Retinoic acid as a vaccine adjuvant enhances CD8+ T cell response and mucosal protection from viral challenge

Vaccine-induced memory T cells localized at mucosal sites can provide rapid protection from viral infection. All-trans-retinoic acid (ATRA) has been shown to act physiologically to induce the expression of gut-homing receptors on lymphocytes. We tested whether the administration of exogenous ATRA during a systemic vaccination of mice could enhance the generation of mucosal CD8(+) T cell immunity, which might represent a strategy for establishing better protection from viral infection via mucosal routes. ATRA induced the expression of CCR9 and α4β7 on both mouse and human CD8(+) T cells activated in vitro. The administration of ATRA to mice during in vivo priming with a replication-defective recombinant adenovirus vector expressing the lymphocytic choriomeningitis virus glycoprotein (LCMVgp) (Ad5gp) increased numbers of both effector and memory T cells in intestinal mucosal tissues and showed higher frequencies of systemic central memory-like T cells that exhibited enhanced proliferation during boosting immunization with recombinant modified vaccinia virus Ankara expressing LCMVgp (MVAgp). Mice that received ATRA during Ad5gp vaccination were more resistant to intravaginal challenge by recombinant vaccinia virus expressing LCMVgp (VVgp), reflecting in part stronger T cell recall responses in situ. Thus, ATRA appears to be useful as an adjuvant during vaccination to increase memory T cell responses and protection from viral infection at mucosal sites and may facilitate the development of more effective vaccines against mucosally transmitted pathogens such as HIV.     

Evidence for a Cystic Fibrosis Enteropathy

BackgroundPrevious studies have suggested the existence of enteropathy in cystic fibrosis (CF), which may contribute to intestinal function impairment, a poor nutritional status and decline in lung function. This study evaluated enterocyte damage and intestinal inflammation in CF and studied its associations with nutritional status, CF-related morbidities such as impaired lung function and diabetes, and medication use.MethodsSixty-eight CF patients and 107 controls were studied. Levels of serum intestinal-fatty acid binding protein (I-FABP), a specific marker for enterocyte damage, were retrospectively determined. The faecal intestinal inflammation marker calprotectin was prospectively studied. Nutritional status, lung function (FEV1), exocrine pancreatic insufficiency (EPI), CF-related diabetes (CFRD) and use of proton pump inhibitors (PPI) were obtained from the medical charts.ResultsSerum I-FABP levels were elevated in CF patients as compared with controls (p<0.001), and correlated negatively with FEV1 predicted value in children (r-.734, p<0.05). Faecal calprotectin level was elevated in 93% of CF patients, and correlated negatively with FEV1 predicted value in adults (r-.484, p<0.05). No correlation was found between calprotectin levels in faeces and sputum. Faecal calprotectin level was significantly associated with the presence of CFRD, EPI, and PPI use.ConclusionThis study demonstrated enterocyte damage and intestinal inflammation in CF patients, and provides evidence for an inverse correlation between enteropathy and lung function. The presented associations of enteropathy with important CF-related morbidities further emphasize the clinical relevance.     

Antifungal Activity of Natural Naphthoquinones and Anthraquinones against Madurella mycetomatis

Eumycetoma, the fungal form of the neglected tropical disease mycetoma, is a crippling infectious disease with low response rates to currently available antifungal drugs. In this study, a series of natural naphthoquinones and anthraquinones was evaluated for their activity against Madurella mycetomatis, which is the most common causative agent of eumycetoma. The metabolic activity of Madurella mycetomatis as well as the viability of Galleria mellonella larvae upon treatment with quinones was investigated. Several hydroxy-substituted naphthoquinones exhibited activity against Madurella mycetomatis. In particular, naphthazarin (5,8-dihydroxy-1,4-naphthoquinone) was identified as a considerably active antifungal compound against Madurella mycetomatis (IC₅₀=1.4 μM), while it showed reduced toxicity to Galleria mellonella larvae, which is a well-established in vivo invertebrate model for mycetoma drug studies.     

