Exploring the modulatory role of bovine lactoferrin on the microbiome and the immune response in healthy and Shiga toxin‑producing E.coli challenged weaned piglets

Background Post-weaned piglets suffer from F18+Escherichia coli(E.coli)infections resulting in post-weaning diar-rhoea or oedema disease.Frequently used management strategies,including colistin and zinc oxide,have contrib-uted to the emergence and spread of antimicrobial resistance.Novel antimicrobials capable of directly interacting with pathogens and modulating the host immune responses are being investigated.Lactoferrin has shown promising results against porcine enterotoxigenic E.coli strains,both in vitro and in vivo.Results We investigated the influence of bovine lactoferrin(bLF)on the microbiome of healthy and infected weaned piglets.Additionally,we assessed whether bLF influenced the immune responses upon Shiga toxin-producing E.coli(STEC)infection.Therefore,2 in vivo trials were conducted:a microbiome trial and a challenge infection trial,using an F18+STEC strain.BLF did not affect theα-andβ-diversity.However,bLF groups showed a higher relative abundance(RA)for the Actinobacteria phylum and the Bifidobacterium genus in the ileal mucosa.When analysing the immune response upon infection,the STEC group exhibited a significant increase in F18-specific IgG serum levels,whereas this response was absent in the bLF group.Conclusion Taken together,the oral administration of bLF did not have a notable impact on theα-andβ-diversity of the gut microbiome in weaned piglets.Nevertheless,it did increase the RA of the Actinobacteria phylum and Bifi-dobacterium genus,which have previously been shown to play an important role in maintaining gut homeostasis.Furthermore,bLF administration during STEC infection resulted in the absence of F18-specific serum IgG responses.

Leuprolide acetate induces structural and functional recovery of injured spinal cord in rats

Gonadotropin-releasing hormone（Gn RH） and its synthetic analog leuprolide acetate, a Gn RH agonist, have neurotrophic properties. This study was designed to determine whether administration of leuprolide acetate can improve locomotor behavior, gait, micturition reflex, spinal cord morphology and the amount of microglia in the lesion epicenter after spinal cord injury in rats. Rats with spinal cord compression injury were administered leuprolide acetate or saline solution for 5 weeks. At the 5th week, leuprolide acetate-treated rats showed locomotor activity recovery by 38%, had improvement in kinematic gait and exhibited voiding reflex recovery by 60%, as compared with the 1st week. By contrast, saline solution-treated rats showed locomotor activity recovery only by 7%, but voiding reflex did not recover. More importantly, leuprolide acetate treatment reduced microglial immunological reaction and induced a trend towards greater area of white and gray matter in the spinal cord. Therefore, leuprolide acetate has great potential to repair spinal cord injury.

Rescue of autoimmune hepatitis by soluble MHC class II molecules in an altered concanavalin A-induced experimental model

Background:Soluble major histocompatibility complex class II(sMHCII)molecules have been described to maintain tolerance through the suppression of autoreactive T lymphocytes.In order to evaluate their ability to rescue autoimmune hepatitis(AIH)symptoms,the present work attempted to administer sMHCII molecules to an in vitro as well as in vivo concanavalin A(ConA)-induced AIH model.Methods:The in vitro AIH model consisted of splenocyte stimulation with ConA in the presence or absence of serum-isolated sMHCII molecules.An in vivo ConAmodified model with or without sMHCII treatment was developed.The cytokine profile in culture supernatants and serum was tested by ELISA.Cell markers were evaluated by immunofluorescence,while cell proliferation by tritiated thymidine uptake.AIH symptoms were assessed by daily observations for the establishment of a disease severity scoring system and liver histology was evaluated using a biomolecular imager.Results:The presence of sMHCII molecules in the ConA-stimulated cell cultures leads to a significant reduction of cell proliferation.The administration of sMHCII molecules to the ConA-treated animals showed a significant reduction in the levels of IL-2,IL-4,and IL-10,as well as a decrease in the number of spleen CD4+and CD8+cells.Upon development of a scoring system,it was shown that the sMHCII treatment was accompanied by a slower progression of the disease,while rescuing fibrotic liver morphology.Conclusion:The results presented in this study confirm the ability of sMHCII proteins to alleviate autoimmune hepatitis,possibly highlighting new therapeutic approaches for autoimmune diseases.

About a Case of Neurotic Angioedema Induced by Angiotensin Converting Enzyme Inhibitor

Neurotic angioedema may be secondary to ACE (Angiotensin-converting enzyme) inhibitor. From a case of neurotic angioedema in a hypertensive man under ACE (Angiotensin-converting enzyme) inhibitor, we expose the clinical characteristics typical of the edema and its evolution. A 73-year-old man has consulted for edema of the face and redness of the palmar surface of the hand not pruriginous for 2 days. He has already had conventional anti-edematous treatments but no changes. In the absence of a technical platform, no paraclinical examination was carried out. The cessation of ACE inhibitor and the administration of tranexamic acid were made immediately. Signs regressed within 24 hours. Neurotic angioedema is a diagnostic problem in countries where biological examination is still limited and if practitioners are unaware of the possibility of its occurrence during IEC treatment. While the patient’s prognosis depends on the precocity of management.

