2.6 Flashcards by sophie rosen

phagocyte with ingested microbes in vesicles (3)

CD4+ effector T cells (Th1 & Th17 cells)
cytokine secretion
macrophage activation: killing of microbes
& inflammation, killing of microbes

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infected cell with microbes in cytoplasm (2)

CD8+ T cells (CTLs)

killing of infected cells

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Discovery of Cell-Mediated Immunity: immunity transferred from
one lab animal to a naïve animal only by cells (T-cells)

In vitro test of which
cells doing the killing of
microbes: T cells
transferred, but
macrophages become
activated to kill

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subset of CD4+ helper T lymphocytes: Th1
defining cytokines:
target cells:
host defense:
role in disease:

IFN
macrophages
intracellular pathogens
autoimmunity; chronic inflammation

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subset of CD4+ helper T lymphocytes: Th2
defining cytokines: (3)
target cells:
host defense:
role in disease:

Il4, Il5, IL13
eosinophils
parasites (helminths)
allergy

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subset of CD4+ helper T lymphocytes: Th17
defining cytokines: (2)
target cells:
host defense:
role in disease:

IL17, IL22
neutrophils
extracellular pathogens
autoimmunity

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general properties of T cell cytokines
property: produced transiently in response to antigen
significance:

cytokine provided only when needed

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general properties of T cell cytokines
property: usually acts on same cell that produces the cytokine or nearby cells (autocrine/paracrine)
significance:

systemic effects of cytokines usually reflect severe infections or autonomy

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general properties of T cell cytokines
property: pleiotropism: each cytokine has multiple biological actions
significance:

provides diversity of actions but may limit clinical utility of cytokines because of unwanted effects

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general properties of T cell cytokines
property: redundancy: multiple cytokines may share the same or similar biological activities
significance:

blocking any one cytokine may not achieve a desired effect

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cytokine: IL-2
principle action:
cellilar source(s):

T cell proliferation, regulatory T cell survival

early: activation of T cells

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cytokine: INF gamma
principle action:
cellilar source(s):

activation of macrophages

CD4+/CD8+ T cells, NK cells

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cytokine: IL-4
principle action:
cellilar source(s):

B cell switching to IgE

CD$+ cells; other cells

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cytokine: IK-5
principle action:
cellilar source(s):

activation of eosinophils

C4+ T ce;;s, mast cells, innate lymphoid cells

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cytokine: IL-17
principle action:
cellilar source(s):

stimulation of acute inflammation

CD$+ T cells, other cells

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cytokine: IL-22
principle action:
cellilar source(s):

maintenance of epithelial barrier fx

CD4+ T cells, NK cells, innate lymphoid cells

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cytokine: TGF beta
principle action:
cellilar source(s):

inhibition of T cell activation, differentiation of regulatory T cells

CD4+ T cells, many other cell types

th1 cells

INF gamma released

classical macrophage activaiton (enhanced microbial killing)

secretion of cytokines (TNF, IL1, IL12, chemokines)
increased expression of MHC and costimulators (B7 molecules)

macrophage response: production of reactive oxygen species, NO, increased lysosomal enzymes
role in cell mediated immunity:

killing of microbes in phagolysosomes (effect fx of macrophages)

macrophage response: secretion of cytokines (TNF, IL1, IL12, chemokines
role in cell mediated immunity:

TNF, IL1, chemokines: leukocyte recruitment (inflammation)

IL12: th1 differentiation, INF gamma production

macrophage response: increased expression of B7 costimulators, MHC molecules
role in cell mediated immunity:

increased T cell activation (amplification of T cell response)

Th1 cell development

intracellular microbes (myobacteria) 
dendritic cell: IL12
NK cell: IFN gamma 
antigen activated cell
th1 cell

th2 cells

antibody production
mast cell degranulation
intestinal mucus secretion and peristalsis
eosinophil activation
alternative macrophage activation (enhanced fibrosis/tissue repair)

Th1 cytokine IFNgamma inhibits (2)developmental

possibilities

Th2 and

Th17

Th2 cytokines IL-4 & IL13 inhibit

classical macrophage activation (M1)

classically activated macrophage (M1)

microbicidal actions: phagocytosis and killing of bacteria and fungi inflammation

alternatively activated macrophage (M2)

antiinflammatory effects, would repair, fibrosis

The sequence of events in immediate hypersensitivity.

Immediate hypersensitivity reactions are initiated by the introduction of an allergen, which stimulates TH2 reactions and immunoglobulin E (IgE) production. IgE binds to Fc receptors (FcΕRI) on mast cells, and subsequent exposure to the allergen activates the mast cells to secrete the mediators that are responsible for the pathologic reactions of immediate hypersensitivity

leishmania major response outcome

most mouse strains: Th1= recovery | BALB/c mice: Th2= disseminated infection

mycobacterium leprae response outcome

some patients: Th1= tuberculoid leprosy some patients: defective Th1 or dominant Th 2= lepromatous leprosy (high bacterial count)

th2 cell developme t

``` helminths mast cells, eosinophils IL4 antigen activated T cell Th2 cell ```

th17 cells | Major function:

Recruitment of neutrophils, | resulting in inflammation

th17 cells effects (3)

inflammation ,neutrophil response antimicrobial peptides increased barrier integrity

th17b cell developmnent

extracellular fungi, bacteria IL1, 6, 23, TGF beta antigen activated t cell th17 cell

Development and function of CD8+ cytotoxic T lymphocytes (3)

antigen recognition an`d binding of CTL to target cell CTL activation and granule exocytosis apoptosis of target cell

. Cooperation between CD4+ and CD8+ T cells in

eradication of | intracellular infections

Host counter defense to reduced MHC class I display on cell surfaces:

activation of natural | killer cells

microbe: mycobacteria mechanism:

inhibition of phagolysosome fusion | mycobacteria survive within phagosome

microbe: HSV mechanism:

inhibition of antigen presentation: HSV peptide interferes with TAP transporter (inhibition of antigen presentation)

microbe: cytomegalovirus (cmv) mechanism:

``` inhibition of antigen presentation: inhibition of proteasomal activity; removal of class 1 MHC molecules from ER (inhibition of antigen presentation ```

microbe: EBV mechanism: (2)

inhibition of antigen presentation: inhibition of proteasomal activity (inhibition of antigen presentaiton) production of IL-10 inhibition of macrophage and dendritic cell activation (inhibition of macrophage activation)

microbe: pox virus mechanism:

inhibition of effector cell activaiton: production of soluble cytokine receptors (block cytokine activation of effector cells)