Ch. 22 The Lymphatic System and Immunity

Martini - Fundamentals of Anatomy and Physiology 12th Edition

Martini, Nath, Bartholomew12th EditionFundamentals of Anatomy and PhysiologyISBN: 9780137854011Not the one you use?Change textbook

Martini, Nath, Bartholomew 12th Edition

Ch. 22 The Lymphatic System and Immunity

Problem 21

Chapter 22, Problem 21

How does a cytotoxic T cell destroy another cell displaying antigens bound to class I MHC proteins?

Verified step by step guidance

Understand that cytotoxic T cells recognize infected or abnormal cells by detecting antigens presented on class I MHC (Major Histocompatibility Complex) proteins on the surface of these target cells.

Recall that the T cell receptor (TCR) on the cytotoxic T cell specifically binds to the antigen-MHC class I complex, which activates the cytotoxic T cell.

Once activated, the cytotoxic T cell releases cytotoxic molecules such as perforin and granzymes toward the target cell.

Perforin forms pores in the target cell's membrane, allowing granzymes to enter the cytoplasm of the target cell.

Granzymes trigger apoptosis (programmed cell death) in the target cell, leading to its destruction without causing inflammation.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Cytotoxic T Cell Function

Cytotoxic T cells (CD8+ T cells) are immune cells that identify and kill infected or abnormal cells. They recognize antigens presented by class I MHC molecules on target cells and induce apoptosis to eliminate cells displaying foreign or abnormal peptides.

Class I MHC Antigen Presentation

Class I Major Histocompatibility Complex (MHC) proteins present endogenous peptides, including viral or abnormal proteins, on the surface of almost all nucleated cells. This presentation allows cytotoxic T cells to monitor and detect infected or transformed cells.

Mechanisms of Target Cell Killing

Upon recognition, cytotoxic T cells release perforin and granzymes that create pores and trigger apoptosis in the target cell. They can also engage death receptors like Fas to initiate programmed cell death, effectively destroying the infected or abnormal cell.

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Related Practice

Textbook Question

How does the formation of an antigen–antibody complex cause the elimination of an antigen?

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Textbook Question

Blocking the antigen receptors on the surface of lymphocytes would interfere with

(a) Phagocytosis of the antigen

(b) That lymphocyte's ability to produce antibodies

(d) The ability of the lymphocyte to present antigen

(e) Opsonization of the antigen

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Textbook Question

An anesthesia technician is advised that she should be vaccinated against hepatitis B, which is caused by a virus. She is given one injection and is told to come back for a second injection in a month and a third injection after 6 months. Why is this series of injections necessary?

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Textbook Question

Compared with innate defenses, adaptive defenses

(a) Do not distinguish between one threat and another

(b) Are always present at birth

(d) Deny the entry of pathogens to the body

Textbook Question

Compare and contrast the effects of complement with those of interferon.

Textbook Question

Give one example of each type of immunity: innate immunity, naturally acquired active immunity, artificially acquired active immunity, artificially acquired passive immunity, and naturally acquired passive immunity.

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