MΦ comprise a heterogeneous population of cells, which contribute to host defense and maintenance of immune homeostasis. MΦ may be infected by human cytomegalovirus (HCMV), which has evolved different strategies to subvert the immune response. In the present study, we comparatively analyzed the natural killer (NK) cell response against HCMV (TB40E)-infected proinflammatory (M1) and antinflammatory (M2) MΦ, derived from autologous monocytes, cultured in the presence of GM-CSF and M-CSF, respectively. M1 MΦ were more resistant to infection and secreted IL-6, TNF-α, IFN-α, and IL-12; by contrast, in HCMV-infected M2 MΦ, proinflammatory cytokines, IL-10, and IFN-α production were limited and IL-12 was undetectable. NK cell degranulation was triggered by interaction with HCMV-infected M1 and M2 MΦ at 48 h postinfection. The response was partially inhibited by specific anti-NKp46, anti-DNAM-1, and anti-2B4 mAb, thus supporting a dominant role of these activating receptors. By contrast, only HCMV-infected M1 MΦ efficiently promoted NK cell-mediated IFN-γ secretion, an effect partially related to IL-12 production. These observations reveal differences in the NK cell response triggered by distinct, HCMV-infected, monocyte-derived cell types, which may be relevant in the immunopathology of this viral infection.

Psoriasis and atopic dermatitis are skin diseases affecting millions of patients. Here, we characterize benzoxaborole phosphodiesterase (PDE)-4 inhibitors, a new topical class that has demonstrated therapeutic benefit for psoriasis and atopic dermatitis in phase 2 or phase 3 studies.are potent PDE4 inhibitors with similar affinity for PDE4 isoforms and equivalent inhibition on the catalytic domain and the full-length enzyme. These benzoxaboroles are less active on other PDE isozymes. Compd4 binds to the catalytic domain of PDE4B2 with the oxaborole group chelating the catalytic bimetal and overlapping with the phosphate in cAMP during substrate hydrolysis, and the interaction extends into the adenine pocket. In cell culture, benzoxaborole PDE4 inhibitors suppress the release of tumor necrosis factor-a, interleukin (IL)-23, IL-17, interferon-g, IL-4, IL-5, IL-13, and IL-22, and these cytokines contribute to the pathologic changes in skin structure and barrier functions as well as immune dysregulation in atopic dermatitis and psoriasis. Treatment with compd3 or N 6 ,29-O-dibutyryladenosine 39,59-cyclic monophosphate increases cAMP response element binding protein phosphorylation in human monocytes and decreases extracellular signal-regulated kinase phosphorylation in human T cells; these changes lead to reduced cytokine production and are among the mechanisms by which compd3 blocks cytokine release. Topical compd3 penetrates the skin and suppresses phorbol myristate acetate-induced IL-13, IL-22, IL-17F, and IL-23 transcription and calcipotriol-induced thymic stromal lymphopoietin expression in mouse skin. Skin thinning is a major dose-limiting side effect of glucocorticoids. By contrast, repeated application of compd3 did not thin mouse skin. These findings show the potential benefits and safety of benzoxaborole PDE4 inhibitors for the treatment of psoriasis and atopic dermatitis.

Leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1) has been reported to interact with a wide spectrum of HLA class I (HLA-I) molecules, albeit with different affinities determined by allelic polymorphisms and conformational features. HLA-G dimerization and the presence of intracellular Cys residues in HLA-B7 have been shown to be critical for their recognition by LILRB1. We hypothesized that dimerization of classical HLA class Ia molecules, previously detected in exosomes, might enhance their interaction with LILRB1. A soluble LILRB1-Fc fusion protein and a sensitive cellular reporter system expressing a LILRB1-ζ chimera were employed to assess receptor interaction with different HLA class Ia molecules transfected in the human lymphoblastoid 721.221 cell line. Under these conditions, intracellular Cys residues and HLA-I dimerization appeared associated with increased LILRB1 recognition. On the other hand, a marginal interaction of LILRB1 with primary monocytic cells, irrespective of their high HLA-I expression, was enhanced by type I interferon (IFN). This effect appeared disproportionate to the cytokineinduced increase of surface HLA-I expression and was accompanied by detection of HLA class Ia dimers. Altogether, the results support that a regulated assembly of these noncanonical HLA-I conformers during the immune response may enhance the avidity of their interaction with LILRB1.Keywords: HLA class I dimers r LILRB1 r Macrophages r Type-I interferon Additional supporting information may be found in the online version of this article at the publisher's web-site IntroductionThe leukocyte immunoglobulin-like receptor subfamily B member 1 (LILRB1), also termed ILT2, LIR-1 or CD85j, is an inhibitory receptor expressed by different leukocyte lineages which specifically interacts with HLA class I (HLA-I) molecules and the UL18 human cytomegalovirus glycoprotein [1,2]. Monocytic cells display higher cell surface levels of LILRB1 than lymphocytes, Correspondence: Miguel López-Botet e-mail: miguel.lopez-botet@upf.edu reflecting the involvement of different promoters in transcriptional regulation [3].LILRB1 comprises an extracellular region with four Iglike domains (D1-D4) and a cytoplasmic tail containing four immunoreceptor tyrosine-based inhibition motifs (ITIM) which recruit the SHP-1 tyrosine phosphatase [1,2]. Similarly to the role of other HLA-I inhibitory receptors in NK and T cells, LILRB1 contributes to control leukocyte activation and differentiation. * These authors contributed equally to this work. * * These authors contributed equally to this work as senior co-authors. LILRB1 engagement was reported to inhibit NK cell-mediated cytotoxicity and cytokine production [1,4,5] as well as TCR-and BCR-triggered responses [1,6,7]. In monocytes, co-engagement of LILRB1 with CD64 prevented tyrosine phosphorylation of the FcεR-I γ chain adaptor and intracellular Ca 2+ mobilization [8]. LILRB1 modulated monocyte-derived dendritic cell differentiation and suppressed in vitro osteoclast development induc...

Our results point to the immunomodulatory effects of IFN-α on different lymphocyte subpopulations and a possible role of Th1 response and Tregs in patients with HCV who developed IIT.