IgG Activity Research Articles

Preparation and in vitro delivery performance of chitosan–alginate microcapsule for IgG

ABSTRACTThe study aimed to develop chitosan–alginate microcapsule as an oral delivery carrier for IgG. Bovine serum albumin (BSA) was used as the protein to be encapsulated while determining the microcapsule formula by evaluating encapsulation efficiency (EE), loading capacity (LC) and release profile. Results suggested that the optimal formula was composed of 0.1% chitosan, 0.5% CaCl2, 2% sodium alginate and the loading rate of BSA reached 25%. IgG was substituted for BSA and an IgG microcapsule was prepared following the above formula. The EE and LC of the resulted IgG microcapsule reached 76.83% and 18.53%. After 2 h incubation in simulated gastric fluid, the activity of IgG in the microcapsule remained at 79.79% and the total release rate of IgG in a simulated intestinal fluid reached 82.52%. This encapsulation formula was proved to be an effective oral delivery system which would protect the IgG from severe gastric conditions and guarantee an efficient release in the intestinal tract.

Sialylation converts arthritogenic IgG into inhibitors of collagen-induced arthritis.

Rheumatoid arthritis (RA)-associated IgG antibodies such as anti-citrullinated protein antibodies (ACPAs) have diverse glycosylation variants; however, key sugar chains modulating the arthritogenic activity of IgG remain to be clarified. Here, we show that reduced sialylation is a common feature of RA-associated IgG in humans and in mouse models of arthritis. Genetically blocking sialylation in activated B cells results in exacerbation of joint inflammation in a collagen-induced arthritis (CIA) model. On the other hand, artificial sialylation of anti-type II collagen antibodies, including ACPAs, not only attenuates arthritogenic activity, but also suppresses the development of CIA in the antibody-infused mice, whereas sialylation of other IgG does not prevent CIA. Thus, our data demonstrate that sialylation levels control the arthritogenicity of RA-associated IgG, presenting a potential target for antigen-specific immunotherapy.

ADAMTS13 autoantibodies cloned from patients with acquired thrombotic thrombocytopenic purpura: 1. Structural and functional characterization in vitro.

Acquired thrombotic thrombocytopenia purpura (TTP) is a life-threatening illness caused by autoantibodies that decrease the activity of ADAMTS13, the von Willebrand factor-cleaving protease. Despite efficacy of plasma exchange, mortality remains high and relapse is common. Improved therapies may come from understanding the diversity of pathogenic autoantibodies on a molecular or genetic level. Cloning comprehensive repertoires of patient autoantibodies can provide the necessary tools for studying immunobiology of disease and developing animal models. Anti-ADAMTS13 antibodies were cloned from four patients with acquired TTP using phage display and characterized with respect to genetic origin, inhibition of ADAMTS13 proteolytic activity, and epitope specificity. Anti-idiotypic antisera raised to a subset of autoantibodies enabled comparison of their relatedness to each other and to polyclonal immunoglobulin (Ig)G in patient plasma. Fifty-one unique antibodies were isolated comprising epitope specificities resembling the diversity found in circulating patient IgG. Antibodies directed both to the amino terminal domains and to those requiring the ADAMTS13 cysteine-rich/spacer region for binding inhibited proteolytic activity, while those solely targeting carboxy-terminal domains were noninhibitory. Anti-idiotypic antisera raised to a subset of antibody clones crossreacted with and reduced the inhibitory activity of polyclonal IgG from a set of unrelated patients. Anti-ADAMTS13 autoantibodies isolated by repertoire cloning display the diversity of epitope specificities found in patient plasma and provide tools for developing animal models of acquired TTP. Shared idiotypes of inhibitory clones with circulating IgG from multiple patients suggest common features of pathogenic autoantibodies that could be exploited for developing more targeted therapies.

