Basic Concepts in Immunity

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What is immunology?

The study of immune responses - of the cellular and molecular events that occur after an organism encounters microbes and other foreign macromolecules.

What is the historical origin of the term 'immunity'?

Derived from the Latin word immunitas, which originally meant protection from legal prosecution offered to Roman senators during their tenures in office.

What is the immune system?

The cells and molecules responsible for immunity, collectively constituting the immune system.

What is the immune response?

The collective and coordinated response of the immune system to the introduction of foreign substances. Signup and view all the answers

What is the physiological function of the immune system?

Defense against infectious microbes. Signup and view all the answers

What is the most effective means of controlling infectious diseases?

Vaccination Signup and view all the answers

Give an example of an autoimmune disease induced by dysregulated immune systems.

Rheumatoid arthritis Signup and view all the answers

What type of immunity is mediated by the early reactions of innate immunity and the later responses of adaptive immunity?

Protective immunity Signup and view all the answers

What type of immunity is specific for different microbial and nonmicrobial antigens?

Adaptive immunity Signup and view all the answers

How is adaptive immunity enhanced?

By repeated exposures to antigen (immunologic memory) Signup and view all the answers

Why is understanding adaptive immune responses important?

For the control of allergies, autoimmune disease, and organ rejection Signup and view all the answers

Why are an4gen receptors considered clonally distributed in T and B cells?

Each clone of lymphocytes has a unique an4gen receptor, contributing to a diverse total repertoire. Signup and view all the answers

What is the role of B lymphocytes in humoral immunity?

B lymphocytes secrete antibodies that prevent infections and eliminate extracellular microbes. Signup and view all the answers

What are the cardinal features of adaptive immune responses?

Memory, specificity, and contraction of adaptive immune responses. Signup and view all the answers

What is the main reason why secondary immune responses are typically stronger than primary immune responses?

Memory cells accumulate and become more numerous, reacting more rapidly and vigorously to antigen challenge. Signup and view all the answers

How do helper T lymphocytes contribute to cell-mediated immunity?

Helper T lymphocytes activate macrophages and neutrophils to kill phagocytosed microbes. Signup and view all the answers

Where do lymphocytes develop from precursors?

Lymphocytes develop from precursors in the generative lymphoid organs, like the bone marrow and thymus. Signup and view all the answers

How does immunologic memory contribute to combating infections by prevalent microbes?

Memory enables heightened responses to recurring exposure, aiding in combating infections by prevalent microbes. Signup and view all the answers

What is the main function of cytotoxic T lymphocytes in the immune response?

Cytotoxic T lymphocytes directly destroy infected cells. Signup and view all the answers

Explain why memory responses to the same antigen are usually more rapid and greater in magnitude.

Memory cells react more rapidly and vigorously than naive lymphocytes. Signup and view all the answers

What is the significance of an4gens X and Y inducing the production of different antibodies?

It demonstrates specificity in the immune response, showing that different antigens lead to the production of distinct antibodies. Signup and view all the answers

What defines the two types of adaptive immunity mentioned in the text?

Humoral immunity and cell-mediated immunity are induced by different types of lymphocytes. Signup and view all the answers

Where do B lymphocytes and T lymphocytes originate and mature?

B lymphocytes originate and mature in the bone marrow, while T lymphocytes originate in the bone marrow and mature in the thymus. Signup and view all the answers

What are the two major subsets of lymphocytes and how do they differ?

B cells and T cells; they differ in their antigen receptors and functions. Signup and view all the answers

Describe the process by which the adaptive immune response is initiated.

It is initiated by the recognition of foreign antigens by specific lymphocytes. Signup and view all the answers

What is the role of specialized APCs in the adaptive immune response?

Specialized APCs capture microbial antigens and display them for recognition by lymphocytes. Signup and view all the answers

Explain the function of effector cells in the adaptive immune response.

Effector cells work to eliminate the antigen. Signup and view all the answers

How does memory cell function differ from that of effector cells in the immune response?

Memory cells show enhanced responses on subsequent encounters with the antigen, while effector cells work to eliminate the antigen. Signup and view all the answers

What is the mechanism of defense against extracellular microbes in the immune system?

Humoral immunity, mediated by antibodies secreted by B lymphocytes. Signup and view all the answers