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Understanding the interaction between the gut microbiota and Trichinella spiralis is of interest for the early diagnosis and development of therapeutics for trichinellosis and to reveal the potential role of microbiota in the mechanism of immunomodulation of this tissue-dwelling helminth. In this study, we utilized 16S rRNA gene sequencing to monitor the dynamics of the microbes in BALB/c mice challenged with T. spiralis. Flow cytometry and ELISA were used to analyze cytokines at the same time. Histopathological analysis of the duodenum was also conducted. We found that microbial perturbations occurred during infection. The abundance of the Lachnospiraceae NK4A136 group, Ruminococcus 1 and Lactococcus decreased. However, the abundance of proinflammatory Parabacteroides increased over time after infection. T. spiralis infection also tended to inhibit IFN-γ production, and promote IL-4 and IL-10 levels. In total, T. spiralis disrupts gut homeostasis and impairs the development of the intestinal ecosystem. Defining the bacterial populations affected by T. spiralis infection might help identify microbial markers for diagnosis of the disease, and the populations could also be further exploited as a novel option to treat T. spiralis infection.

Chicken coccidiosis is a protozoan parasitic disease that leads to considerable economic losses in the poultry industry. In this study, we used invasive Lactobacillus plantarum (L.P) expressing the FnBPA protein as a novel bacterial carrier for DNA delivery into epithelial cells to develop a live oral DNA vaccine. A fusion DNA vaccine co-expressing EtMIC2 and chicken IL-18 (chIL-18) was constructed and then delivered to the host by invasive L.P. Its efficacy against Eimeria tenella challenge was evaluated in chickens by examining the relative weight gain rate; caecal lesion score; OPG; anti-coccidial index (ACI); levels of EtMIC2 antibody, FnBPA, IL-4, IL-18, IFN-γ and SIgA; and proliferation ability and percentages of CD4+ and CD8+ splenocytes. The experimental results showed that chickens immunized with invasive L.P carrying the eukaryotic expression vector pValac-EtMIC2 (pValac-EtMIC2/pSIP409-FnBPA) had markedly improved immune protection against challenge compared with that of chickens immunized with non-invasive L.P (pValac-EtMIC2/pSIP409). However, invasive L.P co-expressing EtMIC2 with the chIL-18 vector exhibited the highest protection efficiency against E. tenella. These results indicate that invasive Lactobacillus-expressing FnBPA improved humoural and cellular immunity and enhanced resistance to E. tenella. The DNA vaccine delivered by invasive Lactobacillus provides a new concept and method for the prevention of E. tenella.

Largemouth bass iridovirus (LMBV) can cause high mortality and lead to heavy economic loss in the cultivation of largemouth bass, but there was no effective treatment. Here, the present study constructed a recombinant

Avian influenza viruses can be efficiently transmitted through mucous membranes, and conventional vaccines are not effective in protecting against mucosal infection by influenza viruses. To induce multiple immune responses in an organism, we constructed a recombinant Lactobacillus plantarum expressing the influenza virus antigen HA1 with the adjuvant dendritic cell-targeting peptide (DCpep). The recombinant L. plantarum strains NC8Δ-pWCF-HA1 and NC8Δ-pWCF-HA1-DCpep were used to immunize mice via oral administration, and the humoral, cellular and mucosal immune responses were evaluated. In addition, the serum levels of specific antibodies and hemagglutination inhibition (HI) levels were also measured. Our results showed that recombinant L. plantarum activated dendritic cells in Peyer’s patches (PPs), increased the numbers of CD4+IFN-γ+ and CD8+IFN-γ+ cells in the spleen and mesenteric lymph nodes (MLNs), and affected the ability of CD4+ and CD8+ cells to proliferate in the spleen and MLNs. Additionally, recombinant L. plantarum increased the number of B220+IgA+ cells in PPs and the level of IgA in the lungs and different intestinal segments. In addition, specific IgG, IgG1 and IgG2a antibodies were induced at high levels in the mice serum, specific IgA antibodies were induced at high levels in the mice feces, and HI potency was significantly increased. Thus, the recombinant L. plantarum strains NC8Δ-pWCF-HA1 and NC8Δ-pWCF-HA1-DCpep have potential as vaccine candidates for avian influenza virus.

Eimeria tenella (E. tenella) is the most pathogenic genus in Eimeria and can lead to a huge number of deaths of chickens, causing significant economic losses in the poultry industry worldwide. As a natural alkaloid, sanguinarine has many medicinal effects; to a certain extent, it can replace antibiotics and has good application prospects in veterinary medicine. To evaluate the effect of sanguinarine on sporozoites of E.tenella, we used flow cytometry and immunofluorescence staining to detect reactive oxygen species (ROS), mitochondrial membrane potential (MMP), calcium ion (Ca

Zinc finger and BTB domain containing 1(Zbtb1) is a transcriptional suppressor protein, and a member of the mammalian Zbtb gene family. Previous studies have shown that Zbtb1 is essential for T-cell development. However, the role of Zbtb1 in T-cell lymphoma is undetermined. In this study, an EL4 cell line with Zbtb1 deletion was constructed using the CRISPR-Cas9 technique. The expression profiles of microRNA and circRNA produced by the control and gene deletion groups were determined by RNA-seq. In general, 24 differentially expressed microRNA and 16 differentially expressed circRNA were found between normal group and gene deletion group. Through further analysis of differentially expressed genes, GO term histogram and KEGG scatter plot were drawn, and three pairs of miRNA and circRNA regulatory relationships were found. This study describes the differentially expressed microRNA and circRNA in normal and Zbtb1-deficient EL4 cell lines, thus providing potential targets for drug development and clinical treatment of T-cell lymphoma.