Plasmodium falciparum infection and age influence parasite growth inhibition mediated by IgG in Beninese infants

Antibodies that impede the invasion of Plasmodium falciparum (P. falciparum) merozoites into erythrocytes play a critical role in anti-malarial immunity. The Growth Inhibition Assay (GIA) is an in vitro measure of the functional capacity of such antibodies to limit erythrocyte invasion and/or parasite growth. Up to now, it is unclear whether growth-inhibitory activity correlates with protection from clinical disease and there are inconsistent results from studies performed with GIA. Studies that have focused on the relationship between IgGs and their in vitro parasite Growth Inhibition Activity (GIAc) in infants aged less than two years old are rare. Here, we used clinical and parasitological data to precisely define symptomatic or asymptomatic infection with P. falciparum in groups of infants followed-up actively for 18 months post-natally. We quantified the levels of IgG1 and IgG3 directed to a panel of candidate P. falciparum vaccine antigens (AMA-1, MSP1, 2, 3 and GLURP) using ELISA and the functional activity of IgG was quantified using GIA. Data were then correlated with individuals' infection status. At 18 months of age, infants harbouring infections at the time of blood sampling had an average 19% less GIAc than those not infected (p=0.004, multivariate linear regression). GIAc decreased from 12 to 18 months of age (p=0.003, Wilcoxon matched pairs test). Antibody levels quantified at 18 months in infants were strongly correlated with their exposure to malarial infection, however GIAc was not correlated with malaria infectious status (asymptomatic and symptomatic groups). In conclusion, both infection status at blood draw and age influence parasite growth inhibition mediated by IgG in the GIA. Both factors must be taken into account when correlations between GIAc and anti-malarial protection or vaccine efficacy have to be made.

Anti-DNA antibodies in the blood of patients with schizophrenia possess DNA-hydrolyzing activity

IntroductionAutoantibodies (Abs) to different neuronal receptors and DNA were detected in the blood of patients with schizophrenia. Abs hydrolyzing DNA were detected in pool of polyclonal autoantibodies in autoimmune and infectious diseases, such catalytic Abs were named abzymes.ObjectivesTo investigate the level of anti-DNA antibodies and DNA-hydrolyzing activity of IgG from the serum of patients with schizophrenia depending on leading clinical symptoms.Aims– To measure the concentration of anti-DNA Abs in serum of patients with leading positive and negative symptoms;– to determine DNA-hydrolyzing activity of IgG.MethodsIn our study, 51 patients were included. The levels of antiDNA Abs were determined using ELISA. DNA-hydrolyzing activity was detected as the level(%) of supercoiled pBluescript DNA transition in circular and linear forms. Statistical analysis was performed in “Statistica 9.0”.ResultsAnti-DNA Abs of patients with schizophrenia not only bind DNA, but quite efficiently hydrolyze the substrate. IgG of patient with schizophrenia were shown to possess DNA hydrolyzing activity. It should be noted that DNAase activity of IgG in patients with schizophrenia with a negative symptoms was significantly higher, than in patients with positive symptoms (Table 1).ConclusionsThe data show a correlation with the level of DNase activity and leading symptoms of patients with schizophrenia.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Effect of Spirulina platensis as feed supplement on growth performance, immune response and antioxidant status of mono-sex Nile Tilapia (Oreochromis niloticus)

To evaluate the effect of Spirulina platensis inclusion in diets for Nile tilapia fingerlings, a completelyrandomized experimental design was developed with 4 treatments and three replicates. Diets with 4inclusion levels (control diet (Sp0), 0.5% (Sp0.5), 1% (Sp1) and 1.5% (Sp1.5)) were prepared. 180 Niletilapia fingerlings with average initial weight of 8.46±0.17 g were assigned to twelve experimental tanks.The experiment lasted for ten weeks. At the end of the experiment; growth performance, the whole bodycomposition was determined and serum samples for lysozyme, IgG, IgM values and catalase activitywere collected and antioxidant status of Nile tilapia muscle were determined. The results showed thatgroup supplemented with 1% S. Platensis have higher body weight and lower FCR than the controlgroup and other groups. S. platensis inclusion increased activity of glutathione reductase, and reduceMDA formation. Levels of lysozyme, IgG and catalase activity were higher in S. platensis supplementedgroups but don’t have significant effect on IgM level. In conclusion, Spirulina platensis supplementationincreased antioxidant protective capacities. It also affected some innate and humoral immunityparameters as well as don’t have negative effect on fish growth

