The Histopathologic Features of Early COVID Pneumonia in a Pediatric Patient: New Insight into the Role of Macrophages.

A life-threatening complication of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection is acute respiratory distress syndrome. Our understanding of the pathologic changes in coronavirus disease 2019 (COVID-19) is based almost exclusively on post-mortem analyses of adults. These studies established several hallmarks of SARS-CoV-2 lung infection, including diffuse alveolar damage, microvascular thrombi, and acute bronchopneumonia.

Latent CMV infection of Lymphatic endothelial cells is sufficient to drive CD8 T cell memory inflation.

CMV, a ubiquitous herpesvirus, elicits an extraordinarily large T cell response that is sustained or increases over time, a phenomenon termed 'memory inflation.' Remarkably, even latent, non-productive infection can drive memory inflation. Despite intense research on this phenomenon, the infected cell type(s) involved are unknown.

Cytomegalovirus vectors expressing Plasmodium knowlesi antigens induce immune responses that delay parasitemia upon sporozoite challenge.

The development of a sterilizing vaccine against malaria remains one of the highest priorities for global health research. While sporozoite vaccines targeting the pre-erythrocytic stage show great promise, it has not been possible to maintain efficacy long-term, likely due to an inability of these vaccines to maintain effector memory T cell responses in the liver. Vaccines based on human cytomegalovirus (HCMV) might overcome this limitation since vectors based on rhesus CMV (RhCMV), the homologous virus in rhesus macaques (RM), elicit and indefinitely maintain high frequency, non-exhausted effector memory T cells in extralymphoid tissues, including the liver.

Prevention of tuberculosis in rhesus macaques by a cytomegalovirus-based vaccine.

Despite widespread use of the bacille Calmette-Guérin (BCG) vaccine, tuberculosis (TB) remains a leading cause of global mortality from a single infectious agent (Mycobacterium tuberculosis or Mtb). Here, over two independent Mtb challenge studies, we demonstrate that subcutaneous vaccination of rhesus macaques (RMs) with rhesus cytomegalovirus vectors encoding Mtb antigen inserts (hereafter referred to as RhCMV/TB)-which elicit and maintain highly effector-differentiated, circulating and tissue-resident Mtb-specific CD4 and CD8 memory T cell responses-can reduce the overall (pulmonary and extrapulmonary) extent of Mtb infection and disease by 68%, as compared to that in unvaccinated controls, after intrabronchial challenge with the Erdman strain of Mtb at ∼1 year after the first vaccination. Fourteen of 34 RhCMV/TB-vaccinated RMs (41%) across both studies showed no TB disease by computed tomography scans or at necropsy after challenge (as compared to 0 of 17 unvaccinated controls), and ten of these RMs were Mtb-culture-negative for all tissues, an exceptional long-term vaccine effect in the RM challenge model with the Erdman strain of Mtb.

Intratumoral Infection with Murine Cytomegalovirus Synergizes with PD-L1 Blockade to Clear Melanoma Lesions and Induce Long-term Immunity.

Cytomegalovirus is an attractive cancer vaccine platform because it induces strong, functional CD8(+) T-cell responses that accumulate over time and migrate into most tissues. To explore this, we used murine cytomegalovirus expressing a modified gp100 melanoma antigen. Therapeutic vaccination by the intraperitoneal and intradermal routes induced tumor infiltrating gp100-specific CD8(+) T-cells, but provided minimal benefit for subcutaneous lesions.

Cytomegalovirus pp65 limits dissemination but is dispensable for persistence.

The most abundantly produced virion protein in human cytomegalovirus (HCMV) is the immunodominant phosphoprotein 65 (pp65), which is frequently included in CMV vaccines. Although it is nonessential for in vitro CMV growth, pp65 displays immunomodulatory functions that support a potential role in primary and/or persistent infection. To determine the contribution of pp65 to CMV infection and immunity, we generated a rhesus CMV lacking both pp65 orthologs (RhCMVΔpp65ab).

Immune clearance of highly pathogenic SIV infection.

Established infections with the human and simian immunodeficiency viruses (HIV and SIV, respectively) are thought to be permanent with even the most effective immune responses and antiretroviral therapies only able to control, but not clear, these infections. Whether the residual virus that maintains these infections is vulnerable to clearance is a question of central importance to the future management of millions of HIV-infected individuals. We recently reported that approximately 50% of rhesus macaques (RM; Macaca mulatta) vaccinated with SIV protein-expressing rhesus cytomegalovirus (RhCMV/SIV) vectors manifest durable, aviraemic control of infection with the highly pathogenic strain SIVmac239 (ref.

