Human Tumor-Derived Heat Shock Protein 96 Mediates In Vitro Activation and In Vivo Expansion of Melanoma- and Colon Carcinoma-Specific T Cells

Abstract Heat shock proteins (hsp) 96 play an essential role in protein metabolism and exert stimulatory activities on innate and adaptive immunity. Vaccination with tumor-derived hsp96 induces CD8+ T cell-mediated tumor regressions in different animal models. In this study, we show that hsp96 purified from human melanoma or colon carcinoma activate tumor- and Ag-specific T cells in vitro and expand them in vivo. HLA-A*0201-restricted CD8+ T cells recognizing Ags expressed in human melanoma (melanoma Ag recognized by T cell-1 (MART-1)/melanoma Ag A (Melan-A)) or colon carcinoma (carcinoembryonic Ag (CEA)/epithelial cell adhesion molecule (EpCAM)) were triggered to release IFN-γ and to mediate cytotoxic activity by HLA-A*0201-matched APCs pulsed with hsp96 purified from tumor cells expressing the relevant Ag. Such activation occurred in class I HLA-restricted fashion and appeared to be significantly higher than that achieved by direct peptide loading. Immunization with autologous tumor-derived hsp96 induced a significant increase in the recognition of MART-1/Melan-A27–35 in three of five HLA-A*0201 melanoma patients, and of CEA571–579 and EpCAM263–271 in two of five HLA-A*0201 colon carcinoma patients, respectively, as detected by ELISPOT and HLA/tetramer staining. These increments in Ag-specific T cell responses were associated with a favorable disease course after hsp96 vaccination. Altogether, these data provide evidence that hsp96 derived from human tumors can present antigenic peptides to CD8+ T cells and activate them both in vitro and in vivo, thus representing an important tool for vaccination in cancer patients

Registered replication report: a large multilab cross-cultural conceptual replication of Turri, Buckwalter, & Blouw (2015)

According to the Justified True Belief account of knowledge (JTB), a person can only truly know something if they have a belief that is both justified and true (i.e., knowledge is justified true belief). This account was challenged by Gettier (1963), who argued that JTB does not explain knowledge attributions in certain situations, later called Gettier-type cases, wherein a protagonist is justified in believing something to be true, but their belief was only correct due to luck. Lay people may not attribute knowledge to protagonists with justified but only luckily true beliefs. While some research has found evidence for these so-called Gettier intuitions (e.g., Machery et al., 2017a), Turri et al. (2015) found no evidence that participants attributed knowledge in a counterfeit-object Gettier-type case differently than in a matched case of justified true belief. In a large-scale, cross-cultural conceptual replication of Turri and colleagues’ (2015) Experiment 1 (N = 4,724) using a within-participants design and three vignettes across 19 geopolitical regions, we did find evidence for Gettier intuitions; participants were 1.86 times more likely to attribute knowledge to protagonists in standard cases of justified true belief than to protagonists in Gettier-type cases. These results suggest that Gettier intuitions may be detectable across different scenarios and cultural contexts. However, the size of the Gettier intuition effect did vary by vignette, and the Turri et al. (2015) vignette produced the smallest effect, which was similar in size to that observed in the original study. Differences across vignettes suggest epistemic intuitions may also depend on contextual factors unrelated to the criteria of knowledge, such as the characteristics of the protagonist being evaluated

