The activation of mature B-cell is done by antigen. When antigen come in contact with B-cells, it undergoes clonal proliferation and divided into memory cells and plasma cells.

In thymus independent B-cell pathway, antigen activates B-cell without the participation of TH cell. Response generated by thymus independent antigens only generate IgM and do not give rise to memory.

CD19, CD81, and CD21 are present on the B-cell membrane and known as a B-cell coreceptor. These receptors are used to determine a cell’s identity and for transducing signals.

Transcription factors like NF-AT, CREB, JUN, FOS, and AP-1 promote gene expression required for B-cell proliferation into a plasma cell and the memory cell.

It is a method which is used for the production of hybridoma of B-cells. This hybridoma B-cell later used for the production of monoclonal antibodies. Monoclonal antibodies are highly specific against a single epitope of the antigen.