Biomedical subjects

Mary Tschoi

Publications and source records attributed to Mary Tschoi.

3 recordsLinked to original sources

PubMed2006

Intralymphatic dendritic cell vaccination induces tumor antigen-specific, skin-homing T lymphocytes.

PURPOSE: The identification of tumor antigens recognized by cytotoxic and T helper lymphocytes has led to the development of specific cancer vaccines. Immunization with tumor antigen-pulsed dendritic cells has proved effective at eliciting elevated levels of tumor antigen-specific T cells in patient blood, but objective clinical responses remain rare, suggesting that vaccine-induced T cells are not trafficking optimally to site(s) of tumor burden. Accumulating evidence from animal models suggests that route of immunization can have a substantial influence on the subsequent migration of primed, activated T cells in vivo. EXPERIMENTAL DESIGN: In a clinical trial designed to elicit more effective cytotoxic T-cell mediated antitumor responses, metastatic melanoma patients were immunized directly via a peripheral intralymphatic route with autologous dendritic cells pulsed with HLA-A*0201-restricted melanoma-associated peptide antigens derived from MART-1 and gp100. RESULTS: Within 10 days of intralymphatic dendritic cell vaccination, four of six patients developed dramatic and diffuse erythematous rashes in sun-exposed areas of skin that showed extensive T-cell infiltration. CTLs grown from rash biopsies were strongly enriched for tumor antigen-specific T cells that had elevated expression of cutaneous lymphocyte antigen and chemokine receptor-6, consistent with a skin-homing phenotype. Of note, the only patient in the study with cutaneously localized disease showed a significant regression of metastatic lesions following the development of a surrounding rash. CONCLUSIONS: The evidence presented here is consistent with immunization studies in animal models and supports the concept that T cells are "imprinted" in peripheral lymph node sites to express specific ligands and chemokine receptors that allow them to migrate to skin. Furthermore, the preferential migration of the T cells to sun-exposed cutaneous sites suggests that inflammation plays a critical role in this migration. These observations suggest that further study of the effects of immunization route and inflammation on T-cell migration in humans is warranted, and could lead to vaccination approaches that would more reliably direct trafficking of activated T cells to diverse sites of metastatic disease.

Adult↗

PubMed2005

Skin flaps.

Open wounds, particularly around the face, often require complicated techniques for optimal closure. The approach to the closure of the complicated wound depends largely on the nature of the wound, including the location and size of the defect, the functional outcome after closure, the medical comorbidities of the patient, neighboring structures, and whether the defect is secondary to a malignancy or trauma. The goals of wound management are optimal aesthetic outcome, preservation of function, and patient satisfaction. The authors briefly review basic skin closure options and discuss use of skin flaps, particularly of the head and neck region.

Facial Injuries↗

PubMed2003

In vivo antitumor activity of interleukin 21 mediated by natural killer cells.

Immunotherapy with high-dose interleukin (IL) 2 has been shown to successfully treat tumors in animal models and cause dramatic tumor regressions in some patients with metastatic melanoma, renal cell carcinoma, and non-Hodgkin's lymphoma. However, toxicity associated with IL-2 administration has compromised its widespread use in the clinic. IL-21 is a more recently discovered cytokine produced by activated CD4(+) T cells that shares significant sequence homology to IL-2, IL-4, and IL-15. Because IL-21 and IL-2 and their receptors share significant sequence similarities and both cytokines can stimulate T and natural killer (NK) cells, we sought to study whether IL-21, like IL-2, exhibits antitumor effects in vivo. In this study, we treated established s.c. tumor in mice by systemically administering plasmid DNA encoding murine IL-21 using a hydrodynamics-based gene delivery technique. Administration of IL-21 plasmid DNA resulted in high levels of circulating IL-21 in vivo. Treatment of tumor-bearing mice with IL-21 plasmid DNA significantly inhibited the growth of B16 melanoma and MCA205 fibrosarcoma in a dose-dependent manner without significant toxicity and increased the survival rate, compared with mice treated with control plasmid DNA. In vivo depletion of either CD4(+) or CD8(+) T cells did not affect IL-21-mediated antitumor activity. However, depletion of NK cells completely abolished IL-21-induced tumor inhibition. Consistent with this, the antitumor activity of IL-21 seemed to be mediated through enhanced cytolytic activity of NK cells. Our study suggests that IL-21 has significant antitumor activity and may have therapeutic potentials as an antitumor agent in the clinic.

Animals↗