To evaluate the efficiency of preventing pathogenic avian influenza by vaccination with recombinant Lactobacillus plantarum (L. plantarum) that expresses conserved antigens, the mucosal and systemic immune responses in animals vaccinated with recombinant L. plantarum NC8-409-1 (NC8-pSIP409-pgsA'-HA2) and NC8-409-2 (NC8-pSIP409-pgsA'-3M2e-HA2) were evaluated. Our results showed that recombinant L. plantarum NC8-409-1 and NC8-409-2 could substantially stimulate the specific IgA titer in the intestine and the specific IgG antibody titer in the serum. We also found that recombinant L. plantarum induced increases in the number of B220+ IgA+ cells in Peyer's patches (PPs), in lymphocyte proliferation and in the number of IFN-γ+ producing CD8+ T cells after immunization in mice. Most importantly, the mice that were vaccinated with recombinant L. plantarum NC8-409-2 and NC8-409-1 were to some extent protected against infection challenge with the H9N2 and H1N1 viruses. In particular, NC8-409-2 provided up to 80% protection against the H9N2 virus, and NC8-409-1 provided up to 60% protection. Lung tissue pathology was also reduced. Therefore, recombinant L. plantarum NC8-409-2 and NC8-409-1 may be candidate oral vaccines against bird flu.

Aims Genotype VII Newcastle disease (ND) is one of the most epidemic and serious infectious diseases in the poultry industry. A novel vaccine targeting VII Newcastle disease virus (NDV) is still proving elusive. Methods and results In this study, we constructed regulated delayed lysis Salmonella strains expressing either a fusion protein (F) alone under an eukaryotic CMV promoter or together with chicken IL-18 (chIL-18) as a molecular adjuvant under prokaryotic Ptrc promoter, named pYL1 and pYL23 respectively. Oral immunization with recombinant strains induced NDV-specific serum IgG antibodies in both pYL1- and pYL23-immunized chickens. The presence of chIL-18 significantly increased lymphocyte proliferation in immunized chickens, as well as the percentages of CD3+ CD4+ and CD3+ CD8+ T cells in serum, even if a statistically significant difference did not exist. After a virulent challenge, pYL23 immunization provided about 80% protection at day 10 postinfection, compared with 60% of protection offered by pYL1 immunization and 100% protection in the inactivated vaccine group, indicating the enhanced immune response provided by chIL-18, which was also confirmed by histochemical analysis. Conclusions Recombinant lysis Salmonella-vectored DNA vaccine could provide us a novel potential option for controlling NDV infection. Significance and impact of the study This study took use of a regulated delayed lysis Salmonella vector for the design of an orally administrated vaccine against NDV.

Trichinellosis is a food-borne zoonotic parasitic disease that causes serious harm to human health and the pig breeding industry. However, there are reports that Trichinella spiralis (T. spiralis) infection can treat autoimmune diseases, including enteritis and experimental autoimmune encephalitis (EAE). However, research on the mechanism of T. spiralis infection in infectious enteritis has not been fully elucidated. Therefore, this experiment used Citrobacter rodentium (C. rodentium) to induce colitis in mouse models and explored its underlying mechanisms. In this experiment, a total of 72 C57BL/6 mice were randomly divided into four groups. Experimental mice in the TS and TS + CR groups were orally inoculated with individual T. spiralis larvae. At 21 days postinfection (dpi) with T. spiralis, experimental animals in the CR and TS + CR groups were inoculated by orogastric gavage with C. rodentium. The control group received PBS only. The results indicated that the weight loss and macroscopic and microscopic colon damage of mice in the TS + CR group were significantly decreased compared with those observed in the CR group. The results of flow cytometry showed that the expression levels of IL-4, IL-10 and CD4

African swine fever (ASF) is a severe disease affecting pigs with high economic losses and endemicity in various parts of the world. So, it represents a serious threat to the global food safety. The disease was discovered in sub-Saharan Africa where still endemic, and first case was recorded in Kenya in 1921. It is now found all over the world; in Africa, Europe, Asia, and the Pacific it already affects more than 50 countries including Republic of Korea, China, Malaysia, Germany, Bhutan, and India. The P72 protein encoded by the B646L gene is the major protein that reveals high reactogenicity and antigenicity. While the P54 plays a significant role in virus pathogenesis especially cell apoptosis. Multiple virus proteins can suppress the apoptosis of the infected cell at an early stage. The disease spreads through contact with the diseased cases, contaminated fomites, and tick bites. Meanwhile, contaminated water sources might be an essential source of infection. The recovered animals have a significant role in disease persistence as silent carriers. Multiple factors might lead to the observed disease seasonality. Route of exposure, infectious dose, and herd immunity are the main determinants of disease severity and clinical signs. The several types of PCR are well-accepted standard tests for early diagnosis. Although commercial ELISAs were stipulated by OIE, it should be combined with some other virology inspections or serological assays. The ASFV-free countries should be protected against the virus entrance especially that all developed vaccines failed to provoke enough immunity status against the challenged virus. Moreover, it accelerates the speed of revealing clinical symptoms.

Some protozoa (Plasmodium falciparum, Toxoplasma gondii, etc) are used to treat cancer because they can improve tumour-induced immunosuppression. This study aims to evaluate the antitumour effect of Eimeria stiedae oocyst soluble protein (ESSP). ESSP was extracted, and mice were injected with 5 × 105 CT26 cells in the right axilla, and then, 50 μg of ESSP was intraperitoneally injected for 5 continuous days. The effect of ESSP on tumour immunity was detected by flow cytometry 25 days after the CT26 inoculation. The results showed that ESSP can inhibit the growth of CT26 subcutaneous tumours; significantly increase the expression of MHC I, MHC II, CD80 and CD86 on the surface of splenic dendritic cells; and enhance the level of IL-12 secretion. ESSP induced an increase in the number of NK cells in the mouse spleen, and the levels of IFN-γ and CD107 were upregulated in the NK cells and CD8+ T cells. The number of metastatic nodules in the lung tumours in the mice was significantly reduced, and the number of tubes, area of the loops and total length of the tubes were significantly reduced. ESSP enhances the antitumour immune response and inhibits tumour growth, metastasis and angiogenesis.

