Exam 1: Dr. Kaplan Bridging Innate and Adaptive Immunity Flashcards
What does the adaptive response depend in for initiation?
Innate cells
What are the professional APCs?
Dendritic cell
Macrophage
B cell
What are the “inbetweeners”?
Cells that possess innate and lymphoid characteristics
List the inbetweeners?
γδ T cells
B-1 cells]
NKT cells
Innate lymphoid cells
What MHC is presented on all nucleated cells?
MHC class I
What MHC is presented on professional APCs?
MHC class I and II
What T cell does MHC class I recognize?
CD8
What T cell does MHC class II recognize?
CD4
What are innate-like lymphocytes?
Innate-like cells that impact adaptive immunity
What is different about innate-like lymphocytes when compared to lymphocytes?
Limited receptor rearrangement
No clonal expansion when stimulated
React promptly to infection
What are γδ T cells?
Innate-like T cell that expresses γδ TCR instead of the traditional αβ TCR
Where do γδ T cells reside?
Within epithelia, especially skin. Also in lymphoid tissue, genital tract
What are possible ligands for γδ T cells?
Proteins that get upregulated in response to infection or unusual nucleotides or phospholipids
What is different about what is recognized by γδ T cells when compared to αβ T cells?
The don’t usually recognize the antigen as an epitope presented by MHC, but rather recognize the antigens directly
What does γδ T cells recognizing antigen directly allow for?
Rapid response to a wide variety of molecules
What do γδ T cells secrete?
IFN-γ, TNF-α, antibacterial peptides, and granulysin
What do γδ T cells acquire during maturation?
The characteristics of professional APCs
What do γδ T cells express?
Different but limited receptor repertoires in different tissues
What does tissue repair function through in γδ T cells?
The secretion of fibroblast growth factor
What do B-1 B cells express?
CD5
Where do B-1 B cells reside?
Mainly in peritoneal and pleural cavities
What are the antibodies secreted by B-1 B cells like?
Low affinity, polyspecific, and made against bacterial polysaccharides and other carbohydrates
What do B-1 B cells produce antibodies in response to?
Polysaccharides
What type of antibodies are of B-1 origin?
Natural antibodies (antibodies reactive against A and B blood antigens in the absence of active immunization
When do B-1 B cells arise?
Early in embryonic development, their development precedes that of the majority subset
What percentage of B cells do B-1 cells comprise?
5%
What 2 antibodies are expressed on the surface of B cells?
IgM and IgD
What antibody is expressed more of the surface of B-1 B cells?
IgM
Why are γδ T cells and B1 cells innate like?
They can respond to primary infection without first undergoing a lengthy period of clonal expansion and differentiation
What are innate lymphocytes?
Cells that have lymphoid progenitor and morphology but respond rapidly and robustly in a non-specific manner
What makes innate lymphocytes distinct from lymphocytes?
They have limited receptor rearrangement
What are roles of innate lymphocytes?
Tissue defense, repair, immune homeostasis, and contributing or initiating adaptive immune responses
What are group 1 iLCs?
Cells that produce IFN-γ TNF-α
Include NK cells
Anti-viral, anti-tumor
What are group 2 iLCs?
Cells that produce IL-4, 5, 9, and 19 (Th2 like)
Anti-helminthic
Pro-allergy
What are group 3 iLCs?
Cells that produce IL-17 and IL-22 (Th17 like)
Lymphoid organogenesis
Anti-bacterial
What is cytokine production like?
Rapid and sustained “first responders”
What could cytokine production stimulate?
T cell differentiation and/or immune homeostasis
What do NK cells produce?
IFN-γ to induce Th1 responses
What do ILC2 cells produce?
IL-4 to induce Th2 responses
What do ILC2 cells produce?
IL-13 to induce DC homing to lymph nodes, which can also induce Th2 responses
What can NK cells kill?
Immature DC
What iLC groups express MHC class II?
2 and 3 to allow for interactions with CD4 cells
What do iLCs come from?
Lymphoid progenitor
What are receptors like for iLCs?
Limited receptor rearrangement
Where do lymphocytes do?
Lymphoid progenitor
What are receptors like for lymphocytes?
Receptor gene rearrangements allow for specific pathogen recognition
What are NKT cells?
Innate lymphocytes that express αβ TCRs, albeit with limited diversity
What do some NKT cells recognize?
Microbial lipids presented by CD1 proteins
WHat do NKT cells secrete?
Large amounts of IFN-γ and IL-4
How can NKT cells respond to infection?
Rapidly
Do NKT cells generate a memory response?
No
What is CD1?
MHC-like gene but utside of the MHC region in the genome
What does the CD1 protein share features with?
Both MHC I and MHC II
What is the structure of CD1 like?
Similar to MHC 1 and uses β2-microglobulin
How does CD1 behave?
Like MHC II for ligand binding
What do CD1 molecules have?
Hydrophobic channels that bind hydrocarbon alkyl chains
