Major histocompatibility complex class II– fetal skin dendritic cells are potent accessory cells of polyclonal T-cell responses

Whereas dendritic cells (DC) and Langerhans cells (LC) isolated from organs of adult individuals express surface major histocompatibility complex (MHC) class II antigens, DC lines generated from fetal murine skin, while capable of activating naive, allogeneic CD8+ T cells in a MHC class I-restricted fashion, do not exhibit anti-MHC class II surface reactivity and fail to stimulate the proliferation of naive, allogeneic CD4+ T cells. To test whether the CD45+ MHC class I+ CD80+ DC line 80/1 expresses incompetent, or fails to transcribe, MHC class II molecules, we performed biochemical and molecular studies using Western blot and polymerase chain reaction analysis. We found that 80/1 DC express MHC class II molecules neither at the protein nor at the transcriptional level. Ultrastructural examination of these cells revealed the presence of a LC-like morphology with indented nuclei, active cytoplasm, intermediate filaments and dendritic processes. In contrast to adult LC, no LC-specific cytoplasmic organelles (Birbeck granules) were present. Functionally, 80/1 DC in the presence, but not in the absence, of concanavalin A and anti-T-cell receptor monoclonal antibodies stimulated a vigorous proliferative response of naive CD4+ and CD8+ T cells. Furthermore, we found that the anti-CD3-induced stimulation of naive CD4+ and CD8+ T cells was critically dependent on the expression of FcγR on 80/1 DC and that the requirement for co-stimulation depends on the intensity of T-cell receptor signalling

Proteomic Profiling of Advanced Melanoma Patients to Predict Therapeutic Response to Anti-PD-1 Therapy

Purpose: Despite high clinical need, there are no biomarkers that accurately predict the response of patients with metastatic melanoma to anti-PD-1 therapy. Experimental design: In this multicenter study, we applied protein depletion and enrichment methods prior to various proteomic techniques to analyze a serum discovery cohort (n = 56) and three independent serum validation cohorts (n = 80, n = 12, n = 17). Further validation analyses by literature and survival analysis followed. Results: We identified several significantly regulated proteins as well as biological processes such as neutrophil degranulation, cell-substrate adhesion, and extracellular matrix organization. Analysis of the three independent serum validation cohorts confirmed the significant differences between responders (R) and nonresponders (NR) observed in the initial discovery cohort. In addition, literature-based validation highlighted 30 markers overlapping with previously published signatures. Survival analysis using the TCGA database showed that overexpression of 17 of the markers we identified correlated with lower overall survival in patients with melanoma. Conclusions: Ultimately, this multilayered serum analysis led to a potential marker signature with 10 key markers significantly altered in at least two independent serum cohorts: CRP, LYVE1, SAA2, C1RL, CFHR3, LBP, LDHB, S100A8, S100A9, and SAA1, which will serve as the basis for further investigation. In addition to patient serum, we analyzed primary melanoma tumor cells from NR and found a potential marker signature with four key markers: LAMC1, PXDN, SERPINE1, and VCAN