Biomedical subjects

Gehua Yu

Publications and source records attributed to Gehua Yu.

3 recordsLinked to original sources

PubMed2005

B7-H3: another molecule marker for Mo-DCs?

Using a newly generated monoclonal antibody (2E6) against human B7-H3, we explored the expression of the molecule on dendritic cells derived from monocytes (Mo-DCs). Its expression was examined by means of immunostaining and flow cytometric (FCM) analysis. The results showed that B7-H3 was expressed in the course of Mo-DC maturation induced with interleukin 4 (IL-4) and granulocyte/macrophage colony-stimulating factor (GM-CSF). The expression could be detected at all the stages of Mo-DC differentiation, and remained at a quite stable level. Interestingly, B7-H3 was not expressed by T cells and B cells, even these cells were activated respectively by PHA or PWM. A weak expression could be detected on resting monocytes. These data showed that constitutive expression of B7-H3 at a high level was found on imDCs and mDCs derived from monocytes. Due to no expression on T cells and B cells, we speculate that B7-H3 might be another valuable molecule marker for Mo-DCs.

Animals↗

PubMed2004

Distinct overexpression of Fas ligand on T lymphocytes in aplastic anemia.

Increased expression of Fas by hematopoietic progenitors in aplastic anemia (AA) suggests that Fas/Fas ligand (FasL) system plays a key role in the formation of severe pancytopenia. To further confirm the above hypothesis, T cells from 8 patients with AA were systematically studied for their FasL's distribution pattern, releasing manner and proapoptotic activity, compared with normal resting T cells and artificially activated T cell blasts. The results demonstrated that AA T cells abnormally expressed low levels of membrane-bound FasL and contained high levels of intracellular FasL which could be triggered to release by high-dose phytohemagglutinin (PHA) pulse-stimulation. The supernatants from the PHA-stimulated AA T cells had apparent cytotoxicity against FasL-sensitive Jurkat cells, which could be significantly inhibited by monoclonal antibody against FasL in a dose-dependent manner, or nearly completely abrogated by ultracentrifugation. The above phenomena also appeared on artificially activated T cell blasts, but this was not the case on normal resting T cells. These results indicate that AA T cell is a type of "preactivated" T lymphocyte, characterized by overexpression of FasL, especially intracellular FasL which can be stimulated to release in bioactive exosomes-bound form. Taken together, our data provide further and direct evidence for the hypothesis that T cells might mediate the destruction of hematopoietic progenitor in AA through Fas/FasL system.

Adolescent↗

PubMed2002

[Effect of CD(40) on the in vitro biological behavior of malignant B lymphocytes].

OBJECTIVE: To explore the effect of recombinant human soluble CD(40) ligand (rhsCD(40)L) and CD(40)L cDNA transfected cell (CD(40)L-TC) on the behavior of malignant B lymphocytes, and investigate the possibility of using rhsCD(40)L as a new bio-factor in tumor immunotherapy. METHOD: rhsCD(40)L and CD(40)L-TC were obtained by gene recombinant techniques. Multiple myeloma cell lines, XG2, XG7, U266 and 8226, B-lymphoma cell lines, Raji and Daudi were selected to detect responses to rhsCD(40)L and CD(40)L-TC stimulation. Cell growth curve, cell cycle, early apoptosis as well as membrane surface molecules on these cell lines were analyzed. RESULTS: (1) The expression levels of CD(40) molecule on malignant B lymphocytes showed heterogeneity. High level of CD(40) on XG2, moderate on 8266, Raji, and Daudi, and no expression on U266 and XG7 were detected. The rhsCD(40)L stimulation gave rise to a typical homo-type cell aggregation of XG2 and Daudi. Meanwhile, at least 10 to 20 of CD(40)(+) XG2 or CD(40)(+) Daudi cells were found adherent to one pre-treat ed CD(40)L-TC. (2) Co-incubation with rhsCD(40)L (5 micro g/ml), or CD(40)L-TC (tumor cell: CD(40) = 5:1) resulted in a significant inhibition of in vitro cell growth of XG2, Raji and Daudi, with G(1)-phase arrest for XG2 and G(2)-phase for Raji and Daudi. These two kinds of CD(40) stimulators induced XG2, Raji and Daudi cells to apoptosis in vitro. The apoptotic rate for XG2 was 23.3% (rhsCD(40)L) and 18.8% (CD(40)L-TC), for Daudi 14.2% and 15.9%, and for Raji 11.6% and 8.9% respectively. (3) Phenotype analysis showed that CD(95) expression levels were significantly up-regulated on XG2, Raji and Daudi after stimulation with rhsCD(40)L or CD(40)L-TC, and CD(80) and CD(18) expression levels on Raji were respectively enhanced and decreased. CONCLUSION: The abilities to directly inhibit XG2, Daudi and Raji cell proliferation, to induce themapoptosis, as well as to up-regulate immune co-stimulator molecule CD(80) expression on Raji cells would make rhsCD(40)L a potential bio-factor for tumor immuno-therapy.

B-Lymphocytes↗