Morinobu Takahashi

Ultrastructural study of human myeloma cells in relation to its function

The ultrastructure of neoplastic plasma cells from a patient with prolonged multiple myeloma was studied in relation to its function, that is, the secretion of immunoglobulin light chain. Peroxidase-labelled antibodies, each monospecific to its immunoglobulin component chain, were used to localize intracellular immunoglobulin within myeloma cells under the electron microscope. By this method, only the κ type light chain was detected within myeloma cells in bone marrow tissue of this patient, indicating that the occurrence of free κ type light chains in serum and urine was due to the cessation of heavy chain synthesis within the myeloma cells. The κ chain was demonstrated as conspicuous electron-dense precipitates in ergastoplasm, its cisternal space, external layer of nuclear membrane, and ribosomes associated with ergastoplasm and nuclear membrane. No immunoglobulin was demonstrated in an atypical Golgi complex, an organelle which is ordinarily engaged in protein synthesis. Numerous crystalline structures and similar inclusion bodies found in myeloma cells appeared to have arisen from the Golgi area, but they did not ever react with the peroxidase label. Discharge of the κ chain from the cell seems to be carried out through cell fragmentation, possibly caused by progressive distension of the ergastoplasmic cavity.

Ultrastructural study on the ribosome helix and its change after antigenic stimulation in P3-J cells

Abstract Ribosome helices which have been reported in various tissue but very infrequently were observed to exist quite abundantly in the cytoplasm of P3-J culture of Burkitts lymphoma origin. Drastic alteration in ribosomal configuration was observed in cells about 5 days after exposure to coliphage T2. On day 5 of coliphage treatment, originally predominant ribosome helices markedly decreased in number and were almost completely replaced by polysomes scattered singly or in small clusters. Such change in polysome patterns was gradually reversed after day 5 and the originally observed predominance of polysome aggregation emerged on day 12 to day 14 again. The alteration in polysome configuration caused by exposure of P3-J cells to T2 phage coincides very closely with the time of the initiation of antibody formation in P3-J cells stimulated with T2 phage, suggesting the close correlation between these two phenomena.

Simplified method for purification of mouse beta 1H.

A simple three-step method was described for purification of murine beta 1H, one of the essential regulatory proteins of complement system. The method consists of heparin-Sepharose affinity chromatography; gel filtration on a Sepharose 6B column, and DNA-cellulose affinity chromatography. By this method over 10 mg of beta 1H can be purified by more than 200-fold from 100-ml of EDTA serum of various strains. Overall yield of beta 1H was about 45%. The purified beta 1H was homogeneous as judged by SDS-polyacrylamide gel electrophoresis and immunoelectrophoresis. The purified mouse beta 1H showed physicochemical properties very similar to those described for human beta 1H: mouse beta 1H is a beta-globulin consisting of a single polypeptide chain of molecular weight of 160,000. Purified mouse beta 1H retained its functional activity as the essential cofactor for the cleavage of fluid-phase human C3b by the human C3b inactivator. Immunization of rabbits with the purified mouse beta 1H resulted in the production of the potent and monospecific antibody.