Antitumor immunity induced by antibody-based natural killer cell engager therapeutics armed with not-alpha IL-2 variant.

Harnessing innate immunity is emerging as a promising therapeutic approach in cancer. We report here the design of tetraspecific molecules engaging natural killer (NK) cell-activating receptors NKp46 and CD16a, the ß-chain of the interleukin-2 receptor (IL-2R), and a tumor-associated antigen (TAA). In vitro, these tetraspecific antibody-based natural killer cell engager therapeutics (ANKETs) induce a preferential activation and proliferation of NK cells, and the binding to the targeted TAA triggers NK cell cytotoxicity and cytokine and chemokine production. In vivo, tetraspecific ANKETs induce NK cell proliferation and their accumulation at the tumor bed, as well as the control of local and disseminated tumors. Treatment of non-human primates with CD20-directed tetraspecific ANKET leads to CD20+ circulating B cell depletion, with minimal systemic cytokine release and no sign of toxicity. Tetraspecific ANKETs, thus, constitute a technological platform for harnessing NK cells as next-generation cancer immunotherapies.

Evidence of innate lymphoid cell redundancy in humans.

Innate lymphoid cells (ILCs) have potent immunological functions in experimental conditions in mice, but their contributions to immunity in natural conditions in humans have remained unclear. We investigated the presence of ILCs in a cohort of patients with severe combined immunodeficiency (SCID). All ILC subsets were absent in patients with SCID who had mutation of the gene encoding the common γ-chain cytokine receptor subunit IL-2Rγ or the gene encoding the tyrosine kinase JAK3. T cell reconstitution was observed in patients with SCID after hematopoietic stem cell transplantation (HSCT), but the patients still had considerably fewer ILCs in the absence of myeloablation than did healthy control subjects, with the exception of rare cases of reconstitution of the ILC1 subset of ILCs. Notably, the ILC deficiencies observed were not associated with any particular susceptibility to disease, with follow-up extending from 7 years to 39 years after HSCT. We thus report here selective ILC deficiency in humans and show that ILCs might be dispensable in natural conditions, if T cells are present and B cell function is preserved.

Value of three-dimensional contrast-enhanced power Doppler ultrasound for characterizing adnexal masses.

AIMS: The aim of this study was to assess the diagnostic performance of 3-D contrast-enhanced power Doppler ultrasonography (3-D CEPDUS) for differentiating benign and malignant adnexal masses. MATERIAL AND METHODS: Consecutive patients with adnexal masses were included prospectively and underwent 2-D ultrasonography and 3-D CEPDUS in a tertiary centre in Paris, France. The main outcome measure was the diagnostic accuracy of 3-D CEPDUS to diagnose malignant and borderline adnexal masses. The reference standard was the final histological examination. Two-dimensional ultrasonography and 3-D CEPDUS were compared using semiquantitative scores. Three-dimensional CEPDUS assessed vessel density, vessel pattern, and three vascular indexes in a 5-mL region of interest (vascularization index [VI], flow index [FI], and vascularization flow index [VFI]). The 2-D and 3-D examinations were done by different sonographers who were blinded to the other test. The pathologist was blinded to ultrasonography findings. RESULTS: Of 99 patients, 88 had benign tumors and were compared to the 11 patients with borderline (n = 5) or malignant (n = 6) tumors. The sensitivity of the subjective 2-D score was 55% (95% confidence interval [CI], 25-84) and specificity 94% (95%CI, 89-99). The sensitivity of the subjective 3-D score was 82% (95%CI, 58-100) and specificity 90% (95%CI, 83-96). Improvement of detection of malignant or borderline tumors by subjective 3-D score was 150%. Vessel density and patterns were not more efficient than the subjective 3-D score. The mean vascular index values were significantly different between benign and borderline/malignant groups: VI, 7.2 versus 35.5 (P < 0.0001); FI, 37.0 versus 48.2 (P = 0.003); and VFI, 2.9 versus 17.6 (P < 0.0001), respectively. CONCLUSIONS: 3-D CEPDUS improves detection of malignant and borderline adnexal masses.

Endogenous IL-33 is highly expressed in mouse epithelial barrier tissues, lymphoid organs, brain, embryos, and inflamed tissues: in situ analysis using a novel Il-33-LacZ gene trap reporter strain.

IL-33 (previously known as NF from high endothelial venules) is an IL-1 family cytokine that signals through the ST2 receptor and drives cytokine production in mast cells, basophils, eosinophils, invariant NKT and NK cells, Th2 lymphocytes, and type 2 innate immune cells (natural helper cells, nuocytes, and innate helper 2 cells). Little is known about endogenous IL-33; for instance, the cellular sources of IL-33 in mouse tissues have not yet been defined. In this study, we generated an Il-33-LacZ gene trap reporter strain (Il-33(Gt/Gt)) and used this novel tool to analyze expression of endogenous IL-33 in vivo. We found that the Il-33 promoter exhibits constitutive activity in mouse lymphoid organs, epithelial barrier tissues, brain, and embryos. Immunostaining with anti-IL-33 Abs, using Il-33(Gt/Gt) (Il-33-deficient) mice as control, revealed that endogenous IL-33 protein is highly expressed in mouse epithelial barrier tissues, including stratified squamous epithelia from vagina and skin, as well as cuboidal epithelium from lung, stomach, and salivary gland. Constitutive expression of IL-33 was not detected in blood vessels, revealing the existence of species-specific differences between humans and mice. Importantly, IL-33 protein was always localized in the nucleus of producing cells with no evidence for cytoplasmic localization. Finally, strong expression of the Il-33-LacZ reporter was also observed in inflamed tissues, in the liver during LPS-induced endotoxin shock, and in the lung alveoli during papain-induced allergic airway inflammation. Together, our findings support the possibility that IL-33 may function as a nuclear alarmin to alert the innate immune system after injury or infection in epithelial barrier tissues.

PLD2 is enriched on exosomes and its activity is correlated to the release of exosomes.

Exosomes are small vesicles secreted by different immune cells and which display anti-tumoral properties. Stimulation of RBL-2H3 cells with ionomycin triggered phospholipase D2 (PLD2) translocation from plasma membrane to intracellular compartments and the release of exosomes. Although exosomes carry the two isoforms of PLD, PLD2 was enriched and specifically sorted on exosomes when overexpressed in cells. PLD activity present on exosomes was clearly increased following PLD2 overexpression. PLD2 activity in cells was correlated to the amount of exosome released, as measured by FACS. Therefore, the present work indicates that exosomes can vehicle signaling enzymes.