A vaccine against Trichinella spiralis infection is urgently needed to interrupt its transmission from domestic animals to humans. However, no vaccine against T. spiralis is currently available. Our previous study demonstrated that the use of the 43-kDa glycoprotein present in excretory-secretory (ES) proteins of muscle larvae (ML) as an intramuscular DNA vaccine led to a 52.1% protection rate against T. spiralis infection. Attenuated Salmonella strains have the advantage of eliciting mucosal immunity, which is important for controlling T. spiralis infections at the intestinal stage and can be provided as vaccines via oral or intranasal routes. Therefore, in this study, complete 43-kDa glycoprotein (Ts43) sequences of T. spiralis were cloned into the vector pYA3681, and the recombinant plasmid pYA3681-Ts43 was transformed into the attenuated Salmonella typhimurium strain χ11802. The results showed that oral vaccination of mice with attenuated Salmonella carrying the recombinant plasmid pYA3681-Ts43 induced an evident elevation of the local intestinal mucosal sIgA and serum IgG antibody responses. The flow cytometry results showed that the percentages of CD4+ T cells and secreted IFN-γ, IL-4, and IL-17A in CD4+ T cells were significantly increased in the spleen and mesenteric lymph node (MLN) lymphocytes of the vaccinated groups. In addition, increased levels of the IFN-γ, IL-4, and IL-17A cytokines were also observed in the serum of the immunized groups. The above immune response results in the immunized groups demonstrated that protective immunity was elicited in this study. Finally, vaccinated mice demonstrated a significant 45.9% reduction in ML burden after infection with T. spiralis. This study demonstrated that oral vaccination with Ts43 delivered by attenuated Salmonella elicited local and systemic concurrent Th1/Th2/Th17 immune responses and provided partial protection against T. spiralis infection in BALB/c mice. This is a prospective strategy for the prevention and control of trichinellosis.

Trichinellosis is a significant food-borne zoonotic parasitic disease caused by parasite Trichinella. Given the side effects of anti-Trichinella drugs (e.g., Mebendazole) aroused in the course of treatments, an effective vaccine against the parasite is called for. The therapies available to date are in most instances targeting a single stage of Trichinella, resulting in an incomplete protective immunity against the parasite in terms of the complexity of its developmental stages. In this study, a recombinant dual-expression double anchor vector NC8-pLp-TsNd-S-pgsA′-gp43 was constructed carrying two antigen genes from Trichinella spiralis (T. spiralis), encoding the gp43 and T. spiralis Nudix hydrolase (TsNd) proteins which were mainly expressed in muscle larva (ML) and intestinal infective larva stages of the parasite respectively. These two proteins were to be expressed by Lactobacillus plantarum NC8 (L. plantarum NC8) which was designed to express the two anchored peptides, a truncated poly-γ-glutamic acid synthetase A (pgsA′) and the surface layer protein of Lactobacillus acidophilus (SlpA), on its surface for attaching expressed foreign proteins. Oral immunization with the above recombinant vaccine induced higher levels of specific serum IgG and mucosal secretory IgA (SIgA) in BALB/c mice. In addition, cytokines, interferon-γ (IFN- γ), interleukin-4 (IL-4) and IL-17 released by lymphocytes, and CD4+ levels displayed on the surfaces of splenic and mesenteric lymph cells were significantly enhanced by the vaccination. Moreover, after larval challenges, a 75.67 % reduction of adult worms (AW) at 7 days post-infection (dpi) and 57.14 % reduction of ML at 42 dpi were observed in mice immunized with the recombinant vaccine. Furthermore, this oral vaccination reduced the counts of encysted larvae presented in tongue and masseter muscles after infected with T. spiralis in mice. The overall results demonstrated that the recombinant vaccine developed in this study could induce specific humoral, mucosal, and cellular immune responses, and provides protections against different stages (adult worms and muscle larva) of T. spiralis infections in BALB/c mice, which could make it a promising oral vaccine candidate against trichinellosis.

Salmonellosis is a worldwide zoonotic disease that poses a serious threat to the reproduction of livestock and poultry and the health of young animals. Probiotics including Bacillus species, have received increasing attention as a substitute for antibiotics. In this study, chicks infected with Salmonella were fed feed supplemented with the BSH to observe the pathological changes in the liver, detect the number of viable bacteria in the liver and spleen, and record the death of the chicks. The results showed that BSH could reduce the pathological changes in the liver and the invasion of Salmonella into the liver and spleen of chicks. In addition, the survival rate of chicks in the BSH experimental group was 60%, while that in the infected control group was 26%, indicating that BSH had a protective effect on chicks infected with Salmonella. Finally, the fecal microflora of 9-day-old chicks was analyzed by 16S rRNA high-throughput sequencing. The results showed that Salmonella infection could cause intestinal flora changes, while BSH could alleviate this change. In addition, BSH also promoted the proliferation of Lactobacillus salivarius in the cecum of chick. This study emphasized that BSH has anti- Salmonella infection effects in chickens and can be used as a candidate microecological preparation strain.

The major etiologic agent that causes acute gastroenteritis worldwide in young animals and children is Group A rotavirus. Currently, commercially available vaccines do not often prevent porcine rotavirus (PRV) infection. In this study, we evaluated the efficacy of oral recombinant Lactobacillus vaccine against PRV in a mouse model. Lactobacillus plantarum NC8 was used as the host strain, and bacterial vectors were constructed, because the NC8 isolated has shown the capability to survive gastric transit and to colonize the intestinal tract of humans and other mammals. To explore the immunological mechanisms, lactic acid bacterial vectors were used to express VP7 antigen from PRV. We constructed an L. plantarum strain with surface-displayed VP7, named NC8-pSIP409-pgsA-VP7-DCpep. The expressed recombinant protein had a molecular weight of ∼37 kDa. The strain was used to immunize BALB/c mice to evaluate their immunomodulatory characteristics. Mice were orally immunized with recombinant L. plantarum NC8-pSIP409-pgsA-VP7-DCpep at a dose of 2 × 109 colony forming units/200 µl. The results showed that NC8-pSIP409-pgsA-VP7-DCpep significantly stimulated the differentiation of dendritic cells (DCs) in Peyer's patches (PPs) and increased the serum levels of IL-4 and IFN-γ, as measured by enzyme-linked immunosorbent assay in mice treated with NC8-pSIP409-pgsA-VP7-DCpep. Compared to the empty vector group, NC8-pSIP409-pgsA-VP7-DCpep significantly increased the production of B220+ B cells in mesenteric lymph nodes (MLNs) and PPs and also increased the titer levels of the VP7-specific antibodies, including IgG and sIgA. The administration of NC8-pSIP409-pgsA-VP7-DCpep mediated relatively broad cellular responses. This study reveals that clear alternatives exist for PRV control strategies and provides information on PRV infection.

