Highly purified and homogenous hepatitis B core particles were obtained from an autopsy liver. The core particles consisted mainly of an electrophoretically single major polypeptide with a molecular weight of 20,000 daltons. When antigenic conversion from hepatitis B core antigen (HBeAg) to hepatitis B e antigen was achieved by treating these core particles by sonication or by passing them through an anti-HBc IgG-conjugated Sepharose 4B column, no appreciable changes were found in the above protein composition. The same antigenic conversion was also achieved by centrifugation of core particles in CsCl, which revealed the process of morphological disintegration accompanied by antigenic conversion. These observations may support the hypothesis that HBeAg resides on a protein conformation which consists of a polypeptide sharing HBe antigenicity.

A continuous cell line of chimpanzee lymphocytes producing an antibody specifically associated with non-A, non-B hepatitis (NANB) was established. Peripheral blood lymphocytes of a chimpanzee convalescent from experimental infection with NANB hepatitis were transformed in vitro by Epstein-Barr virus infection into lymphoblastoid cell lines.Supernatants of the cell cultures were screened by immunofluorescence for antibody activity against the liver tissue of a chimpanzee with NANB hepatitis. Nineteen of the 1402 cultures were found to be positive for the activity. Ten of these 19 gave cytoplasmic reactions and the remaining 9 gave nuclear reactions in hepatocytes. One culture (48-1) stably producing the antibody was further characterized. The antibody produced in 48-1 was IgM and gave granular cytoplasmic reactions in hepatocytes. Cloning of 48-1 was performed by the soft agar method and cloned cell lines stably producing the antibody were obtained. The 48-1 antibody reacted with liver biopsy specimens from 12 chimpanzees obtained during the acute or chronic phase of hepatitis caused by five different NANB strains, but not with biopsy specimens from chimpanzees with hepatitis A or B or from normal chimpanzees. In addition, examinations of serial liver biopsy specimens obtained from 2 chimpanzees experimentally infected with NANB hepatitis demonstrated that the antibody reacted with the biopsies obtained during the preacute, acute, and chronic hepatitis, but not with those obtained before inoculation, early incubation period, or during convalescence. The present results indicate the specific association of the antibody with NANB hepatitis. Immunoelectron microscopy revealed that the antibody reacted with the microtubular aggregates identical to those previously described in a patient and chimpanzees with NANB hepatitis.

Blood-borne type non-A, non-B (NANB) hepatitisassociated microtubular aggregates protein was isolated and partially sequenced. The microtubular aggregates were isolated from the hepatocytes of NANBinfected chimpanzees and were found to have a buoyant density in sucrose solution of 1.21 to 1-23 g/ml. A single protein, recognized by our anti-microtubular aggregates monoclonal antibodies, was found to have an M~ of 44 000 (p44). This p44 protein was not found in uninfected chimpanzees. We determined a partial amino acid sequence for p44, and showed that it has no homology to any known proteins.

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Epithelial cells in the urinary bladder (urothelium) trigger sensory signals in micturition by releasing ATP in response to distention of the bladder wall. Our previous study revealed the distinct roles of extracellular Ca(2+) and the Ca(2+) stores in the endoplasmic reticulum (ER) in urothelial ATP release. In the present study, we investigated the regulation of urothelial ATP release by Ca(2+) influx from the extracellular space and Ca(2+) release from the ER using a distention assay of the mouse bladder wall in a small Ussing chamber. Stimulation of Ca(2+) release from the ER in the mucosal side of the bladder induced significant ATP release without distention. Blockade of the inositol 1,4,5-triphosphate receptor reduced distention-induced ATP release, suggesting that Ca(2+) release from the ER is essential for the induction of urothelial ATP release. On the other hand, blockade of store-operated Ca(2+) entry (SOCE) from the extracellular space significantly enhanced distention-induced ATP release. Thus Ca(2+) release from the ER causes urothelial ATP release and depletion of Ca(2+) stores in the ER, which in turn causes the depletion-inducing SOCE to suppress the amount of urothelial ATP released.