Cytomegalovirus-based cancer vaccines expressing TRP2 induce rejection of melanoma in mice.

Cytomegalovirus (CMV) induces strong and long-lasting immune responses, which make it an attractive candidate for a cancer vaccine vector. In this study, we tested whether a tumor antigen expressed in CMV can induce a strong anti-tumor effect. We expressed an unmodified melanoma antigen, mouse tyrosinase-related protein 2 (TRP2), in mouse cytomegalovirus (MCMV).

Cytomegalovirus vectors violate CD8+ T cell epitope recognition paradigms.

CD8(+) T cell responses focus on a small fraction of pathogen- or vaccine-encoded peptides, and for some pathogens, these restricted recognition hierarchies limit the effectiveness of antipathogen immunity. We found that simian immunodeficiency virus (SIV) protein-expressing rhesus cytomegalovirus (RhCMV) vectors elicit SIV-specific CD8(+) T cells that recognize unusual, diverse, and highly promiscuous epitopes, including dominant responses to epitopes restricted by class II major histocompatibility complex (MHC) molecules. Induction of canonical SIV epitope-specific CD8(+) T cell responses is suppressed by the RhCMV-encoded Rh189 gene (corresponding to human CMV US11), and the promiscuous MHC class I- and class II-restricted CD8(+) T cell responses occur only in the absence of the Rh157.

Combinatorial mRNA binding by AUF1 and Argonaute 2 controls decay of selected target mRNAs.

The RNA-binding protein AUF1 binds AU-rich elements in 3'-untranslated regions to regulate mRNA degradation and/or translation. Many of these mRNAs are predicted microRNA targets as well. An emerging theme in post-transcriptional control of gene expression is that RNA-binding proteins and microRNAs co-regulate mRNAs.

Bone marrow stromal cells from multiple myeloma patients uniquely induce bortezomib resistant NF-kappaB activity in myeloma cells.

Background: Components of the microenvironment such as bone marrow stromal cells (BMSCs) are well known to support multiple myeloma (MM) disease progression and resistance to chemotherapy including the proteasome inhibitor bortezomib. However, functional distinctions between BMSCs in MM patients and those in disease-free marrow are not completely understood. We and other investigators have recently reported that NF-kappaB activity in primary MM cells is largely resistant to the proteasome inhibitor bortezomib, and that further enhancement of NF-kappaB by BMSCs is similarly resistant to bortezomib and may mediate resistance to this therapy.

C/EBPbeta mediates synergistic upregulation of gene expression by interferon-gamma and tumor necrosis factor-alpha in bone marrow-derived mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are potent immunoregulators and have shown clinical utility in suppressing immunity. MSC function is modulated by cytokines, since inflammatory cytokines, such as interferon-gamma (IFNgamma) concomitant with tumor necrosis factor-alpha (TNFalpha), induce their immunoregulatory capability. Here, we show that IFNgamma and TNFalpha act synergistically to induce high levels of expression of interleukin-6 (IL-6) and several other immune-related molecules in MSCs in vitro.

Bone marrow stromal cells induce apoptosis of lymphoma cells in the presence of IFNgamma and TNF by producing nitric oxide.

Bone marrow stromal cells (BMSCs) have been shown to promote the growth and survival of a wide variety of tumors. However, in the present study, we found that BMSCs induced apoptosis of lymphoma cells in the presence of INFgamma and TNF. IFNgamma and TNF dramatically induced the expression of inducible nitric oxide synthase (iNOS) by BMSCs in culture, and BMSCs generated from iNOS knockout mice did not induce apoptosis of lymphoma cells in the presence of IFNgamma and TNF.

Th17 cells undergo Fas-mediated activation-induced cell death independent of IFN-gamma.

IL-17-secreting CD4+ T cells (Th17 cells) play a critical role in immune responses to certain infections and in the development of many autoimmune disorders. The mechanisms controlling homeostasis in this cell population are largely unknown. In this study, we show that murine Th17 cells undergo rapid apoptosis in vitro upon restimulation through the TCR.

Mesenchymal stem cell-mediated immunosuppression occurs via concerted action of chemokines and nitric oxide.

Mesenchymal stem cells (MSCs) can become potently immunosuppressive through unknown mechanisms. We found that the immunosuppressive function of MSCs is elicited by IFNgamma and the concomitant presence of any of three other proinflammatory cytokines, TNFalpha, IL-1alpha, or IL-1beta. These cytokine combinations provoke the expression of high levels of several chemokines and inducible nitric oxide synthase (iNOS) by MSCs.

