ELE_IVC Cytokines

cytokines

These are considered to be soluble mediators secreted by a large variety of cells and act via interactions with specific receptors on target cells.

regulate immune cells' functions

What is the general function of a cytokine?

autoimmune diseases

These are rare diseases in which 3-5% are in occurrence but chaotic; influenced by many factors such as lifestyle, environment, gender bias, ethnic complexity, demographic origin, etc.

systemic

This type of autoimmune disease is due to the formation of immune complexes.

e.g. rheumatoid arthritis, systemic lupus erythromatosis

organ-specific

This type of autoimmune disease involves the production of antibodies against specific organs/tissues.

e.g. Type 1 DM, Hashimoto Thyroiditis

hemolytic

This type of autoimmune disease involves the production of antibodies against specific blood components.

e.g. hemolytic anemia, leukopenia, thrombocytopenia

<30 kDa

Cytokines' MW doesn't exceed?

True.

Cytokines are proteins or glycoproteins that can be polymeric or monomeric.

T or F?

high

Cytokines bind with very (low, high) affinity to specific receptors.

alteration of gene expression

Cytokines trigger specific signal transduction pathways that lead to?

autocrine

The cell secretes signaling molecules that bind to receptors on its own surface or nearby identical cells.

paracrine

The signaling molecules affect nearby cells within a localized area.

endocrine

The signaling molecules (hormones) travel through the bloodstream to distant target cells.

pleiotropic action

This action mechanism refers to a single cytokine which has multiple effects on different cell types.

redundant action

This action mechanism refers to different cytokines producing the same effect, ensuring backup mechanisms in case one pathway is impaired.

synergistic action

This action mechanism refers to two or more cytokines that work together to amplify a biological effect.

antagonistic action

This action mechanism refers to a cytokine inhibiting or counteracting the effect of another.

primary cytokines

These cytokines are early responders that activate signaling pathways, particularly NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells), which is crucial for inflammation and immune regulation.

secondary cytokines

These cytokines are not produced immediately but are induced after a cell is stimulated by primary cytokines (like IL-1 and TNF).

cytokine receptors

These are multiple polypeptide chain subunits associated with cytoplasmic kinase that is activated upon ligand binding; has cytokine-binding subunit(s) and signal-transducing subunit(s).

False. Many cytokine receptors share common signal-transducing pathways.

Cytokine receptors are very specific and selective regarding the pathways they lead to.

T or F?

NF-kB and JAK-STAT pathway

2 main signal transduction pathways mediated by cytokine receptors:

NF-kB pathway

This pathway is primarily activated by pro-inflammatory signals (e.g., TNF-α, IL-1) and stress, leading to the degradation of IκB, which allows NF-κB to enter the nucleus and promote inflammation, immunity, and cell survival.

Drives inflammation.

JAK-STAT pathway

This pathway is triggered by cytokines (e.g., IL-6, IFN-γ), where JAK phosphorylates STAT proteins, enabling them to dimerize and enter the nucleus to regulate immune responses and cell differentiation.

Fine tunes immune functions based on cytokine signaling.

True.

The expression of cytokine receptors can be limited or upregulated on antigen-activated cells.

T or F?

APCs and T cells

The secretion of cytokines is induced or upregulated by direct interaction between cells such as ___ and ___.

short and transient

The half-life of cytokines is (short, long).

T helper cells

These cells have an effector function restricted to cytokine secretion.

from Th0 (CD4+ T cell) it branches out to:

Th1 (cell-mediated immunity) and Th2 (humoral immunity)

T helper cells have 2 subsets based on the pattern of cytokine secreted and immune responses promoted which are:

IFN-gamma and IL-4

Which cytokines fall under Th0 (2)?

IL-2, IFN-gamma, LT-alpha

Which cytokines fall under Th1 (3)?

1. IL-4

2. IL-5

3. IL-6

4. IL-9

5. IL-10

6. IL-13

Which cytokines fall under Th2 (6)?

IL-5 & TGF-beta

These 2 cytokines induces class switch to IgA.

IL-4

This cytokine upregulates MHC II expression and induces switch to IgE with IL-5.

IL-10

This cytokine downregulates MHC II expression.

IL-2 & IL-12

These 2 cytokines synergistically induce differentiation into CTL.

IFN alpha/beta

These 2 cytokines inhibit viral replication.

IFN gamma

This cytokine upregulates immunoregulatory processes like switching to certain IgG subclasses and mononuclear phagocytosis.

iL-18

This cytokine induces INF-gamma.

allergy

This condition corresponds to excessive responses in atopic individuals.

