Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Micro - Immunology > Lec 5 antigens > Flashcards

Lec 5 antigens Flashcards

1
Q

What are antigens?

A

any substances recognized by the immune system and react with T or B lymphocytes. Can be self or non-self.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Immunogen

A

any foreign substance which can stimulate the immune system to produce a specific immune response(humoral or cellular)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Hapten

A

substances of low molecular weight, cannot induce an immune response unless coupled to a protein carrier.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Examples of haptens

A

drugs such as penicillin, aspirin or cosmetics and soap

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Criteria needed for immunogenicity

A

1-Foreighness.
2-Molecular weight : more than 10 kDa(kilo-Dalton).
3-Chemical complexity.(proteins,CHO3,lipids,nucleic acids)
4-Epitopes: variable multiple epitopes.
5-Degradability: susceptible to enzymatic degradation in APCs
6-Dose: high or low: number of doses(booster doses)
7-Route of administration: parenteral or oral
8-Adjuvants:substances when mixed with an antigen before administration will increase the immune response to that antigen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Types of antigens

A 
1-Bacterial antigens
2-Viral antigens
3-Human tissue antigens
4- Blood group antigens
5-Histocompatability antigens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Bacterial antigens can be

A 
soluble antigens(products of a microbe): exotoxins,enzymes,hemolysins
cellular antigens: capsular,flagellar,somatic antigens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Examples of soluble antigens

A

products of a microbe: exotoxins,enzymes,hemolysins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Examples of cellular antigens

A

capsular,flagellar,somatic antigens.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Viral antigens may be

A
  • protein coat viral antigens

- soluble antigens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Examples of soluble antigens

A

soluble nucleoproteins in Inlfluenza viruses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Blood group antigens examples

A

A,B and Rhesus antigens.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Histocompatability antigens examples

A
  • MHC I on surface of all nucleated cells

- MHC II on APCs(B-cells,macrophages,dendritic cells and activated T-cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Antigens can be either ___ or ____

A

infectious / microbial , or noninfectious

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Examples of infectious/microbial antigens

A
  • bacterial
  • viral
  • protozoal
  • helminths
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Examples of noninfectious antigens

A
  • self antigens
  • food antigens
  • plant products
  • dust
  • cell surface proteins
  • synthetic chemicals
  • venoms
  • insect toxins
17
Q

What are antigen epitopes?

A

the smallest part of the antigen that binds to the antigen receptor (TCR or BCR).

18
Q

What may each epitope be composed of?

A

4-7 amino-acids or monosaccharide residues

19
Q

Chemical families of antigens

A

1- Proteins
2- Polysaccharides
3- Nucleic acids
4- Lipids

20
Q

Describe protein antigens

A

(most potent immunogens) and all proteins are immunogenic.

21
Q

Describe polysaccharide antigens

A

blood group antigens(A and B antigens on RBCs) glycoproteins: potentially but not always immunogenic.

22
Q

Describe nucleic acid antigens

A

poor immunogens ,but immunogenic when coupled to a protein carrier.

23
Q

Describe lipid antigens

A

rarely immunogenic but lipoproteins are immunogenic.

24
Q

What do T-cell receptors recognize?

A

Recognize fragments of protein (peptides) associated with MHC molecules on surface of APCs (MHC restricted)

25
Q

What do T helper cells recognize?

A

-recognizes peptide associated with MHC II molecules

26
Q

What do cytotoxic T cells recognize?

A

-recognize peptides associated with MHC I

27
Q

Relationship between T cells and MHC

A

T-cells are MHC restricted

28
Q

What do B-cells receptors =?

A

IgM and IgD

29
Q

What do IgM and IgD recognize?

A 
Proteins.
Polysaccharides.
Nucleic acids.
 Some lipids (glycolipids and lipoproteins)
Haptens
30
Q

Relationship between B cells and MHC

A

Do not need MHC to recognize an antigen(not MHC restricted),can recognize soluble antigens

31
Q

Relationship between B cell receptors and APCs

A

Do not need the antigen to be processed or degraded by APCs

32
Q

What are superantigens?

A

Class of antigens that result in excessive activation of the immune system.
Not processed by APCs.

33
Q

Where do superantigens bind?

A

Can bind to both the variable region of ß chain on TCR of T-cells and to MHC II on APCs.

34
Q

What do superantiens act as between the variable region of ß chain on TCR of T-cells and to MHC II on APCs?

A

They act as a clamp between the two, providing a signal for T cell activation.

35
Q

What do superantigens activate?

A

Activates large number of T-cells resulting in massive cytokines release and massive pathological effect.

36
Q

How do superantigens differ from classic antigens?

A

1-Superantigens are not processed. They interact with the MHC molecules outside the peptide-binding groove.
2-They are active at very low concentrations
3-Stimulate many T-cells causing the release of large amounts of cytokines. This causes systemic toxicity

37
Q

Examples of superantigens

A
  • Staphylococcal enterotoxins
  • Staphylococcal Toxic Shock Toxin
  • Staphylococcal Exfoliating toxin
  • Streptococcal pyrogen exotoxin

Micro - Immunology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions