The Mucosae-Associated Epithelial Chemokine (MEC/CCL28) Modulates Immunity in HIV Infection

BACKGROUND. CCL28 (MEC) binds to CCR3 and CCR10 and recruits IgA-secreting plasma cells (IgA-ASC) in the mucosal lamina propria (MLP). Mucosal HIV-specific IgA are detected in HIV-infection and exposure. The CCL28 circuit was analyzed in HIV-infected and-exposed individuals and in HIV-unexposed controls; the effect of CCL28 administration on gastrointestinal MLP IgA-ASC was verified in a mouse model. METHODOLOGY/FINDINGS. CCL28 was augmented in breast milk (BM) plasma and saliva of HIV-infected and –exposed individuals; CCR3+ and CCR10+ B lymphocytes were increased in these same individuals. Additionally: 1) CCL28 concentration in BM was associated with longer survival in HIV vertically-infected children; and 2) gastro-intestinal mucosal IgA-ASC were significantly increased in VSV-immunized mice receiving CCL28. CONCLUSIONS. CCL28 mediates mucosal immunity in HIV exposure and infection. CCL28-including constructs should be considered in mucosal vaccines to prevent HIV infection of the gastro-intestinal MLP via modulation of IgA-ASC.Istituto Superiore di Sanita' "Programma Nazionale di Ricerca sull' AIDS"; DG Right to Health and Solidarity Policy; EMPRO and AVIP EC WP6 Projects; Japan Health Science Foundation; National Institutes of Child Health and Human Development (HD 39611, HD 40777

Acquired Complement Regulatory Gene Mutations and Hematopoietic Stem Cell Transplant–Related Thrombotic Microangiopathy

Abstract Hematopoietic stem cell transplant–related thrombotic microangiopathy (HSCT-TMA) is a severe complication whose pathophysiology is unknown. We describe 6 patients in which the disease was associated with complement regulatory gene abnormalities received from their respective donors. It is suggested that mutated and transplanted monocyte-derived cells are responsible for production of abnormal proteins, complement dysregulation, and, ultimately, for the disease. This observation might have important drawbacks as far as HSCT-TMA pathophysiology and treatment are concerned

Proof of concept of a new plasma complement Factor H from waste plasma fraction

IntroductionComplement factor H (FH) is a major regulator of the complement alternative pathway, its mutations predispose to an uncontrolled activation in the kidney and on blood cells and to secondary C3 deficiency. Plasma exchange has been used to correct for FH deficiency and although the therapeutic potential of purified FH has been suggested by in vivo experiments in animal models, a clinical approved FH concentrate is not yet available. We aimed to develop a purification process of FH from a waste fraction rather than whole plasma allowing a more efficient and ethical use of blood and plasma donations.MethodsWaste fractions from industrial plasma fractionation (pooled human plasma) were analyzed for FH content by ELISA. FH was purified from unused fraction III and its decay acceleration, cofactor, and C3 binding capacity were characterized in vitro. Biodistribution was assessed by high-resolution dynamic PET imaging. Finally, the efficacy of the purified FH preparation was tested in the mouse model of C3 glomerulopathy (Cfh−/− mice).ResultsOur purification method resulted in a high yield of highly purified (92,07%), pathogen-safe FH. FH concentrate is intact and fully functional as demonstrated by in vitro functional assays. The biodistribution revealed lower renal and liver clearance of human FH in Cfh-/- mice than in wt mice. Treatment of Cfh-/- mice documented its efficacy in limiting C3 activation and promoting the clearance of C3 glomerular deposits.ConclusionWe developed an efficient and economical system for purifying intact and functional FH, starting from waste material of industrial plasma fractionation. The FH concentrate could therefore constitute possible treatments options of patients with C3 glomerulopathy, particularly for those with FH deficiency, but also for patients with other diseases associated with alternative pathway activation

CCL28 Induces Mucosal Homing of HIV-1-Specific IgA-Secreting Plasma Cells in Mice Immunized with HIV-1 Virus-Like Particles