The role of IL-6 in inhibition of lymphocyte apoptosis by mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are widely distributed throughout the body. Despite intensive studies on the immunosuppressive effect of MSCs, little is known about whether MSCs affect lymphocyte apoptosis. We investigated the effect of MSCs on the spontaneous death of lymphocytes and found that MSCs inhibit the apoptosis of splenocytes and thymocytes as well as purified T and B cells.

Apoptosis signaling pathways and lymphocyte homeostasis.

It has been almost three decades since the term "apoptosis" was first coined to describe a unique form of cell death that involves orderly, gene-dependent cell disintegration. It is now well accepted that apoptosis is an essential life process for metazoan animals and is critical for the formation and function of tissues and organs. In the adult mammalian body, apoptosis is especially important for proper functioning of the immune system.

CD11b facilitates the development of peripheral tolerance by suppressing Th17 differentiation.

Antigen-induced immune suppression, like T cell activation, requires antigen-presenting cells (APCs); however, the role of APCs in mediating these opposing effects is not well understood, especially in vivo. We report that genetic inactivation of CD11b, which is a CD18 subfamily of integrin receptors that is highly expressed on APCs, abolishes orally induced peripheral immune tolerance (oral tolerance) without compromising APC maturation or antigen-specific immune activation. The defective oral tolerance in CD11b(-/-) mice can be restored by adoptive transfer of wild-type APCs.

Immunosuppressive properties of cloned bone marrow mesenchymal stem cells.

Mesenchymal stem cells (MSCs), derived from adult tissues, are multipotent progenitor cells, which hold great promise for regenerative medicine. Recent studies have shown that MSCs are immunosuppressive in vivo and in vitro in both animals and humans. However, the mechanisms that govern these immune modulatory functions of MSCs remain largely elusive.

Role of IFN-gamma in induction of Foxp3 and conversion of CD4+ CD25- T cells to CD4+ Tregs.

IFN-gamma is an important Th1 proinflammatory cytokine and has a paradoxical effect on EAE in which disease susceptibility is unexpectedly heightened in IFN-gamma-deficient mice. In this study, we provide what we believe is new evidence indicating that IFN-gamma is critically required for the conversion of CD4+ CD25- T cells to CD4+ Tregs during EAE. In our study, the added severity of EAE in IFN-gamma knockout mice was directly associated with altered encephalitogenic T cell responses, which correlated with reduced frequency and function of CD4+ CD25+ Foxp3+ Tregs when compared with those of WT mice.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) and T-cell responses: what we do and don't know.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is an important hematopoietic growth factor and immune modulator. GM-CSF also has profound effects on the functional activities of various circulating leukocytes. It is produced by a variety of cell types including T cells, macrophages, endothelial cells and fibroblasts upon receiving immune stimuli.

Role of osteopontin in amplification and perpetuation of rheumatoid synovitis.

Osteopontin (OPN) is an extracellular matrix protein of pleiotropic properties and has been recently recognized as a potential inflammatory cytokine. In this study, we demonstrate, for the first time to our knowledge, that overexpression of OPN in synovial T cells is associated with local inflammatory milieu and that OPN acts as an important mediator in amplification and perpetuation of rheumatoid synovitis. The study revealed that mRNA expression of OPN was highly elevated in CD4(+) synovial T cells derived from patients with RA, which correlated with increased OPN concentrations in synovial fluid (SF).

Overexpression of osteopontin in rheumatoid synovial mononuclear cells is associated with joint inflammation, not with genetic polymorphism.

Objective: Osteopontin (OPN) is thought to play an important role in rheumatoid synovitis. We investigated the expression of OPN in rheumatoid synovial fluid mononuclear cells (SFMC) and its potential association with genetic polymorphism of the OPN gene and joint inflammation in rheumatoid arthritis (RA).

Methods: 1.

Identification of variations of gene expression of visceral adipose and renal tissue in type 2 diabetic rats using cDNA representational difference analysis.

Objectives: To identify differences in gene expression in renal and visceral adipose tissue in type 2 diabetic rats using cDNA representational difference analysis (RDA) and to explore the molecular pathogenesis of type 2 diabetes and its chronic vascular complications.

Methods: A rat model of type 2 diabetes was generated by administration of a high fat and calorie diet combined with a low dose of streptozocin (STZ) injected into the tail vein. The difference bands were generated by cDNA representational difference analysis (cDNA RDA).