Biomedical subjects

Tian-Cheng Li

Publications and source records attributed to Tian-Cheng Li.

6 recordsLinked to original sources

PubMed2003

Characterization of self-assembled virus-like particles of human polyomavirus BK generated by recombinant baculoviruses.

The major structural protein of the human polyomavirus BK (BKV), VP1, was expressed by using recombinant baculoviruses. A large amount of protein with a molecular mass of about 42 kDa was synthesized and identified by Western blotting. The protein was detected exclusively in the nuclei by immunofluorescent analysis and it was released into culture medium. The expressed BKV VP1 protein was self-assembled into virus-like particles (BK-VLPs) with two different sizes (50 and 26 nm in diameter), which migrated into four different bands in CsCl gradient with buoyant densities of 1.29, 1.30, 1.33, and 1.35 g/cm(3). The immunological studies on the BK-VLPs suggested that they have similar antigenicity with those of authentic BKV particles. Cryoelectron microscopy and 3D image analysis further revealed that the larger BK-VLPs were composed of 72 capsomers which all were pentamers arranged in a T = 7 surface lattice. This system provides useful information for detailed studies of viral morphogenesis and the structural basis for the antigenicity of BKV.

Amino Acid Sequence↗

PubMed2003

Prevalence of antibody against hepatitis E virus in various species of non-human primates: evidence of widespread infection in Japanese monkeys (Macaca fuscata).

We screened 495 serum samples from 20 species of non-human primates for the antibody against hepatitis E virus (HEV). Anti-HEV IgG was detected in 84 of 232 (36.2%) Japanese monkeys, 2 of 19 (10.5%) cynomolgus monkeys, 3 of 83 (3.6%) rhesus monkeys, and 1 of 1 (100%) Taiwanese monkey, respectively. These results suggest that HEV is circulating among monkeys belonging to the genus macaca. A high prevalence of anti-HEV IgG was observed in Japanese macaques (M. fuscata) despite the fact that Japan is non-endemic for hepatitis E. It is possible that HEV can be transmitted from Japanese macaques to humans. Further, the rate of antibody positivity was found to increase with age in Japanese macaques. Seropositive macaques were found throughout Japan, but the seroprevalence rate differed among geographic regions.

Animals↗

PubMed2003

Molecular epidemiology of hepatitis viruses and genotypic distribution of hepatitis B and C viruses in Harbin, China.

We carried out a molecular-based epidemiological survey of hepatitis viruses, including hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis E virus (HEV), in Harbin, China. The study population of 358 subjects consisted of 132 healthy blood donors and 226 liver disease patients residing in Harbin City and surrounding suburbs. The infection rate of each virus among healthy subjects was 14.4% (19/132) for HBV and 2.3% (3/132) for HCV. In contrast, among liver disease patients, the infection rates were 72.6% (164/226) for HBV and 7.5% (17/226) for HCV, respectively (P < 0.01 and P < 0.05, respectively). In particular, nearly 64% of hepatocellular carcinoma patients in Harbin was found to be infected with HBV. The most common viral genotypes were HBV type C (80%) and HCV type 1b (31.3%). Interestingly, a high prevalence of the HBV pre-S1/S2 deletion mutant was found in 13 of 58 (22.4%) subjects. Moreover, testing for HEV among 202 subjects resulted in the detection of anti-HEV IgG in 53 cases (26.2%). The prevalence of anti-HEV IgG has already reached 20% in tested cases aged less than 10 years. These results suggest that HBV infection is widespread in Harbin, China and has led to a high incidence of acute and chronic liver disease in this region.

Adult↗

PubMed2003

[Hepatitis E].

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Animals↗

PubMed2002

Chimeric recombinant hepatitis E virus-like particles as an oral vaccine vehicle presenting foreign epitopes.

Many viral and bacterial pathogens establish infections through mucosal surfaces in their initial stage. However, only a few nonreplicating molecules successfully induce strong mucosal immune reaction without the addition of adjuvants by oral administration. To overcome this difficulty, we investigated whether hepatitis E virus-like particles (HEV-VLPs) could be utilized as a carrier molecule for foreign antigenic epitopes and to stimulate mucosal immunity without the need for adjuvants. To accomplish this goal, we incorporated a B cell epitope tag, consisting of 11 amino acids at the C-terminal of HEV-VLP. The chimeric VLP showed morphology similar to that of the mature HEV virion and VLP. The inserted epitope was reactive with a specific monoclonal antibody in the VLP form, suggesting that it was exposed on the surface of the VLP. After oral administration without adjuvant, this chimeric HEV induced significant levels of specific IgG and IgA to both the inserted epitope and HEV-VLP in intestinal secretions. These humoral immune responses were observed as early as 2 weeks after the first immunization. These results suggest the potential of HEV-VLP as a mucosal vaccine carrier vehicle for the presentation of antigenic epitopes through oral administration.

Administration, Oral↗

PubMed2002

Hepatitis e virus infection in fulminant hepatitis patients and an apparently healthy population in Bangladesh.

This is the first study comparing hepatitis E virus (HEV) infection in Bangladesh in fulminant hepatitis (FH) patients presumed to have a viral cause and in the apparently healthy population. Sera from 22 FH patients were analyzed for antibodies to hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C and D viruses, and HEV and for hepatitis B surface antigen (HBsAg). Anti-HEV immunoglobulin M (IgM) was detected in the sera of 63.6% of patients, whereas 35.7% were positive for HBsAg. A high prevalence of HEV infection (83.3%) was noted in the HBV carriers. Serum samples from 273 apparently healthy individuals were tested for antibodies to HAV and HEV. Anti-HEV IgM was detected in 7.3% of the samples. The seroprevalence of HAV differed from that of HEV in the same population because all samples were negative for anti-HAV IgM. These data indicate that HEV infection is highly endemic in Bangladesh.

Adolescent↗