ANATOMY

Detailed explanation-1: -Antibodies are produced by B cells (specialized white blood cells). When an antigen comes into contact with a B cell, it causes the B cell to divide and clone. These cloned B cells-or plasma cells-release millions of antibodies into your bloodstream and lymph system.

Detailed explanation-2: -B-cells are the type of cells that produce antibodies to fight bacteria and viruses. These antibodies are Y-shaped proteins that are specific to each pathogen and are able to lock onto the surface of an invading cell and mark it for destruction by other immune cells.

Detailed explanation-3: -Membrane-bound immunoglobulin on the B-cell surface serves as the cell’s receptor for antigen, and is known as the B-cell receptor (BCR). Immunoglobulin of the same antigen specificity is secreted as antibody by terminally differentiated B cells-the plasma cells.

Detailed explanation-4: -Helper T cells that have been primed earlier in an infection by macrophages or dendritic cells presenting these internal peptides can then activate the B cell to make antibodies that recognize the coat protein (Fig. 9.3).