We report on the demonstration of three-dimensional optical trapping inside the core of a hollow-core microstructured optical fiber specifically designed and fabricated for this purpose. Optical trapping was achieved by means of an external tweezers beam incident transversely on the fiber and focused through the fiber cladding. Trapping was achieved for a range of particle sizes from 1 to 5 µm, and manipulation of the particles in three-dimensions through the entire cross-section of the fiber core was demonstrated. Spectroscopy was also performed on single fluorescent particles, with the fluorescence captured and guided in the fiber core. Video tracking methods allowed the optical traps to be characterized and photobleaching of single particles was also observed and characterized.

Adoptive cell therapy using patient-derived chimeric receptor antigen (CAR) T cells redirected against tumor cells has shown remarkable success in treating hematologic cancers. However, wider accessibility of cellular therapies for all patients is needed. Manufacture of patient-derived CAR T cells is limited by prolonged lymphopenia in heavily pre-treated patients and risk of contamination with tumor cells when isolating T cells from patient blood rich in malignant blasts. Donor T cells provide a good source of immune cells for adoptive immunotherapy and can be used to generate universal off-the-shelf CAR T cells that are readily available for administration into patients as required. Genome editing tools such as TALENs and CRISPR-Cas9 and non-gene editing methods such as short hairpin RNA and blockade of protein expression are currently used to enhance CAR T cell safety and efficacy by abrogating non-specific toxicity in the form of graft versus host disease (GVHD) and preventing CAR T cell rejection by the host.

Children with esophageal atresia (EA) receive proton pump inhibitors (PPIs) long-term due to gastroesophageal reflux disease susceptibility. They have also demonstrated greater susceptibility to eosinophilic esophagitis (EoE) compared to the general pediatric population. No studies have investigated EoE risk factors in EA. This study aimed to determine whether PPI exposure and early-life factors are associated with an increased risk for subsequent EoE development in children with EA. A retrospective chart review was undertaken at a paediatric hospital in Sydney, Australia. The study cohort consisted of children with EA who had their repair and/or follow-up at this hospital between 1 January 2005 and 31 December 2020. Children with EA and EoE (cases) were matched (1:2) with those with only EA (controls), for sex, prematurity and presence of long-gap, to compare PPI exposure. Other early-life factors were analysed without matching, using simple and multivariable logistic regression. Of the 184 children with EA, 46 (25%) developed EoE during this period. Thirty-eight EoE participants were matched to 76 controls. Children with EA and EoE received PPI for significantly higher durations (p = 0.018) and at significantly higher cumulative doses (p = 0.017) than children with EA but no EoE. Food allergy (adjusted odds ratio [aOR], 10.515; 95% confidence interval [CI], 2.659–41.581), family history of atopy (aOR, 5.312; 95% CI, 1.575–17.911) and infantile antibiotic exposure (aOR, 1.048; 95% CI, 1.011–1.086) were also significantly associated with an increased risk of developing EoE in the EA cohort. Longer durations of PPI exposure and exposure to higher cumulative doses of PPI were both associated with the subsequent development of EoE in children with EA. Other early life factors such as atopic family history, food allergy and infantile antibiotic exposure were also significantly associated with an increased risk of developing EoE in children with EA.

Purpose Despite the success of chimeric antigen receptor (CAR) T cells in clinical studies, a significant proportion of responding patients eventually relapsed, with the latter correlating with low CAR T cell expansion and persistence. Methods and Results Using patient-derived xenograft (PDX) mouse models of CD19 + B cell acute lymphoblastic leukemia (B-ALL), we show that priming leukemia-bearing mice with 5-azacytidine (AZA) enhances CAR T cell therapy. AZA given 1 day prior to CAR T cell infusion delayed leukemia growth and promoted CAR T cell expansion and effector function. Priming leukemia cells with AZA increased CAR T cell/target cell conjugation and target cell killing, promoted CAR T cell divisions and expanded IFNγ + effector T cells in co-cultures with CD19 + leukemia Nalm-6 and Raji cells. Transcriptome analysis revealed activation of diverse immune pathways in leukemia cells isolated from mice treated with AZA. We propose that epigenetic priming with AZA induces transcriptional changes that sensitize tumor cells to subsequent CAR T cell treatment. Among the candidate genes up-regulated by AZA is TNFSF4 which encodes OX40L, one of the strongest T cell co-stimulatory ligands. OX40L binds OX40, the TNF receptor superfamily member highly specific for activated T cells. TNFSF4 is heterogeneously expressed in a panel of pediatric PDXs, and high TNFSF4 expression correlated with increased CAR T cell numbers identified in co-cultures with individual PDXs. High OX40L expression in Nalm-6 cells increased their susceptibility to CAR T cell killing while OX40L blockade reduced leukemia cell killing. Conclusion We propose that treatment with AZA activates OX40L/OX40 co-stimulatory signaling in CAR T cells. Our data suggest that the clinical use of AZA before CAR T cells could be considered.

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