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Semester 5 November > Immunology > Flashcards

Flashcards in Immunology Deck (32)
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Function of B cell Abs

1. Neutralization (bind bacteria and prevent their entry into cells, neutralize toxins)
2. Opsonise extracellular bacteria (FCC receptors on phagocytes or NK cells can bind FCC portion and kill)
3. Complement activation (Ab/Ag complex)

1

Summary of general B cell development

Haemopoietic stem cell -> VDJ rearrangement -> negative selection -> mature cells move to BM periphery -> activation leads to plasma or memory cell formation

2

Molecules expressed by mature B cell

BCR (IgM and IgD)
MHCll
CD40
CD19

3

Describe Ab response to protein

Ag specific B cell binds Ag
Ag internalized (endocytosis)
High density specific Ag presented
Primed T cell interact with B cells
Clonal expansion of plasma cwlls

4

Three pathways to making plasma cells / Ab

T independent. - limited range of Ag -> neutralizing
Extra follicular - w/wout T cell depending on Ag, low affinity Ab is formed
Germinal centers - high affinity Ab, plasma cells and memory cells

5

How long does it take to make T cells

Roughly 1 week

6

Describe T cell development

In thymus
VDJ rearrangement - diversity
MHC restriction - positive selection
Lineage commitment
Eliminate autoreactive cells - negative selection

7

Define cytokines

Small soluble proteins secreted by one cell that can alter behavior/properties of the cell itself or other cells

8

CD4 subsets and their primary cytokines

Th1 - IFN-y (TNFa)
Th2 - IL-4
Th17 - IL-17
Treg - TGF-B

9

What types of pathogens do Th1 cells target

Intracellular eg. Viruses and bacteria

10

What are the effector functions of Th1 cells

Activate macs (NO,O2-,proteases)
Kills chronically infected cells (bacteria released)
Induce T cell proliferation
Induce macrophage differentiation
Activate endothelium (diapedesis)
Chemotaxis for macs

11

What pathogens do Th2 cells respond to

Extracellular pathogens

12

Function of Th2 cells

Activate B cell
Promote isotope switching ESP to IgE

13

Role of Treg cells

Suppress activation and development of naive T cells

14

What do CD8 cells release to kill cells

Perforin
Granzymes
Granulysin
FAS ligand
(INF-y and TNF)

15

Action of perforin

Aids in delivering granule contents to cytoplasm of target cell

16

Action of Granzymes

Serine proteases that activate apoptosis

17

Action of granulysin

Antimicrobial action to induce apoptosis

18

What does MAC do

Creates a pore in bacterial cells membrane leading to osmotic lysis of bacteria

19

Role of phagocytes in killing bacteria

Phagocytose
Kill bacteria in phagolysosome

20

Immunological processes that protect neonate from infection at birth

IgG - maternal, across placenta
IgA and IgG - breast milk ingestion, neutralize organisms, IgG crosses gut epithelium

21

Effector cells responsible in type l diabetes

Autoreactive CD4, CD8
T cell mediated type IV hypersensitivity

22

Self Ags recognized by immune cells in IDDM

Pancreatic islet cell Ag
Pancreatic B-cell proinsulin/insulin
Glutamic acid decarboxylase

23

Active immunity is ..

Production of Abs as a result of exposure to antigen (natural or artificial Ag)

24

Passive immunity is ...

The direct transfer of Abs formed by another person/animal

25

Effect of maternal Ab on vaccination of neonate

Limit replication of live virus
Mask B cell epitopes = prevent vaccine binding to infant B cells

Allows generation of memory B cells
Does not inhibit T cell responses

26

T dependent Ags must contain..

Protein component

27

Effector cells responsible for tissue damage in type 1 diabetes

- Autoreactive cd4 cells and cd8 cells
- type 4 hypersensitivity

28

Self- antigens recognized that leads to type 1 diabetes

- pancreatic beta cell hormone pro insulin
- pancreatic islet cell antigen

29

HLA group in diabetes type 1

Dr3/4