Yutaka Mano

PRIMARY CULTURE OF CHOLANGIOCYTES FROM NORMAL MOUSE LIVER

Dear Editor: Cholangiocytes have been thought to play a role as antigen presenting cells or target cells in immune-mediated cholangitis. The aberrant expression of MHC class II proteins on cholangiocytes in primary biliary cirrhosis raises the possibility that cholangiocytes can function as antigen presenting ceils and, in immune-mediated cholangitis, cholangiocytes appeared to be targeted by lymphocytes (8). To explore the immune mechanisms underlying cholangitis, a culture of mouse cholangiocytes is essential, because the mouse is indispensable for immunological study. Cholangiocytes are a minor component of liver ceils, comprising only 3-4% of the rodent liver cells. Most extensively studied cultured

Association between S21 substitution in the core protein of hepatitis B virus and fulminant hepatitis

BACKGROUND The viral factors of hepatitis B virus (HBV), such as genotypes and mutations, were reported to affect the development of fulminant hepatitis B (FHB), but the mechanism is still unclear. OBJECTIVES To investigate HBV mutations associated with FHB, especially in the subgenotype B1/Bj HBV (HBV/B1), which are known to cause FHB frequently in Japan. STUDY DESIGN A total of 96 serum samples from acute self-limited hepatitis B (AHB) patients and 13 samples from FHB patients were used for full-genome/partial sequencing. A total of 107 chronic infection patients with HBV were also examined for the distribution of mutants. RESULTS In the analysis of full-genome sequences of HBV/B1 (FHB, n=11; non-FHB, n=35) including those from the databases, mutations at nt 1961 [T1961V (not T)] and nt 1962 [C1962D (not C)], which change S21 in the core protein, were found more frequently in FHB than in non-FHB (100% vs. 20%, 55% vs. 3%, respectively). When our FHB and AHB samples were compared, T1961V and C1962D were significantly more frequent in FHB than in AHB, both in the overall analysis (46% vs. 6%, 39% vs. 3%, respectively) and in HBV/B1 (100% vs. 29%, 100% vs. 14%, respectively). A newly developed PCR system detecting T1961V showed that HBV/B1 and low viral load were independent factors for the mutation among chronic infection patients. CONCLUSIONS T1961V/C1962D mutations were found frequently in FHB, especially in HBV/B1. The resulting S21 substitution in the core protein may play important roles in the development of FHB.

Primary biliary cirrhosis with antibody against carbonic anhydrase II associates with distinct immunological backgrounds

Objective: a part of patients with primary biliary cirrhosis (PBC) has anti-human carbonic anhydrase II (CA II) autoantibodies, although several contradictional reports followed. Since immunization of mice with CA II results in cholangitis in a susceptible strain, PBC with anti-CA II antibody may have distinct clinical features. Thus, we tested the sera of patients with PBC for anti-CA II antibodies and compared clinical characteristics of PBC patients with and without anti-CA II antibodies in Japanese patients. Methods: anti-CA II antibodies were detected in nine of 50 (18%) PBC patients by immunoblotting. The evaluation of these patients included various clinical parameters, autoantibodies, and immunological backgrounds. Results: the levels of serum liver tests and the prevalence of serum anti-mitochondrial antibody (77.8 vs. 92.7%) were not different between the patients with and without anti-CA II antibody. However, the prevalence of anti-nuclear antibody (ANA) was significantly higher in the patients with anti-CA II antibody than that in the patients without anti-CA II antibody (66.7 vs. 25.6%, P=0.044), although their mean titers were not statistically different. Association of Sjøgrens syndrome tended to be more frequent in the patients with anti-CA II antibody than those without it (33.3 vs. 14.6%, P=0.327). Studies of HLA class I allotype revealed that three of five (60.0%) patients with anti-CA II antibodies and one patients from 34 (3.0%) patients without anti-CA II antibodies had HLA B51 allotype; the difference in the prevalence of this allotype was significant (P=0.004, Pc=0.01), and the prevalence of other HLA class I and HLA DR allotypes was similar between the patients with and those without anti-CA II antibody. Administration of ursodeoxycholic acid (600 mg per day) was accompanied by change in liver tests in a similar way between the two patient groups. Conclusions: These results suggest that, although clinical features are not distinctive, PBC patients with anti-CA II antibody may have a genetic background, which may contribute to a susceptibility to immune-mediated cholangitis.

