Immune System: Chapter 2 Receptor-Ligand Interactions Overview

What triggers the activation of leukocytes in immune responses?

Chemokines
Antibodies
Cytokines
Ligand-receptor interactions (correct)

Which factor determines the strength of interaction between a ligand and its receptor?

Signal type received by the cell
Kind of ligands bound
Number of receptors on the cell
Shapes of receptors and ligands (correct)

In the context of the immune system, what are antigens recognized by?

Chemokines
Complement proteins
Antibodies
Immune cells (correct)

Which molecules can antigens be composed of in the immune system?

Proteins and carbohydrates (B) Signup and view all the answers

What are antigens in the immune system considered as?

Targets of the immune response (C) Signup and view all the answers

What is the primary function of preformed receptors in the immune system?

To provide a rapid response to pathogens by recognizing conserved molecular patterns (A) Signup and view all the answers

Which of the following is NOT a type of preformed receptor in the immune system?

Somatically-Generated Receptors (D) Signup and view all the answers

What is the primary function of Toll-like receptors (TLRs) in the immune response?

To detect pathogen-associated molecular patterns and trigger defensive responses (D) Signup and view all the answers

Which of the following factors is NOT known to influence the immunogenicity of an antigen?

pH of the environment (B) Signup and view all the answers

What is the primary difference between preformed receptors and somatically-generated receptors in the immune system?

Preformed receptors are part of the innate immune system, while somatically-generated receptors are part of the adaptive immune system (D) Signup and view all the answers

How do Toll-like receptors (TLRs) contribute to the immune response against pathogens?

TLRs bind to pathogen-associated molecular patterns and trigger defensive responses, such as cytokine release and immune cell recruitment (A) Signup and view all the answers

What is the primary function of Killer Activation Receptors (KARs) found on Natural Killer (NK) cells?

To detect alterations in host cells infected or altered by virus (B) Signup and view all the answers

What is the primary function of Killer Inhibition Receptors (KIRs) found on Natural Killer (NK) cells?

To monitor the MHC class I molecules found on nucleated cells of the body (A) Signup and view all the answers

What is the role of complement receptors on phagocytic cells and B-lymphocytes?

To bind to complement proteins that have been activated and tag target cells for destruction (D) Signup and view all the answers

What is the primary role of the complement system in the immune response?

To attract immune cells and result in cell killing of target cells (A) Signup and view all the answers

How do host cells that are stressed (by cancer or viral infection) typically respond in terms of MHC class I molecule expression?

They decrease the number of MHC class I molecules on their surface (D) Signup and view all the answers

What is the significance of complement in transfusion medicine?

Complement is particularly important in the immune response to transfused cells or products (A) Signup and view all the answers

Which of the following statements about epitopes or antigenic determinants is correct?

They are the smallest part of an antigen that reacts with immune receptors. (D) Signup and view all the answers

What is the characteristic of immunogens?

They are antigens that can induce an immune response and can react with the products of the immune response. (C) Signup and view all the answers

What happens when there is subsequent exposure to an immunogen?

It leads to a heightened secondary response by the adaptive immune system. (A) Signup and view all the answers

Which of the following statements about haptens is correct?

Haptens are small molecules that cannot induce an immune response but can react with the products of the immune response when coupled to a carrier. (D) Signup and view all the answers

What is the characteristic of tolerogens?

They are antigens that are tolerated and result in immune unresponsiveness, and exposure to them results in a diminished response. (A) Signup and view all the answers

What is the primary function of Fc receptors?

To recognize and bind to the tail of immunoglobulin molecules on the surface of phagocytic cells (D) Signup and view all the answers

What is the key difference between B cell receptors (BCRs) and T cell receptors (TCRs)?

All of the above (D) Signup and view all the answers

Which of the following is NOT considered a physical barrier to infection?

Commensal microbes (B) Signup and view all the answers

What is the primary function of the acidic pH of the skin, stomach, and vagina in terms of defense against infection?

To inhibit the growth and survival of most pathogenic microorganisms (B) Signup and view all the answers

How do commensal microbes contribute to the body's defense against infection?