Clinical Case: About a Probable Case of Post-Transfusion Purpura in a Homozygous Sickle Cell

Alloimmunization to platelet antigens exposes to a serious immunological incident. We report a probable case of a post-transfusion purpura from homozygous sickle cell child alloimmunized against platelet antigen. We detail the challenges of alloantibody identification and transfusion management. These challenges are due to the lack of laboratory techniques for typing HLA and HPA system and the use of leukocyte-depleted (filtered) blood products.

Canova medication changes TNF-α and IL-10 serum levels in mice infected with Trypanosoma cruzi Y strain

Objective:To identify whether Canova medication changes TNF-α and IL-10 serum levels in mice infected with Trypanosoma cruzi Y strain.Methods:Animals were divided into five groups:non-treated infected animals(I); benznidazole-treated infected animals(Bz; 100 mg/kg body weight,single daily dose by gavage); Canova medication(CM) treated infected animals(CM;0.2 mL/animal,single daily dose by gavage); benznidazole- and Canova medication–treated infected animals with the above-mentioned dose(Bz+CM);and non-infected animals(C).TNF-α and IL-10 levels were determined in serum aliquots after 4,7,10,13,and 29 days of infection.An ELISA technique was employed with R&D System Inc.antibody pairs.Results:A high increase in TNF-α and IL-10 levels occurred in the infected and CM-treated groups within the treatment employed on the 10 th day after infection,coupled with a IL-10 decrease on the 13 th day after infection when compared with the other experimental groups.Conclusions:CM may change the balance between plasma cytokine levels(TNF-α and IL-10) in mice infected with Y strain T.cruzi,with important consequences leading towards a more severe infection.

Molecular epidemiology and evolution of worldwide enterovirus 71 strains isolated from 1970 to 2004

Human enterovirus 71 (EV71) is one of the major etiological agents of the hand-foot-and-mouth disease (HFMD) that often causes severe neurological complications. Recently,its outbreaks mainly take place in the torrid zone of the Asia-Pacific region. To study the evolution and genetic variability,we collected 532 EV71 strains with almost complete or complete VP1 sequences (891 nt) isolated worldwide from 1970 to 2004. The pairwise homologies and genetic distances were analyzed. Most strains belong to previously identified genotype B and C. However,a unique strain R13223-IND-01 appears not to fall into current three genotypes (A,B and C),and probably represents a new genotype D. Some orphan strains were observed in the genotypes B and C,and their significance in the EV71 evolution was discussed. Moreover,there is a significant co-variance of 6 discrete positions on VP1 (amino acid 43,58,164,184,240 and 249). This high co-variability is tightly related with the subgenotypes.

Spike protein homology between the SARS-associated virus and murine hepatitis virus implies existence of a putative receptor-binding region

Coronavirus has been determined to be the cause of the recent outbreak of severe acute respiratory syndrome (SARS). Human coronavirus 229E had been studied well and its receptor-binding domain was restricted to aa417—547 of S protein. However, this region has no homology with the newly separated SARS-associated virus (Hong Kong isolate CUHK-W1). Then we analyzed the phylogenesis of S1 subunit of the coronavirus spike protein (SARS-associated virus, Hong Kong isolate CUHK-W1). Interestingly, the highest homology between murine hepatitis virus (MHV) and SARS-associated coronavirus was found. And the important sites (aa62—65 and aa214—216) on the spike protein of MHV with receptor-binding capacity were highly conservative in comparison with the newly separated SARS-asso- ciated virus (the corresponding sites are aa51—54 and aa195—197). These results from bioinformatics analysis might help us to study the receptor-binding sites of SARS-associ- ated virus and the mechanism of the virus entry into the target cell, and design antiviral drugs and potent vaccines.

Characterization of the Antigenicity and Immunogenicity of the Escherichia Coli Produced RNase Domain of the Classical Swine Fever Virus Glycoprotein E^(rns)

Ems is a highly glycosylated envelope protein of classical swine fever virus （CSFV） with RNase ac- tivity. Ems can induce neutralizing antibodies and provide immune protection against CSFV infection. In this study, the RNase domain of the Ems was produced in Eschenchia coil. Its reactivity with CSFV-positive sera and its ability to induce antibodies and to provide protective immunity were then investigated. The serological tests showed that the prokaryotically expressed RNase domain of the Ems retained its antigenicity and in- duced high titers of humoral responses. However, only partial protection and a limited amount of neutralizing antibodies were demonstrated by an in vitro neutralization test and an immunization/challenge test. The re- sults suggest that other essential factors rather than simply enhancing the immunogenicity of Ems should be taken into consideration when Er＂s is enrolled as one of the components of a candidate vaccine.

