<prompt> Plasma cells are derived from -B lymphocytesT lymphocytesNK cellsMonocytes  <response>: Ans. is a i.e., B lymphocytes o B-cells are able to make a specific antibody against a specific antigen. It is due to present of specific receptor on B-cells - B-cell receptor BCR, that is usually an immunoglobulin Ig M or Ig D. An antigen interacts with B-cell that shows best fit by virtue of its BCR. The antigen binds to this receptor, and the B-cell is stimulated to divide and form a clone clonal selection. This clone of cells will become plasma cells that will secretes antibody of a particular specificity and same class.o Although, B-cells are the major source of antibodies after their conversion into plasma cells. Helper - T cells are also important. Helper T-cells activate B-cells by secreting cytokines lymphokines. These lvmphokines than stimulate the specific clone of B-cells to differentiate into plasma cells clonal selectionAntigen exposureAntigen presenting cells present this antigen to helper T cellsT cells are activatedSecretion of lymphokine by T-cellsB-cells that carrv BCR specific to that antigen are. stimulated clonal selectionB-cells proliferate and differentiate in to plasma cellsPlasma cells synthesize an immunoglobulin of same specificity as that carried by the B-cell precursors 