Canine parvovirus (CPV) is highly contagious and can cause haemorrhagic enteritis and myocarditis in dogs. To understand the current epidemic situation of CPV in Jilin Province, China, a total of 44 fecal or intestinal tissue samples of pet dogs suspected of being infected with CPV from February 2018 to November 2019 in Changchun and Liaoyuan City, Jilin Province were collected.All of the 44 collected samples were tested positive to CPV-2 by a PCR assay. The sequencing and analyzing of complete VP2 genes showed that CPV-2c was the most prevalent variant (n = 31;70.4 %), followed by new-CPV-2a (n = 8;18.2 %), new-CPV-2b (n = 4; 9.1 %) and CPV-2 (n = 1; 2.3 %). Phylogenetic analysis revealed that the 31 CPV-2c strains in our study are closely related to local CPV-2c isolates in cluster I. The VP2 protein of the acquired CPV 2c strains all possessed the substitutions Ala5Gly, Phe267Tyr, Tyr324Ile, and Gln370Arg only one with a novel Arg481Lys mutation. These findings demonstrate that CPV-2c was the most prominent type of CPV circulating in Jilin in 2018–2019, clustered in a separate group that is far from the vaccine strains and suggest that further and extensive epidemiological investigation among pet dogs are warranted to provide information for usage and research of current vaccines.

Rabies remains an important public health threat in most developing countries. To develop a more effective and safe oral vaccine against rabies, we constructed recombinant Lactobacillus plantarum NC8 carrying one or two copies of the G gene with a dendritic cell-targeting peptide (DCpep) fused at the C-terminal designated NC8-pSIP409-sRVG or NC8-pSIP409-dRVG, respectively. The immunogenicity and protective efficacy of these recombinant Lactobacillus plantarum against RABV were evaluated by oral administration in a mouse model. The results showed that recombinant NC8-pSIP409-dRVG possessed more G protein, resulting in more functional maturation of DCs. After three cycle of oral immunization, NC8-pSIP409-dRVG induced significantly higher levels of specific IgG antibody and mixed Th1/Th2 with a strong Th1-biasd immune response in mice. Most importantly, although the titers of RABV neutralizing antibody (VNA) were below the threshold of 0.5 IU/mL, the NC8-pSIP409-dRVG could protect 60 % of inoculated mice against lethal RABV challenge. These data reveal that recombinant NC8-pSIP409-dRVG may be a novel and promising oral vaccine candidate to prevent and control of animal rabies.

Background Avian coccidiosis posts a severe threat to poultry production. In addition to commercial attenuated vaccines, other strategies to combat coccidiosis are urgently needed. Lactobacillus plantarum has been frequently used for expression of foreign proteins as an oral vaccine delivery system using traditional erythromycin resistance gene (erm). However, antibiotic selection markers were often used during protein expression and they pose a risk of transferring antibiotic resistance genes to the environment, and significantly restricting the application in field production. Therefore, a food-grade recombinant L. plantarum vaccine candidate would dramatically improve its application potential in the poultry industry. Results In this study, we firstly replaced the erythromycin resistance gene (erm) of the pLp_1261Inv-derived expression vector with a non-antibiotic, asd-alr fusion gene, yielding a series of non-antibiotic and reliable, food grade expression vectors. In addition, we designed a dual-expression vector that displayed two foreign proteins on the surface of L. plantarum using the anchoring sequences from either a truncated poly-γ-glutamic acid synthetase A (pgsA′) from Bacillus subtilis or the L. acidophilus surface layer protein (SlpA). EGFP and mCherry were used as marker proteins to evaluate the surface displayed properties of recombinant L. plantarum strains and were inspected by western blot, flow cytometry and fluorescence microscopy. To further determine its application as oral vaccine candidate, the AMA1 and EtMIC2 genes of E. tenella were anchored on the surface of L. plantarum strain. After oral immunization in chickens, the recombinant L. plantarum strain was able to induce antigen specific humoral, mucosal, and T cell-mediated immune responses, providing efficient protection against coccidiosis challenge. Conclusions The novel constructed food grade recombinant L. plantarum strain with double surface displayed antigens provides a potential efficient oral vaccine candidate for coccidiosis.

BackgroundEimeriaspp. are responsible for chicken coccidiosis which is the most important enteric protozoan disease resulting in tremendous economic losses in the poultry industry. Understanding the interaction between the avian cecal microbiota and coccidia is of interest in the development of alternative treatments that do not rely on chemotherapeutics and do not lead to drug resistance.MethodsWe utilized16SrRNA gene sequencing to detect the dynamics of the cecal microbial community in AA broilers challenged withEimeria tenella. Histopathological analysis of the cecum was also conducted.ResultsWe found that microbial shifts occur during the infection.Lactobacillus,Faecalibacterium,RuminococcaceaeUCG-013,RomboutsiaandShuttleworthiadecreased in abundance. However, the opportunistic pathogensEnterococcusandStreptococcusincreased in abundance over time in response to the infection.ConclusionsEimeria tenelladisrupts the integrity of the cecal microbiota and could promote the establishment and growth of potentially pathogenic bacteria. Defining bacterial populations affected by coccidial infection might help identify bacterial markers for intestinal disease as well as populations or species that could be beneficial in maintaining and restoring gut homeostasis during and after infection withE. tenella.

