hassall’s corpuscles
Epithelial cells and Hassall’s corpuscles分泌thymic hormones，催化T cell
Thymic selection
Thymus induces the death of those T cells
- that cannot recognize antigen-MHC complexes
- that react with self-antigen-MHC and pose a danger of causing autoimmune diseas
The biggest lymph node
Spleen
Where are Bcells and T cells located in lymph node?
B- cells: cortex
Plasma cells: medulla
T-cells: paracortex
Macrophage: Medullary sinus
how is lymph go into blood stream
right upper part: drain into right lymphatic duct
rest of the body: drain into throracic duct
both of the ducts drain into superior vena cava
Periarteriolar lymphoid sheath(PALS)
where T-cells mainly locate in spleen
red and white pulps of speen
red pulp: recycling wasted RBC
white pulp: training immune cells
Recombination signal sequence (RSS)
-Protein complex containing recombination activator Rag-1 and Rag-2
Exist at the end of each segment
- 連接VD、DJ、VJ之間的橋樑，
- divided into one-turn RSS & two-turn RSS：
one-turn RSS：中間是12bp，右邊e有7對AT-rich(含氮鹼基)(Palindromic heptamer)，左邊有9對(nonamer)
two-turn RSS：中間是23bp，右邊有9對含氮鹼基(nonamer)，左邊有7對(heptamer)
※原則：one-turn RSS一定要配two-turn RSS
P-nucleotide addition
N-nucleotide addition
TdT enzymes
- For N-addition occured in recombination of heavy chain of antibody
somatic hypermutation
(1) 原本已經重排重組好，但突然發生突變Mutation的現象
(2) presence of antigen increases the mutataion chance
(2) 發生於Germinal center，可以說是B cell最後增加多樣性的機會。
(3) Mutation rate突變率: 10-3/bp/division per every2 cell divisionà at least one
Allelic exclusion
- when the gene from one allele is expressed sucessfully, it would prevent the expression of the other.
- B cell會收到分別來自父母(母為Maternal,父為paternal)的κ、λ、及heavy chain(H)。
- 當要合成anti-body時，就只會選一個heavy-chain(父或母)
細胞的篩選從heavy chain開始選，記得每個gene都有兩種alllele可以試(一個from爸一個from媽)，若全都不行則淘汰(後面也是一樣)
κ、λ of light chain隨後加入篩選，直到挑中為止（先會用k，不行再用λ）
note that cell death is incurred once non-productive alleles happen for twice for the same chain!!!
HLA
H-2
MHC (gene) for humans and mice respectively
anchor residue
anchor residues: amino acid residues that are complementary with the binding cleft and anchor the peptide into the groove of the MHC molecule.
- MHC I最愛的peptide長度是9 aa.(nonameric peptide) 然後2nd & 9th aa.向下陷落成anchor residues(屬於hydrophobic型)
IL-2
a protein cytokine, (autocrine) released by activated T-cell, binds to IL-2R on its self-membrane.
使細胞進入mitosis，並開始增生成memory cells / effector cells （for more effective the vaccine, the more memory cell is differentiated
