Lecture12: (Part I) B cell activation and antibody production

Question 1

Ag activates mature naive B cells by binding to membrane ___ and __ on these cells

Answer 1

IgM and IgD

Question 2

Question 3

Question 4

Heavy chain isotype switching and affinity maturation are increased in the ______ responses (multiple) to protein Ags

Answer 4

secondary responses

Question 5

most mature naive B lymphocytes are follicular B cells which are also called

Answer 5

Recirculating B cells or B-2 cells

Question 6

The _____ chemokine secreted by follicular DCs guides the movement of B cells to follicles

Answer 6

CXCL13

Question 7

small soluble Ags (generally smaller than 70kD) are delivered to Follicular B cells through

Answer 7

afferent lymphatics and via conduits

Question 8

Large Ags are delivered to follicular B cells by

Answer 8

subcapsular sinus Macrophages or by DCs in the medulla

Question 9

In the spleen, Ags in immune complexes my bind to ____ complement receptors on marginal zone B cells

Answer 9

• CR2
  
  • MZ B cells can transfer the immune-complex containing Ags to follicular B cells

Question 10

Blood-borne pathogens may be captured by ______ in the blood and transported to the spleen, where they may be delivered to marginal zone B cells

Answer 10

Plasmacytoid DCs (pDCs)

Question 11

Polysaccharide Ags can be captured by macrophages in the _______ of splenic lymphoid follicles and displayed or transferred to b cells in this area

Answer 11

marginal zone

Question 12

• ____ B cells respond to protein Ags and thus initiate T-dependeent Ab responses
• T-independent responses to multivalent Ags are mediated mainly by _____ B cells in the spleen and _____ in mucosal sites

Answer 12

• Follicular B cells respond to protein Ags and thus initiate T-dependent Ab responses
• T-independent responses to multivalent Ags are mediated mainly by marginal zone B cells in the spleen and B-1 cells in mucosal sites

Question 13

B-1 cells, arise form the fetal liver by the ____ gestational week

Answer 13

eighth

Question 14

Question 15

A specialized type of helper T cell, called a _____, facilitates the formation of germinal centers (GCs) where activated B cells proliferate

Answer 15

• Follicular Helper T cells

Question 16

Ab responses to ____ Ags require participation of CD4+ T helper lympocyte

Answer 16

• Protein Ags
  
  • therefore, proteins are classified as T-dependent (TD) Ags

Question 17

Ab responses to multivalent non-protein Ags with repeating epitopes, such as ____, some ____, and _____, do not require Ag-specific helper T lympocytes

Answer 17

• Polysaccharides, some lipids, and nucleic acids
  
  • mutivalent Ags are called T-independent (TI) Ags

Question 18

Follicular B cell survival depends on signals from the BCR as well as on inputs received from cytokine called _____

Answer 18

BAFF ( B cell-activating factor of the TNF family)

Question 19

BAFF is mainly produced by

Answer 19

myeloid cells in lymphoid follicles and in the bone marrow

Question 20

Question 21

Question 22

Extrafollicular B cell transcription factors

Answer 22

Blimp-1

Question 23

Follicular/Germinal Center Transcription factors

Answer 23

Bcl-6

Question 24

Question 25

The generation of T_FH cells requires sequential activation of T cells, first by ___ and then by ______. The T_FH cells migrate into ____, where they

Answer 25

• The generation of T_FH cells requires sequential activation of T cells, first by DCs and then by activated B cells. The T_FH cells migrate into GCs, where they activate B cells

Question 26

T_FH secrete

Answer 26

• IL-21
  
  • is required for GC development and generation of plasma cells
• IFN-gamma
• IL-4

Question 27

T_FH cells express

Answer 27

• ICOS (inducible costimulator)
• PD-1 (programmed death-1)
• IL-21
• IL-4
• IFN-gamma
• Bcl-6 (transcription factor)

Question 28

Activated B cells migrate into the follicle and proliferate, forming dark zone of the germinal center. These B cells udnergo extensive isotype switching and somatic hypermutation of Ig ___ genes

Answer 28

Ig V genes

Question 29

expression of ____ on B cells induces migration of cells toward the T cell zone

Answer 29

CCR7