Interleukin-4 (IL-4), an immunomodulatory cytokine derived from activated T lymphocytes were shown to regulate Th2-type immune responses. It plays an important role in anti-parasitic infections. In this study, a recombinant plasmid was designed using murine IL-4 co-expressed with pgsA anchor system of Lactobacillus plantarum NC8 and was delivered by live Lactobacillus plantarum NC8, which exhibited an enhanced immunogenicity in protection of BALB/c mice from infection with Trichinella spiralis. The results showed that the levels of serum IgG1 and mucosal secretory IgA (sIgA) were both increased significantly in mice orally inoculated with NC8-pSIP409-pgsA-mIL-4, and the Th2 phenotype immune response was up-regulated. A 29.9 % reduction in adult worm burden at 7 days post-infection (dpi) and 83.3 % reduction in muscle larvae burden at 28 dpi were observed in immune-stimulated mice with NC8-pSIP409-pgsA-mIL-4. Moreover, weight loss and pathological changes were also improved in mice of NC8-pSIP409-pgsA-mIL-4 group. Taken together, it suggests that NC8-pSIP409-pgsA-mIL-4 could improve the intestinal mucosal immunity and promoted the elimination of the adult worm in Trichinella-infected mice. This study laid the foundation for the development of a novel vaccines against Trichinellosis.

The present study was undertaken to investigate the antiparasitic activity of extracellular products of Streptomyces albus. Bioactivity-guided isolation of chloroform extracts affording a compound showing potent activity. The structure of the compound was elucidated as salinomycin (SAL) by EI-MS, 1H NMR and 13C NMR. In vitro test showed that SAL has potent anti-parasitic efficacy against theronts of Ichthyophthirius multifiliis with 10 min, 1, 2, 3 and 4 h (effective concentration) EC50 (95% confidence intervals) of 2.12 (2.22–2.02), 1.93 (1.98–1.88), 1.42 (1.47–1.37), 1.35 (1.41–1.31) and 1.11 (1.21–1.01) mg L−1. In vitro antiparasitic assays revealed that SAL could be 100% effective against I. multifiliis encysted tomonts at a concentration of 8.0 mg L−1. In vivo test demonstrated that the number of I. multifiliis trophonts on Erythroculter ilishaeformis treated with SAL was markedly lower than that of control group at 10 days after exposed to theronts (P < 0.05). In the control group, 80% mortality was observed owing to heavy I. multifiliis infection at 10 days. On the other hand, only 30.0% mortality was recorded in the group treated with 8.0 mg L−1 SAL. The median lethal dose (LD50) of SAL for E. ilishaeformis was 32.9 mg L−1.

H9N2 avian influenza viruses are of significance in poultry and public health for the past two decades. Vaccination plays an important role in preventing the infection in domestic poultry. Current H9N2 vaccines have not yet offered ideal protection and eliminated shedding of G57 genotype viruses responsible for H9N2 outbreaks during 2010–2013. Targeted vaccination is a promising strategy to improve vaccine effectiveness. Such a vaccine strategy can be achieved if it is targeted to dendritic cells (DCs) that directly elicit mucosal and adaptive immune responses against microbe challenge. For this purpose, we develop a DC-targeted mucosal vaccine for the oral delivery of the HA protein fused to a DCpep by using Lactobacillus plantarum as an antigen delivery system against G57 virus infection. It showed that Lactobacillus plantarum expressing HA-DCpep confers efficient protection against G57 H9N2 infection, due to have the potential to activate DCs by the TLR-induced NF-κB pathway, to promote DC migration by the CCR7-CCL19/CCL21 axis, thereby enhancing the presentation of immunogen to T and B lymphocytes, resulting in skewing T cells polarization towards Th1, Th2 and Treg cells and evoking more efficient mucosal and adaptive immunity responses. The presented oral mucosal vaccine strategy illustrates the feasibility and efficacy of antigen targeting to DCs through genetic fusion of vaccines to DC-targeting peptides and aids in the design and selection of indications that could be used with this oral vaccine platform against influenza.

Regulatory B cells (Bregs), a subset of B lymphocytes discovered in the past few decades, have the capacity to suppress the immune response and dampen inflammation by secreting cytokines (IL-10 and TGF-β). Whether Bregs are involved in Trichinella spiralis infection and the phenotypic characteristics of these cells after infection are still unknown. We investigated the phenotype of and dynamic changes in IL-10-producing Bregs in Trichinella spiralis infection in BALB/c mice. We used multicolour fluorescence immunostaining of microwave-treated paraffin sections to investigate the number of Bregs in T. spiralis infection. Flow cytometry (FCM) was used to determine the frequency of Bregs and related subgroups and cytokines in the spleen and mesenteric lymph nodes (MLNs). High levels of IL-10 were detected in the spleen and MLNs of mice after infection with T. spiralis. Furthermore, the frequencies of IL-10-producing CD19+CD1dhighCD5+ regulatory B cells and CD19+ cells were increased during T. spiralis infection. We also showed that the induced phenotype was similar to that of transitional type 2 marginal zone precursor B cells (T-MZP) cells after T. spiralis infection in mice. This study is the first demonstration of the expansion of Bregs following T. spiralis infection.

Interferon (IFN)-λ plays an essential role in mucosal cells which exhibit strong antiviral activity.

The highly infectious porcine transmissible gastroenteritis virus (TGEV), which belongs to the coronaviruses (CoVs), causes diarrhea and high mortality rates in piglets, resulting in severe economic losses in the pork industry worldwide. In this study, we used Lactobacillus plantarum (L. plantarum) to anchor the expression of TGEV antigen (S) to dendritic cells (DCs) via dendritic cell-targeting peptides (DCpep). The results show that S antigen could be detected on the surface of L. plantarum by different detection methods. Furthermore, flow cytometry and ELISA techniques were used to measure the cellular, mucosal, and humoral immune responses of the different orally gavaged mouse groups. The obtained results demonstrated the significant effect of the constructed L. plantarum expressing S-DCpep fusion proteins in inducing high expression levels of B7 molecules on DCs, as well as high levels of IgG, secretory IgA, and IFN-γ and IL-4 cytokines compared with the other groups. Accordingly, surface expression of DC-targeted antigens successfully induced cellular, mucosal, and humoral immunity in mice and could be used as a vaccine.

