Amy Popple

The chemokine, CXCL12, is an independent predictor of poor survival in ovarian cancer.

Background:The chemokine CXCL12 and its cognate receptor, CXCR4, have been implicated in numerous tumour types where expression promotes tumour growth, angiogenesis, metastasis and suppresses tumour immunity.Methods:Using a tissue microarray of 289 primary ovarian cancers coupled to a comprehensive database of clinicopathological variables, the expression of CXCL12 and CXCR4 was assessed by immunohistochemistry and its impact in terms of survival and clinicopathological variables was determined.Results:Patients whose tumours expressed high levels of CXCL12 had significantly poorer survival (P=0.026) than patients whose tumours failed to produce this chemokine. Lack of CXCL12 expression within tumours was associated with a 51-month survival advantage for patients when compared with patients whose tumours expressed high levels of CXCL12. FIGO stage, adjuvant chemotherapy and the absence of macroscopic disease after surgery were all shown to predict prognosis independently of each other in this cohort of patients. CXCL12 was independently predictive of prognosis on multivariate analysis (P=0.016). There was no correlation between CXCL12 and any clinicopathological variable.Conclusion:The chemokine CXCL12 is an independent predictor of poor survival in ovarian cancer. High expression of CXCL12 was seen in only 20% of the tumours, suggesting a role for anti-CXCL12/CXCR4 therapy in the management of these patients.

Fractionated radiation therapy stimulates anti-tumor immunity mediated by both resident and infiltrating polyclonal T-cell populations when combined with PD1 blockade

Purpose: Radiotherapy is a highly effective anticancer treatment forming part of the standard of care for the majority of patients, but local and distal disease recurrence remains a major cause of mortality. Radiotherapy is known to enhance tumor immunogenicity; however, the contribution and mechanisms of radiotherapy-induced immune responses are unknown. Experimental Design: The impact of low-dose fractionated radiotherapy (5 × 2 Gy) alone and in combination with αPD-1 mAb on the tumor microenvironment was evaluated by flow cytometry and next-generation sequencing of the T-cell receptor (TCR) repertoire. A dual-tumor model was used, with fractionated radiotherapy delivered to a single tumor site to enable evaluation of the local and systemic response to treatment and ability to induce abscopal responses outside the radiation field. Results: We show that fractionated radiotherapy leads to T-cell infiltration at the irradiated site; however, the TCR landscape remains dominated by polyclonal expansion of preexisting T-cell clones. Adaptive resistance via the PD-1/PD-L1 pathway restricts the generation of systemic anticancer immunity following radiotherapy, which can be overcome through combination with αPD-1 mAb leading to improved local and distal tumor control. Moreover, we show that effective clearance of tumor following combination therapy is dependent on both T cells resident in the tumor at the time of radiotherapy and infiltrating T cells. Conclusions: These data provide evidence that radiotherapy can enhance T-cell trafficking to locally treated tumor sites and augment preexisting anticancer T-cell responses with the capacity to mediate regression of out-of-field tumor lesions when delivered in combination with αPD-1 mAb therapy. Clin Cancer Res; 23(18); 5514–26. ©2017 AACR.

The lymphocyte transformation test in allergic contact dermatitis: New opportunities

Abstract Allergic contact dermatitis (ACD) is driven by the activation and proliferation of allergen-specific memory T-lymphocytes and is currently diagnosed by patch testing with a selected panel of chemical allergens. The lymphocyte transformation test (LTT) can be used to monitor ex vivo T-lymphocyte responses to antigens, including contact allergens. The LTT is not viewed as being an alternative to patch testing, but it does seek to reflect experimentally skin sensitization to specific chemicals. The LTT is based on stimulation in vitro of antigen-driven T-lymphocyte proliferation. That is, exposure in culture of primed memory T-lymphocytes to the relevant antigen delivered in an appropriate configuration will provoke a secondary response that reflects the acquisition of skin sensitization. The technical aspects of this test and the utility of the approach for investigation of immune responses to contact allergens in humans are reviewed here, with particular emphasis on further development and refinement of the protocol. An important potential application is that it may provide a basis for characterizing those aspects of T-lymphocyte responses to contact allergens that have the greatest influence on skin sensitizing potency and this will be considered in some detail.

Anti-hapten antibodies in response to skin sensitization.

