Lymphatics, MHC, and Antigen Presentation Flashcards
2 primary lymphoid organs
Bone marrow and thymus
Lymphoid organs where lymphocytes are generated and mature
Primary lymphoid organs (bone marrow and thymus)
Lymphoid organs where lymphocytes interact with antigen-presenting cells
Secondary lymphoid organs (adenoid, tonsil, spleen, lymph nodes)
Naive, mature lymphocytes exit circulation and enter lymph nodes via these
High endothelial venules
High endothelial venules allow lymphocytes to travel from circulation into these
lymph nodes
Lymphocytes exit the lymph node via this
Efferent lymphatic vessel
Lymphocytes return to the blood via this
Thoracic duct
Thoracic duct drains into this
Left subclavian vein
Pathogen-loaded dendritic cells enter lymph nodes via these
Afferent lymphatic vessels
Type of vessels that drain fluid from tissue and carry pathogens and APCs to the lymph node
Afferent lymphatic vessels
Site of B cell proliferation in the lymph node
Germinal center
Part of the lymph node that contains mostly B cells
Follicles
Part of the lymph node where T cells reside
Paracortical area
Blood-borne antigens are capture by APCs in this organ
Spleen
Organ that removes dead red blood cells
Spleen
The spleen is important for this type of pathogen
Blood-borne pathogens
In the spleen, germinal centers form along this
Periarteriolar lymphoid sheath (PAS)
Marginal zone B cells surround this in the spleen
Follicle
Part of the spleen that contains few T cells but is rich in macrophages and resident non-circulating B cells
Marginal zone
Marginal zone B cells produce this type of antibody
IgM
Mucosal associated lymph tissue is a central dome of this type of cell surrounded by these cells
Central dome of B cells surrounded by T cells
Mucosa-associated lymph tissue collects antigen from epithelial surfaces via these cells
M Cells
Number of transmembrane domains in MHC I
1
Number of transmembrane domains in MHC II
2
All nucleated cells express this type of MHC
MHC I
Do erythrocytes express MHC I?
No; they don’t have nuclei
MHC primarily expressed by professional antigen-presenting cells
MHC II
3 types of professional antigen presenting cells
Dendritic cells, B cells, macrophages
MHC II expression is increased/induced on dendritic cells and macrophages by this molecule
IFN-gamma
Level of expression of MHC II on dendritic cells
Constitutive
Expression of MHC II on macrophages
Low
Expression of MHC II on B cells
Constitutive
MHC variability is present in this part of the molecule
Peptide binding groove
2 peptides that make up the peptide binding groove in MHC I
Alpha 1 and 2
2 peptides that make up the peptide binding groove in MHC II
Alpha 1 and beta 1
Transmembrane peptide(s) in MHC I
Alpha 3
Transmembrane peptide(s) in MHC II
Alpha 2 and Beta 2
MHC I presents peptides that are this long
8-11 aa (shorter)
MHC II presents peptides that are this long
10-30 aa (longer)
Residues that determine the binding affinity between antigen peptide and MHC
Very small (typically 2-3 aa)
Anchor residues
MHC I isotypes
A, B, C, E, F, G
MHC II isotypes
D
MHC I isotypes that present antigen to CD8 T cells
HLA-A, -B, -C
MHC I isotypes that interact with NK cell receptors
HLA-E and -F
MHC II isotypes that present antigen to CD4 T cells
HLA-DP, HLA-DQ, HLA-DR
MHC II isotypes that are intracellular and aid in the antigen presentation process
HLA-DM and -DO
MHC that presents antigen from intracellular/cytosolic sources
MHC I
MHC that presents antigen from extracellular sources
MHC II
Peptides for MHC I presentation are broken down in the cytosol by this
Proteasome
Peptides for MHC I presentation are broken down here by the proteasome
Cytosol
Transporter used to transport degraded antigen proteins from the cytoplasm into the ER
Transporter associated with antigen processing (TAP)
4 chaperones that prevent antigen from binding to MHC I molecules in the ER
Calnexin, Calreticulin, Erp57, Tapasin
Chaperone that retains a partially folded state of MHC I
Calnexin
Chaperone that is a thiol reductase and maintains disulfide bonds
Erp57
TAP associated protein that acts as a bridge between MHC I and TAP
Tapasin
The T cell receptor recognizes a little bit of self, aka this
MHC
The T cell receptor recognizes non-self, aka this
Peptide antigen
Component that is not complexed with the MHC I molecule prior to peptide loading
Beta 2-microglobulin
Beta 2 microglobulin is associated with this
MHC I
MHC I is not moved to the cell surface until this is loaded
Peptide
Enzyme that removes amino acids from the N-terminal end of peptides to improve their fit for the MHC I molecule
“Peptide trimming”
Endoplasmic reticulum aminopeptidase (ERAP)
ER aminopeptidase (ERAP) is involved in this process
Peptide trimming for loading onto MHC I
Enzymes that are inactive until endosome acidifies, and then cleave antigen into peptide fragments for MHC II
Endosomal proteases
MHC II molecules are folded in this intracellular location
ER
Molecule that blocks that peptide-binding groove of MHC II and prevents cytoplasmic proteins in the ER from binding
Invariant chain (Ii)
The invariant chain blocks this
Peptide-binding groove on MHC II
Prevents cytoplasmic proteins in the ER from binding
Short peptide fragment of the invariant chain that remains on MHC II until removal by HLA-DM
CLIP (class II invariant chain peptide)
CLIP is a short fragment of this, which remains on MHC II peptide binding groove
Invariant chain
Molecule that removes CLIP from MHC II, allowing internalized, degraded peptides to bind in the fused vesicle/acidified endosome
HLA-DM
Function of HLA-DM
Removes CLIP from MHC II (allows internalized degraded peptides to bind)
Beta 2 microglobulin is associated with what?
MHC I
Site of peptide loading of MHC I
ER
Site of peptide loading of MHC II
Late endosomes and lysosomes
