L5

Question 1

Clonal deletion

Answer 1

Process where self-reactive immature B cells in the bone marrow undergo apoptosis

Question 2

Receptor editing

Answer 2

Rearrangement of light chain genes in B cells to avoid self-reactivity

Question 3

Hematopoietic Stem Cells (HSCs)

Answer 3

Multipotent stem cells in bone marrow capable of self-renewal and giving rise to all blood cell types

Question 4

Common Lymphoid Progenitors (CLPs)

Answer 4

Progenitor cells derived from HSCs that give rise to B cells, T cells, and NK cells

Question 5

Follicular dendritic cells (FDCs)

Answer 5

Retain antigens on their surface in germinal centers to select B cells with high-affinity receptors

Question 6

V(D)J recombination

Answer 6

Process during B-cell development combining variable, diversity, and joining segments to generate diversity

Question 7

Junctional diversity

Answer 7

Addition or deletion of nucleotides at V-D-J junctions, increasing antibody variability

Question 8

Somatic hypermutation (SHM)

Answer 8

Mutations introduced in antibody variable regions after B-cell activation to improve antigen affinity

Question 9

Class-switch recombination (CSR)

Answer 9

Process allowing B cells to change antibody isotype while maintaining antigen specificity

Question 10

Activation-induced cytidine deaminase (AID)

Answer 10

Enzyme crucial for somatic hypermutation and class-switch recombination

Question 11

IFN-_

Answer 11

Cytokine promoting IgG production and Th1 responses

Question 12

IL-4

Answer 12

Cytokine inducing IgE class switching

Question 13

TGF-_

Answer 13

Cytokine promoting IgA class switching and immune tolerance

Question 14

Hyper IgM syndrome

Answer 14

Condition caused by defects in CD40 or CD40L, impairing isotype switching and leading to high IgM levels

Question 15

Naive B cells

Answer 15

Mature B cells that have not yet encountered their specific antigen

Question 16

Plasma cells

Answer 16

Differentiated B cells that produce large quantities of antibodies

Question 17

Memory B cells

Answer 17

Long-lived B cells that rapidly respond to re-exposure to their specific antigen

Question 18

T-dependent B-cell responses

Answer 18

Require T cell help and involve germinal center formation, affinity maturation, and memory development

Question 19

T-independent B-cell responses

Answer 19

Do not require T cell help and primarily produce low-affinity IgM antibodies

Question 20

Somatic hypermutation

Answer 20

Occurs in germinal centers, introducing mutations to enhance antibody affinity but may cause self-reactivity

Question 21

Neutralization

Answer 21

Antibody-mediated mechanism preventing pathogens or toxins from binding to host cells

Question 22

Opsonization

Answer 22

Process where antibodies coat pathogens, enhancing their phagocytosis by immune cells

Question 23

Complement activation

Answer 23

Antibody-mediated activation of the complement cascade leading to pathogen lysis or inflammation