Immunology Flashcards
What are Toll-like receptors (TLRs) and what is their function? Are they part of the innate or adaptive immune system?
They are pattern recgonition receptors that recognize pattern-associated molecular patterns (PAMPs); innate immune system
Which subdivision of the immune system is germline encoded?
innate immune system
Which cell of lymphoid origin is considered part of the innate immune system?
Natural Killer cells
Which subdivision of the immune system achieves variation through VDJ recombination during lymphocyte development?
adaptive immune system
What is the initial role of complement in the immune response?
some complement fragments coat bacteria, and others induce vasodilation
What are the three main roles of complement?
opsonization (leading to phagocytosis), vasodilation, lysis (by recruiting bacteriolytic complement proteins)
which innate immune cells possess the key effector function of phagocytosis?
neutrophils, eosinophils, macrophages
which innate immune cells possess the key effector function of degranulation?
neutrophils, basophils, mast cells, eosinophils
NK cells have enhanced specificity for what types of pathogens?
virus
What is the role of dendritic cells (DCs) in T cell activation?
DCs ingest foreign pathogens, migrate to draining lymph nodes, and activate T cells
An activated DC is also called a what?
Antigen presenting cell (APC)
What are the main role of T helper cells (Th)?
to secrete cytokines, activate B cells, and activate innate cells
What are the main effector functions of cytotixic T cells (CTL)?
secrete cytokines, kill infected cells
What is the difference in pathogen specificity between Th and CTL cells?
Th: anti-bacterial, anti-fungal, anti-parasitic, anti-viral
CTL: anti-viral
What are the main effector functions of antibodies?
neutralize (prevent infections), activate complement, activate innate cells
Which two elements of the innate immune system allow immediate binding of pathogens?
complement, and PAMPs
Which cell types carry pattern recognition receptors (PRRs)?
All WBCs
What is the immediate result of PRR-mediated pattern recognition?
release of inflammatory cytokines and chemokines
Which lymphoid organs are considered primary?
Bone marrow and thymus
Where do developing T cells migrate to mature?
the thymus
What is the main difference in antigen binding between B and T cells?
T cells can only recognize antigen presented by MHC; B cells can bind antigens in many forms
MHC class I activates which type of T cell?
CD8+ T cells (CTL)
MHC class II activates which type of T cell?
CD4+ T cells (Th)
What are the 3 Human Leukocyte Antigen (HLA) genes associated with MHC class I?
HLA-A, HLA-B, HLA-C
What types of cells present MHC class I?
All nucleated cells
Which cell types present MHC class II?
Dendritic cells (DC), B cells, and macrophages
What process occurs involving developing T cells in the thymus cortex?
Positive selection for T cell receptors (TCRs) that bind MHC (95%+ T cells destroyed at this stage)
What process occurs involving thymocytes in the thymus medulla?
Negative selection of autoreactive thymocytes
What is the immediate reaction of a macrophage to encountering a PAMP?
release cytokines
In the spleen/lymph nodes, a primary follicle contains what type of cells?
naive B cells
Where do the T cells reside in the lymph nodes?
the paracortex
Where do the T cells reside in the spleen?
the periarteriolar lymphoid sheath (PALS)
What is clonal expansion?
rapid growth of a cell type, usually as a triggered response
What is the first signal required for T cell activation by DC?
TCR + pMHC +co-receptor (CD4 or CD8) +CD3
What is the second signal required for T cell activation by DC?
costimulation (B7:CD28)
By what cytokine do Th1 cells enhance the activity of macrophages?
interferon gamma
Antigen-mediated activation of B cells induces what type of antibody response?
IgM
The germinal center (spleen/lymph nodes) forms as a result of what interaction with naive B cells?
Th cells
What cells are responsible for releasing antibodies?
plasma cells (further differentiation of activated B cells)
What type of antibodies can activate complement?
IgM, IgG
What type of antibody is responsible for activating mast cells?
IgE
Where do B cells develop and mature?
Bone marrow
Which region of the antibody determines the immunoglobulin isotype?
the constant region
