Expression of B7-1 by Pam 212 squamous cell carcinoma enhances tumor cell interactions with dendritic epidermal cells but does not affect in vivo tumor growth

Perforins Expression by Cutaneous Gamma Delta T Cells

Gamma delta (GD) T cells are an unconventional T cell type present in both the epidermis and the dermis of human skin. They are critical to regulating skin inflammation, wound healing, and anti-microbial defense. Similar to CD8+ cytotoxic T cells expressing an alpha beta (AB) TCR, GD T cells have cytolytic capabilities. They play an important role in elimination of cutaneous tumors and virally infected cells and have also been implicated in pathogenicity of several autoimmune diseases. T cell cytotoxicity is associated with the expression of the pore forming protein Perforin. Perforin is an innate immune protein containing a membrane attack complex perforin-like (MACPF) domain and functions by forming pores in the membranes of target cells, which allow granzymes and reactive oxygen species to enter the cells and destroy them. Perforin-2, encoded by the gene MPEG1, is a newly discovered member of this protein family that is critical for clearance of intracellular bacteria. Cutaneous GD T cells express both Perforin and Perforin-2, but many questions remain regarding the role that these proteins play in GD T cell mediated cytotoxicity against tumors and bacterial pathogens. Here, we review what is known about Perforin expression by skin GD T cells and the mechanisms that contribute to Perforin activation.

Anti-Tumor Immunity in Head and Neck Cancer: Understanding the Evidence, How Tumors Escape and Immunotherapeutic Approaches

Many carcinogen- and human papilloma virus (HPV)-associated head and neck cancers (HNSCC) display a hematopoietic cell infiltrate indicative of a T-cell inflamed phenotype and an underlying anti-tumor immune response. However, by definition, these tumors have escaped immune elimination and formed a clinically significant malignancy. A number of both genetic and environmental mechanisms may allow such immune escape, including selection of poorly antigenic cancer cell subsets, tumor produced proinflammatory and immunosuppressive cytokines, recruitment of immunosuppressive immune cell subsets into the tumor and expression of checkpoint pathway components that limit T-cell responses. Here, we explore concepts of antigenicity and immunogenicity in solid tumors, summarize the scientific and clinical data that supports the use of immunotherapeutic approaches in patients with head and neck cancer, and discuss immune-based treatment approaches currently in clinical trials.

Nanotechnology in vaccine development: a step forward

The study of nanotechnology for epicutaneous delivery of pharmaceuticals and vaccines is burgeoning. Topically applied nanomaterials have been shown to enter tape-stripped skin and reach draining lymph nodes in an inbred strain of mice. Nanomaterials in the form of plasmid DNA, proteins, and virus particles accumulate in hair follicles, diffuse via dendritic cells to draining lymph nodes, and elicit antigen-specific humoral and cell-mediated immunity. Topically immunized mice have also demonstrated resistance to infection with live virus. Advantages of nanotechnology include uniformity, reproducibility, and precision in the synthesis and manufacture of candidate compounds. Combined with novel pharmacokinetics and the possibility of targeted therapy, nanotechnology-based vaccines may prove superior to existing vaccines and have the potential to open therapeutic avenues for treating infectious disease and malignancy.

Transfection of CD40 in a human oral squamous cell carcinoma keratinocyte line upregulates immune potency and costimulatory molecules

BACKGROUND

There is upregulation of class II molecules of the major histocompatibility complex (MHC) by keratinocytes in oral squamous cell carcinoma (OSCC) and inflammatory diseases such as lichen planus. The significance of this expression, or whether it is accompanied by upregulation of membrane-bound costimulatory molecules, is unknown.

OBJECTIVES

To compare the expression of CD40, CD80, CD86, MHC class II and intercellular adhesion molecule-1 (ICAM-1), and the ability to induce allogeneic T-lymphocyte proliferation in vitro, of a CD40- OSCC cell line, its CD40+ transfected derivative and null transfectants.

METHODS

OSCC cell lines and purified T lymphocytes were cocultured and T cell proliferation recorded. Phenotypes were analysed by flow cytometry.

RESULTS

After T lymphocyte proliferation, which all OSCC cell lines were able to induce, there was upregulation of MHC class II and ICAM-1. However, the CD40+ transfectants were the most immunologically potent and were the only cells to show increased expression of CD86 (as well as further upregulation of CD40 and a statistically insignificant rise in CD80). The effects of blocking antibodies on T-cell proliferation were only statistically significant with the CD40+ transfectants.

CONCLUSIONS

While not essential, expression of CD40 by OSCC cells is necessary for optimal induction of allogeneic T lymphocytes, possibly because of concurrent upregulation of other membrane-bound costimulatory molecules.

Decreased expression of CD80 is a marker for increased tumorigenicity in a new murine model of oral squamous-cell carcinoma

We established a new syngeneic murine model of oral squamous-cell carcinoma (SCC) to analyze the potential role of immune recognition determinants in the early development of oral cancer. In this study, we examined whether SCC that undergo transformation and development in the absence of specific immunity exhibit differences in tumorigenicity that relate to differences in expression of CD80, CD86 or MHC class I. Mucosal keratinocytes from BALB/c mice were transformed in vitro with 4-nitroquinolone-1-oxide (4-NQO) and inoculated into SCID mice to obtain tumorigenic cell lines. Five SCC cell lines were re-isolated from tumors, and 4 retained cytokeratin and beta4-integrin markers of epithelial origin. Their growth was compared in BALB/c and in congenic SCID mice to establish whether the cell lines exhibit differences in immunogenicity. Three lines that showed slower growth or completely regressed when implanted in immune competent hosts retained or developed increased expression of CD80 during development in SCID mice. Conversely, 2 SCC lines that lost expression of CD80 after passage in vivo grew progressively in immune-competent hosts. MHC-class-I and CD86 expression did not correlate with tumorigenicity. These observations provide evidence that decreased expression of CD80 may serve as a marker for increased tumorigenicity during early development of oral SCC. The development of this new murine oral SCC model should prove useful in determining the potential effects of CD80 expression on the immune pathogenesis and therapy of SCC.