Vectorial transport of bile acids in immortalized mouse bile duct cells.

In ileal epithelial cells, apical sodium-dependent bile acid transporter (ASBT) is responsible for the uptake of bile acids from the lumen. Furthermore, ASBT is expressed in the apical plasma membrane of intrahepatic bile duct cells (BECs). Using cultured immortalized mouse intrahepatic BECs that form monolayers or cysts, vectorial transport of bile acids was studied. [3H]-taurocholic acid ([3H]-TCA) was transported through monolayers transcellularly almost exclusively from the apical to the basolateral side in a Na(+)- and a temperature-dependent manner. Transport of [3H]-TCA was inhibited by 59.3+/-18.6% in the presence of taurochenodeoxycholic acid. Uptake of lysyl fluorescein-conjugated bile acid, Cholyl-[Nepsilon-NBD]-lysine, was seen in a Na(+)- and a temperature-dependent manner from the apical side of BECs that form monolayer or cysts. Reverse transcription-polymerase chain reaction for mRNAs in the cells showed presence of mRNAs for ASBT and farnesoid X receptor (FXR), a nuclear bile acid receptor. In conclusion, intrahepatic BECs transport bile acids mainly from the apical to the basolateral side in concert with ASBT and maybe FXR in the cells.

Up-regulation of CD11a (LFA-1) expression on peripheral CD4+ T cells in primary biliary cirrhosis.

Up-regulation of CD11a expression on CD4+ T lymphocytes is considered to be one of the mechanisms involved in the initiation of the Th-1-mediated immune response. In this study, peripheral blood mononuclear cells from patients with primary biliary cirrhosis (PBC) were evaluated for CD11ahighCD2low T cells and populations of type 1 (Th-1) and type 2 (Th-2) helper T cells. CD11ahighCD2low T cells were found in PBC (7/15) and in active rheumatoid arthritis (4/4), but not in chronic hepatitis C (0/5) or in healthy subjects (0/6). The population of Th-1 had a positive correlation with that of CD4+CD11ahighCD2+ cells in patients with PBC (P = 0.034). The serum levels of interferon-γ also had a weak correlation with the population of CD4+CD11ahighCD2low cells (P = 0.050). There was no statistically significant correlation of Th-2 population (P = 0.295) or serum interleukin-4 level (P = 0.685) with the population of CD4+CD11ahighCD2low cells. These results suggest that CD4+CD11ahigh cells play a role in Th-1-predominance and in the autoimmune process of PBC.

Shifting hepatitis B virus genotypes of acute hepatitis B patients in northeast Japan

It has been reported that acute hepatitis B (AHB) patients with genotype A HBV (HBV/A) have been increasing since the 1990s in metropolitan areas in Japan. However, little is known about the trends of HBV genotypes in AHB patients in northeast Japan where genotype B HBV (HBV/B) prevails more than in other areas. In this study, we aimed to clarify the changes in the HBV genotypes and clinical characteristics of AHB patients in this area. HBV genotypes were determined by direct sequencing (n = 125) or enzyme immunoassay (n = 9) using serum samples from AHB patients including fulminant hepatitis in 1987–2014. Among 134 patients, 26 (19%), 33 (25%), and 75 (56%) patients were infected with HBV of genotypes A, B, and C, respectively. HBV/A emerged from 2001 and the percentage was increased gradually up to 48% in 2010–2014, whereas HBV/B was reduced from 40% in 1987–1994 to 10% in 2010–2014. Phylogenetic analysis showed that three major subgenotype A2 strains had come into this area serially. The levels of HBV DNA and prothrombin time were higher in HBV/A patients than other genotypes. This study could not show significant difference in the HBsAg‐positive period among genotypes nor the effect of nucleoside analogues to shorten the HBsAg‐positive period. A higher level of initial HBV DNA was associated with late disappearance of HBsAg. In conclusion, the percentage of HBV/A in AHB patients has been increasing in northeast Japan since 2001, which is later than metropolitan areas, whereas that of HBV/B is decreasing. J. Med. Virol. 88:69–78, 2016.