Trafficking of tumor peptide‐specific cytotoxic T lymphocytes into the tumor microcirculation

Abstract

The major histocompatibility complex class I-restricted CD8 ؉ cytotoxic T-lymphocyte (CTL) effector arm of the adaptive immune response can specifically recognize and destroy tumor cells expressing peptide antigens. Although adoptive T-cell therapy has been successfully used for the treatment of viral and malignant diseases, little is known of the trafficking and fate of adoptively transferred antigenspecific T cells. In the present study, splenocytes derived from mice that rejected their tumors (CT26 or CT26-clone 25 tumors) in response to direct intratumor injection of disabled infectious single-cycle herpes simplex virus (DISC-HSV) encoding murine GM-CSF were restimulated with peptide in vitro. CTLs specific for the AH-1 and ␤-gal peptides expressed by CT26 and CT26-clone 25 tumor cells, respectively, were generated and used for adoptive cellular therapy and trafficking studies. Intravenous administration of AH-1-specific CTLs 3 days following i.v. injection of CT26 cells resulted in significant tumor growth inhibition, whereas administration of control CTLs generated against a bacterial ␤-gal peptide did not inhibit the growth of tumors. Trafficking of AH-1-specific lymphocytes and their interaction with the CT26 tumor microcirculation was analyzed using realtime in vivo microscopy (IVM). AH-1-specific but not ␤-galspecific CTLs adhered and localized in the CT26 tumor microvasculature, but neither population adhered to the endothelium of the normal microcirculation. This study provides direct visual evidence suggesting that AH-1-specific CTLs that mediate a therapeutic response traffic to and localize within the tumor microenvironment. © 2004 Wiley-Liss, Inc. Key words: cytotoxic T lymphocytes; adoptive transfer; traffickingThe immune system consists of a complex network of cells that mediate innate and antigen-specific responses to invading microbes and tumors. Processing and presentation of antigen by antigen-presenting cells (dendritic cells) via peptide antigens bound to cell surface major histocompatibility complex (MHC) antigens is a prerequisite for the stimulation of T-cell responses (cytotoxic and helper T cells). 1,2 Tumor-specific cytotoxic T lymphocytes (CTLs) play an important role against cancer; this has been demonstrated using a number of experimental approaches, including the adoptive transfer of tumor-specific CTLs in animal models and clinical trials. 3,4 Beneficial antitumor effects have been reported using adoptive cellular therapy with lymphokine-activated killer (LAK) cells, autolymphocyte therapy (ALT) and in vitro expanded tumor-infiltrating lymphocytes. [5][6][7] The efficacy of adoptive cellular immunotherapy with cultured lymphocytes activated toward tumor antigens requires effector cells to migrate into tumor tissue and, once resident at the tumor site, to mediate an antitumor rejection response either by direct killing of tumor cells and/or indirectly through cytokine release and recruitment of other cells. Using the A2/K b transgenic mouse model, Sutmuller et al. 3 have shown t...

Intravital imaging of anti-tumor immune response and the tumor microenvironment

“…In general, the relative roles of T cell receptor (TCR) specificity versus other non-antigen-specific interactions were studied by visualizing the behavior of fluorescently labeled, adoptively transferred T cells in tumor-bearing mice. Upon adoptive transfer of polyclonal tumor-immune CTL or naive T cells into mice implanted with colon carcinoma, their relative retention in the tumor vasculature was followed in real time [67, 68]. As expected, tumor-immune T cells extravasated preferentially while naïve T cells passed by, in agreement with poor retention of naïve T cells in peripheral tissues [68].…”

Immunotherapeutic potential of DISC-HSV and OX40L in cancer

“…Adoptive transfer experiments using AH-1 peptide specific CTLs into tumor bearing animals led to regression of tumors in these animals whereas administration of CTLs directed against an irrelevant peptide did not influence tumor growth. Not only was the presence of these CTLs observed in the tumors by immunohistochemistry, but their specific trafficking into the tumors was also confirmed by real time in vivo microscopy (IVM) using fluorescently labeled CTLs [4,5].…”

Age-dependent tolerance to an endogenous tumor-associated antigen

“…In CT26 tumor cells, a unique glycoslylated I-E d -restricted epitope contributes to the CD4+ antitumor response [26], and CD8+ T cells respond to the dominant antigen gp70 423-431 /H-2L d (the AH1 antigen) [18]. Gp70 mRNA and T cell responses to gp70-derived antigens are also detectable in other murine tumor cells and models including the 4T1 mammary carcinoma [27], A20 lymphoma [28], and B16 and S91 melanoma cells [18,29]. These findings suggest that the shared gp70 antigen is a bona fide TAA, since these epitopes are derived from a non-mutated self-antigen that is up-regulated during the transformation process.…”