Major Histocompatibility Complex (MHC) Overview

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Questions and Answers

Which type of MHC molecule is found on all nucleated cells in the body?

MHC Class II

Neither MHC Class I nor II

Both MHC Class I and II

MHC Class I (correct)

MHC Class II molecules display peptides from inside the cell.

False

What type of T-cell is activated by antigens presented on MHC Class I molecules?

Cytotoxic T-cells

Helper T-cells are activated by antigens presented on MHC Class ___ molecules.

II Signup and view all the answers

Which of the following is NOT a professional antigen-presenting cell?

Cytotoxic T-Cells Signup and view all the answers

What is the primary function of dendritic cells?

Present antigens to naive T-cells in lymph nodes Signup and view all the answers

B cells, once activated, produce cytokines.

False Signup and view all the answers

Match the following cell types with their primary function:

Cytotoxic T-cells = Destroy infected or abnormal cells Helper T-cells = Coordinate the immune response by activating other immune cells Macrophages = Engulf and digest pathogens and present antigens Dendritic Cells = Present antigens to naive T-cells Signup and view all the answers

What is the primary function of Helper T-cells?

Stimulate B-cells to produce antibodies Signup and view all the answers

Cytotoxic T-cells primarily function by releasing cytokines.

False Signup and view all the answers

What role do Regulatory T-cells (Tregs) play in the immune system?

Suppress overactive immune responses Signup and view all the answers

Natural Killer (NK) Cells do not rely on MHC for __________.

activation Signup and view all the answers

Which of the following are key functions of cytokines?

Stimulate growth and activation of immune cells Signup and view all the answers

Match the following immune cell types with their functions:

Helper T-cells = Stimulate B-cells Cytotoxic T-cells (CD8+) = Kill infected or cancerous cells Natural Killer (NK) Cells = Target cells with downregulated MHC Class I Regulatory T-cells (Tregs) = Suppress overactive immune responses Signup and view all the answers

What is the function of the complement system in the immune response?

Tag pathogens for destruction and enhance inflammation Signup and view all the answers

The main role of Interferons is to stimulate immune cell growth.

False Signup and view all the answers

Study Notes

Major Histocompatibility Complex (MHC)

MHC molecules act like cellular billboards, displaying protein fragments (antigens) to immune cells.
Two main types of MHC molecules: Class I and Class II.

MHC Class I

Found on all nucleated cells.
Purpose: Displays protein fragments from inside the cell (e.g., from viruses if infected).
Function: If a cell is infected or cancerous, it displays abnormal proteins. This alerts cytotoxic T-cells (CD8+ T-cells) to destroy the infected or abnormal cell.
Analogy: Like a security guard checking IDs; suspicious IDs (foreign proteins) trigger removal of the threat.

MHC Class II

Found only on professional antigen-presenting cells (APCs) like macrophages, dendritic cells, and B-cells.
Purpose: Displays protein fragments from pathogens engulfed and digested by the APC.
Function: MHC Class II presents these peptides to helper T-cells (CD4+ T-cells). Helper T-cells coordinate the immune response by activating other immune cells (e.g., B-cells to produce antibodies or cytotoxic T-cells to kill infected cells).
Analogy: Like a teacher sharing information with students so they can respond effectively.

Cellular Defense Mechanisms

Antigen-Presenting Cells (APCs) are crucial in initiating immune responses.
Dendritic cells, macrophages, and B-cells are key APCs, each presenting antigens in varying ways.

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Description

This quiz covers the essential concepts of the Major Histocompatibility Complex (MHC), including its two main classes, Class I and Class II. Learn how MHC molecules function to present antigens to immune cells and their critical role in the immune response. Delve into the specific roles of cytotoxic T-cells and helper T-cells in recognizing and responding to infections.