Chapter 6 Flashcards
(48 cards)
1
Q
Body’s 3rd line of defense
A
Adaptive Immunity
2
Q
Key players of Adaptive Immunity
A
- B Cells
- T Cells
3
Q
Lymphoid Cells
A
- B Lymphocytes
- T Lymphocytes
- NK Cells
4
Q
Lymphocytes Appearance
A
Lymphocytes appear very similar, but different sets carry different cluster of differentiation (CD) molecules on their surface
5
Q
Immunoglobulins (Ig)
A
- Synthesized by B cells
- Synthesized & Secreted by Plasma Cells
- Antibodies
6
Q
Antibody
A
- Ig with specficity for epitope on antigen
- Non-covalently bind antigens to immoblixe them or tag them for destruction
- Important in HUMORAL immunity
7
Q
Effector Cells
A
Carry out specific functions to combat pathogen
8
Q
Memory Cells
A
Persist in host, & upon re-challenge with same antigen, mediate immune response quicker & stronger than initial encounter
9
Q
B Lymphocytes (B Cells) [Types]
A
- Plasma Cells
- Memory B Cells
10
Q
Plasma Cells
A
- Produce antibody in a form that can be secreted & have little or no membrane-bound antibody
- Short-lived
- Effector Cells
11
Q
Memory B Cells
A
- Express membrane-bound antibody as parent B Cell
- Long Lived
12
Q
Basic Structure of Antibodies
A
- 2 Identical Heavy (H) Chains
- 2 Identical Light (L) Chains
- A Variable (V) Region
- A Constant (C) Region
13
Q
Variable (V) Region
A
Antigen-Binding sites
14
Q
Constant (C) Region
A
Limited variation in amino acid sequence
15
Q
Enzymes that cleave Antibodies
A
- Papain - Fc
- Pepsin - F(ab)2
16
Q
5 Immunoglobulin Isotypes
A
- IgA
- IgD
- IgE
- IgG
- IgM
17
Q
IgG
A
- Most Abundant Class in Serum
- 2 gamma heavy chains & 2 kappa OR 2 lambda light chains
- Most abundant in secondary response
- IgG3 is most effective complement activator
- IgG4 is NOT able to activate complement
18
Q
IgM
A
- Serum Ig
- Monomeric is membrane-bound on B cells
- Secreted as a Pentamer
- First Ig produced in primary response
- Complement Activator
19
Q
IgA
A
- Serum Ig
- Predominant Ig in external secretions
- Exists primarily as monomer, but polymer can form (Dimer)
20
Q
IgE
A
- Allergies
- Highly specialized toward recruiting effector functions of mast cells in epithelium, activated eosinophils present at mucosal surfaces, & basophils in blood
- Mediate Hypersensitivity reactions
21
Q
IgD
A
- Together with IgM, is the major membrane-bound Ig expressed by mature B cells
22
Q
Classical Pathway of Complement Activation
A
- Antigen-Antibody interaction
- begins with activation of C1
- Membrane attack complex
- C3b - increase opsonization
- Produce C3a, C5a, C4a
23
Q
Opsonization
A
C3b receptors on surface of many phagocytes
24
Q
Chemotaxis
A
- C5a & C5, C6, C7 complex attract neutrophils
- C5a also enhance neutrophil adhesion
25
Anaphylatoxin
C3a, C4a, & C5a cause degranulation of mast cells with release of mediators
26
Cytolysis
* Insertion of C5b, 6, 7, 8, 9 complex into cell membrane leads to lysis of many cells
* MAC
27
Enhancement of Antibody Production
Binding of C3b to its receptors on surface of activated B cells
28
Major Histocompatibility Molecules (MHC)
* Also called Human Leukocyte Antigen (HLA) Complex
* Self-Proteins
* cell membrane proteins
* Leads to transplant rejection
29
MHC I
* Expressed by nearly all nucleated cells of vertebrate species
* Associates with beta2 microglobulin (beta2m)
* Associates with CD8 / cytotoxic T cells
* Presents antigens from intracellular pathogens
30
MHC II
* Expressed only by Antigen-Presenting Cells (APCs)
* Dendritic Cells
* Macrophages
* B Cells
* Associates with CD4 / T helper cells
* Presents antigens from extracellular pathogens
31
T Cell Receptors (TCRs)
* alpha-beta OR gamma-delta polypeptide pair
* alpha-beta TCR characterized by high degree of specificity
* TCR is associated with CD3
* **Cannot bind soluble epitopes, only fragments**
32
TCR vs. BCR
1. TCR is always membrane-bound
2. Antigen-binding interaction of TCRs is weaker than that of antibodies
3. **Most TCRs are specific to anitgen combined with MHC, not to antigen itself**
4. TCR can't bind soluble epitopes, ony fragments.
33
Cytokines
Low molecular weight soluble protein messengers
* Endocrine Action
* Paracrine Action
* Autocrine Action
34
Chemokines
Chemoattractant cytokines
35
Endocrine Action
Released into the bloodstream to effect distant cells
36
Paracrine Action
Released to effect nearby cells
37
Autocrine Action
Released, but then bind to receptors on the cell that produced them.
38
Innate Immunity System Cytokines
* IL-1
* TNF-alpha
* CXCL8
39
Adaptive Immunity Cytokines
* IL-2
* IL-4 (Big in inflammation)
* IL-17
40
Adhesion Molecules
Provide stable cell-to-cell contact
* Integrins
* Selectins
* Addressins
41
Integrins
Strengthen contact between WBCs & many cell types (vascular epithelium)
42
Selectins & Addressins
Limited in tissue distribution
43
Cluster of Differentiation (CD) Molecules
* CD3
* CD4
* CD8
44
CD3
Support TCR & initiate signal transduction
45
CD4
* Recognize non-peptide binding portion of MHC II
* T helper cells
46
CD8
* Recognize non-peptide binding portion of MHC I
* Cytotoxic T Cell
47
Tyrosine Phosphorylation
* An early step in many signaling pathways
* CD3 (T Cells) & Igalpha/beta (B Cells) are phosphorylated on Immunoreceptor Tyrosine Activation Motifs (ITAMs)
48
Signal Transduction Molecules
* JAK-STAT Pathway
* Ras-MAP Kinase Pathway