Avian influenza virus (AIV) can infect poultry, mammals, and other hosts and causes enormous economic losses to the global poultry industry. In this study, to develop a novel and potent oral vaccine based on Lactobacillus plantarum (L. plantarum) for controlling the spread of AIV in the poultry industry, we constructed a recombinant L. plantarum strain displaying the 3M2e-HA2 protein of the influenza virus and determined the effect of N/pgsA'-3M2e-HA2 against AIV in chicks. We first confirmed that the 3M2e-HA2 fusion protein was expressed on the surface of L. plantarum via flow cytometry and immunofluorescence experiments. Our experimental results demonstrated that chicks immunized with N/pgsA'-3M2e-HA2 could induce specific humoral, mucosal, and T cell-mediated immune responses, eliciting the host body to protect itself against AIV. Additionally, compared to oral administration, the intranasal immunization of chicks with N/pgsA'-3M2e-HA2 provided a stronger immune response, resulting in a potent protective effect that hindered the loss of body weight, decreasing pulmonary virus titers and reducing lung and throat pathological damages. Thus, our results indicate that our novel approach is an effective method of vaccine design to promote mucosal immunity.

African swine fever (ASF) is an acute, hemorrhagic, and highly contact infectious disease caused by African swine fever virus (ASFV) infecting domestic pigs or wild boars, the mortality rate up to 100 %. Evasion of host innate immunity plays a vital role in the pathogenesis of ASFV. Studies have showed that the MGF505 genes involve in regulating the IFN-I response, but its mechanism of action remains poorly understood. In our present study, ASFV MGF505-11R inhibited IFN-β and ISRE activation induced by cGAS, IRF7, IRF3-5D, STING, IKKε and TBK1 accompanied by decreases of IFN-β, ISG15 and ISG56 mRNA transcription. ASFV MGF505-11R interacted with STING, degrading STING expression by the lysosomal, ubiquitin-proteasome and autophagy pathways. Moreover, ASFV MGF505-11R could inhibit the phosphorylation of TBK1 and IRF3 stimulated by cGAS/STING overexpression. Finally, the truncation mutation analysis indicated that the 1-191 aa and 182-360 aa of ASFV MGF505-11R could inhibit cGAS-STING-mediated activation of IFN-β promoters. In short, these results demonstrated that ASFV MGF505-11R involved in regulating the IFN-I response by negatively regulating the cGAS signaling pathway. In summary, this study preliminarily clarified the molecular mechanism of ASFV MGF505-11R gene antagonizing IFN-I-mediated antiviral, which will helpfully provide new strategies for treatment and prevention of ASF.

H9N2 subtype, a low pathogenic avian influenza virus, is emerging as a major causative agent circulating poultry workplaces across China and other Asian countries. Increasing case number of interspecies transmissions to mammals reported recently provoked a great concern about its risks inducing global pandemics. In an attempt to understand the underlying mechanism of how the H9N2 virus disrupts the interspecies segregation to transmit to mammals. A mutant H9N2 strain was obtained by passaging the wildtype H9N2 A/chicken/Hong Kong/G9/1997 eight times from lung to lung in BALB/c mice. Our finding revealed that mice manifested severe clinical symptoms including losses of body weight, pathological damages in pulmonary sites and all died within two weeks after infected with the mutated H9N2, whereas all mice survived upon infected with wildtype strain in comparison, which suggested increased pathogenicity of the mutant strain. In addition, mice showed enhanced levels of proinflammatory cytokines in sera, including IL-6, TNF-α and IL-1β compared to those subjected to wildtype viral infections. Sequence analysis showed that five amino acid substitutions occurred at PB2627, HA87, HA234, NP387 and M156, and a deletion mutation happened in the M gene (M157). Of these mutations, PB2 E627K played key roles in modulating lethality in mice. Taken together, the mutant H9N2 strain obtained by serial passaging of its wildtype in mice significantly increased its virulence leading to death of mice, which might be associated the accumulated mutations occurred on its genome.

Trichinellosis is a very important food-borne parasitic disease, that seriously endangers animal husbandry and food safety. Therefore, it is necessary to develop a safe and effective vaccine against Trichinella spiralis infection. In this experiment, invasive Lactobacillus plantarum carrying the FnBPA gene served as a live bacterial vector to deliver nucleic acids to the host to produce a novel oral nucleic acid vaccine. Coexpression of the T. spiralis cathepsin F-like protease 1 gene (TsCPF1) and murine IL-4 (mIL-4) by the nucleic acid vaccine was constructed and subsequently delivered to intestinal epithelial cells via invasive L. plantarum. Thirty-seven days after the first immunization, the experimental mice were challenged with 350 T. spiralis infective larvae by oral gavage. The results showed that mice orally immune-stimulated with invasive L. plantarum pValac-TsCPF1/pSIP409-FnBPA not only produce anti-TsCPF1-specific IgG antibodies, sIgA, Th1/Th2 cytokine distinctly increased but also intestinal damage and worm burden relieved compare to non-invasive TsCPF1 group (pValac-TsCPF1/pSIP409). Most notably, experimental mice immunized with invasive L. plantarum coexpressing TsCPF1 and mIL-4 (pValac-TsCPF1-IL-4/pSIP409-FnBPA) exhibited the highest protection efficiency against T. spiralis infection. The above results reveal that invasive L. plantarum-expressing the FnBPA protein improved mucosal and cellular immunity and enhanced resistance to T. spiralis. The nucleic acid vaccine delivered by invasive L. plantarum described in this study offers a novel idea for the prevention of T. spiralis.

It has been considered that the Avian influenza virus (AIV) causes severe threats to poultry industry. In this study, we constructed a series of recombinant Lactobacillus plantarum (L. plantarum) with surface displayed hemagglutinin subunit 2 (HA2) alone or together with heat-labile toxin B subunit (LTB) from enterotoxigenic Escherichia coli. Balb/c mice were used as model to evaluate the protective effects of recombinant L. plantarum strains against H9N2 subtype challenge. The results showed that the presence of LTB significantly increased the percentages of CD3+CD4+IL-4+, CD3+CD4+IFN-γ+ and CD3+CD4+IL-17+ T cells, as well as CD3+CD8+IFN-γ+ T cells in spleen and MLNs determined by Fluorescence-Activated Cell Sorting assay. Similar increased production of serum IFN-γ was also confirmed by enzyme linked immunosorbent assay (ELISA). The L. plantarum with surface displayed HA2-LTB also dramatically increased the percentages of B220+ IgA+ B cells in peyer patch, in consistent with elevated production of mucosal SIgA antibody determined by ELISA. Finally, the orally administrated HA2-LTB expressing strain efficiently protected mice against H9N2 subtype AIV challenge shown by increased survival percentages, body weight gains and decreased lung lesions in histopathologic analysis. In conclusion, this study provides more detail mechanisms underlying the adjuvant effects of LTB on heterologous antigen produced in recombinant lactic acid bacteria.