Th2 over Th1

In allergies, the presentation of a low dose of antigen favors the activation of ______ over ______ cells.

desensitization

This allergy treatment approach involves shifting Th2 (IgE) to Th2 (IgG) by injecting the individual with escalating doses of allergen + adjuvant.

cytokine therapy

This allergy treatment approach involves reducing IgE responses through IFN-gamma, IL-12, TGF-beta, and IL-4R.

inhibition of eosinophil recruitment

This allergy treatment approach involves inhibition of eotacin receptor CCR-3 on Th2 cells.

bacterial septic shock

This cytokine-related disease involves bacterial cell wall endotoxins stimulating MO to overproduce IL-1 and TNF-alpha.

TNF and IL-1

Bacterial toxic shock is induced by high levels of (2):

IL-6

In lymphoid and myeloid cancers, levels of this cytokine are secreted by cardiac myxoma cells, myeloma and plasma-cytoma cells, and cervical & bladder cancer cells.

Chaga's disease

This cytokine-related disease is characterized by reduced expression of the alpha subunit of the IL-2 receptor.

Tru.

Autoimmune diseases are characterized by the immune system failing to distinguish self from foreign.

autoantibodies and sensitized Tc cells

in autoimmune diseases, there is a production of _________ and __________ that destroy body tissues.

True.

Most instances of autoimmune diseases occur with multiple mechanisms which makes treatment difficult.

T or F?

estrogen = triggers autoimmunity; testosterone = protect against it

in general, this hormone can trigger autoimmunity while this other hormone can protect against it.

females because:

1. they produce a higher titer of ABs which lead to more vigorous immune responses

2. slightly higher cortisol secretion

3. higher levels of CD4+ T cells and serum IgM

Which sex is more prone to autoimmune diseases?

prolactin

Estrogen stimulates the secretion of this molecule to help regulate the immune response.

CRH (corticotropin-releasing hormone)

Estrogen stimulates the gene for ______ that promotes cortisol secretion.

inflammation

Estrogen causes more Th!-dominated immune responses thereby promoting ____________-.

Th2

During pregnancy, females mount more of a __-like response; the change in hormone creates an anti-inflammatory environment due to high cortisol levels.

Th2-like

Diseases enhanced by __-like responses are exaggerated and inflammatory responses are suppressed.

microchimerism

This phenomenon occurs when fetal cells persist in the mother's blood or the mother's cells may appear in the fetus.

unknown

What is the cause of rheumatoid arthritis?

rheumatoid factor (Rf)

This refers to autoantibodies (mostly IgM, but also IgG and IgA) that target the Fc region of IgG antibodies.

Grave's disease

A person with this disease makes autoantibodies to the receptor for TSH; the binding of these autoantibodies to the receptor mimics the normal action of TSH, without the regulation, leading to the overstimulation of the thyroid.

thyroid-stimulating hormones (TSH)

The production of thyroid hormones is regulated by?

adenylate cyclase

The binding of TSH to a receptor on thyroid cells activates this enzyme.

thyroxine and triiodothyronine

The binding of TSH to a receptor on thyroid cells stimulates the synthesis of 2 thyroid hormones namely:

long-acting TSH

The autoantibodies in Grave's disease are called:

propanolol

Beta blockers such as ________ are often used to treat symptoms of rapid heart rate, sweating, and anxiety until the hyperthyroidism is controlled.

vitamin B12

Pernicious anemia is characterized by a deficiency in what B vitamin?

intrinsic factor

Pernicious anemia is caused by the switching of autoantibodies to?

hemolytic anemia

This type of anemia results from monoclonal antibodies to normal RBC constituents; antibodies coat the RBCs causing clumping, lysis, and premature clearance by the spleen.

True.

Hemolytic anemia can be induced by parasites, drugs, or toxins that adhere to the RBC.

T or F?

False. Symptoms only appear when the immune system collapses.

Acquired Immune Deficiency Syndrome (AIDS)'s symptoms can appear prematurely.

T or F?

CD4 receptor

HIV-coated glycoprotein complex attached to ___ receptor which allows its entry to the cell and uses reverse transcriptase to produce DNA from its viral RNA.

provirus

The DNA copy of AIDS called a ______ directs the host cell to make viral RNA and proteins, enabling the virus to reproduce.

fusion inhibitors

This antiviral drug used to treat AIDS blocks HIV's entry into the cell.

integrase inhibitors

This antiviral drug used to treat AIDS blocks viral RNA integration into the host's DNA.

reverse transcriptase and protease inhibitors

This antiviral drug used to treat AIDS inhibits viral replication enzymes.