Cells of the Adaptive Immune System

Question 1

Dendritic Cells

Answer 1

have long cytoplasmic projections (dendrites) that enable them to trap antigens. They increase the cell surface area, increasing the efficiency of antigen trapping. Located in lymphoid organs and under epithelial surfaces. 100x more effective than macrophages.

Question 2

Only antigen processing ells that can activate naive T cells

Answer 2

dendritic cells

Question 3

Types of Dendritic Cell

Answer 3

Plasmacytoid, classical type I, classical type II, follicular, Langherhans cells

Question 4

What do Lymphoid Organs Do?

Answer 4

1. regulate the production of lymphocytes
2. provide an environment for trapping foreign antigens, processing them
3. Maximize the opportunity for lymphocytes to encounter and interact with these foreign antigens

Question 5

Types of Lymphoid Organs

Answer 5

primary and seecondary

Question 6

Primary Lymphoid Organs

Answer 6

where lymphocytes mature and self-reactive cells are eliminated. Thymus, bursa, peyer’s patches, bone marrow

Question 7

Secondary Lymphoid Organs

Answer 7

where lymphocytes encounter and respond to antigens. Tonsils, spleen, lymph nodes, Peyer’s Patches, bone marrow

Question 8

Sources of lymphocytes

Answer 8

yolk sac- fetal liver- bone marrow

Question 9

Where do T cells mature?

Answer 9

thymus

Question 10

Where do B cells mature?

Answer 10

birds- bursa of Fabricius
primates and rodents- bone marrow
rabbits and ruminants- intestinal lymphoid tissues

Question 11

Thymus

Answer 11

source of T cells, eliminate self-reactive cells (negative selection) and stimulate the remaining T cells (positive selection)

Question 12

Negative Selection

Answer 12

thymocytes with receptors that bind self-antigens strongly and that could therefore cause autoimmunity are killed by apoptosis. Thymocytes with no receptor and thus cant react to any processed antigen are also killed

Question 13

Peyer’s Patches

Answer 13

primary lymphoid organ in some species (ruminants and pigs). secondary in all other species

Question 14

Lymph Nodes

Answer 14

filter lymphatic fluid. Major site of antigen-lymphocyte interaction. Cortex is major site of B cell responses. Paracortex inhabited by T cells. Medulla rich in antigen-processing cells, DC, and macrophages

Question 15

Germinal Centers

Answer 15

major site of B cell somatic mutation and selection. B cells dividing and mutating in dark zone. B cells responding to antigen presentation in light zone. Low-affinity B cells undergo apoptosis. High-affinity B cells continue to multiply.

Question 16

Spleen

Answer 16

filters antigens from blood
T cells form periarteriolar lymphoid sheaths. B cells form follicles containing germinal centers. Macrophages and DC are located in the marginal zone surrounding the white pulp

Question 17

Red Pulp

Answer 17

red cell storage and hematopoiesis

Question 18

White Pulp

Answer 18

lymphoid tissue

Question 19

Positive Selection

Answer 19

immature T cells are selected so that only those thymocytes with receptors can engage peptide-MHC complexes on thymic epithelium survive to become MHC-restricted T cells and weakly recognixe self-antigen

Question 20

IL-8

Answer 20

chemokine. Primary cytokine involved in the recruitment of neutrophils to the site of damage or infection through chemotaxis.

Question 21

What are the adaptive immune cells

Answer 21

B cell, plasma cell, T cell, cytotoxic T cells, helper T cells, regulatory T cells