Dendritic cells and Class II MHC/HLA

Question 1

In vivo Dendritic cells are derived form

Answer 1

CD34+ bone marrow stem cells

Question 2

In vivo immature dendritic cell differentiation

Answer 2

under influence of GM-CSF, M-CSF, Flt3 ligand. Myeloid precursors enter circulation and differentatie to dendritic cells

Question 3

In vivo maturation of dendritic cells

Answer 3

mature after they endocytose an antigen

Question 4

In Vitro dendritic cell precursors

Answer 4

Blood monocytes or CD24+

Question 5

to differentiate dendritic cells invitro add

Answer 5

GM-CSF, Flt3, IL-4

Question 6

FLt3 receptor is also known as

Answer 6

CD135

Question 7

Role of dendritic cells

Answer 7

• antigen presentation
• link innate immunity to adaptive immunity (+cytokines)
• secrete cytokines( IL12,15,18,23)
• capture antigen and transport to secondary lymphoid tissue to present to CD4+(immature)

Question 8

Distribution of dendritic cells

Answer 8

all lymphoid and non lymphoid tissue except brain

Question 9

Phenotype for dendritic cell and other APCs for antigen presentation

Answer 9

HLA-Class II, B7-1/CD80, B7-2/CD86

Question 10

other cell surface molecules of dendritic cells

Answer 10

Fc-gamma-R, CD-40, LFA-3, ICAM1, ICAM2

Question 11

Structure of Class II MHC

Answer 11

Heterodimer, isoypes DP, DQ, DR. Binds antigenic fragments of 15-30 amino acids long

Question 12

properties of Class II MHC

Answer 12

• only expresed on APC’s
• normally express all three isotypes
• polymorphic in population
• codominant expresion= six stable heterodimers
• IFN-gamma upregulates expression

Question 13

Nomenclature for HLA class II molecules

Answer 13

Class II MHC- major histocompatibility complex-any species

HLA-Class II- Human leukocyte antigen

H-2 mouse(histocompatibility-2 mouse IH2-IA, H2-IE

Human Class Region- HLA-DP, DQ, DR

Question 14

dendricit cell antigen processing

Answer 14

endocytose into endosome and fuse with lysosome.

Question 15

HLA class II molecules and innvariant chain are assmbled in

Answer 15

ER

Question 16

complex HLA-class II=

Answer 16

trimeric, invariant chian blocks heterdimer antigen binding site

Question 17

HLA class II is transported

Answer 17

in vesicles toward membrane

Question 18

en route to membrane, HLA vesicles

Answer 18

fuse with endosome-lysosome vesicle and form chimeric vesicle

Question 19

lysosomal enzymes degrade

Answer 19

invariant chain (Li)

Question 20

antigen peptides bind to

Answer 20

groove in heterodimer

Question 21

after antigen binds to chimeric vesicle it is

Answer 21

transported to and fused with membrane

Question 22

both antigen and peptide complex on dendritic cells are

Answer 22

displayed on the cell surface.

Question 23

activation interactions of dendritic and CD4+

Answer 23

HLA- class II peptide w/ t Cell antigen receptor -HLA class II receptor w/ CD4 -B7-1/CD80 w/ CD28(costimulatory) -B7-2/CD86 w/ CD28(costimulatory) - LFA-3 w/CD2 (adhesion - ICAM-1 w/ LFA-1(adhesion) - ICAM-2 w/LFA-1 (adhesion) - CD40 w/ CD40L (CD154) (enhances T cell response)

Question 24

down regulation of ineraction of Dendritic cell with Tcell

Answer 24

B7-1/CD80 and B7-2/CD86 with CTLA4/CD152 causes inhibtion of T-cell

Question 25

Cross presentation

Answer 25

process by which exogenous antigens(normally are processed in phagolysosomes) are presented on APC cell surface

Question 26

only cell to mediate cross presentation for the most part

Answer 26

dendritic cells

Question 27

following cross presentation exogenous antigens can be presented

Answer 27

within the context of Class I MHC, to CD8+

Question 28

Antigen presenting cells

Answer 28

dendritic cells, macrophages(only CD4+ in primary response ), b-cells(Only to CD4+ in primary response) which all express FcgammaR

Question 29

neutorphils and NK cells express

Answer 29

FcGamma R but are not APC

Question 30

IN Vitro FLT3/CD135 regulates

Answer 30

differentiation, growth and survival of CD34+ progenitor cells.

Question 31

dendritic receptors for chemokines direct them

Answer 31

to the secondary lymphoid tissue after they encounter an antigen

Question 32

dendrites secrete cytokines when

Answer 32

they present to t- cells in the immune response site.

Question 33

antigen presentation delivers the first

Answer 33

signal in T cell activation

Question 34

MHC genes are located on

Answer 34

chromosome 6

Question 35

Class II MHC restriction

Answer 35

CD4+ molecules only recognize antigenic peptides ifthey are displayed with Class II MHC molecules.

Question 36

after association with class II MHC CD4+ cells

Answer 36

are further activated to secrete cytokines in the presence of costimulatory signals

Question 37

when microbes thrive extracellularly some are

Answer 37

endocytosed by APCs

Question 38

CD4

Answer 38

expressed by dendrite cells, determines T-cell lineage and function. is a receptor for HIV type 1

Question 39

HIV-1 infection is initiated by

Answer 39

interaction of viral envelope proteins with CD4 and either CCr5/CXCR4

Question 40

immature dendritic cells express both

Answer 40

CD4 and chemokine receptors.

Question 41

people with defective CCR5 can be resistant to

Answer 41

infection with HIV-1