Anatomy II: Chapter 21 pt 4

What is another name for the cell-mediated immune response?

Cellular immunity

Which type of antigen requires a cell-mediated immune response?

Intracellular pathogens

Which cells are primarily involved in cell-mediated immunity?

T cells

How do T cells recognize antigens?

Displayed on antigen-presenting cells (APCs)

What is the first step in T cell activation?

Binding to an antigen on an APC

What is the purpose of co-stimulation in T cell activation?

Prevents T cells from attacking normal body cells

Which molecules influence T cell activation and differentiation?

Cytokines

What are cytokines?

Chemical messengers that influence immune responses

What happens to most activated T cells after an immune response?

They undergo apoptosis

What is the benefit of T cell apoptosis?

Prevents excessive immune responses

What are the two major types of T cells?

CD4 and CD8 T cells

What is the function of CD8 (cytotoxic) T cells?

Directly destroy infected or abnormal cells

What is the function of CD4 (helper) T cells?

Help activate B and T cells

What type of T cell is essential for regulating the immune response?

Regulatory T cells

What would happen if there were no helper T cells?

The immune response would be severely weakened

Helper T cells interact with antigen-presenting cells using:

MHC class II molecules

What molecule is released by helper T cells to stimulate the immune response?

Interleukin-2

How do cytotoxic T cells kill infected cells?

They release perforin and granzymes

What do perforin molecules do?

Form pores in the target cell membrane

Which immune cell directly destroys cancer cells?

Cytotoxic T cells

What is the role of memory T cells?

Provide long-term immunity

Which T cell is involved in preventing autoimmune diseases?

Regulatory T cells

What is the most common type of organ transplant?

Allograft

Why do transplant patients require immunosuppressive drugs?

To prevent the body from rejecting the transplant

Which immunodeficiency is caused by a genetic defect in B and T cells?

SCID (Severe Combined Immunodeficiency)

What is the primary cause of AIDS?

HIV attacking CD4 cells

Which type of hypersensitivity reaction is an allergy?

Type I

What chemical is released in allergic reactions?

Histamine

Anaphylactic shock is a severe allergic reaction that requires:

Epinephrine

What is an autoimmune disease?

When the immune system attacks the body’s own tissues

Which of the following is an example of an autoimmune disease?

Type 1 diabetes

What is the function of interleukins?

Activate and regulate immune responses

Which type of hypersensitivity is delayed and involves T cells?

Type IV

What is the hygiene hypothesis?

Lack of exposure to microbes increases immune disorders

Autografts

from one body site to another in the same person

Isografts

between identical twins

Allografts

between individuals who are not identical twins

Xenografts

from another animal species