Upon exposure to antigens, cells of this type differentiate into plasma cells and secrete antibodies.
Mice in which the Ikaros transcription factor has been displaced exhibit a complete lack of cells of this kind, and in order to survive the earliest stage of development, cells of this type require contact with stromal cells. The marginal zone variant of these cells are characterized by a lack of CD5 expression, and activation of these cells results in the translocation of their namesake  signaling complex into lipid rafts while excluding CD22 and CD45. These cells can be recruited by (*) clonally expanded effector helpers after those helper cells have interacted with activated dendritic cells. Upon exposure to antigens, cells of this type differentiate into plasma cells and secrete antibodies. Produced in humans in the fetal liver and later in bone marrow, for 10 points, identify these cells of the immune system which are responsible for humoral immunity.
Mice in which the Ikaros transcription factor has been displaced exhibit a complete lack of cells of this kind, and in order to survive the earliest stage of development, cells of this type require contact with stromal cells.
B cells or B lymphocytes