Spacer or co-stimulatory components in chimeric antigen receptor (CAR) design influence CAR T cell effector function. Few preclinical mouse models optimally support CAR candidate pre-selection for ...clinical development. Here we use a model in which murine CAR T cells can be exploited with human tumor xenografts. This mouse-in-mouse approach avoids limitations caused by species-specific factors crucial for CAR T cell survival, trafficking and function. We compared trafficking, expansion and tumor control for T cells expressing different CAR construct designs targeting two antigens (L1CAM or HER2), structurally identical except for spacer (long or short) or co-stimulatory (4-1BB or CD28) domains to be evaluated. Using monoclonal, murine-derived L1CAM-specific CAR T cells in Rag-/- mice harboring established xenografted tumors from a human neuroblastoma cell line revealed a clear superiority in CAR T cell trafficking using CD28 co-stimulation. L1CAM-targeting short spacer-CD28/ζ CAR T cells expanded the most at the tumor site and induced initial tumor regression. Treating patient-derived neuroblastoma xenografts with human L1CAM-targeting CAR T cells confirmed the superiority of CD28 co-stimulus. CD28 superiority was also demonstrated with HER2-specific CAR T cells (targeting ovarian carcinoma xenografts). Our findings encourage incorporating CD28 signaling into CAR design for adoptive T cell treatment of solid tumors.
A family of G-protein-coupled chemoattractant receptors is known to mediate the transport and activation of neutrophils and macrophages This family includes receptors for chemokines, such as ...interleukin-8, bacterial formylated peptides, platelet-activating factor, leukotriene B4, and the complement anaphylatoxins. The apparent redundancy of these receptors suggests that they have an important underlying role in host defence. To isolate the contribution of particular molecules, we disrupted a gene that encodes a single chemoattractant receptor. Here we show that mice deficient in the chemoattractant C5a receptor, in comparison to their wild-type littermates, were unable to clear intrapulmonary-instilled Pseudomonas aeruginosa, despite a marked increase in neutrophil influx, and succumbed to pneumonia. These C5a-receptor-deficient mice challenged with sublethal inocula of Pseudomonas become superinfected with secondary bacterial strains. We conclude that the C5a receptor has a non-redundant function, and is required for mucosal host defence in the lung.
The formation of intrapulmonary immune complexes in mice generates a vigorous inflammatory response characterized by microvascular permeability and polymorphonuclear neutrophil influx. Gene-targeted ...disruption of the substance P receptor (NK-1R) protected the lung from immune complex injury, as did disruption of the C5a anaphylatoxin receptor. Immunoreactive substance P was measurable in fluids lining the lung at time points before neutrophil influx and may thus be involved in an early step in the inflammatory response to immune complexes in the lung.
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