Cell Signaling and Immunology

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Questions and Answers

What is the result of IP3 triggering calcium mobilization?

The activation of nuclear factor of activated T cells (NF-AT) (correct)
The activation of protein kinase C (PKC)
The activation of the Ras-mitogen-activated protein kinase (MAPK) pathway
The activation of transcription factor AP-1

What is the function of Ras guanine nucleotide-releasing protein?

To activate the Ras-mitogen-activated protein kinase (MAPK) pathway (correct)
To activate protein kinase C (PKC)
To activate transcription factor NF κ B
To activate nuclear factor of activated T cells (NF-AT)

What is the characteristic of T-independent antigens?

They are only found in viruses
They require T-cell help for activation
They have a low density of repeating antigenic determinants
They have a high density of repeating antigenic determinants (correct)

What is the role of B cells in the immune system?

To defend against extracellular pathogens and their toxins (A) Signup and view all the answers

What is the result of the interaction of B-cell receptors with antigen?

The signal transduction events that result in the activation of transcription factors (D) Signup and view all the answers

What is the structure of the antibody molecule depicted in?

Figure 19 (B) Signup and view all the answers

What is the characteristic of antigens that do not have repeating determinants?

They require T-cell help (B) Signup and view all the answers

What is the predominant antibody in the primary immune response?

IgM (A) Signup and view all the answers

What is the function of IgA?

To block entrance of pathogens through mucous membranes (A) Signup and view all the answers

What is the result of class switching within a given B-cell clone?

Progression from synthesis of IgM to synthesis of IgE (B) Signup and view all the answers

What is the effect of immunosuppressants on the immune system?

They suppress various components of the immune system (A) Signup and view all the answers

What is the role of eicosanoids in the body?

They mediate inflammatory responses (B) Signup and view all the answers

What is the action of cyclooxygenase (COX) in the biosynthesis of eicosanoids?

It catalyzes the rate-determining step in the conversion of arachidonic acid to prostanoids (B) Signup and view all the answers

What is the effect of low-dose aspirin on COX-1?

It irreversibly inhibits COX-1 (D) Signup and view all the answers

What is the characteristic of coxibs?

They selectively and reversibly inhibit COX-2 (A) Signup and view all the answers

What is the function of IgE?

It acts as a mediator of allergy and parasitic immunity (A) Signup and view all the answers

What is the primary function of prostanoids in the body?

To mediate pain, fever, and inflammation (C) Signup and view all the answers

What is the main difference between COX-1 and COX-2?

COX-1 is constitutively expressed, while COX-2 is induced during inflammation (C) Signup and view all the answers

What is the therapeutic effect of NSAIDs?

Reducing inflammation, fever, pain, and platelet aggregation (D) Signup and view all the answers

What is the advantage of COX-2 selective drugs over non-selective NSAIDs?

They have a lower incidence of GI side effects (C) Signup and view all the answers

What is the mechanism of action of glucocorticoids?

Binding to cytoplasmic receptors and changing gene transcription (B) Signup and view all the answers

What is the primary effect of lipoxygenase pathway activation?

Production of leukotrienes (D) Signup and view all the answers

What is the primary clinical relevance of the lipoxygenase pathway?

In the pathophysiology of asthma (C) Signup and view all the answers

What is the therapeutic effect of COX-2 selective inhibitors?

Producing an anti-inflammatory effect with a lower incidence of GI side effects (C) Signup and view all the answers

What is the risk associated with the use of COX-2 selective inhibitors?

Increased risk of thrombosis, myocardial infarction, and stroke (B) Signup and view all the answers

What is the function of EETs in the body?

Unknown (B) Signup and view all the answers

What is the function of EETs in the cardiovascular system and kidney?

Vasodilation (C) Signup and view all the answers

What is the primary function of the immune system?

To recognize and defend against pathogens (C) Signup and view all the answers

What is the role of phagocytes in the immune response?

To surround and absorb pathogens (C) Signup and view all the answers

What is the function of lymphocytes in the immune response?

To recognize and remember pathogens (C) Signup and view all the answers

What is the role of B lymphocytes in the immune response?

To produce antibodies (B) Signup and view all the answers

What is the role of T lymphocytes in the immune response?

To destroy compromised cells (A) Signup and view all the answers

What is the function of immunoglobulin G (IgG)?

To mark microbes for recognition (D) Signup and view all the answers

What is the function of immunoglobulin M (IgM)?

To kill bacteria (A) Signup and view all the answers

What is the term for the ability of the immune system to distinguish between self and non-self?

Self-tolerance (A) Signup and view all the answers

What is the term for any substance that can spark an immune response?

Antigen (B) Signup and view all the answers

Which immune cells are responsible for initiating immune responses?

Dendritic cells (A) Signup and view all the answers

What is the role of eicosanoids in the immune response?

They connect innate and adaptive immunity by acting on cells of both systems (D) Signup and view all the answers

What is the effect of increased secretion of inflammatory endogenous mediators on dendritic cells?

It activates them (C) Signup and view all the answers

What is the role of PGE2 in the immune response?

