CD47 restricts antiviral function of alveolar macrophages during influenza virus infection

CD47 is an ubiquitously expressed surface molecule with significant impact on immune responses. However, its role for antiviral immunity is not fully understood. Here, we revealed that the expression of CD47 on immune cells seemed to disturb the antiviral immune response as CD47-deficient mice (CD47−/−) showed an augmented clearance of influenza A virus (IAV). Specifically, we have shown that enhanced viral clearance is mediated by alveolar macrophages (aMФ). Although aMФ displayed upregulation of CD47 expression during IAV infection in wildtype mice, depletion of aMФ in CD47−/− mice during IAV infection reversed the augmented viral clearance. We have also demonstrated that CD47 restricts hemoglobin (HB) expression in aMФ after IAV and severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection, with HB showing antiviral properties by enhancing the IFN-β response. Our study showed a negative role for CD47 during antiviral immune responses in the lung by confining HB expression in aMФ

The interplay of thyroid hormones and the immune system - where we stand and why we need to know about it

Over the past few years, growing evidence suggests direct crosstalk between thyroid hormones (THs) and the immune system. Components of the immune system were proposed to interfere with the central regulation of systemic TH levels. Conversely, THs regulate innate and adaptive immune responses as immune cells are direct target cells of THs. Accordingly, they express different components of local TH action, such as TH transporters or receptors, but our picture of the interplay between THs and the immune system is still incomplete. This review provides a critical overview of current knowledge regarding the interaction of THs and the immune system with the main focus on local TH action within major innate and adaptive immune cell subsets. Thereby, this review aims to highlight open issues which might help to infer the clinical relevance of THs in host defence in the context of different types of diseases such as infection, ischemic organ injury or cancer