T cells isolated from patients with checkpoint inhibitor-resistant melanoma are functional and can mediate tumor regression.

Background: Almost half of the patients with metastatic melanoma obtain only short-term or no benefit at all from checkpoint inhibitor (CPI) immunotherapy. In this study, we investigated whether the immune system of patients progressing following CPI treatment was able to generate functional tumor-specific immune responses. Materials and methods: Tumor-infiltrating lymphocytes (TILs) were isolated and expanded from metastatic melanoma lesions which progressed during or after anti-programmed cell death protein 1 (PD)-1 and anti-Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) treatment. Tumor-specific immune responses were assessed with co-culture assays of TILs and autologous tumor cells. Results: TILs from 23 metastases of individual patients could be assessed for T cells recognition of autologous tumor cells. All metastases were progressive on or following anti-PD-1 (23/23, 100%), and the majority also after anti-CTLA-4 (17/23, 74%). Functional antitumor immune responses were detected in 19/23 patients (83%). Both CD8+ (in 18/23 patients, 78%) and CD4+ (in 16/23 patients, 70%) TILs were able to recognize autologous tumors. A large fraction of CD8+ TILs (median 23%, range 1.0%-84%) recognized tumor cells. This is similar to the cohorts of unselected patient populations with metastatic melanoma presented in previous studies. The localization of intratumoral immune infiltrates was heterogeneous among samples. In a phase I/II clinical trial, TILs were administered with lymphodepleting chemotherapy, pegIFNα2b and interleukin-2 to 12 patients with CPI-resistant melanoma. Out of 12 patients who previously failed CPI therapy, treatment with TILs resulted in two partial responses, of which one is ongoing. Conclusions: Tumor-reactive T cells appear to heavily infiltrate the tumor microenvironment of patients who failed previous CPI treatment. These patients can still respond to an infusion of unselected autologous TILs. Our results warrant further testing of novel immune re-activation strategies in melanoma patients who failed multiple CPI therapy.

The use of cell culture platforms to identify novel markers of bone and dentin resorption.

OBJECTIVES: 1) To test the hypothesis that there would be proteomic differences in the composition of exosomes isolated from osteoclasts and odontoclasts and 2) to determine the clinical usefulness of these in vitro biomarker candidates. MATERIALS AND METHODS: Mouse bone marrow-derived precursors were cultured on either dentin or bone slices and allowed to mature and begin resorption. Exosomes were isolated from cell culture media and characterized by mass spectrometry. The proteomic data obtained from this in vitro study were compared with the data obtained from human samples in our previous work. RESULTS: There was a difference in the proteomic composition of exosomes from osteoclasts and odontoclasts. A total of 40 exosomal proteins were only present in osteoclast media, whereas six unique exosomal proteins were identified in odontoclast supernatants. Approximately 50% of exosomal proteins released by clastic cells in vitro can be found in oral fluids. CONCLUSION: Our data suggest that the mineralized matrix type plays a role in the final phenotypic characteristics of mouse clastic cells. Many in vitro biomarker candidates of bone and dentin resorption can also be found in human oral fluids, thus indicating that this approach may be a viable alternative in biomarker discovery.

Effects of different orthodontic retention protocols on the periodontal health of mandibular incisors.

OBJECTIVES: To test the following two hypotheses: 1) different types of retainers result in distinct levels of biomarkers in gingival crevicular fluid (GCF) and 2) the retainer bonded to all mandibular anterior teeth induces more detrimental outcomes to the periodontium. SETTING AND SAMPLE POPULATION: The Department of Orthodontics at the University of Florida. The population consisted of individuals in the retention phase of orthodontic treatment. MATERIAL AND METHODS: This was a cross-sectional study that enrolled 36 individuals. Subjects in group 1 had retainers bonded to the mandibular canines only. Group 2 consisted of individuals having retainers bonded to all mandibular anterior teeth. Group 3 included patients using mandibular removable retainers. After clinical examination, GCF was collected from the mandibular incisor and biomarker levels were compared between the groups. RESULTS: Plaque accumulation and gingivitis differed significantly among groups, with the highest median values in group 2 subjects. Pairwise comparison of the groups with respect to gingivitis showed significant differences between groups 1 and 2. Significant differences among groups were detected for RANKL, OPG, OPN, M-CSF, MMP-3, and MMP-9. The ratio RANKL/OPG was significantly higher in group 2 subjects, with pairwise comparisons indicating that groups 1 and 2 differed from group 3. CONCLUSION: An association was found between orthodontic retention groups and GCF biomarker levels, which should be further explored in longitudinal studies. The presence of retainers bonded to all anterior teeth seems to increase plaque accumulation and gingivitis.