10th Page Flashcards

1
Q

What is an immunogen?

A

A substance capable of triggering an adaptive immune response by inducing formation of antibodies or sensitized T cells.

Immunogens are typically proteins with a molecular weight (MW) that is immunogenic.

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2
Q

What is an antigen?

A

A substance that can combine with an antibody but may or may not invoke an immune response.

Antigens can be non-protein and are classified as antigenic.

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3
Q

Increase MW, protein, immunogenic

A

Immunogen

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4
Q

Decrease MW, protein, immunogenic

A

Antigen

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5
Q

Relationship of host to immunogenic

A

The more different an antigen is from the host, the more immunogenic it is.

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6
Q

What are the categories of antigens in relation to the host?

A
  1. Autoantigen:
  2. Alloantigen
  3. Heterologous antigen
  4. Heterophile antigen
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7
Q

Autoantigen

A

same individual

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8
Q

different individual, same species

A

Alloantigen

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9
Q

Relationship of size to immunogenic

A

The greater the size, the more immunogenic.

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9
Q

Ag in unrelated plants/animals but cross-reacting with other Abs

A

Heterophile antigen

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9
Q

different individual, different species

A

Heterologous antigen

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10
Q

Size requirement for immunogenicity?

A

The molecular weight (MW) should be at least 10,000 daltons

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11
Q

second most immunogenic (less immunogenic than proteins)

A

Carbohydrates

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12
Q

least or non-immunogenic alone

A

Lipids and nucleic acids

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13
Q

What is an epitope?

A

An epitope is a specific part of an antigen that is recognized by the immune system.

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14
Q

What is an epitope?

A

Part of an antigen/immunogen that binds to the paratope of the antibody.

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15
Q

What is a paratope?

A

Part of an antibody that binds to the antigenic determinant site

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16
Q

What are the types of epitopes?

A

The types of epitopes are linear and conformational.

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17
Q

What is a linear epitope?

A

consists of sequential amino acids on a single polypeptide chain.

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18
Q

What is a conformational epitope?

A

result from folding a polypeptide chain or chains, bringing non-sequential amino acids into close proximity.

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19
Q

What is a hapten?

A

A hapten is a nonimmunogenic material that, when combined with a carrier, creates new antigenic determinants.

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20
Q

What are adjuvants?

A

Adjuvants are substances added to vaccines to enhance immune adherence.

21
Q

Major Histocompatibility Complex (MHC)?

A

A tightly linked cluster of genes whose products play an important role in intercellular recognition and in discrimination between self and non-self.

22
Q

MHC is originally referred as

A

MHA / HLA.

23
Q

Where are the genes coding for MHC molecules found in humans?

A

On the short arm of chromosome 6 at band 21.

24
Q

What is the function of T MHC?

A

To bring or present antigens in the body to the surface cells for recognition of T cells.

25
Q

Where are MHC molecules synthesized/produced?

A

In the rough endoplasmic reticulum.

26
Q

What are the genetic loci for MHC Class I?

A

HLA - A, B, C.

27
Q

What are the genetic loci for MHC Class II?

A

HLA - DP, DQ, DP.

28
Q

What is the cell distribution for MHC Class I?

A

Found in all nucleated cells.

29
Q

What is the cell distribution for MHC Class II?

A

Limited to antigen-presenting cells (APCs).

30
Q

What is the chain structure of MHC Class I?

A

Contains an alpha chain (2) and a beta microglobulin (1).

31
Q

What is the chain structure of MHC Class II?

A

Contains two beta chains (2).

Alpha and Beta

32
Q

What is the size of peptides bound by MHC Class I?

A

8 to 11 amino acids.

33
Q

What is the size of peptides bound by MHC Class II?

A

13 to 18 amino acids.

34
Q

What is the nature of the peptide binding cleft for MHC Class I?

A

Closed at both ends.

35
Q

What is the nature of the peptide binding cleft for MHC Class II?

A

Open at both ends.

36
Q

To whom does MHC Class I present antigens?

A

CD8

37
Q

To whom does MHC Class II present antigens?

A

CD4

38
Q

What type of antigen presentation does MHC Class I use?

A

Endogenous pathway.

39
Q

What type of antigen presentation does MHC Class II use?

A

Exogenous pathway.

40
Q

What degrades endogenous antigen within the cytosol?

A

proteasome

41
Q

How are peptides transported into the endoplasmic reticulum?

A

TAP (transporter associated with antigen processing).

42
Q

What does the alpha chain of class I MHC bind to?

A

beta microglobulin.

43
Q

What does the alpha chain of class I MHC bind?

A

peptide

44
Q

Where is the peptide-class I MHC transported?

A

Golgi complex and then to the cell surface.

45
Q

To which T cell does class I MHC peptide bind?

A

CD8+ T cell.

46
Q

What does class II MHC bind to block endogenous antigen binding?

A

invariant chain

47
Q

What happens to the MHC complex after binding the invariant chain?

A

goes through the Golgi complex.

48
Q

What is left after the invariant chain is degraded?

A

CLIP (class II invariant chain peptide) fragment.

49
Q

How is exogenous antigen processed?

A

taken in, degraded, and routed to intracellular vesicle.

50
Q

What replaces the CLIP fragment?

A

antigenic peptide.

51
Q

Where is the class II MHC antigenic peptide transported?

A

cell surface.

52
Q

To which T cell does class II MHC peptide complex bind?

A

CD4+ T cell.