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

Immunology 2.0 > Lecture12: (Part I) B cell activation and antibody production > Flashcards

Flashcards in Lecture12: (Part I) B cell activation and antibody production Deck (29):
1

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

IgM and IgD

2

3

4

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

secondary responses

5

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

Recirculating B cells or B-2 cells

6

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

CXCL13

7

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

afferent lymphatics and via conduits

8

Large Ags are delivered to follicular B cells by 

subcapsular sinus Macrophages or by DCs in the medulla

9

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

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

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

Plasmacytoid DCs (pDCs) 

11

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

marginal zone 

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

  • 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 

13

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

eighth

14

15

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

  • Follicular Helper T cells 

16

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

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

17

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

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

18

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

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

19

BAFF is mainly produced by 

myeloid cells in lymphoid follicles and in the bone marrow 

20

21

22

Extrafollicular B cell transcription factors 

Blimp-1

23

Follicular/Germinal Center Transcription factors 

Bcl-6

24

25

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

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

26

TFH secrete

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

27

TFH cells express

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

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

Ig V genes

29

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

CCR7