CD4+CXCR5+ T cells activate CD27+IgG+ B cells via IL-21 in patients with hepatitis C virus infection

Chronic hepatitis C virus (HCV) infection causes the skewing and activation of B cell subsets, but the characteristics of IgG+ B cells in patients with chronic hepatitis C (CHC) infection have not been thoroughly elucidated. CD4+CXCR5+ follicular helper T (Tfh) cells, via interleukin (IL)-21 secretion, activate B cells. However, the role of CD4+CXCR5+ T cells in the activation of IgG+ B cells in CHC patients is not clear. The frequency of IgG+ B cells, including CD27-IgG+ B and CD27+IgG+ B cells, the expression of the activation markers (CD86 and CD95) in IgG+ B cells, and the percentage of circulating CD4+CXCR5+ T cells were detected by flow cytometry in CHC patients (n=70) and healthy controls (n=25). The concentrations of serum IL-21 were analyzed using ELISA. The role of CD4+CXCR5+ T cells in the activation of IgG+ B cells was investigated using a co-culture system. A significantly lower proportion of CD27+IgG+ B cells with increased expression of CD86 and CD95 was observed in CHC patients. The expression of CD95 was negatively correlated with the percentage of CD27+IgG+ B cells, and it contributed to CD27+IgG+ B cell apoptosis. Circulating CD4+CXCR5+ T cells and serum IL-21 were significantly increased in CHC patients. Moreover, circulating CD4+CXCR5+ T cells from CHC patients induced higher expressions of CD86 and CD95 in CD27+IgG+ B cells in a co-culture system; the blockade of the IL-21 decreased the expression levels of CD86 and CD95 in CD27+IgG+ B cells. HCV infection increased the frequency of CD4+CXCR5+ T cells and decreased the frequency of CD27+IgG+ B cells. CD4+CXCR5+ T cells activated CD27+IgG+ B cells via the secretion of IL-21.

Isolation, preparation, and assessment of the immunogenicity effectiveness of a novel inactivated rotavirus vaccine strain: ZTR-68, rotavirus A genotype G1P[8

BackgroundRotavirus is one of the leading causes of diarrhoea in children in both developed and developing countries, resulting in an estimated 600 000 deaths worldwide each year. In China, roughly 13 400 children younger than 5 years die from rotavirus infection each year. We aimed to isolate and characterise a human virus for use as a candidate human inactivated rotavirus vaccine strain. We studied the preparation of the vaccine and assessed its immunogenicity effectiveness. MethodsFrom September, 2009, to November, 2012, we collected 206 stool specimens from children in Yunnan, China, and tested for the presence of rotaviruses by use of enzyme immunoassay and double-stranded RNA-PAGE. G and P typing of the positive samples were done by one-step RT-PCR and sequencing. A new human rotavirus was isolated from a child aged 3 months with acute gastritis from the First People's Hospital of Zhaotong City, Zhaotong, China, and was designated ZTR-68. We did a full genomic analysis of ZTR-68 and tested for identifiable characteristics of the virus. A scalable inactivated rotavirus vaccine was cultured by rolling bottles, purified using low-velocity centrifuge, microfiltration clarification, ultrafiltration concentration, and size-exclusion chromatography, and inactivated by the addition of formaldehyde. Its immunogenicity was studied in Balb/c mice by intramuscular injection. FindingsStrain ZTR-68 was isolated and plaque purified, and its complete genome was sequenced. ZTR-68 is a rotavirus A of genotype G1P[8] and has a close phylogenetic relation to Wa. We confirmed that our rotavirus vaccine was completely inactivated, and rotavirus antigen can be measured by ELISA. After intramuscular injection of the vaccine into BalB/c mice aged 6 weeks, high titres of rotavirus-specific IgG (>20 000) and neutralising activity (roughly 3000) were recovered in the sera of these mice. InterpretationThis newly isolated rotavirus, ZTR-68, is being used to establish a new strain of inactivated rotavirus vaccine. Our findings show that the inactivated rotavirus vaccine has good immunogenicity and provide evidence for further clinical development as an alternative candidate vaccine. FundingThis research was financially supported by the State Project for Essential Drug Research and Development, the Chinese national “Twelfth Five-Year” plan (project number: 2014ZX09102041004); the National High Technology Research and Development Program (“863” Program) of China (project number: 2012AA02A404); and the Yunnan Research Program of Application Foundation and Advanced Technology, self-raised funds (project number: 2013FZ140).