Cytomegalovirus infection in Gambian infants leads to profound CD8 T-cell differentiation

Cytomegalovirus (CMV) infection is endemic in Gambian infants, with 62% infected by 3 months and 85% by 12 months of age. We studied the CD8 T-cell responses of infants to CMV following primary infection. CMV-specific CD8 T cells, identified with tetramers, showed a fully differentiated phenotype (CD28(-) CD62L(-) CD95(+) perforin(+) granzyme A(+) Bcl-2(low)). Strikingly, the overall CD8 T-cell population developed a similar phenotype following CMV infection, which persisted for at least 12 months. In contrast, primary infection was accompanied by up-regulation of markers of activation (CD45R0 and HLA-D) on both CMV-specific cells and the overall CD8 T-cell population and division (Ki-67) of specific cells, but neither pattern persisted. At 12 months of age, the CD8 T-cell population of CMV-infected infants was more differentiated than that of uninfected infants. Although the subpopulation of CMV-specific cells remained constant, the CMV peptide-specific gamma interferon response was lower in younger infants and increased with age. As the CD8 T-cell phenotype induced by CMV is indicative of immune dysfunction in the elderly, the existence of a similar phenotype in large numbers of Gambian infants raises the question of whether CMV induces a similarly deleterious effect.     

Complexes of (dG-dC)20 with Mn2+ ions: a study by vibrational circular dichroism and infrared absorption spectroscopy

The B-Z transition of the synthetic oligonucleotide, (dG-dC)20, induced by Mn2+ ions at room temperature, was investigated by absorption and Vibrational Circular Dichroism (VCD) spectroscopy in the range of 1800-800 cm(-1). Metal ion concentration was varied from 0 to 0.73 M Mn2+ (0 to 8.5 moles of Mn2+ per mole of oligonucleotide phosphate, [Mn]/[P]). While both types of spectra showed considerable changes as the Mn2+ concentrations were raised, differences between the two were often complementary in their expression and extent, those displayed by VCD being more clearly evident due to the inversion of the opposite helical sense from the right-handed to the left-handed conformation. The main phase of the transition occurred in the metal ion concentration between 0.8-1.1 [Mn]/[P]. Gradual changes that took place in the spectra were interpreted in terms of simultaneous processes that depended on metal ion concentration, namely B-Z transformation, binding of Mn2+ to phosphates and to nitrogen bases, and partial denaturation. Below approximately 0.6 [Mn]/[P], only a small portion of the oligonucleotide adopted the Z conformation within a 3 hour period, whereas conversion was completed in the same time interval for concentrations between 0.9-1.2 [Mn]/[P]. At [Mn]/[P] >1.7, complete transition to the Z-form took place immediately on adding Mn2+. Applying VCD spectroscopy in combination with conventional infrared absorption proved most useful for corroborating changes in the absorption spectra, and for detecting in an unique manner, not attainable by absorption methods, conformational changes that lead to the inversion of the helical sense of the oligonucleotide.     

The Ras guanine nucleotide exchange factor RasGRF1 promotes matrix metalloproteinase-3 production in rheumatoid arthritis synovial tissue

Introduction  

Fibroblast-like synoviocytes (FLS) from rheumatoid arthritis (RA) patients share many similarities with transformed cancer cells, including spontaneous production of matrix metalloproteinases (MMPs). Altered or chronic activation of proto-oncogenic Ras family GTPases is thought to contribute to inflammation and joint destruction in RA, and abrogation of Ras family signaling is therapeutic in animal models of RA. Recently, expression and post-translational modification of Ras guanine nucleotide releasing factor 1 (RasGRF1) was found to contribute to spontaneous MMP production in melanoma cancer cells. Here, we examine the potential relationship between RasGRF1 expression and MMP production in RA, reactive arthritis, and inflammatory osteoarthritis synovial tissue and FLS.