91Ó°ÊÓ

In adaptive immunity, immune cells and antibodies target and eliminate foreign invaders. They also remember what they look like and build a new immune response to prevent further illness in the future.

White blood cells, known as lymphocytes, including T and B cells, are responsible for adaptive immunity.

A material that causes a B or T cell reaction is an antigen. Antigen receptors, present on B cells and T cells, allow them to bind to antigens, such as bacterial or viral proteins.

An antigen receptor attaches to a single part of a molecule from a specific pathogen, such as a bacterium or a virus.

Y-shaped proteins are made of four polypeptide chains: two identical heavy chains and two identical light chains. Disulfide bridges connect chains. Each light or the heavy chain has a constant region (C) and a variable region (V).

The amino acid sequences differ slightly in the C region between receptors on different B cells. However, the V region contains the antigen-binding site of the immunoglobulins (Ig)

B cells are activated by interacting with antigens via their antigen receptors, which cause them to release soluble versions of their receptors. Immunoglobulins (Ig) are released proteins called antibodies.