Acute hemorrhagic conjunctivitis: anti-coxsackievirus A24 variant secretory immunoglobulin A in acute and convalescent tear

PurposeThe purpose of this paper is to present the clinical course of a laboratory-acquired case of acute hemorrhagic conjunctivitis (AHC) caused by coxsackievirus A24 variant (CA24v). Also, the anti-CA24v neutralizing activity and anti-CA24v immunoglobulin (Ig) G and secretory IgA (sIgA) in acute and convalescent tears and/or sera are presented.CaseA 60-year-old male presented with acute-onset left eyelid edema, tearing, conjunctival erythema, pain, foreign body sensation, and subconjunctival hemorrhage 24 hours after suspected laboratory exposure. Bilateral conjunctivitis presented 24 hours later and resolved in 10 days.MethodsTear and blood samples were collected for virus isolation and neutralizing assays. CA24v-reactive IgG and sIgA in tear and/or serum samples were detected by immunofluorescent antibody analysis of ethanol-fixed virus-infected cells.ResultsPeak tear neutralization titers (1,000–1,500 U/mL) against the isolated virus occurred 1 day post-onset (po) of AHC. Tear neutralization titers became undetectable by the sixth day as serum neutralization titers became detectable on the ninth day po (60 U/mL), peaked by 21 days (3,000 U/mL), declined by 1 year to 200 U/mL, and remained at 30 U/mL 5 years po. Antibody to human IgG, IgA, and secretory component (sIgA) reacted with CA24v-infected cells treated with pooled acute tears collected 1–4 days po. Predominantly, sIgA was detected in CA24v-infected cells treated with tears collected 4 years and 5 years post-AHC, while convalescent serum contained predominantly anti-CA24v IgG.ConclusionAHC was confirmed by CA24v isolation, tear anti-CA24v neutralizing activity, and seroconversion. The detection of CA24v-reactive IgG, sIgA, and neutralizing activity in tears collected 1–4 days po of AHC supports plasma extravasation of IgG and suggests a defensive role for tear anti-CA24v sIgA. The results suggest that immunofluorescent antibody analysis of tears for persistent anti-CA24v sIgA may be useful in epidemiological monitoring of AHC.

The activation of IgM- or isotype-switched IgG- and IgE-BCR exhibits distinct mechanical force sensitivity and threshold.

B lymphocytes use B cell receptors (BCRs) to sense the physical features of the antigens. However, the sensitivity and threshold for the activation of BCRs resulting from the stimulation by mechanical forces are unknown. Here, we addressed this question using a double-stranded DNA-based tension gauge tether system serving as a predefined mechanical force gauge ranging from 12 to 56 pN. We observed that IgM-BCR activation is dependent on mechanical forces and exhibits a multi-threshold effect. In contrast, the activation of isotype-switched IgG- or IgE-BCR only requires a low threshold of less than 12 pN, providing an explanation for their rapid activation in response to antigen stimulation. Mechanistically, we found that the cytoplasmic tail of the IgG-BCR heavy chain is both required and sufficient to account for the low mechanical force threshold. These results defined the mechanical force sensitivity and threshold that are required to activate different isotyped BCRs.

