Oops, you're using an old version of your browser so some of the features on this page may not be displaying properly.

MINIMAL Requirements: Google Chrome 24+Mozilla Firefox 20+Internet Explorer 11Opera 15–18Apple Safari 7SeaMonkey 2.15-2.23

Chapter 1: The Immune System

B-cell Diversity Figure 1

Source: Talk Design Page on "Evolving Immunity" by Matt Inlay. (link correct at time of publication; June 2015)

In B-cells the variable regions of the Ig L chains are encoded by the random joining of one of many variables (V) and joining (J) segment genes.

In addition to the above, for the H chain gene, a diversity (D) gene must also be rearranged.

The result of this random process is the expression on any individual naive B-cell surface of a unique Ig with Ag specificity: the B-cell receptor (BCR).

B-cell Diversity Figure 2

Source: Levy N., Professor at Dartmouth College (link correct at time of publication; June 2015)

Naive B-cells exit the BM and circulate between blood, LN, and secondary lymphoid tissue in search of an Ag that will match the randomly determined BCR.

When naive B-cells encounter an antigen within the germinal centre (GC) of a LN they undergo further variation and selection.

Binding of an Ag to the BCR, with the help of T-cells and antigen-presenting cells (APC), initiates Ag-dependent germinal centre reaction.

In the peripheral dark zone of the GC, rapidly dividing B-cells (centroblasts, CB) introduce random mutations in the H and L chains (somatic hypermutation).

B-cell Diversity Figure 3

Source: Klein U, et al. Nat Rev Immunol 2008; 8:22 -33

In the central light zone, CBs mature to centrocytes (CC) and are selected for affinity with the help of follicular helper T-cells and dendritic cells.

High-affinity CC mature to either plasma cells or memory B-cells and leave the GC. They may undergo Ig class switch by changing the Ig H chain.

Revision Questions

  1. What are the phases of B-cell development and where do they take place?
  2. How is the diversity of immunoglobulin specificity derived?
  3. What is meant by “somatic hypermutation”?
Immunoglobulins and B-Cell Development T-Cells and NK-Cells

This site uses cookies. Some of these cookies are essential, while others help us improve your experience by providing insights into how the site is being used.

For more detailed information on the cookies we use, please check our Privacy Policy.

Customise settings
  • Necessary cookies enable core functionality. The website cannot function properly without these cookies, and you can only disable them by changing your browser preferences.