Dendritic cells (DCs) have the potential to elicit long-lasting anti-tumour immune responses. Most of the clinical trials of anti-cancer DC vaccines are based on monocyte-derived DCs (Mo-DCs). However, their outcomes have shown limited promise especially in multiple myeloma (MM) patients. Here, we investigated whether in vitro generated Mo-DCs from MM patients (MM-DCs) possess impaired functionality, thus contributing to the limited success of DC vaccines. We generated MM-DCs and compared them with DCs from healthy donors (HD-DCs). The yield of DCs in MM was 3.5 fold lower than in HD sets. However morphology, phenotype, antigen uptake and allo-T cell stimulation were comparable. Migration and secretion of IL12p70 and IFN-γ (in DC-T cell co-cultures) were significantly reduced in MM-DCs. Thus, MM-DCs were compromised in functionality. This impairment could be attributed to autocrine secretion of IL6 by MM-monocytes and activation of their P38 MAPK pathway. This indicates a need to look for alternative sources of DCs.

Bacteriophage therapy has been regaining interest as a potential therapeutic in treating a wide range of infections. However, there is a paucity of knowledge regarding numerous aspects of bacteriophage therapy, thereby hindering the development of proper treatment protocols and effective clinical trials. In this report, the activities of three bacteriophages are evaluated against clinical bacterial isolates in the presence and absence of human plasma (HP). The bacteriophages used in this experiment were residual therapeutic doses from the United States Food and Drug Administration (FDA) approved compassionate use cases to treat recalcitrant prosthetic joint infections (PJIs). Herein we demonstrate that in the presence of HP, the infectivity of these Staphylococcal bacteriophages was significantly reduced compared to the infectivity in the absence of HP. Inhibition of infectivity ranged from 48% to 81% for two methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates independently infected with the same bacteriophage and 98% for a third MRSA clinical isolate infected with a different bacteriophage. In contrast, bacteriophage infectivity of an Enterococcus faecalis clinical isolate was not affected by the presence of HP. We hypothesize that the inhibition is correlated with plasma proteins binding to Staphylococcal surface proteins masking the receptors associated with bacteriophage attachment, thereby reducing infectivity. This has clinical ramifications for bacteriophage therapy use in treating Staphylococcal bacteremia and periprosthetic joint infections.

BACKGROUND: Dendritic cell (DC) vaccination involves administration of multiple doses. Cryopreservation of tumor antigen-pulsed DCs can provide a ready to use vaccine source and eliminate the need of frequent withdrawal of the patient's blood for vaccine preparation. The aim of this study was to assess the effect of addition of trehalose in the freezing medium on the recovery of DCs after cryopreservation.STUDY DESIGN AND METHODS: DCs were generated from mononuclear cells from apheresis samples of healthy donors. For long-term storage of 6 months, cells were frozen with a rate-controlled programmable freezer and stored in liquid nitrogen. For short-term storage of 1 month, cells were frozen and stored at −80 C. DCs frozen with Iscove's Modified Dulbecco's Medium + 10% dimethyl sulfoxide + 20% fetal bovine serum served as the control group, while the test group was additionally supplemented with 50 μg/mL of trehalose. After revival of control and test DCs, they were assessed for viability, morphology, phenotype, and functions. RESULTS:The addition of trehalose to the conventional freezing medium helped to preserve the viability and functionality of DCs better than dimethyl sulfoxide alone in both long-and short-term cryopreservation. Trehalose also protected the mitochondrial membrane potential and cytoskeleton integrity of DCs, which are necessary for their functionality. Mediators of the intrinsic apoptotic pathway like Caspase-9 and Bim-1 were found to be low in the test. CONCLUSION: Supplementation of conventional freezing medium with trehalose results in better quality of DCs revived after cryopreservation. This finding could help improve DC vaccine preparation for cancer immunotherapy. ABBREVIATIONS: CFSE = carboxyfluorescein succinimidyl ester; CPAs = cryoprotective agents; CTL = cytotoxic T-lympocyte; DC = dendritic cell; DMSO = dimethyl sulfoxide; FBS = fetal bovine serum; HLA = human leukocyte antigen; IMDM = Iscove's Modified Dulbecco's Medium; NCCS = National Centre for Cell Science; PBS = phosphate-buffered saline; PCR = polymerase chain reaction; TMRE = tetramethylrhodamine, ethyl ester. From the

In multiple myeloma (MM), dendritic cells (DCs), and their precursors are prone to malignant cell-mediated regulation of function leading to low efficacy of DC vaccine. DCs taken directly from MM patient's body or derived from monocytes are fewer in numbers and are also dysfunctional. Here, we investigated the functionality of Hematopoietic stem cell-derived DCs (SC-DCs) from MM patients. Mature-MM-SC-DCs showed all essential functions like antigen uptake, allogenic T cells simulation and migration comparable to those derived from healthy donor (HD) samples. A comparison of Mo-DCs and SC-DCs obtained from the same MM patients' samples revealed that the expression of IL-6 was higher in the precursors of Mo-DCs leading to their impaired migration. In addition, expression of CCR7 which is responsible for DCs migration was found to be lower in MM-Mo-DCs. The chromatin permissiveness as observed by H3K4me 3 histone modification at the Ccr7 promoter in MM-Mo-DCs was significantly lower than those in MM-SC-DCs. Levels of Zbtb46-a hall mark DC transcription factor mRNA was also found to be reduced in MM-Mo-DCs. Cytotoxic T cells generated from MM-SC-DCs from autologous naïve T cells exhibited reduced antitumor activity because the T cells were exhausted. Blocking of CTLA-4 on autologous T cells could partially restore T cell proliferation and activation. Thus, a combination of MM-SC-DC vaccine and anti-CTLA-4 antibody may serve as a better candidate for immunotherapy of MM. This study has implications in increasing the efficacy of cancer immunotherapy in MM.