Antigens and Antigen Presentation Flashcards Preview

CMBM E4 CB > Antigens and Antigen Presentation > Flashcards

Flashcards in Antigens and Antigen Presentation Deck (23):
1

What is an antigen?

Substance that reacts with the products of a specific immune response (molecule recognized by T or B cells)

2

What is an immunogen?

Substance that induces a specific immune response

3

What is an antibody?

A specific protein produced in response to an immunogen and reacts with an antigen

4

What is an epitope?

Site of an Ag that is bound by lymphocyte receptors or antibody

Also known as antigenic determinant

5

What is a Bc epitope?

Specific portion of a macromolecular Ag to which an Ab binds

6

What is a Tc epitope?

The peptide portion that is recognized by a TCR when it is displayed bound to an MHC molecule

7

Can directly stimulate B cells to produce Ab without T cell help

T-Independent Antigen

8

Cannot directly stimulate Ab production without the help of T cells

T-Dependent Antigen

9

How do follicular dendritic cells present antigens?

Display Ags to B-CELLS to initiate humoral immunity

10

What is the role of dendritic cells in antigen capture and display?

1. DC captures antigen and enters lymphatic vessels
2. Transported to lymph node or spleen
3. Protein antigens displayed for recognition by T-CELLS

11

How do B cell epitopes differ from T cell epitopes?

B-Cell:
Antigen is polypeptide, polysaccharide, or nucleic acid
Linear or conformational
Recognized/bound by BCR
Extracellular or on cell surface

T-Cell:
Antigen is a protein
Linear
Bound by TCR only after being processed/display by MHC
Intra- or extracellular

12

How do T-dependent antigens interact with B-cells?

They are processed by APCs, presented via MHC, and bound by TCR

13

What chromosome contains the HLA genes?

6p21.3

14

What is MHC?

Complex of genes encoding cell surface protein molecules that are required for antigen presentation to T cells

15

Which HLA types are preferred for transplantation?

HLA-DR > HLA-B > HLA-A

16

HLA types encoded by MHC Class II Locus

DR, DQ, DP

17

HLA types encoded by MHC Class I Locus

B, C, A

18

What is encoded in MHC Class III Locus?

Complement proteins
Cytokines

19

Which cells contain MHC I?

All nucleated cells

20

Which cells contain MHC II?

APCs

21

What forms the peptide binding groove in MHC I and II?

I: alpha chain only
II: alpha and B2M chain

22

How many peptides can MHC molecules display at one time?

One peptide per MHC

23

In the MHC I pathway, how are degraded peptide fragments transported to the ER?

Via TAP1 and TAP2