Whereas T lymphocyte (T cell) activation is the key event in the acquisition of skin sensitization and subsequent elicitation of allergic contact dermatitis, the humoral component of immune responses to organic contact allergens has received little consideration. There is evidence that, in experimental animals, topical exposure to potent contact allergens is associated with B cell activation and proliferation, and hapten‐specific antibody production. However, there is very limited evidence available for anti‐hapten antibody responses being induced following topical exposure of humans to contact allergens. Nevertheless, it is important to appreciate that there are almost no negative studies in which evidence for antibody production as the result of skin sensitization has been sought and not found. That is, there is absence of evidence rather than evidence of absence. Furthermore, exposure to chemical respiratory allergens, in which the skin has been implicated as a potential route of sensitization, results in anti‐hapten antibody responses. It is proposed that skin sensitization to contact allergens will normally be accompanied by antibody production. The phenomenon is worthy of investigation, as anti‐hapten antibodies could potentially influence and/or regulate the induction of skin sensitization. Moreover, such antibodies may provide an informative correlate of the extent to which sensitization has been acquired.

T lymphocyte dynamics in methylisothiazolinone‐allergic patients

Methylisothiazolinone (MI), a preservative that is commonly used in personal care products, is now recognized as an important contact allergen in both cosmetic and occupational settings.

The T Cell Response to the Contact Sensitizer Paraphenylenediamine Is Characterized by a Polyclonal Diverse Repertoire of Antigen-Specific Receptors

Paraphenylenediamine (PPD) is a common component of hair dyes and black henna tattoos and can cause skin sensitization and allergic contact dermatitis (ACD). The cutaneous inflammatory reaction associated with ACD is driven by both CD4+ and CD8+ T cells. However, the characteristics of such responses with respect to clonal breadth and magnitude are poorly defined. In this study, we have characterized the in vitro recall response of peripheral blood T cells prepared from PPD-allergic individuals to a PPD–human serum albumin (HSA) conjugate (PPD–HSA). Quantitative high throughput sequencing was used to characterize the changes in the repertoire of T cell receptor (TCR) α and β genes after exposure to antigen in vitro. The PPD conjugate induced expansion of T cells carrying selected TCRs, with around 800 sequences (around 1%) being 8 or more times as abundant after culture than before. The expanded sequences showed strong skewing of V and J usage, consistent with an antigen-driven clonal expansion. The complementarity-determining region 3 sequences of the expanded TCRs could be grouped into several families of related amino acid sequence, but the overall diversity of the expanded sample was not much less than that of a random sample of the same size. The results suggest a model in which PPD–HSA conjugate stimulates a broad diversity of TCRs, with a wide range of stimulation strengths, which manifest as different degrees of in vitro expansion.

Abstract 1562: Choosing the right preclinical model for cancer immunotherapy: The “SyngenOmic” toolbox..

Recent FDA approvals of ipilimumab and sipuleucel-T for the treatment of metastatic melanoma and castrate-resistant prostate cancer respectively have validated the approach to modulate the immune system for the clinical treatment of cancer. MedImmune Oncology, has an extensive pipeline and expertise in investigational Immune Mediated Therapy in Cancer (IMT-C) drugs (e.g. tremelimumab and MEDI4736), and is heavily invested in this novel era of cancer therapeutics. Pre-clinical assessment of the validity of potential IMT-C drugs can be enabled by the use of syngeneic tumours established in immuno-competent animals. MedImmune9s pharmacology team has lead efforts to develop such models, to a point that a panel of 15 different validated syngeneic tumour types is available in house for studies to progress projects. The intention of selecting relevant models and of minimizing animal experimentation, reduces the number of models tested for each project, and allows for detailed genetic and proteomic characterization of treatment dependent effects within our models. Utilising both in vitro and in vivo approaches, we have generated transcriptomic and genomic data for our cell lines, the resulting implanted tumours and for the relevant lymphatic organs (draining lymph node and spleen). Using key proteomic/cell markers through IHC and FACS analysis, we are also evaluating the immune profile/status of our tumour bearing animals in parallel. Finally, in order to establish the disease relevance and prognostic value of our models we are analyzing our cell panel for the presence of somatic mutations in 50 genes previously implicated in human cancers. Once completed, the resulting dataset will hopefully help pre-clinical scientists to refine their in vivo plans and deliver more clinically-relevant pharmacology packages for the progression of cancer immunotherapy drug candidates. Citation Format: James A. Harper, John Prime, Athula Herath, Jane Howell, Marianna Papaspyridonos, Amy Popple, Judith Anderton, Michelle Morrow, Arthur Lewis, Liz Henley, Matthew McCourt, Richard Sainson. Choosing the right preclinical model for cancer immunotherapy: The “SyngenOmic” toolbox. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1562. doi:10.1158/1538-7445.AM2013-1562