116. Members of Adenovirus Subgroup B Utilize CD80 (B7.1) and CD86 (B7.2) as Primary Cellular Attachment Receptors

Abstract

OX40 ligand (OX40L), the ligand for OX40 on T cells, is essential for induction of antigen-specific T-cell responses, a critical component of the immune response to tumors. In this study, we examined in vivo transduction of tumors with recombinant adenovirus (Ad) vector of mouse OX40L (AdOX40L) to elicit therapeutic antitumor immunity in three different murine tumor models in two strains of mice. In the Colon-26 (H-2d, colon cancer) and the B16 (H-2b, melanoma) murine models, intratumoral injection of 109 pfu AdOX40L to established subcutaneous tumors resulted in sustained tumor regression. Intratumoral injection of AdOX40L also significantly suppressed growth of weakly immunogenic Lewis lung carcinoma (H-2b) established tumors. In vivo AdOX40L modification of tumors to express OX40L elicited tumor-specific cytolytic T lymphocytes responses. These results support the concept that in vivo transduction of tumors with a recombinant OX40L Ad vector may be a useful strategy to help develop cancer immunotherapy.