T cell maturation and development of their antigen-specific receptors takes place in the . B cells mature in the where they also develop their specificity to a single antigen. This specificity in both B and T cells is made possible through genetic . The genes that code for the variable regions of both B and T cell receptors are cut and spliced during the process of both cells. Because genetic rearrangement occurs at the level of the rather than in the RNA following , the changes are permanent, resulting in each cell being capable of binding to a single antigen in a pool of up to 1018 possible variations. B cell receptors are that are comprised of four and have two identical antigen binding sites. The region of the immunoglobulin is embedded in the cell membrane, and the variable regions are facing outward in order to bind to their potential antigenic match. Unlike B cell receptors, T cell receptors are comprised of two polypeptides and have antigen binding site(s) that is exposed. Like B cell receptors, their specificity to a single antigen is determined any encounters with antigens.

When a B cell or T cell is stimulated by antigen, it divides, producing many identical copies of itself. This is an important part of the selection model.

B cells, but not T cells, undergo affinity maturation. This may explain why only _______.1 pointT cells require co-receptors for stable bindingB cells produce a variety of classes of receptorT cells do not produce soluble versions of their receptorsB cells can present antigen on class I MHC

The T cell receptor (TCR):Select one alternative:Has enormous binding diversity created by gene segment rearrangement.Consists of 2 protein chains, each with variable and constant domains.Contains only one antigen-binding site.All of the above

How do T and B lymphocytes recognize different antigens?Multiple choice question.T and B lymphocytes secrete antigen-binding molecules, each of which can bind to a variety of nonself proteins.Each lymphocyte has antigen receptors in its plasma membrane, which can bind to only one specific antigen.Each lymphocyte has a general receptor for non-self proteins in its plasma membrane, which can bind to many foreign antigens.T cells and B cells use cytokines to direct their binding to receptors.

Which of the following mechanisms produces the MOST diversity in T cell receptors?