Biomedical subjects

Weila Wang

Publications and source records attributed to Weila Wang.

3 recordsLinked to original sources

PubMed2005

The cytotoxic T lymphocyte response against a protein antigen does not decrease the antibody response to that antigen although antigen-pulsed B cells can be targets.

The role of activated CD8+ T cells in shaping the dynamics of in vivo antigen presentation and immune responses is a subject receiving more attention. We studied whether cytotoxic T lymphocyte (CTL) would limit antibody responses by targeting antigen-specific B cells. A modified in vivo CTL assay was developed and used herein to demonstrate cytotoxicity in vivo, and to show that antigen-specific B cells that process exogenous antigen and present peptide in association with MHC class I can be the targets of CD8+ T cells. B cells from C57BL/6 mice immunized with ovalbumin (OVA)/alum were pulsed with OVA in vitro, and transferred into C57BL/6 recipient mice that had been immunized with vaccinia virus expressing SIINFEKL minigene to generate CD8+ CTL against K(b)/SIINFEKL. OVA-pulsed B220+ B cells from OVA-immunized mice were killed to a greater extent than B220+ B cells from naïve mice (28+/-20% versus 12+/-16%, p=0.0042). However, mice receiving vaccinia-SIINFEKL and generating CTL, did not appear to target endogenous B cells, since both primary and secondary antibody responses to OVA were unaffected. Our findings indicate that CTL responses to the protein antigen do not interfere with endogenous B cell responses, even though exogenous B cells expressing the CTL epitope can be efficiently lysed.

Animals↗

PubMed2005

Identification of a novel immunodominant cytotoxic T lymphocyte epitope derived from human factor VIII in a murine model of hemophilia A.

Gene therapy of hemophilia A could be complicated by the development of immune responses against the vector as well as the Factor VIII (FVIII) transgene. Previous efforts have been focused on identifying FVIII inhibitor antibody epitopes, whereas the cytotoxic T lymphocyte (CTL) epitopes have not been characterized. CTL would kill cells expressing such epitopes and thus limit the efficacy of gene therapy. To investigate CTL responses against human FVIII in a mouse model of hemophilia A, a computer algorithm program (BIMAS) was employed to predict CTL epitopes of human FVIII. The potential binding of these predicted peptides to MHC class I K(b) was evaluated in a TAP-deficient cell line. When recombinant vaccinia virus expressing B domain-deleted human FVIII (vv-FVIII) was used to immunize E16 hemophilia A mice, a specific CTL response against FVIII152-159 was generated. In contrast, a CTL response to four other FVIII peptides was not detected. Therefore, FVIII152-159 represents a dominant CTL epitope. Identification of this epitope raises the possibility that CTL response to FVIII gene-transduced cells can be diminished by deliberatively mutating the dominant CTL epitope while retaining the biologic function of FVIII for hemophilia A gene therapy.

Algorithms↗

PubMed2002

Rhesus monocyte-derived dendritic cells modified to over-express TGF-beta1 exhibit potent veto activity.

BACKGROUND: The tolerogenic activity of allogeneic bone marrow cells (BMCs) associates with functional inactivation of alloreactive T cells and has been attributed to a veto effect. Studies in mice and rhesus monkeys indicated that the CD8alpha molecule expressed on a subpopulation of allogeneic BMCs is necessary to induce signal transduction within the BMCs to increase veto effector molecules such as transforming growth factor (TGF)-beta1. In vitro activation of alloreactive cytotoxic T-lymphocyte precursor enhances their susceptibility to veto-mediated functional inactivation by specific alloantigen-bearing BMCs. Accordingly, we examined a hypothesis that mature rhesus monkey (Rh) monocyte-derived dendritic cells (MDDCs) modified by gene transfer to over-express active TGF-beta1 might mediate veto activity without the need to express CD8alpha. METHODS: Rh MDDCs were modified by recombinant adenovirus (Ad) transduction and characterized by phenotype and functional studies. RESULTS: Rh MDDC transduction with Ad vectors using conventional methods was remarkably inefficient. However, a single-chain anti-CD40/soluble Coxsackie and adenovirus receptor-fusion protein (G28/sCAR) permitted high-efficiency transduction of Rh MDDCs by retargeting Ad to Rh MDDC CD40. Mature Rh MDDCs that were transduced to overexpress active TGF-beta1 (AdTGF-beta1 Rh MDDC) significantly suppressed alloimmune responses in [ H]thymidine uptake mixed leukocyte reaction assays. We showed by the carboxyfluorescein succinimidyl ester dilution method that allogeneic mature AdTGF-beta1 Rh MDDCs inhibited proliferation of CD4 and CD8 responder T cells. Notably, AdTGF-beta1 Rh MDDC abrogated alloimmune responses induced by control AdGFP Rh MDDC in an antigen-specific manner. CONCLUSIONS: These results suggest that nonhuman primate mature MDDCs can be genetically engineered to function as alloantigen-specific cellular immunosuppressants, an approach that has potential to facilitate induction of allograft tolerance in vivo.

Adenoviridae↗