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FIRST AID IMMUNOLOGY > Cellular Components > Flashcards

Flashcards in Cellular Components Deck (43):
1

Innate immunity COMPONENTS

Neutrophils, macrophages, monocytes, dendritic cells, natural killer (NK) cells (lymphoid origin), complement, physical epithelial barriers, secreted enzymes

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Innate immunity MECHANISM

Germline encoded

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Innate immunity RESISTANCE

Resistance persists through generations; does not change within an organism’s lifetime

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Innate immunity RESPONSE TO PATHOGENS

Nonspecific
Occurs rapidly (minutes to hours)
No memory response

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Innate immunity SECRETED PROTEINS

Lysozyme, complement, C-reactive protein (CRP), defensins

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Innate immunity KEY FEATURES IN PATHOGEN RECOGNITION

Toll-like receptors (TLRs): pattern recognition receptors that recognize pathogen-associated molecular patterns (PAMPs) and lead to activation of NF-κB. Examples of PAMPs include LPS (gram ⊝ bacteria), flagellin (bacteria), nucleic acids (viruses).

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Adaptive immunity COMPONENTS

T cells, B cells, circulating antibodies

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Adaptive immunity MECHANISM

Variation through V(D)J recombination during lymphocyte development

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Adaptive immunity RESISTANCE

Microbial resistance not heritable

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Adaptive immunity RESPONSE TO PATHOGENS

Highly specific, refined over time

Develops over long periods; memory response is faster and more robust

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Adaptive immunity SECRETED PROTEINS

Immunoglobulins

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Adaptive immunity KEY FEATURES IN PATHOGEN RECOGNITION

Memory cells: activated B and T cells; subsequent exposure to a previously encountered antigen p stronger, quicker immune response

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MHC I LOCI

HLA-A, HLA-B, HLA-C

(MHC I loci have 1 letter)

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MHC I BINDING

TCR and CD8

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MHC I STRUCTURE

1 long chain, 1 short chain

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MHC I EXPRESSION

All nucleated cells, APCs, platelets

Not on RBCs

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MHC I FUNCTION

Present endogenously synthesized antigens (eg, viral or cytosolic proteins) to CD8+ cytotoxic T cells

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MHC I ANTIGEN LOADING

Antigen peptides loaded onto MHC I in RER after delivery via TAP (transporter associated with antigen processing)

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MHC I ASSOCIATED PROTEINS

β2-microglobulin

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MHC II LOCI

HLA-DP, HLA-DQ, HLA-DR

(MHC II loci have 2 letters)

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MHC II BINDING

TCR and CD4

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MHC II STRUCTURE

2 equal-length chains (2 α, 2 β)

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MHC II EXPRESSION

APCs

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MHC II FUNCTION

Present exogenously synthesized antigens (eg, bacterial proteins) to CD4+ helper T cells

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MHC II ANTIGEN LOADING

Antigen loaded following release of invariant chain in an acidified endosome

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MHC II ASSOCIATED PROTEINS

Invariant chain

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A3 Disease

Hemochromatosis

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B8 Disease

ADDISON disease,
MYasthenia gravis,
GRAVEs disease

(don’t Be late(8), dr. ADDISON, or else you’ll send MY patient to the GRAVE)

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B27 Disease

Psoriatic arthritis,
Ankylosing spondylitis,
IBD-associated arthritis,
Reactive arthritis

(PAIR. Also known as seronegative arthropathies)

30

DQ2/DQ8 Disease

Celiac disease

(I ate (8) too (2) much gluten at Dairy Queen)

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DR2 Disease

MULTIPLE sclerosis,
HAY fever,
SLE,
goodPASTURE syndrome

(MULTIPLE HAY PASTURES have DiRt)

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DR3 Disease

diabetes mellitus type 1,
SLE,
graves disease,
hashimoto thyroiditis,
addison disease

(2-3, S-L-E)

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DR4 Disease

RHEUMatoid arthritis,
diabetes mellitus type 1,
addison disease

(There are 4 walls in a “rheum” (room).)

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DR5 Disease

Hashimoto thyroiditis

(Hashimoto is an odd doctor (DR3, DR5).)

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Natural killer cells

Use perforin and granzymes to induce apoptosis of virally infected cells and tumor cells

enhanced by IL-2, IL-12, IFN-α, and IFN-β

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B cells Major functions

Humoral immunity

Recognize antigen: undergo somatic hypermutation to optimize antigen specificity.

Produce antibody: differentiate into plasma cells to secrete specific immunoglobulins.

Maintain immunologic memory: memory B cells persist and accelerate future response to antigen

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T cells Major functions

Cell-mediated immunity.

CD4+ T cells help B cells make antibodies and produce cytokines to recruit phagocytes and activate other leukocytes.

CD8+ T cells directly kill virus-infected cells.

Delayed cell-mediated hypersensitivity (type IV).

Acute and chronic cellular organ rejection

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Positive selection

Thymic cortex. T cells expressing TCRs capable of binding self-MHC on cortical epithelial cells survive.

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Negative selection

Thymic medulla. T cells expressing TCRs with high affinity for self antigens undergo apoptosis or become regulatory T cells. Tissue-restricted self-antigens are expressed in the thymus due to the action of autoimmune regulator (AIRE); deficiency leads to autoimmune polyendocrine syndrome-1

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Macrophage lymphocyte interaction

Th1 cells secrete IFN-γ, which enhances the ability of monocytes and macrophages to kill microbes they ingest. This function is also enhanced by interaction of T cell CD40L with CD40 on macrophages

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Cytotoxic T cells

Kill virus-infected, neoplastic, and donor graft cells by inducing apoptosis.

Release cytotoxic granules containing preformed proteins (eg, perforin, granzyme B).

Cytotoxic T cells have CD8, which binds to MHC I on virus-infected cells.

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Regulatory T cells

Help maintain specific immune tolerance by suppressing CD4 and CD8 T-cell effector functions.

Identified by expression of CD3, CD4, CD25, and FOXP3.

Activated regulatory T cells (Tregs) produce anti-inflammatory cytokines (eg, IL-10, TGF-β).

43

IPEX (Immune dysregulation, Polyendocrinopathy, Enteropathy, X-linked) syndrome

genetic deficiency of FOXP3 p autoimmunity. Characterized by enteropathy, endocrinopathy, nail dystrophy, dermatitis, and/or other autoimmune dermatologic conditions. Associated with diabetes in male infants