SUMMARY
HSP70i and other stress proteins have been used in anti-tumor vaccines. This begs the question whether HSP70i plays a unique role in immune activation. We vaccinated inducible HSP70i (Hsp70-1) knockout mice and wild-type animals with optimized TRP-1, a highly immunogenic melanosomal target molecule. We were unable to induce robust and lasting depigmentation in the Hsp70-1 knockout mice, and in vivo cytolytic assays revealed a lack of CTL activity. Absence of T cell infiltration to the skin and maintenance of hair follicle melanocytes was observed. By contrast, depigmentation proceeded without interruption in mice lacking a tissue specific constitutive isoform of HSP70 (Hsp70-2) vaccinated with TRP-2. Next, we demonstrated that HSP70i was necessary and sufficient to accelerate depigmentation in vitiligo-prone Pmel-1 mice, accompanied by lasting phenotypic changes in dendritic cell subpopulations. In summary, these studies assign a unique function to HSP70i in vitiligo, and identify HSP70i as targetable entity for treatment.
HSP70i and other stress proteins have been used in anti-tumor vaccines. This begs the question whether HSP70i plays a unique role in immune activation. We vaccinated inducible HSP70i (Hsp70-1) knockout mice and wild-type animals with optimized TRP-1, a highly immunogenic melanosomal target molecule. We were unable to induce robust and lasting depigmentation in the Hsp70-1 knockout mice, and in vivo cytolytic assays revealed a lack of CTL activity. Absence of T cell infiltration to the skin and maintenance of hair follicle melanocytes was observed. By contrast, depigmentation proceeded without interruption in mice lacking a tissue specific constitutive isoform of HSP70 (Hsp70-2) vaccinated with TRP-2. Next, we demonstrated that HSP70i was necessary and sufficient to accelerate depigmentation in vitiligo-prone Pmel-1 mice, accompanied by lasting phenotypic changes in dendritic cell subpopulations. In summary, these studies assign a unique function to HSP70i in vitiligo, and identify HSP70i as targetable entity for treatment.
The antibody HMB45 is used to diagnose lymphangioleiomyomatosis, a hyperproliferative disorder of lung smooth muscle cells with mutations in both alleles of either TSC1 or TSC2. A subset of these tumor cells expresses the melanoma-associated antigens gp100 and melanoma antigen recognized by T cells (MART-1). To explore the feasibility of targeting tumors in lymphangioleiomyomatosis by melanoma immunotherapy, we therefore assessed melanoma target antigen expression and existing immune infiltration of affected tissue compared with normal lung and melanoma as well as the susceptibility of cultured lymphangioleiomyomatosis cells to melanoma reactive cytotoxic T lymphocytes in vitro. Tumors expressed tyrosinase-related proteins 1 and 2 but not tyrosinase, in addition to gp100 and MART-1, and were densely infiltrated by macrophages, but not dendritic cells or T cell subsets. Although CD8 ؉ lymphocytes were sparse compared with melanoma, cells cultured from lymphangioleiomyomatosis tissue were susceptible to cytotoxic, gp100 reactive, and major histocompatibility complex class I restricted CD8 ؉ T cells in functional assays. Responder T cells selectively clustered and secreted interferon-␥ in response to HLA-matched melanocytes and cultured lymphangioleiomyomatosis cells. This reactivity exceeded that based on detectable gp100 expression; thus , tumor cells in lymphangioleiomyomatosis may process melanosomal antigens different from melanocytic cells. Therefore , boosting immune responses to gp100 in lymphangioleiomyomatosis may offer a highly desirable treatment option for this condition.
Expression of proliferation markers PCNA and MIB 1 was evaluated in 17 verrucous carcinomas and in five cases of normal squamous epithelium of the oral cavity. Immunohistochemistry revealed no significant differences in the proliferative activities. Highest expression was seen in the basal zones. Proliferative activity in more than 26% of cells is no longer compatible with verrucous carcinoma, but favours the diagnosis of squamous cell carcinoma.
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