Another presentation of human antibody.ppt

Another extra presentation

1. Introduction to Antibodies

2. How are antibodies
produced?
Produced in B-lymphocytes (B-
cells)
Can be either membrane bound on B -
cells or secreted into the blood
stream.
Membrane bound antibodies

3. What do they do?
Identify and bind to foreign
substances in the body (antigens).
Most commonly:
Cell surface proteins
Cell surface glycoproteins

4. How are Antibodies
Structured?
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

5. How are they structured?
Antibodies are made up of four peptide
chains joined by cysteine disulfide
bonds.
The long peptides are called the heavy
chains.
The short peptide are called the light
chains.
Most antibodies are Y-shaped.

6. More on antibody
structure
There are also two main regions on
every antibody protein.
One region is constant in its amino acid
composition (constant region).
The other region is variable between
antibodies (variable region).

7. Variable Region
Because the variable region varies from
antibody to antibody it allows a large
number of possible antigens to be
identified.
Even though the variable region that is
produced by each B-cell differs, once a
B-cell produces a particular kind of
antibody, that B-cell can only make that
kind of antibody.

8. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

9. How do they bind
antigens?
Variable region is the part of the
antibody that binds the antigen.
Only one portion of the antigen is
bound by the antigen (epitope or
antigenic determinant).

10. Membrane-bound
Antibodies
B-cells can do two things if an antigen
binds to the membrane-bound antigen
(activation).
Cell can be transformed to perform rapid
antibody production
Cell can be transformed to a memory cell, a
cell that will remain in the blood stream for
years so that it can identify the antigen if it
reemerges.