Identification of Non-HIV Immunogens That Bind to Germline b12 Predecessors and Prime for Elicitation of Cross-clade Neutralizing HIV-1 Antibodies.

A fundamental challenge for developing an effective and safe HIV-1 vaccine is to identify vaccine immunogens that can initiate and maintain immune responses leading to elicitation of broadly neutralizing HIV-1 antibodies (bnAbs) through complex maturation pathways. We have previously found that HIV-1 envelope glycoproteins (Env) lack measurable binding to putative germline predecessors of known bnAbs and proposed to search for non-HIV immunogens that could initiate their somatic maturation. Using bnAb b12 as a model bnAb and yeast display technology, we isolated five (poly)peptides from plant leaves, insects, E. coli strains, and sea water microbes that bind to b12 putative germline and intermediate antibodies. Rabbit immunization with the (poly)peptides alone induced high titers of cross-reactive antibodies that neutralized HIV-1 isolates SF162 and JRFL. Priming rabbits with the (poly)peptides followed by boosts with trimeric gp140SF162 and then resurfaced Env (RSC3) induced antibodies that competed with mature b12 and neutralized tier 1 and 2 viruses from clade B, C and E, while control rabbits without (poly)peptide priming induced antibodies that did not compete with mature b12 and neutralized fewer isolates. The degree of competition with mature b12 for binding to gp140SF162 correlated with the neutralizing activity of the rabbit IgG. Reversing the order of the two boosting immunogens significantly affected the binding profile and neutralization potency of the rabbit IgG. Our study is the first to provide evidence that appears to support the concept that non-HIV immunogens may initiate immune responses leading to elicitation of cross-clade neutralizing antibodies.

Effect of gamma irradiation on the structural stability and functional activity of plasma-derived IgG

Plasma-originated commercial intravenous immunoglobulin, which is used for a variety of clinical purposes, has been studied to determine the effect of virus-inactivating doses of gamma irradiation on the structural-functional characteristics of the protein. A detailed analysis has been performed in response to a concern that the use of conventional gamma irradiation may damage biologically active proteins. The results demonstrate that although gamma irradiation of the IgG may have some impact on protein structure, the damage can be reduced or even prevented by appropriate irradiation conditions. At the virucidal dose of gamma irradiation (50 kGy) and a temperature of −80 °C, the integrity of the polypeptide chain of immunoglobulin and the secondary structure of IgG can be completely protected, while conformational changes in tertiary structure are significantly minimized to a level that preserves functional activity. The irradiated IgG retains specific antigen-binding properties and Fc-binding activity, indicating that the conformational integrity of the most important structural regions is not affected by γ-irradiation. These results present strong evidence that gamma irradiation treatment can be effectively implemented for inactivation of pathogens in IgG solutions that are used for intravenous injection.

IgG abzymes with peroxidase and oxidoreductase activities from the sera of healthy humans.

We present the evidence showing that small fractions of electrophoretically homogeneous immunoglobulin G (IgGs) from the sera of healthy humans and their Fab and F(ab)2 fragments oxidize 3,3'-diaminobenzidine through a peroxidase activity in the presence of H2 O2 and through an oxidoreductase activity in the absence of H2 O2 . During purification on protein G-Sepharose and gel filtration, the polyclonal IgGs partially lose the Me(2+) ions. After extensive dialysis of purified Abs against agents chelating metal ions, the relative peroxidase activity decreased dependently of IgG analyzed from 100 to ~10-85%, while oxidoreductase activity from 100 to 14-83%. Addition of external metal ions to dialyzed and non-dialyzed IgGs leads to a significant increase in their activity. Chromatography of the IgGs on Chelex non-charged with Cu(2+) ions results in the adsorption of a small IgG fraction bound with metal ions (~5%), while Chelex charged with Cu(2+) ions bind additionally ~38% of the total IgGs. Separation of Abs on both sorbents results in IgG separation to many different subfractions demonstrating various affinities to the chelating resin and different levels of the specific oxidoreductase and peroxidase activities. In the presence of external Cu(2+) ions, the specific peroxidase activity of several IgG subfractions achieves 20-27 % as compared with horseradish peroxidase (HRP, taken for 100%). The oxidoreductase activity of these fractions is ~4-6-fold higher than that for HRP. Antioxidant enzymes such as superoxide dismutases, catalases, and glutathione peroxidases are known to represent critical defence mechanisms for preventing oxidative modifications of DNA, proteins, and lipids. Peroxidase and oxidoreductase activities of human IgGs could also play an important role in the protection of organisms from oxidative stress and toxic compounds.

