Definitions 5 Flashcards
What is a dendritic cell?
A special type of cell found in tissues that boosts the immune response by showing antigens on its surface to other cells of the immune system.
What is a follicular dendritic cell?
Specialized type of antigen-presenting dendritic cells that are largely restricted to lymphoid follicles.
What is a naive T cell?
Know what antigen they’re looking for but haven’t encountered it yet (don’t know what to do with it when they find it)
- Have to be activated in lymph node
- Blood > HEV > 2nd lymphoid tissues > efferent lymphatics > blood
What is a memory T cell?
A class of T cells that persists after having previously responded to antigenic stimulation
What is a T Helper 1 cell?
Respond to intracellular pathogens such as mycobacterium bovis, brucella, leishmania, toxoplasma and viruses.
- Driven by CD4+ T cells (and CD8+ T cells), T FH cells, and B cells
- CD4+ cells produce: IL-2, TNF-alpha and INF-gamma
- Induced by production of IL-12 from DC - Activate macrophages to kill intravesicular pathogens
- Secretion of IL-3 and GM-CSF
What is a T Helper 2 cell?
Respond to parasitic helminths
- multicellular, macro pathogens - roundworms and flatworms
- Allergic responses
- Cell types: CD4+ T cells, B cells, eosinophils, macrophages, mast cells
What is a T Helper 17 cell?
Aid in maintaining homeostatic conditions
- maintain gut-microbiome balance
- Associated with response to extracellular bacteria and fungi
- Mediated by CD4 (Th17) cells and neutrophils
- Produce IL-17 A/F and IL-22
What is a T Follicular Helper cell?
- Will develop under multiple T helper environments
- supports antibody production - Driven by IL-6 and IL-21
- Produce IL-21
- Found within germinal centers
- Enhance B cell responses, isotype class switch
What is a T regulatory cell?
Suppress responses and prevent autoimmunity
- Natural T reg
- generated in the thymus
- Inducible T reg
- generated in the periphery
- Produce immunomodulatory cytokines
Suppressive mechanisms (target T cells, B cells, and DC)
- inhibit their function via: inhibitory receptors, cytokine production, depriving survival signals, direct killing
What is an NK cell?
Natural Killer cell
- effector lymphocyte of the innate immune system
- control several types of tumors and microbial infections by limiting their spread and subsequent tissue
damage
What is interferon gamma?
It is the major activator of macrophages through superoxide and nitric oxide production
Augments antigen presentation through both MHC I and MHC II pathways increasing the immunogenicity of tumor cells and enhancing their detection and killing by immune surveillance and effector mechanisms
What is IL4?
Anti-inflammatory cytokine that functions by suppressing the pro-inflammatory milieu
What is IL12?
An immune cell stimulator that promotes differentiation and proliferation of T cells and enhances the production of interferon gamma
What is apoptosis?
Programmed cell death (not inflammatory)
What is necrosis?
Non-programmed cell death (inflammatory)
