We propose to work on the following problems in our study of antibody formation. 1) The proportion of cells responding to antigen stimulation and the proportion of each kind of IgM, IgG, IgA, and I hope IgE, in the cell containing antibody. 2) The manipulation of the suppressor population by colchicine. 3) The study of clones of human B cell growing in continuous culture. BIBLIOGRAPHIC REFERENCES: Swain, S., Modabber, F., and Coons, A.H. 1976. Characterization of T and B Antigen-Binding Cells for beta-Galactosidase-binding Cells in the Thymus and Spleen of Normal Mice. J. Immunol. 116, 915-922. Swain, S. and Coons, A.H. 1976. Characterization of T and B Antigen Binding Cells For beta-Galactosidase. II. T Antigen Binding Cells. J. Immunol. 116, 923-928.