Rotavirus (RV) infection causes acute, watery dehydrating diarrhea and even death in infants and other young animals, resulting in a severe economic burden; however, little is known about the innate immune mechanisms associated with RV infection. Dendritic cells (DCs), which are professional antigen-presenting cells (APCs), serve as a bridge connecting the innate and adaptive immune system. In this study, the interaction between murine bone marrow-derived DCs (BMDCs) and porcine rotavirus (PRV) was investigated in vitro. Upon stimulation, the expression levels of MHC-II, CD40, CD80, CD86 and CD83 in BMDCs increased in a time-dependent manner, indicating activation and maturation by PRV. In addition, up-regulated Toll-like receptor 2 (TLR2), TLR3 and NF-κB increased the production of interleukin-12 and interferon-γ. The PRV-stimulated BMDCs also showed increased stimulatory capacity in mixed lymphocyte reactions and promoted the Th1 subtype response.

Recombination activating gene 2 (RAG2) is necessary for immature B cell differentiation. Antibodies to human and rabbit RAG2 are currently commercially available, but antibodies to swine RAG remain unavailable to date. In this study, the swine RAG2 genes sequence was synthesized and then cloned into a pET-28a vector. The recombinant fusion protein was successfully expressed in E. coli, purified through nickel column chromatography, and further digested with Tobacco Etch Virus protease. The cleaved protein was purified by molecular-exclusion chromatography and named pRAG2. We used pRAG2 to immunize rabbits, collected the serum and purified rabbit anti-pRAG2 polyclonal antibodies. The rabbit anti-pRAG2 polyclonal antibodies were tested via immunofluorescence on eukaryotic cells overexpressing pRAG2 and also able to recognize pig natural RAG2 and human RAG2 protein in western blotting. These results indicated that the prepared rabbit anti-pRAG2 polyclonal antibodies may serve as a tool to detect immature B cell differentiation of swine.

Goose parvovirus (GPV) continues to be a threat to goose farms and has significant economic effects on the production of geese. Current commercially available vaccines only rarely prevent GPV infection. In our study, Lactobacillus (L.) plantarum NC8 was selected as a vector to express the VP2 gene of GPV, and recombinant L. plantarum pSIP409-VP2/NC8 was successfully constructed. The molecular weight of the expressed recombinant protein was approximately 70 kDa. Mice were immunized with a 2 × 109 colony-forming unit/200 μL dose of the recombinant L. plantarum strain, and the ratios and numbers of CD11c+, CD3+CD4+, CD3+CD8+, and interferon gamma- and tumor necrosis factor alpha-expressing spleen lymphocytes in the pSIP409-VP2/NC8 group were higher than those in the control groups. In addition, we assessed the capacity of L. plantarum SIP409-VP2/NC8 to induce secretory IgA production. We conclude that administered pSIP409-VP2/NC8 leads to relatively extensive cellular responses. This study provides information on GPV infection and offers a clear framework of options available for GPV control strategies.

FaeG is the major subunit of K88 fimbriae. These cell surface attachments are considered to be the major virulence factor of enterotoxigenic Escherichia coli (ETEC), which causes diarrhoea in piglets. The use of dendritic cell-targeting peptide (DCpep) has been demonstrated to be an effective approach to enhance the immunity of vaccines. Lactobacillus plantarum is an attractive candidate for oral vaccination owing to its beneficial effects and safety. In this study, L. plantarum was employed to deliver a FaeG-DCpep fusion antigen, and the immune response in mice was evaluated. The synthesis of FaeG-DCpep dramatically increased the adhesion of recombinant L. plantarum (RLP) to IPEC-J2 cell surfaces, resulting in direct competition between L. plantarum and ETEC during adhesion assays. Significantly higher levels of body weight gain, sera immunoglobulin G and intestinal immunoglobulin A were observed in BALB/c mice immunised with RLP. In addition, the number of CD19+B cells and CD11c+DC cells and the expression levels of several cytokines in the spleen and lymph nodes increased significantly compared to non-immunised mice. The oral administration of RLP also alleviated the symptoms of ETEC challenge, as shown by haematoxylin-eosin staining, indicating that RLP may be an efficient vaccine candidate.

Avian influenza virus (AIV) is spreading worldwide and is a serious threat to the health of poultry and humans. In many countries, low pathogenic AIVs, such as H9N2, have become an enormous economic burden on the commercial poultry industry because they cause mild respiratory disease and decrease egg production. A recombinant Lactobacillus plantarum NC8 strain expressing NP-M1-DCpep from H9N2 AIV has been studied in a mouse model. However, it remains unknown whether this L. plantarum strain can induce an immune response and provide protection against H9N2 AIV in chickens. In this study, chickens that were orally vaccinated with NC8-pSIP409-NP-M1-DCpep exhibited significantly increased T cell-mediated immune responses and mucosal sIgA and IgG levels, which provided protection against H9N2 AIV challenge. More importantly, compared with oral administration of NC8-pSIP409-NP-M1-DCpep, intranasal administration induced stronger immune responses and provided effective protection against challenge with the H9N2 virus by reducing body weight loss, lung virus titers, and throat pathology. Taken together, these findings suggest that L. plantarum expressing NP-M1-DCpep has potential as a vaccine to combat H9N2 AIV infection.

