Antigen Recognition pt 1

Question 1

Mannose receptor - Innate immunity

Answer 1

The mannose receptor is a C-type lectin

• primarily present on the surface of macrophages, immature dendritic cells and liver sinusoidal endothelial cells
• also expressed on the surface of skin cells such as human dermal fibroblasts and keratinocytes.

Question 2

What does mannose receptor recognise?

Answer 2

The receptor recognises terminal mannose, N-acetylglucosamine and fucose residues on glycans attached to proteins found on the surface of some microorganisms

• plays a role in both the innate and adaptive immune systems.

Question 3

MACs, Immature DCs and endothelial cells have identical mannose receptors (T/F)

Answer 3

True

Question 4

Innate immune system is fixed in genome structures (T/F)

Answer 4

True

Question 5

PRRs on adaptive immune cells detect molecular patterns found on host cells (T/F)

Answer 5

PRRs on innate immune cells detect molecular patterns that are not found on host cells

Question 6

Receptors in adaptive immune system are?

Answer 6

Diverse antigen specific receptors

Question 7

Innate receptor gene characteristics

Answer 7

Limited set of genes fixed in genome at time of birth

Question 8

Adaptive receptor gene characteristics

Answer 8

Receptors diverse and generated via somatic gene arrangement

Question 9

Somatic gene arrangement

Answer 9

Cells of the adaptive immune system physically cut out small regions of DNA and then paste the remaining pieces of DNA back together in an error-prone way.

Question 10

Receptor distribution in innate immunity

Answer 10

Non-clonal; all cells of a class identical

Question 11

Receptor distribution in adaptive immunity

Answer 11

Clonal: All cells of a class distinct
• Ex. T cell 1 ≠T cell 2

Question 12

Discrimination of self and non self - does it occur in innate immunity?

Answer 12

Yes

• But Host cells are not recognized
• • The host cells may express molecules that prevent innate immune rxns

Question 13

Discrimination of self and non self - does it occur in adaptive immunity?

Answer 13

Yes
- Based on selection against self-reactive lymphocytes; may be imperfect (can cause autoimmunity)

For developing T cells, the ability to distinguish self from non-self is acquired in the thymus, where the majority of self-reactive cells are eliminated.

Question 14

Adaptor proteins - function

Answer 14

Adaptor proteins contain a variety of protein-binding modules that link protein-binding partners together and facilitate the creation of larger signaling complexes.

By linking specific proteins together, cellular signals can be propagated that elicit an appropriate response from the cell to the environment

Question 15

Kinase function in cell

Answer 15

The phosphorylation of a protein can make it active or inactive. Kinase is an enzyme that phosphorylates proteins.

Question 16

Function of Transcription factors in cell

Answer 16

Protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence.

The function of TFs is to regulate—turn on and off—genes , by binding to nearby DNA, in order to make sure that they are expressed in the right cell at the right time and in the right amount

Question 17

Purpose of transcription

Answer 17

Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).
The newly formed mRNA copies of the gene then serve as blueprints for protein synthesis during the process of translation

Question 18

Purpose of chemokines

Answer 18

regulate immunity, inflammation and hematopoiesis

Question 19

Hematopoiesis - define

Answer 19

Hematopoiesis is the production of all of the cellular components of blood and blood plasma i.e. RBC’S, WBC’S and platelets

Question 20

Process occurring in cell when TLR recognizes PAMP from bacteria or other pathogen

Answer 20

1. The immune cell or epithelial cell brings in these adapter proteins to conduct signal transferring - happens when TLRs recognize PAMPs - can happen with extracellular or intracellular TLRs
2. Then the signals can bring in protein kinases
3. I assume the protein kinase activates the transcription factors which conducts gene transcription to make proteins aka cytokines

Question 21

All of the TLRs activate similar signaling mechanisms, resulting in cellular responses that are central to innate immunity. IFN, interferon; IL, interleukin; IRF­3, interferon response factor­3; LPS, lipopolysaccharide; MCP­1 and RANTES are two chemokines; NFκB, nuclear factor κB; PAMPs, pathogen­associated molecular patterns; TNF, tumor necrosis factor… What does this imply?

Answer 21

Different TLRs respond to different products of

microbes.

Question 22

Last step in process of TLR - PAMP binding

Answer 22

Signals generated by TLRs activate transcription factors that stimulate expression of cytokines and other proteins involved in the inflammatory response and in the antimicrobial functions of activated phagocytes and other cells.

Question 23

One of important transcription factors activated by TLR signals

Answer 23

Members of the nuclear factor κB (NF-κB) family

• promotes expression of cytokines and endothelial adhesion molecules that play important roles in inflammation, and interferon regulatory factors (IRFs), which stimulate production of the antiviral cytokines, type I interferons

Question 24

Ligand - define

Answer 24

A molecule that binds to another. Often, a soluble molecule such as a hormone or neurotransmitter that binds to a receptor.