It is a prostanoid that has a great impact on inflammatory and immune responses (B) Signup and view all the answers

What is the effect of eicosanoids on cells of the immune system?

They modulate cytokine release, cell differentiation, survival, migration, antigen presentation, and apoptosis (B) Signup and view all the answers

What is the role of dendritic cells in the immune response?

They control the responses of several types of lymphocytes and play a central role in the transition between innate and adaptive immunity (D) Signup and view all the answers

What is the primary function of IgA in the body?

To protect gateways into the body (B) Signup and view all the answers

What is the main difference between innate and adaptive immunity?

Innate immunity is general, while adaptive immunity is specific (B) Signup and view all the answers

What is the function of Killer T cells in the immune system?

To attack infected cells (D) Signup and view all the answers

What is the characteristic of specific immune response?

It is specific and long-lived (B) Signup and view all the answers

What is the difference between primary and secondary immune responses?

Primary immune response is slower, while secondary immune response is faster (A) Signup and view all the answers

What is the role of pattern recognition receptors in the innate immune response?

To phagocytose microorganisms and induce an innate inflammatory response (C) Signup and view all the answers

What is the function of Helper T cells in the immune system?

To coordinate the immune response (C) Signup and view all the answers

What is passive immunity?

A type of immunity that is borrowed from another source (C) Signup and view all the answers

What is the characteristic of the secondary immune response?

It is faster and stronger than the primary immune response (D) Signup and view all the answers

What is the main function of antibodies in the immune system?

To mark antigens for destruction (D) Signup and view all the answers

Study Notes

Immune Response

The immune system is essential for our survival, defending us against bacteria, viruses, parasites, and more.
It is a complex network of cells, organs, proteins, and tissues that can distinguish self from non-self.

Types of Leukocytes

Phagocytes: surround and absorb pathogens, breaking them down.
- Neutrophils: attack bacteria.
- Monocytes: largest type, with multiple roles.
- Macrophages: patrol for pathogens, remove dead and dying cells.
- Mast cells: help heal wounds, defend against pathogens.
Lymphocytes: help the body remember previous invaders and recognize them if they come back.
- B lymphocytes (B cells): produce antibodies, alert T lymphocytes.
- T lymphocytes (T cells): destroy compromised cells, alert other leukocytes.

Antigen and Antibody Response

An antigen is any substance that can spark an immune response.
B cells recognize the antigen, secrete antibodies (antigen is short for “antibody generators”).
Antibodies are special proteins that lock onto specific antigens.
Types of antibodies:
- Immunoglobulin G (IgG): marks microbes for other cells to recognize and deal with.
- IgM: kills bacteria.
- IgA: congregates in fluids, protecting gateways into the body.
- IgE: protects against parasites, responsible for allergies.
- IgD: stays bound to B cells, helping them to start the immune response.

T Lymphocytes

Helper T cells (Th cells): coordinate the immune response.
Killer T cells (cytotoxic T lymphocytes): attack and destroy infected cells.

Types of Immunity

Innate immunity: born with it, general protection.
Adaptive immunity: develops throughout life, specific to diseases.
Passive immunity: borrowed from another source, short-term.

Eicosanoids

Signaling molecules derived from arachidonic acid.
Play a role in mediating inflammatory responses.
Include prostaglandins, leukotrienes, and thromboxanes.

Cyclooxygenase (COX) Pathway

COX is an enzyme that converts arachidonic acid to prostanoids.
Two isozymes: COX-1 and COX-2.
COX-1: constitutively expressed in most cells and tissues.
COX-2: upregulated during inflammation.

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs)

Inhibit COX, reducing prostaglandin synthesis.
Examples: aspirin, ibuprofen, naproxen.
Therapeutic effects: reduce inflammation, fever, pain, and platelet aggregation.
Side effects: affect GI tract, kidney, and cardiovascular system.

COX-2 Selective Inhibitors (Coxibs)

Selectively inhibit COX-2.
Examples: celecoxib (Celebrex).
Lower incidence of GI side effects compared to non-selective NSAIDs.
Associated with increased risk of thrombosis, myocardial infarction, and stroke.

Glucocorticoids

Effects result from changes in gene expression.
Therapeutic responses require several hours to develop.
Metabolic effects: hyperglycemia, changes in fat deposition.
Anti-inflammatory effects: mediated by transcriptional inhibition.

Lipoxygenase/Leukotriene Pathway

Activated in leukocytes, resulting in the conversion of arachidonic acid to leukotrienes.
Leukotrienes: inflammatory mediators, resulting in bronchoconstriction, increased secretion of mucus, leukocyte chemotaxis, and histamine release.

Epoxyeicosatrienoic Acids (EETs)

Produced by cytochrome P450 epoxygenase.
Act as short-range hormones in the cardiovascular system and kidney.
Produce vasodilation by activating Ca-activated K channels.

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Description

Test your knowledge on cell signaling pathways and immunology concepts, including IP3, NF-AT, PKC, NF κ B, Ras, MAPK, and AP-1. Learn about the structure of antibody molecules and B-cell receptors.