Serodiagnosis of Mycobacterium abscessus complex infection in cystic fibrosis.

Early signs of pulmonary disease with Mycobacterium abscessus complex (MABSC) can be missed in patients with cystic fibrosis (CF). A serological method could help stratify patients according to risk. The objective of this study was to test the diagnostic accuracy of a novel method for investigating IgG activity against MABSC.A prospective study of all patients attending the Copenhagen CF Centre was conducted by culturing for MABSC during a 22-month period and then screening patients with an anti-MABSC IgG ELISA. Culture-positive patients had stored serum examined for antibody kinetics before and after culture conversion.307 patients had 3480 respiratory samples cultured and were then tested with the anti-MABSC IgG ELISA. Patients with MABSC pulmonary disease had median anti-MABSC IgG levels six-fold higher than patients with no history of infection (434 versus 64 ELISA units; p<0.001). The test sensitivity was 95% (95% CI 74-99%) and the specificity was 73% (95% CI 67-78%). A diagnostic algorithm was constructed to stratify patients according to risk.The test accurately identified patients with pulmonary disease caused by MABSC and was suited to be used as a complement to mycobacterial culture.

Safety, tolerability, and immunogenicity of 15-valent pneumococcal conjugate vaccine in healthy adults

BackgroundPneumococcal disease remains an important health priority despite successful implementation of pneumococcal conjugate vaccines (PCVs) in infant immunization programs, mainly due to the emergence of diseases caused by serotypes not included in licensed PCVs. A 15-valent pneumococcal conjugate vaccine (PCV-15) containing the 7 serotypes (4, 6B, 9V, 14, 18C, 19F, and 23F) included in licensed PCV-7 available at study initiation plus 8 additional serotypes (1, 3, 5, 6A, 7F, 19A, 22F, 33F) was developed and evaluated in healthy adults 18–45 years of age. MethodsSixty subjects received one dose of PCV-15 or PCV-7. Injection-site and systemic adverse events (AEs) were collected for 14-days postvaccination and serious AEs were collected for 30-days postvaccination. Safety laboratory tests (hematology, chemistry, and urinalysis) were evaluated prior to vaccination and 14-days postvaccination. Serotype-specific IgG and opsonophagocytic killing activity (OPA) responses to 15 serotypes included in PCV-15 were measured immediately prior to vaccination and 30-days postvaccination. ResultsAE incidences were comparable between vaccine groups although numerically higher frequencies of erythema (33.3% versus 13.3%), swelling (50.0% versus 23.3%), and myalgia (63.3% versus 36.7%) were reported among PCV-15 versus PCV-7 recipients. Majority of AEs, irrespective of vaccine received, were transient and of mild-to-moderate intensity. No clinically significant differences were observed when comparing AE duration and severity. No laboratory abnormalities, vaccine-related SAEs or discontinuations from the study due to AEs were reported. IgG concentrations for the shared serotypes substantially increased postvaccination at comparable levels between recipients of PCV-15 and PCV-7. Substantial increases in antibody (IgG and OPA) responses to 8 serotypes unique to PCV-15 were observed in PCV-15 recipients. Slight increases to 2 serotypes unique to PCV-15, serotypes 6A and 19A, were also noted in PCV-7 recipients. ConclusionPCV-15 displays an acceptable safety profile and induces IgG and OPA responses to all serotypes included in the vaccine.

