Chapter 5_T cell mediated immunity

What is the primary function of T-cells in cellular immunity?

• • Produce antibodies

• • Recognize antigens and initiate immune responses

• • Phagocytosis of pathogens

• • Transport oxygen

Answer explanation

T-cells play a crucial role in cellular immunity by recognizing antigens and initiating immune responses.

Where do naïve T-cells develops from hematopoietic stem cells. Where are hematopoetic stem cells derived from?

• • Liver

• • Spleen

• • Bone marrow

• • Lungs

Answer explanation

Hematopoietic stem cells originate from the bone marrow.

What is the purpose of CD4 and CD8 receptors on naïve T-cells?

• • Bind to antigens

• • Activate macrophages

• • Indicate specific antigens

• • Regulate immune responses

Answer explanation

CD4 and CD8 receptors on naïve T-cells regulate immune responses by interacting with MHC molecules on antigen-presenting cells.

What is the role of IL-2 in T-cell activation?

• • Induces apoptosis

• • Inhibits cell proliferation

• • Stimulates survival and proliferation of T-cells

• • Enhances phagocytosis

Answer explanation

IL-2 stimulates the survival and proliferation of T-cells, aiding in the immune response.

Which adhesion molecule stabilizes the binding of T-cells to APCs?

• CD3

• ICAM-1

• LFA-1

• CD28

What triggers the exit of naïve T-cells from lymph nodes to circulation?

• • Antigen recognition

• • IL-2 secretion

• • S1P gradient

• • CD69 expression

What happens to activated T-cells that don't recognize specific antigens in lymph nodes?

• • They undergo apoptosis

• • They remain in lymph nodes

• • They migrate to peripheral tissues

• • They return to circulation

Which molecule is essential for the activation of T-cells by cross-presentation of cytosolic antigens?

• CD4

• CD8

• CD40L

• CD25

Answer explanation

CD8+ T-cells recognize class I MHC-associated peptides and are essential for cross-presentation of cytosolic antigens.

What are the subsets of memory T-cells?

• • Afferent and efferent memory cells

• • Central memory cells and effector memory cells

• • Primary and secondary memory cells

• • IgM and IgG memory cells

Answer explanation

Memory T-cells have subsets including central memory cells (present in lymphoid organs) and effector memory cells (localized in mucosal and peripheral tissues).

Which chemokine is responsible for the migration of naïve T-cells to lymph nodes?

• • CCL19

• • CXCL10

• • CCL5

• • CXCL12

Answer explanation

Naïve T-cells express CCR7, which binds to CCL19 in high endothelial venules of lymph nodes, facilitating their entry.