Biomedical subjects

Weiping Zang

Publications and source records attributed to Weiping Zang.

5 recordsLinked to original sources

PubMed2005

MHC Class II-mediated apoptosis by a nonpolymorphic MHC Class II peptide proceeds by activation of protein kinase C.

It was demonstrated previously that a peptide derived from a conserved region of MHC class II, HLA-DQA1, inhibits proliferation of allogeneic T cells in vitro. Administration of HLA-DQA1 in conjunction with allogeneic cells at the time of priming or at the time of rechallenge prevented the development of the delayed type hypersensitivity response in vivo. The immunomodulatory effects of HLA-DQA1 were associated with the induction of apoptosis in B cells, macrophages, and dendritic cells via a caspase-independent pathway. This study investigated the binding site and mechanism that mediates cell death induced by HLA-DQA1. It was demonstrated that HLA-DQA1 binds to MHC class II on the cell surface, causing MHC class II signaling, initiation of protein kinase C signaling, and mitochondrial membrane depolarization with resultant apoptosis. The data indicate that HLA-DQA1 binds to MHC class II outside the groove, in a manner similar to superantigen. These results suggest that HLA-DQA1 is a novel immunotherapy that may provide an effective means of targeting professional antigen-presenting cells, in particular B cells.

Animals↗

PubMed2004

Differential expression of chemokines and chemokine receptors in murine islet allografts: the role of CCR2 and CCR5 signaling pathways.

Chemokines and their receptors play a pivotal role in the initiation and amplification of the immune response. Investigated was their differential expression after syngeneic and allogeneic islet transplantation. During the 7 d after transplantation, the chemokines MCP-1, MCP-2, RANTES, MIG, IP-10, I-TAC, and two CC chemokine receptors CCR2 and CCR5 were highly expressed in allografts when compared with isografts. Disrupting the CCR2 and CCR5 pathways individually resulted in prolongation of the survival time 16.1 +/- 0.4 and 15.8 +/- 0.9 d, respectively, of fully major histocompatibility complex-mismatched islet grafts compared with wild-type controls (11.2 +/- 1.0 d). Blockade of both receptors had no synergistic effect. Rapamycin-treated wild-type recipients rejected their grafts at 17.4 +/- 2.2 d, in contrast to rapamycin-treated CCR2-/- recipients at 38 +/- 8.6 d (P = 0.025). The disruption of the CCR2 and CCR5 signaling, alone or in combination, moderately prolong islet allograft survival. However, the combination of low-dose immunosuppression and targeting of CCR2 greatly augmented islet graft survival.

Animals↗

PubMed2003

Viral IL-10 gene transfer inhibits the expression of multiple chemokine and chemokine receptor genes induced by inflammatory or adaptive immune stimuli.

Previously we have shown that adenovirus-mediated gene transfer and expression of vIL-10 are able to prolong cardiac allograft survival, through the inhibition of the immune response to both alloantigen and adenoviral antigens. In the current study, we have defined further mechanisms of Ad.vIL-10-mediated prolongation of cardiac allograft survival. E1- and E3-deleted adenoviral vectors encoding beta-galactosidase or vIL-10 were transferred into grafts at the time of transplantation, chemokine and chemokine receptor expression were evaluated by a pathway-specific cDNA array, and the results were confirmed with real time RT-PCR on selected genes. Ischemic injury, alloantigen and adenovirus vector induced the expression of multiple pro-inflammatory chemokines in the grafts, which likely amplify allograft rejection. Most of these Th1-related chemokine genes were inhibited or down-regulated by Ad.vIL-10 administration, which may help to decrease leukocytic infiltration and improve graft survival. Among the potent Th1 type chemokines inhibited were the CXCR3 ligands CXCL9 and CXCL10, which could directly inhibit vector-mediated gene expression in myoblasts, although targeting CXCR3 or its ligands did not prolong allograft survival with vIL-10 gene transfer. Ad.vIL-10 administration also induced the expression of the Th2-associated chemokines eotaxin-2 and MIP-1 gamma, suggesting Th1 to Th2 immune deviation. These results demonstrated that the vIL-10 gene transfer inhibits chemokine expression, preventing stimulation of innate and adaptive immunity.

Animals↗

PubMed2000

[Using RevTet-On System to Control Thrombopoietin Gene Expression]

For the purpose of thrombocytopenia gene therapy, recombinant RevTet-On and pRevTRE/TPO retrovirus were packaged and transfected to NIH3T3 after selected with G418 and hygromycin, the two inserting recombinant retrovirus cell strain RevTet-On3T3/TPO were established. TPO expression was controlled and regulated by doxycydine (Dox). After using Dox to control the expression of TPO in RevTet-On3T3/TPO cells, the result showed that when Dox is added to the RevTet-On3T3/TPO cells, cell populations expressed TPO highly in the presence of 2 mg/L of Dox, and lowly in the absence of Dox. By using the RevTet-On gene expression system (the retrovirus vector RevTet-On regulation system to control the expression gene by Dox), it could modulate the expression of multiple genes by tetracyline and its derivatives. This system maybe provides a safe and efficacient way for the thrombocy to penia gene therapy.

Journal Article↗

PubMedDate not supplied

Peptide-mediated immunosuppression.

There is now a substantial body of data demonstrating the abilities of synthetic peptides and peptide analogues to inhibit the auto- and alloimmune response in vitro and in vivo. We have studied the immunomodulatory role of synthetic peptides derived from highly conserved regions of the class II MHC alpha chain. These MHC-derived peptides inhibit the rat, human, and mouse mixed lymphocyte response (MLR), proliferation to autoantigen, cytokine production, and cytolytic T lymphocyte (CTL) generation. Our studies demonstrated that the inhibitory effect of the MHC class II nonpolymorphic peptides is mediated through the induction of apoptosis in APCs via a nonclassic caspase-independent pathway. In addition, T lymphocytes initially stimulated in the presence of HLA-DQA1 are rendered hyporesponsive to subsequent stimuli. Immunomodulation by HLA-DQA1 was effective in vivo because it prevented both the priming and the effector function of primed allogeneic T cells in a murine DTH model. Our data demonstrate that peptides derived from highly conserved regions of the class II MHC alpha chain can alter T-lymphocyte immune responses both in vitro and in vivo. These results have important implications for the development of a novel therapy for immune mediated diseases.

Animals↗