Molecular characterization and functional analysis of a novel C-type lectin receptor-like gene from a teleost fish, Plecoglossus altivelis

C-type lectin-like receptors (CLRs) are important pathogen pattern recognition molecules that recognize carbohydrate structures. However, the functions of these receptors in fish keep less known. In this study, we characterized a novel CLR from a teleost fish, Plecoglossus altivelis (ayu), tentatively named PaCD209L. The cDNA of PaCD209L is 1464 nucleotides (nts) in length, encoding a polypeptide of 281 amino acid residues with a calculated molecular weight of 31.5 kDa. Multiple alignment of the deduced amino acid sequences of PaCD209L and other related fish CLRs revealed that the PaCD209L sequence had typical characteristics of fish CLRs, but without Ca2+-binding sites. Sequence comparison and phylogenetic tree analysis showed that PaCD209L shared the highest amino acid identity (44%) with rainbow trout (Oncorhynchus mykiss) CD209 aE PaCD209L transcripts were detected in all of the tissues examined, mainly expressed in the brain and heart. Upon Vibrio anguillarum infection, PaCD209L transcripts were upregulated in all tested tissues and in monocytes/macrophages (MO/MΦ). We prepared recombinant PaCD209L (rPaCD209L) by prokaryotic expression and raised antiserum against PaCD209L. Western blot analysis revealed that native PaCD209L was glycosylated, and its protein expression significantly increased in ayu MO/MΦ upon V. anguillarum infection. In addition, rPaCD209L was able to bind Gram-positive and Gram-negative bacteria in the absence of Ca2+. After PaCD209L was blocked by anti-PaCD209L IgG, the phagocytosis and bacterial killing activity of MO/MΦ significantly decreased. These results suggest that PaCD209L plays an important role in the regulation of MO/MΦ functions in ayu.

A single glycan on IgE is indispensable for initiation of anaphylaxis.

Immunoglobulin ε (IgE) antibodies are the primary mediators of allergic diseases, which affect more than 1 in 10 individuals worldwide. IgE specific for innocuous environmental antigens, or allergens, binds and sensitizes tissue-resident mast cells expressing the high-affinity IgE receptor, FcεRI. Subsequent allergen exposure cross-links mast cell-bound IgE, resulting in the release of inflammatory mediators and initiation of the allergic cascade. It is well established that precise glycosylation patterns exert profound effects on the biological activity of IgG. However, the contribution of glycosylation to IgE biology is less clear. Here, we demonstrate an absolute requirement for IgE glycosylation in allergic reactions. The obligatory glycan was mapped to a single N-linked oligomannose structure in the constant domain 3 (Cε3) of IgE, at asparagine-394 (N394) in human IgE and N384 in mouse. Genetic disruption of the site or enzymatic removal of the oligomannose glycan altered IgE secondary structure and abrogated IgE binding to FcεRI, rendering IgE incapable of eliciting mast cell degranulation, thereby preventing anaphylaxis. These results underscore an unappreciated and essential requirement of glycosylation in IgE biology.

Supplementation of tributyrin improves the growth and intestinal digestive and barrier functions in intrauterine growth-restricted piglets

Intrauterine growth restriction (IUGR) neonates suffer from growth restriction. Tributyrin (TB), a pro-drug of butyrate, can facilitate the growth of animals. This study was to investigate the effects of TB supplementation on the growth of IUGR neonatal piglets. Sixteen IUGR and 8 NBW (normal body weight) neonatal piglets were chosen, weaned at 7th day and fed basic milk diets (NBW and IUGR group) or the basic diets supplemented with 0.1% tributyrin (IT group, IUGR piglets fed with tributyrin) until day 21 (n=8). The body weights of the piglets on days 0, 7, 10, 14, 17, and 20 were measured. The digestive enzyme activity, intestinal morphology, immunoglobulin levels and gene expression of IgG, FcRn and GPR41 in the small intestines were analyzed. The body weights of the piglets in the IUGR and IT group were similar, and both were lower than the NBW group on days 10 and 14. However, after day 17, the IT group exhibited improved (P<0.05) body weights compared to that of the IUGR group. The piglets were sacrificed on day 21. Compared with the NBW piglets, IUGR impaired the development of immune organs and small intestines, impaired the intestinal villus morphology, decreased (P<0.05) most of the tested intestinal digestive enzyme activities, decreased (P<0.05) the ileal sIgA and IgG levels, and down-regulated (P<0.05) the intestinal IgG and GPR41 expression. Piglets in the IT group exhibited a better-developed (P<0.05) spleen and small intestines, improved intestinal villus morphology, increased (P<0.05) intestinal villus surface areas, enhanced (P<0.05) digestive enzyme activities, and up-regulated (P<0.05) expression of IgG and GPR41 mRNA compared to those of the IUGR group. TB supplementation improves the growth and the intestinal digestive and barrier functions in IUGR piglets during the suckling period.