Mucosae-associated epithelial chemokine (MEC or CCL28) binds to CCR3 and CCR10 and recruits IgA-secreting plasma cells (IgA-ASCs) in the mucosal lamina propria. The ability of this chemokine to enhance migration of IgA-ASCs to mucosal sites was assessed in a mouse immunization model using HIV-1IIIB Virus-like particles (VLPs). Mice receiving either HIV-1IIIB VLPs alone, CCL28 alone, or the irrelevant CCL19 chemokine were used as controls. Results showed a significantly increased CCR3 and CCR10 expression on CD19+ splenocytes of HIV-1IIIB VPL-CCL28-treated mice. HIV-1 Env-specific IFN-γ, IL-4 and IL-5 production, total IgA, anti-Env IgA as well as gastro-intestinal mucosal IgA-secreting plasma cells were also significantly augmented in these mice. Notably, sera and vaginal secretions from HIV-1IIIB VLP-CCL28-treated mice exhibited an enhanced neutralizing activity against both a HIV-1/B-subtype laboratory strain and a heterologous HIV-1/C-subtype primary isolate. These data suggest that CCL28 could be useful in enhancing the IgA immune response that will likely play a pivotal role in prophylactic HIV vaccines

Vitamin D and outcomes in adult critically ill patients: a systematic review and meta-analysis of randomized trials

PURPOSE Low vitamin D blood levels are associated with high mortality in critically ill patients. There is controversy about vitamin D supplementation in this population. The objective of this meta-analysis was to evaluate if vitamin D administration reduces mortality in critically ill patients. MATERIALS AND METHODS Online databases were searched up to September 1(st), 2016 for randomized placebo-controlled trials on the use of vitamin D in adult patients with critical illness. The primary end point was mortality among trials with low risk of bias. The secondary end points were length of hospital stay, length of intensive care unit stay, length of mechanical ventilation, and adverse events. RESULTS Seven studies published between 2011 and 2016, for a total of 716 patients, were included in the analysis. Vitamin D administration was associated with significantly lower mortality compared with placebo (101/320 [32%] in the vitamin D group vs 123/307 [40%] in the placebo group; odds ratio, 0.70 [95% confidence interval, 0.50 to 0.98]; P=.04; I(2)=0%). No differences in adverse events and other secondary end points were found. CONCLUSIONS In critically ill patients, vitamin D administration might be associated with a reduction in mortality without significant adverse events. A large multicenter randomized trial should conclusively confirm these findings

Two Amino Acid Substitutions within the First External Loop of CCR5 Induce Human Immunodeficiency Virus-Blocking Antibodies in Mice and Chickens▿ †

Antibodies to the first loop (ECL1) of CCR5 have been identified in human immunodeficiency virus (HIV)-exposed uninfected individuals (ESN) and in HIV-positive nonprogressing subjects. Thus, these antibodies may confer resistance against HIV infection. To define which amino acids are involved in antibody binding to CCR5, we performed a peptide-scanning assay and studied the immunogenicity of peptides in animal models. A panel of synthetic peptides spanning the CCR5-ECL1 region and displaying glycine or alanine substitutions was assayed for antibody binding with a pool of natural anti-CCR5 antibodies. We used mice and chickens to study the immunogenicity of mutagenized peptide. Structural characterization by nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics simulations were performed to better understand the structural and conformational features of the mutagenized peptide. Amino acid substitutions in positions Ala95 and Ala96 (A95-A96) increased antibody-peptide binding compared to that of the wild-type peptide (Asp95-Phe96). The Ala95-96 peptide was shown to induce, in mice and chickens, antibodies displaying biological activity at very low concentrations. Strikingly, chicken antibodies to the Ala95-96 peptide specifically recognize human CCR5 molecules, downregulate receptors from lymphocytes, inhibit CCR5-dependent chemotaxis, and prevent infection by several R5 viruses, displaying 50% inhibitory concentrations of less than 3 ng/ml. NMR spectroscopy and molecular dynamics simulations proved the high flexibility of isolated epitopes and suggested that A95-A96 substitutions determine a slightly higher tendency to generate helical conformations combined with a lower steric hindrance of the side chains in the peptides. These findings may be relevant to the induction of strong and efficient HIV-blocking antibodies

HIV-1 neutralization of Ig-depleted mucosal secretions.

<p>Experiments were run on pooled IgG- or IgA- or IgG/IgA-depleted vaginal secretions from HIV-1-VLP_IIIB-CCL28, HIV-1-VLP_IIIB-CCL19, HIV-1-VLP_IIIB mice. Upper panel show <i>ex vivo</i> neutralizing activity against HIV-1_IIIB of immune vaginal secretions (<i>A</i>). Lower panels shows <i>ex vivo</i> neutralizing activity against HIV-1_DU174 of immune vaginal secretions (<i>B</i>). The neutralization titer is represented as percentages of the virus replication as compared with control samples. Dotted line indicates 50% neutralizing activity. The data represent the results of two duplicate-sample assays.</p