Characterization of Antibody Responses Against the 2F5 Epitope ELDKWA Using HIV-1 Env-Mediated Membrane Fusion and Neutralization Assays

The epitope ELDKWA, which is located in the membrane-proximal external region （MPER） of HIV-1 gp41, is an important neutralizing epitope. The human monoclonal antibody （mAb） 2F5 against this epitope shows broad neutralizing activity toward many HIV strains. However, several reports have shown that the epitope-specific mAbs induced by peptides containing MPER did not exhibit the same neutralizing activities as human mAb 2F5. In this study, four ELDKWA epitope specific mAbs （9E7, 7E10, 6B5, and 2B4） induced by immunization with the ELDKWA epitope in varied molecular contexts, all showed inhibitory activi- ties with different potencies in HIV-1 Env-mediated membrane fusion assays and pseudovirus neutralization assays. This result indicates that though these antibodies recognize the epitope ELDKWA, their characteri- zations differ from that of neutralizing antibodies, implying that the neutralizing mAbs can be induced but also need to be screened, and the protective ability of a related vaccine antigen depends on the concentra- tion of the neutralizing mAbs in the induced polyclonal antibodies.

The interaction between the membrane-proximal external region and the N-trimer region of HIV-1 gp41: Involvement in viral fusion

The membrane proximal external region (MPER) of gp41 is extremely conserved among diverse HIV-1 variants, implying its important role in viral infection. Interestingly, two of the most broadly neutralizing antibodies, 2F5 and 4E10, specifically recognize this region. Our previous study demonstrated that the antigenicity and immunogenicity of 4E10 epitope are affected by remodeling gp41 fusion core, suggesting that the MPER may be associated with gp41 core and involved in gp41-mediated membrane fusion. Here we measured the binding activity of 4E10 epitope peptide (D4E10P) with various gp41 core-derived peptides and found that the N-trimer region in a construct designated N-trimer-6HB interacted significantly with D4E10P. Using N-trimer-6HB to screen a phage library, we identified a motif (WF) located in 4E10 epitope that may play a certain role in the interaction of gp41 MPER with the N-trimer in gp41 fusion core and, we thus speculated upon the potential involvement of MPER in the fusion process between viral envelope and target cell membrane.

Preliminary Evaluation of a Candidate Multi-Epitope-Vaccine Against the Classical Swine Fever Virus

A multi-epitope-vaccine MEVABc consisting of two linear neutralizing determinants （BCI： aa693-716; A6： aa844-865） located on antigenic unit B/C and unit A of glycoprotein E2 was prepared to evaluate whether a combination strategy is effective in the design of peptide vaccines. After immunization, pig sera collected every one to two weeks were evaluated by enzyme linked immunosorbent assay. C-straininduced anti-sera and hyper-immune sera cannot recognize overlapping peptides that cover the E2 N-terminus, while MEVAgC is able to elicit high levels of peptide-specific antibody response. When compared with previously studied peptide vaccines PV-BC1 and PV-A6, the same dose of either component in the MEMABc increases the BC1- or A6-specific antibodies （to 1/3-1/2 of the levels of the separate vaccines）. However, the synergy between the antibodies may make MEVAgc much more potent. Moreover, anti-C-strain immunity pre-existing in pigs does not disturb the sequent MEVABc vaccination. Thus, MEVABc can be administrated to pigs which already possess anti-classical swine fever virus immunity. MEVAgC is a promising candidate marker vaccine.

Monoclonal Antibodies Recognizing HIV-1 gp41 Could Inhibit Env-Mediated Syncytium Formation

Some monoclonal antibodies （mAbs） could inhibit infection by HIV-1. In this study, four mAbs against HIV-1 gp41 were prepared in mice. All four mAbs could bind to the recombinant soluble gp41 and recognize the native envelope glycoprotein gp160 expressed on the HIV-Env^＋ CHO-WT cell in flow cytometry analysis. Interestingly, the results show that all four mAbs purified by affinity chromatography could inhibit HIV-1 Env-mediated membrane fusion （syncytium formation） by 40%-60% at 10 μg/mL, which implies potential inhibitory activities against HIV-1.

New roots for IgE-producing B cells

In allergic responses, B cells are driven to undergo an immunoglobulin isotype switch, shifting from immunoglobulin M to immunoglobulin E （IgE） synthesis. This process involves the rearrangement of germline DNA in the immunoglobulin heavy-chain locus and is stimulated by cytokines （IL-4 and IL-13） and CD40 activation, but the biology of the IgE-pro- ducing B cells, where they are located when the isotype switch occurs as well if the pro- cess involves an intermediate step of rearrangement to IgGl and later to IgE, is still poorly understood.