Functional differences between antiviral activities of sulfonated and intact intravenous immunoglobulin preparations toward varicella-zoster virus and cytomegalovirus.

Intravenous immunoglobulin (IVIG) is used to treat severe viral infection, especially varicella-zoster virus (VZV) and cytomegalovirus (CMV) infections. The neutralization antibody titers of eleven IVIG preparations from four companies were examined using VZV and CMV with and without complement. The neutralizing antibody titers of intact IgG preparations were three to six times higher after addition of complement. The effectiveness of the sulfonated IgG preparation was not enhanced by complement, but desulfonated IgG regained enhanced neutralization activity with complement. Antibody-dependent cellular cytotoxicity (ADCC) toward VZV-infected cells was observed with both intact and sulfonated IVIG and guinea pig splenocytes, but ADCC toward CMV-infected cells was not, although NK cell activity toward cells infected with VZV or CMV was detected by splenocytes. Sulfonated IVIG had no complement-activated neutralization of VZV and CMV but retained ADCC toward VZV with less activity after dilution than with intact IVIG. Because sulfonated IVIG is converted to the intact form after intravenous administration, it would show complement-enhanced neutralization and ADCC activity similar to that of intact IVIG invivo. In this study we showed the effects of intact and sulfonated IgG on the functional activity of IgG against VZV and CMV.

Immune memory to Sudan virus: comparison between two separate disease outbreaks.

Recovery from ebolavirus infection in humans is associated with the development of both cell-mediated and humoral immune responses. According to recent studies, individuals that did not survive infection with ebolaviruses appear to have lacked a robust adaptive immune response and the expression of several early innate response markers. However, a comprehensive protective immune profile has yet to be described. Here, we examine cellular memory immune responses among survivors of two separate Ebolavirus outbreaks (EVDs) due to Sudan virus (SUDV) infection in Uganda—Gulu 2000–2001 and Kibaale 2012. Freshly collected blood samples were stimulated with inactivated SUDV, as well as with recombinant SUDV or Ebola virus (EBOV) GP (GP1–649). In addition, ELISA and plaque reduction neutralization assays were performed to determine anti-SUDV IgG titers and neutralization capacity. Cytokine expression was measured in whole blood cultures in response to SUDV and SUDV GP stimulation in both survivor pools, demonstrating recall responses that indicate immune memory. Cytokine responses between groups were similar but had distinct differences. Neutralizing, SUDV-specific IgG activity against irradiated SUDV and SUDV recombinant proteins were detected in both survivor cohorts. Furthermore, humoral and cell-mediated crossreactivity to EBOV and EBOV recombinant GP1–649 was observed in both cohorts. In conclusion, immune responses in both groups of survivors demonstrate persistent recognition of relevant antigens, albeit larger cohorts are required in order to reach greater statistical significance. The differing cytokine responses between Gulu and Kibaale outbreak survivors suggests that each outbreak may not yield identical memory responses and promotes the merits of studying the immune responses among outbreaks of the same virus. Finally, our demonstration of cross-reactive immune recognition suggests that there is potential for developing cross-protective vaccines for ebolaviruses.