Immunology

Question 1

Six Types of T Cells

Answer 1

Th1
Th2
Th17
Tfh
Treg
CTL

Question 2

Th1 Cells

Answer 2

Binds APCs in periphary, release INF-gamma for macrophage chemotaxis and maturation to M1s and IL-2 for CTl activation

Question 3

Th17

Answer 3

Release IL-17 for macropahge chemotaxis and M1 maturation, greater effect that Th1s

Question 4

Th2

Answer 4

Bind APCs, release IL-4 for macropahge chemotaxis and maturation into M2 repair macrophages. Activate eosinophils

Question 5

Tfh

Answer 5

follicular helpers, activate B cells in lymph node cortex and promote class switching

Question 6

Treg

Answer 6

Release TGF-beta and IL-10 to reduce/stop immune response by preventing T cell activation

Question 7

CTL

Answer 7

killer T cell, recognize MHC I, not cytokine dependent, cause apoptosis in infected cells

Question 8

All T Cell Surface Marker

Answer 8

CD3

Question 9

B Cell Surface Markers

Answer 9

CD20 and ABs

Question 10

Helper T Cell Surface Markers

Answer 10

CD3 and CD4

Question 11

CTL Surface Markers

Answer 11

CD3 and CD8

Question 12

Cytokine

Answer 12

short range mediator that affects cell behavior of same or other cell

Question 13

Lymphokine

Answer 13

Cytokine released by lymphocyte

Question 14

Chemokine

Answer 14

Small, short range mediators that cause inflammation

Question 15

Follicular Helper details

Answer 15

Either Th1 or Th2 lineage but w/ additional marker CXCR5. Th1 promote complement ABs (IgG) and Th2 promote IgE.
Also regional attributes: IgA promoting in GI tract

Question 16

Mitogen

Answer 16

Molecule that triggers mitosis

Question 17

B Cell vs. T Cell Receptors

Answer 17

B Cell: AB w/ 3 CDRs, 2 heavy and 2 light chains, bind epitopes or opsonize
T Cell: 2/3 CDRs recognize MHC, 1/3 recognize peptides, made of 1 alpha and 1 beta chains, not secreted.

Question 18

Dendritic Cells Cross-Presentation

Answer 18

Extrinsic pathway in DCs place AG on both MHC II for T helper activation and MHC I for CTL activation

Question 19

T-Independent AGs

Answer 19

Molecules w/ same epitope repeated many times (ex carbohydrates), activate B cells w/o T cell help, only IgM is produced

Question 20

Basics of Thymus Maturation

Answer 20

Thymocytes divide, rearrange TCRs and express both CD4 and CD8. Interact w/ thymus endothelial cells that show only self protein. If 2/3 CDR binding to MHC give survival signal, 3/3 CDR binding causes apoptosis (some become Tregs), 0/3 CDR binding causes apoptosis.

Question 21

HLA-A; HLA-B; and HLA-DR

Answer 21

Most important loci in the Human Leukocyte Antigen gene complex for MHC specificity.
HLA-A and B make MHC I
HLA-DR makes MHC II

Question 22

Class I and II MHC antigen structures

Answer 22

MHC I has 1 variable chain and invariable beta-2-microglobulin chain
MHC II has 2 variable alpha and beta chains
30 minor AGs

Question 23

Alloantigen

Answer 23

Antigen present in some people that will react w/ an Allo-Antibody in another person

Question 24

Haplotype

Answer 24

set of alleles/SNPs that are inherited together

Question 25

Which alleles are most important to match in transplants?

Answer 25

MHC II matches (HLA-DR) are most important since it activates helpers to release IFN-G to attract macrophages and IL-2 to make CTls more toxic.
W/o helper activation, CTLs do little damage.

Question 26

One-Way Mixed Leukocyte Reaction

Answer 26

Testing for tissue rejection.
WBCs from both donor and recipient. Donor WBC kills lymphocytes but retains monocytes. Add both together, if recipient lymphocytes react to donor MHC, there will be lymphocyte proliferation.

Question 27

Hyperacute Rejection

Answer 27

Recipient has IgG or IgM to donor HLA or blood type. ABs bind endothelial cells of graft and activated complement. Vasospasm occurs and graft may never get perfused.

Question 28

Alloreaction to foreign MHC

Answer 28

Recognition of foreign MHC is a chance cross-reaction. T cells are programmed to recognize self MHC + some peptide but not self MHC w/o peptide. However, foreign MHC w/o peptide binds self TCRs just differently enough from self MHC that it “feels” like there is self + peptide there.
This explains why T cell immunity is not transfusable between individuals because TCRs will not bind sufficienctly to foreign MHC with peptide to cause activation.

Question 29

Ankylosing Spondylitis

Answer 29

Inflammation of tendon insertions or fibrous joints that produce calcification.
Associated w/ HLA-B27 allele, pathology is uncertain but might involve inability to recognize a pathogen, autoimmunity, or accumulation of misfolded protein.

Question 30

HLA-DR3 and 4

Answer 30

Associated w/ juvenile diabetes

Question 31

Local Immunity

Answer 31

MALT in GI tract produces and secretes IgA which binds pathogens in lumen before invasion

Question 32

Cell-Mediated immunity most effective for…..

Answer 32

viruses, intracellular bacteria

Question 33

Anti-serum

Answer 33

ABs isolated from human or animal that are used to opsonize toxin (ex. tetanus, rattle snake venom)

Question 34

Toxoid

Answer 34

an inactivated toxin that promotes AB production against the active toxin

Question 35

Conjugate Vaccine

Answer 35

Used for T-independent antigens. Give antigen w/ attached second AG that promotes T cell response (thus class switching) when it is expressed on MHC after intrinsic pathway

Question 36

Herd Immunity

Answer 36

Vaccination rate reduces chance that unvaccinated run into infected individuals.
Level necessary for herd protection is based on virulence of specific virus (must be really high w/ measles)