Dendritic cells and Class II MHC/HLA Flashcards
In vivo Dendritic cells are derived form
CD34+ bone marrow stem cells
In vivo immature dendritic cell differentiation
under influence of GM-CSF, M-CSF, Flt3 ligand. Myeloid precursors enter circulation and differentatie to dendritic cells
In vivo maturation of dendritic cells
mature after they endocytose an antigen
In Vitro dendritic cell precursors
Blood monocytes or CD24+
to differentiate dendritic cells invitro add
GM-CSF, Flt3, IL-4
FLt3 receptor is also known as
CD135
Role of dendritic cells
- 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)
Distribution of dendritic cells
all lymphoid and non lymphoid tissue except brain
Phenotype for dendritic cell and other APCs for antigen presentation
HLA-Class II, B7-1/CD80, B7-2/CD86
other cell surface molecules of dendritic cells
Fc-gamma-R, CD-40, LFA-3, ICAM1, ICAM2
Structure of Class II MHC
Heterodimer, isoypes DP, DQ, DR. Binds antigenic fragments of 15-30 amino acids long
properties of Class II MHC
- only expresed on APC’s
- normally express all three isotypes
- polymorphic in population
- codominant expresion= six stable heterodimers
- IFN-gamma upregulates expression
Nomenclature for HLA class II molecules
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
dendricit cell antigen processing
endocytose into endosome and fuse with lysosome.
HLA class II molecules and innvariant chain are assmbled in
ER
complex HLA-class II=
trimeric, invariant chian blocks heterdimer antigen binding site