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A shared Toll for innate immunity
Toll-like receptor 2 (TLR2) is found in various tissues but is best known for its role in the innate immune system of activating sentinel immune cells in response to infection. Using conditional knockout mice, McCoy
et al. found that TLR2 also mediated innate immune signaling within the endothelium. TLR2 in endothelial cells activated proinflammatory signaling that promoted angiogenesis and immune cell recruitment in response to various “danger” signals, such as those produced during infection or tissue damage. Endothelial TLR2 also supported tumor growth in a mouse model of prostate cancer. These findings show that the endothelium contributes to innate immune responses and that TLR2 may be a therapeutic target in cancer (see also the Focus by Mahfoud and Petrova).
Abstract
Cancer immunotherapy with 4-1BB agonists has limited further clinical development because of dose-limiting toxicity. Here, we developed a bispecific antibody (bsAb; B7-H3×4-1BB), targeting human B7-H3 (hB7-H3) and mouse or human 4-1BB, to restrict the 4-1BB stimulation in tumors. B7-H3×m4-1BB elicited a 4-1BB–dependent antitumor response in hB7-H3–overexpressing tumor models without systemic toxicity. BsAb primarily targets CD8 T cells in the tumor and increases their proliferation and cytokine production. Among the CD8 T cell population in the tumor, 4-1BB is solely expressed on PD-1
Rotten egg gas may help protect aging brain cells from Alzheimer’s disease
Typically characterized as poisonous, corrosive and smelling of rotten eggs, hydrogen sulfide s reputation may soon get a face-lift thanks to Johns Hopkins Medicine researchers. In experiments in mice, researchers have shown the foul-smelling gas may help protect aging brain cells against Alzheimer s disease. The discovery of the biochemical reactions that make this possible opens doors to the development of new drugs to combat neurodegenerative disease.
The findings from the study are reported in the Jan. 11 issue of the Proceedings of the National Academies of Science. Our new data firmly link aging, neurodegeneration and cell signaling using hydrogen sulfide and other gaseous molecules within the cell, says Bindu Paul, M.Sc., Ph.D., faculty research instructor in neuroscience in the Solomon H. Snyder Department of Neuroscience at the Johns Hopkins University School of Medicine and lead correspondin
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic continues to spread with devastating consequences. For passive immunization efforts, nanobodies have size and cost advantages over conventional antibodies. Here, we generated four neutralizing nanobodies that target the receptor-binding domain of the SARS-CoV-2 spike protein. We defined two distinct binding epitopes using x-ray crystallography and cryo-electron microscopy. Based on the structures, we engineered multivalent nanobodies with more than 100-fold improved neutralizing activity than monovalent nanobodies. Biparatopic nanobody fusions suppressed the emergence of escape mutants. Several nanobody constructs neutralized through receptor-binding competition, while other monovalent and biparatopic nanobodies triggered aberrant activation of the spike fusion machinery. These premature conformational changes in the spike protein forestalled productive fusion, and rendered the virions non-infectious.