OBJECTIVES: 1. Valence of IgM Clq will be determined. 2. Effect of C on transfer of IgM from site to site will be measured. 3. Combining sites of phosphorylcholine-binding murine IgA myeloma proteins will be probed studying hapten inhibition as a function of pH. 4. Fusion of liposomes marked with IgA myeloma proteins will be studied. 5. Phagocytosis of erythrocytes sensitized with IgM, IgA or IgG myeloma proteins will be studied. BIBLIOGRAPHIC REFERENCES: Jocius, I. B. and Leon, M. A. Properties of a Cell Bound Homogeneous Murine IgM Anti-Dextran-III. Reduction and Alkylation of Cell-Bound IgM. Immunochemistry I2, 73, 1975. Jocius, I. B and Leon, M. A. Properties of a Cell Bound Homogeneous Murine IgM Anti-Dextran-IV. Modification of Reactions of Cell-Bound IgM by Concanavalin A. ibid, 12, 81, 1975.