The B cell receptor is a transmembrane protein on B cells that is composed of a membrane-bound immunoglobulin molecule and a signal transduction moiety. The B cell receptor consists of an Ig molecule anchored to the cell's surface and has two key functions: signal transduction upon antigen interaction and internalization of antigens for processing and presentation to T cells. The B cell co-receptor is a complex of CD19, CD21, and CD81 expressed on mature B cells.

1. B CELL RECEPTOR
BY: DR SADAF MOEEZ

2. B CELL RECEPTOR
is a transmembrane protein on the surface of
a B cell.
A B cell receptor is composed of
a membrane-bound immunoglobulin molecule
 a signal transduction moiety.

3. B CELL RECEPTOR

4. STRUCTURE

5. STRUCTURE

6. STRUCTURE

7. B-cell receptor
The B-cell receptor
consists of an Ig molecule
anchored to the cell’s
surface. CH = heavy
chain constant region;
CL = light chain constant
region; Fab = antigen-
binding fragment;
Fc = crystallizable
fragment; Ig =
immunoglobulin; L-kappa
(κ) or lambda (λ) = 2
types of light chains;
VH = heavy chain
variable region;
VL = light chain variable
region.

8. The B cell receptor (BCR) has two crucial functions upon
interaction with the antigen.
One function is signal
transduction, involving
changes in receptor
oligomerization
The second function is to mediate
internalization for subsequent
processing of the antigen and
presentation of peptides to helper
T cells.

9. B-cell co-receptor
• The B-cell co-receptor is expressed on mature
B cells as a complex of the cell-surface
molecules CD19, CD21, and CD81.