Upon antigen stimulation, B lymphoid cells undergo terminal differentiation into antibody-secreting plasma cells. This process accompanies drastic changes in cell functions such as a loss of B-cell identity, induction of secretory apparatus, and an extremely increased transcription of antibody genes. These changes are the result of re-wiring of a transcription factor network in B and plasma cells. While the transcription repressor Blimp-1 induces plasma cell differentiation, another repressor Bach2 has emerged as a negative regulator of Blimp-1 in B cells. These two transcription factors, together with other several factors, appear to constitute a main transcriptional regulatory network for the terminal differentiation process of plasma cells from B cells.