Natural-Killer-Derived Extracellular Vesicles: Immune Sensors and Interactors

Natural killer (NK) cells contribute to immunosurveillance and first-line defense in the control of tumor growth and metastasis diffusion. NK-cell-derived extracellular vesicles (NKEVs) are constitutively secreted and biologically active. They reflect the protein and genetic repertoire of originating cells, and exert antitumor activity in vitro and in vivo. Cancer can compromise NK cell functions, a status potentially reflected by their extracellular vesicles. Hence, NKEVs could, on the one hand, contribute to improve cancer therapy by interacting with tumor and/or immune cells and on the other hand, sense the actual NK cell status in cancer patients. Here, we investigated the composition of healthy donors’ NKEVs, including NK microvesicles and exosomes, and their interaction with uncompromised cells of the immune system. To sense the systemic NK cell status in cancer patients, we developed an immune enzymatic test (NKExoELISA) that measures plasma NK-cell-derived exosomes, captured as tsg101+CD56+ nanovesicles. NKEV mass spectrometry and cytokine analysis showed the expression of NK cell markers, i.e., NKG2D and CD94, perforin, granzymes, CD40L, and other molecules involved in cytotoxicity, homing, cell adhesion, and immune activation, together with EV markers tsg101, CD81, CD63, and CD9 in both NK-derived exosomes and microvesicles. Data are available via Proteome Xchange with identifier PXD014894. Immunomodulation studies revealed that NKEVs displayed main stimulatory functions in peripheral blood mononuclear cells (PBMCs), inducing the expression of human leukocyte antigen DR isotype (HLA-DR) and costimulatory molecules on monocytes and CD25 expression on T cells, which was maintained in the presence of lipopolysaccharide (LPS) and interleukin (IL)-10/transforming growth factor beta (TGFβ), respectively. Furthermore, NKEVs increased the CD56+ NK cell fraction, suggesting that effects mediated by NKEVs might be potentially exploited in support of cancer therapy. The measurement of circulating NK exosomes in the plasma of melanoma patients and healthy donors evidenced lower levels of tsg101+CD56+ exosomes in patients with respect to donors. Likewise, we detected lower frequencies of NK cells in PBMCs of these patients. These data highlight the potential of NKExoELISA to sense alterations of the NK cell immune status

A platform for high-resolution immune liquid biopsy analysis to predict response in patients with renal cell carcinoma treated with nivolumab or cabozantinib: Preliminary data from I-RENE trial (Meet-URO 8 study)

Background: Nivolumab, an immune checkpoint inhibitor of PD-1, demonstrated a significant OS benefit in patients with metastatic renal cell carcinoma (mRCC), in progression after a previous line of therapy with anti-VEGFR agents. However, the features of effective immune response and predictive biomarkers of clinical benefit to PD-1 blockade have not yet been recognized. Methods: I-RENE is a prospective translational multicenter Italian study of a real-life mRCC patients treated with nivolumab or cabozantinib after failure of therapy with anti-VEGFR agents. 82 patients were enrolled from December 2018 to August 2022 (nivo 60, cabo 22), with blood samples obtained at baseline and at different time points in both treatment groups. An extended concept of "immune liquid biopsy" is being applied to the study, consisting in the phenotypic and transcriptional profile of lymphoid and myeloid subsets, immune-related miRNA quantification, cyto/chemo-kinome and RNAseq of extracellular vesicle. Results: Multiparametric flow cytometry, performed to monitor the blood frequency and different myeloid and lymphoid cells, show that monocyte subsets (classical, intermediate and non-classical CD14+ cells), monocytic myeloid derived suppressor cells (MDSC, such as CD14+HLA-DRneg and CD14+PD-L1+) and polymorphonucleate (PMN)-MDSC, remain either stable or increase during treatment; concomitantly, CD8+PD-1+ T cells (detected by anti-nivolumab IgG4) increment frequency, acquire the effector CD45RA-CCR7+ phenotype and express the proliferating marker Ki67. Patients receiving cabozantinib display instead a remarkable decrease of all myeloid cell subsets, paired by the boost of cytotoxic CD3-CD16+CD56dim NK cells and more marginally of CD8+PD1+ cells, Preliminary correlations indicate that clinical benefit of nivolumab seems to cluster with the lack of CD14+ cells and M-MDSC increase and blood frequency of total, and the boost in CD8+CD45RA-CCR7+Ki67+ effector T cells. In contrast, the cabozantinib-induced immune modulation occurring in patients treated with does not associate with clinical response Conclusions: This first set of data indicate blood as promising source of dynamic biomarkers for the development of algorithms predicting response to PD-1 blockade. Furthermore, the results so far collected suggest that the potent immunomodulation induced by cabozantinib on the immunosuppressive myeloid compartment may not lead to any tumor control in the absence of specific immune stimulation by checkpoint inhibitors. This study was supported by the Italian Ministry of health (RF-2016_02363001). Clinical trials.gov: NCT0489105