Flashcards in Chapter 10: Differentiation and Functions of CD4+ Effector T Cells Deck (44):
Which type of T cell recognizes antigen composed of phagocytosed extracellular microbes?
CD4+ T cells.
Which type of T cell recognizes antigen composes of microbes that reside in the cytoplasm of infected cells?
CD8+ T cells.
Do CD4+ T cells recognize or destroy microbial antigen?
Recognize. Phagocytes actually destroy the pathogen.
What type of hypersensitivity is associated with a T cell reaction causing injury?
Delayed-type hypersensitivity (DTH).
This is the term for an "excessive or damaging immune response."
Three major subsets of CD4+ effector T cells.
Th1 target cell.
Th2 target cell.
Th17 target cell.
Tfh target cell.
Th1 defining cytokine.
Th2 defining cytokines.
IL-4, IL-5, IL-13.
Th17 defining cytokines.
Tfh defining cytokines.
IL-21 (IFN-y, IL-4).
Th1 host defense.
Th2 host defense.
Th17 host defense.
Extracellular bacteria and fungi.
Tfh host defense.
What is the outcome of excessive reactions of different helper T cell subsets?
What cell type produces cytokines that drive the development of CD4+ T cell subsets?
APCs (DCs, macrophages, NK cells, mast cells).
Major effector T cell population in phagocytes-mediated host defense.
Th1 CD4+ T cells.
What 2 cytokines are responsible for Th1 development (activation of Th1 transcription factors)?
IL-22 (produced by DCs and macrophages) and IFN-y (produced by NK cells).
IFN-y and IL-12 stimulate Th1 differentiation by inducing and activating what 3 transcription factors?
Principal function of Th1 cells.
Activate macrophages to ingest and destroy microbes.
What cytokine activates macrophages to kill phagocytose microbes?
Th1 cells activate macrophages by contact-mediated signals delivered by what CD interaction?
In what 3 ways do activated macrophages kill phagocytosed microbes?
1) Actions of NO
2) Lysosomal enzymes
X-linked hyper-IgM syndrome is a mutation in what?
X-linked hyper-IgM syndrome leads to susceptibility of what organism?
Pneumocystis jiroveci (requires T cell-dependent macrophage activation to be eradicated).
Why does X-linked hyper-IgM syndrome lead to defects in helper T cell-dependent antibody production?
Because of the critical role of the CD40L-CD40 interaction in B cell activation.
Th2 development is activated by what 2 transcription factor?
Which cytokine is the signature cytokine of Th2 cells (both inducer and effector cytokine)?
What 2 cytokines contribute to an alternative form of macrophage activation that is distinct from the macrophage response of IFN-y?
IL-4 and IL-13.
What cytokine drives classically activated macrophages (M1)?
What are the 2 functions of classically activated macrophages (M1)?
1) Microbicidal actions
What 2 cytokines drive alternatively activated macrophages (M2)?
IL-4 and IL-13.
What is the function of alternatively activated macrophages (M2)?
Produce IL-10 and TGF-B for its anti-inflammatory effects (control inflammation and promote tissue repair and fibrosis).
The development of Th17 cells is dependent on what 2 transcription factors?
What is the function of Th17 cells?
Recruit leukocytes, mainly neutrophils, to sites of infection.
What are the 2 roles of IL-17?
1) Induces neutrophil-rich inflammation.
2) Stimulates the production of antimicrobial substances.
Job syndrome (hyper-IgE syndrome) is a mutation of what?
What type of infections are seen with Job syndrome (hyper-IgE syndrome)?
Increased susceptibility to cutaneous fungal and bacterial infections. Patients present with multiple bacteria and fungal abscesses of the skin, resembling the biblical accounts of the punishments visited on Job. Defective Th17 function is also associated with chronic mucocutaneous candidiasis.
Pathogenesis of what T helper cells is associated with psoriasis, inflammatory bowel disease, rheumatoid arthritis, and multiple sclerosis?