Activation of B Cells to Make Antibody

The B cell uses its receptor to bind a matching antigen, which it proceeds to engulf and process.

Then it combines a fragment of antigen with its special marker, the class II protein. This combination of antigen and marker is recognized and bound by a T cell carrying a matching receptor. The binding activates the T cell, which then releases lymphokines—interleukins—that transform the B cell into an antibody- secreting plasma cell.