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Biomedical subjects

B S Sun

Publications and source records attributed to B S Sun.

4 recordsLinked to original sources
PubMed1998

Identification of a protein isolated from senescent human cells that binds to hepatitis B virus X antigen.

Hepatitis B virus-encoded X antigen contributes to the development of hepatocellular carcinoma. Given that X antigen functions by binding to other proteins, additional X-binding proteins were sought from an adult human liver cDNA library in a yeast two-hybrid system. The results yielded a clone encoding a 55-kd protein that is associated with replicative senescence (p55sen). Binding of p55sen to X antigen was confirmed in vitro by immunoprecipitation and affinity chromatography. The expression of endogenous p55sen inversely correlated with cell growth. Transient transfection of X antigen or p55sen into HepG2 cells stimulated DNA synthesis by twofold to threefold, whereas cotransfection did not, suggesting that these molecules functionally interact. The detection of p55sen in embryonic mouse liver, its absence in adult mouse and human livers, and its reappearance in livers from carriers with chronic liver disease, suggest that it may play important roles in the regulation of liver cell growth. The similarity between p55sen and a notch ligand, which is involved in cell fate determinations during embryogenesis, implies that the binding of p55sen by X antigen may also contribute to an alteration in cell fate, which is characteristic of carcinogenesis.

Amino Acid Sequence↗
PubMed1991

[Changes in T-lymphocyte subsets and interleukin-2 production in peripheral blood mononuclear cells after thermal injury].

The relative number of peripheral blood T-lymphocyte and its subsets, identified by monoclonal antibodies OKT3, OKT4 and OKT8, and Interleukin-2 (IL-2) were assessed in burn patients by means of indirect immunofluorescence and microassay CTLL-2 3H-TdR incorporation techniques. Comparing with the controls, the relative number of OKT3+ cell in burn patients was decreased occasionally, however, the proportion of OKT4+ cell was significantly reduced and did not recover until the patients were cured. The changes in OKT8+ cell depended on the extent of the burn wound. In minor and moderate burn patients, the proportion of OKT8+ cell was temporarily increased, while in major burn patients, it was increased persistently. The OKT4+/OKT8+ cell ratio declined constantly. The results of the experiment showed that the PBMCs IL-2 production in the patients was persistently lower than normal controls and correlated to the OKT4+/OKT8+ cell ratio. These data indicated that following burn injury, there was insufficiency of relative number in TH cells and relative dominance in Ts cells, which might affect the IL-2 production. These findings suggest that the lowered immunopotency after thermal injury may be attributed to both insufficient TH cells and excessive Ts cells.

Adolescent↗