1. ¹Department of Internal Medicine and the Barrett Cancer Center, University of Cincinnati, Cincinnati, OH 45267, USA
2. ²Department of Otolaryngology–Head and Neck Surgery, University of Pennsylvania Health System, Philadelphia, PA 19104, USA

Correspondence: Sunil K. Chatterjee, Fax: +1 513 558 0505. E-mail: sunil.chatterjee@uc.edu

Received 11 April 2005; Revised 18 May 2005; Accepted 11 June 2005.

Abstract

Induction of T cell immunity following vaccination with a recombinant vaccinia virus expressing interleukin-2 (rvv-IL-2) was studied in an orthotopic murine model (SCCVII/SF) of head and neck squamous cell carcinoma (HNSCC). Mice bearing SCCVII/SF cells in the oral cavity were vaccinated subcutaneously with irradiated, rvv-IL-2-infected tumor cells combined with intratumoral injection of rvv-IL-2, resulting in recruitment of larger numbers of CD3⁺ CD8⁺ and CD3⁺ CD4⁺ T cells in the spleen (Sp) and tumor-draining lymph nodes (TDLN) compared to control vaccine rvv-lacZ. Tumor-specific CD8⁺ T and CD4⁺ helper T cell activities in the Sp and TDLN were significantly increased in rvv-IL-2-treated mice. Sp and TDLN cells from rvv-IL-2-treated mice secreted significantly higher levels of IL-2 and IFN- compared to rvv-lacZ-treated mice, while the levels of IL-4 and IL-5 were comparable. Numbers of IFN--secreting cells were also higher in rvv-IL-2-treated mice. Vaccine efficiency was completely abolished by depletion of CD8⁺/CD4⁺ T cells from rvv-IL-2-vaccinated mice. We conclude that anti-tumor activities of rvv-IL-2 are due to the induction of tumor-specific CD8⁺ CTL and CD4⁺ Th1-type helper T cells, and rvv-IL-2 may be used for treatment of HNSCC patients, since SCC VII/SF closely resembles HNSCC.