The coccidiosis caused by Eimeria tenella (coccidian) and other species is a serious parasitic disease that affects the global poultry breeding industry. Lactobacillus strains exhibit a number of properties that make them attractive candidates as delivery vehicles for presentation to the mucosa of compounds with pharmaceutical interest, particularly vaccines. Here, the recombinant Lactobacillus plantarum (co-expressing SO7 and DCpep gene) was constructed, and its efficacy against E. tenella challenge was evaluated in this study. Broiler chickens were orally immunized with live recombinant L. plantarum NC8-pSIP409-SO7-DCpep for two weeks and were then challenged with 5×104E.tenella sporulated oocysts per chicken. During the experiment, body weight gains, cecum lesion scores, fecal oocyst shedding and antibody responses in serum and intestinal washes were assessed as measures of protective immunity. The results indicated that chickens immunized with live recombinant L. plantarum can increase body weight gains and serum antibody responses compared to the control groups. Meanwhile, fecal oocyst shedding in the immunized group was significantly reduced (p

Lactobacillus reuteri, a typical intestinal symbiotic bacterium, plays an important role in maintaining intestinal flora stability and host health. However, the effect of Lactobacillus reuteri on peritoneal macrophages has not been thoroughly studied. Our study indicated that Lactobacillus reuteri could activate macrophages and that macrophages treated with Lactobacillus reuteri have an enhanced ability to phagocytose and to kill intracellular Salmonella typhimurium. Lactobacillus reuteri may reduce the inflammatory response caused by Salmonella typhimurium by regulating NO, thus effectively protecting mice against Salmonella typhimurium invasion and dissemination to the liver and spleen. Taken together, these data demonstrated the protective effect of Lactobacillus reuteri on macrophages and mice challenged with Salmonella typhimurium through in vitro and in vivo experiments.

Trichinellosis is a zoonotic parasitic disease caused by Trichinella spiralis, and it is also a widely prevalent foodborne parasitic disease. At present, albendazole and benzimidazole are the most commonly used therapeutic drugs for the clinical treatment of trichinellosis, but they have many side effects. Sanguinarine is a benzophenanthridine alkaloid that has biological activity, such as antibacterial, antitumour and antiparasitic activities. Therefore, the present study aimed to evaluate the anti-Trichinella effect of sanguinarine in vivo and in vitro. The results showed that sanguinarine had a lethal effect on muscle larvae, adults and new-borne larvae in vitro. The damage to adults treated with sanguinarine was observed by scanning electron microscopy. Sanguinarine could significantly reduce the burden of worms in mice during the pre-adult, migrating larva and encysted larva stages. The ratio of intestinal villus to crypt (V/C) in mice treated with sanguinarine was significantly higher than that in non-treated control mice. Compared with the non-treated control group, the sanguinarine-treated group exhibited a significantly increased number of small intestine goblet cells. The level of reactive oxygen species (ROS) in the serum of mice treated with sanguinarine was significantly higher than that of the control group mice in the pre-adult and encysted larva stages. This study suggests that sanguinarine is a potential drug against trichinellosis.

SUMMARYToxocariasis is a very prevalent zoonotic disease worldwide. Recently, investigators have focused more on Toxocara spp. seroprevalence in humans. Information regarding Toxocara seroprevalence in people from different ethnic backgrounds in China is limited. For this study, blood samples were collected from a total of 802 Han, 520 Korean, 303 Manchu, and 217 Mongol subjects from Jilin and Shandong provinces. The overall Toxocara seroprevalence was 16·07% (14·21% Han, 20·58% Korean, 11·22% Manchu, 18·89% Mongol). Living in suburban or rural areas, having dogs at home, exposure to soil, and consumption of raw/undercooked meat were risk factors for Toxocara infection. Exposure to soil was identified as the major risk factor for Toxocara seropositivity in all of the tested ethnicities. To the best of our knowledge, this is the first report concerning Toxocara infection in Manchus and Mongols in China. The present study provided baseline data for effective prevention strategies of toxocariasis in northeast China and recommends improvements in personal hygiene standards to achieve this goal.

During a study of ornithophilous viruses in China, a new densovirus (DNV) was isolated from the lung tissue of Parus major (PmDNV-JL). The complete genome of PmDNV-JL was cloned and sequenced. Five open reading frames (ORFs) were identified in the 5166nt sequence, on the basis of deduced amino acids. It was further shown that this virus caused cytopathic effects (CPE) in Feline kidney cells. The NS1 gene sequence of PmDNV-JL shares 70-99% nucleotide sequence identity with isolates of the Blattella germanica densovirus (BgDNV) and BgDNV-like virus. Phylogenetic analysis indicated that the predicted amino acid sequences of capsid (VP) and non-structural domain (NS1) of PmDNV-JL clustered with the BgDNV and were similar to BgDNV-HB within the genus Densovirus.

Newcastle disease virus (NDV) has been considered as one of the most severe threats to poultry industry. In this study, we constructed a series of food grade recombinant Lactobacillus plantarum (L. plantarum) strains (RLP) synthesizing either virus hemagglutinin-neuraminidase protein (HN) alone or HN fused with DC cells targeting peptides (DCpep), named RLP(pSIP409-HN) and RLP (pSIP409-HN-DCpep), respectively. The immune responses and protective efficacy were then evaluated in chickens. Results showed that the presence of DCpep in RLP (pSIP409-HN-DCpep) group significantly increased the production of secretory immunoglobulin A (SIgA) in intestines and the percentages of CD3(+)CD4(+) T cells in spleen and peripheral blood leukocytes (P

Eimeria tenella (E. tenella) has caused severe economic loss in chicken production, especially after the forbidden use of antibiotics in feed. Considering the drug resistant problem caused by misuse of chemoprophylaxis and live oocyst vaccines can affect the productivity of chickens, also it has the risk to reversion of virulence, the development of efficacious, convenient and safe vaccines is still deeply needed. In this study, the EtMic2 protein of E. tenella was anchored on the surface of Lactobacillus plantarum (L. plantarum) NC8 strain. The newly constructed strain was then used to immunize chickens, followed by E. tenella challenge. The results demonstrated that the recombinant strain could provide efficient protection against E. tenella, shown by increased relative body weight gains, percentages of CD4+ and CD8+ T cells, humoral immune response and inflammatory cytokines. In addition, decreased cecum lesion scores and fecal oocyst shedding were also observed during the experiment. In conclusion, this study proves the possibility to use L. plantarum as a vessel to deliver protective antigen to protect chickens against coccidiosis.

Coccidiosis is an intestinal parasitic disease that is caused by Eimeria tenella and other species, and it seriously restricts the economic development of the broiler breeding industry. In this study, a recombinant Lactobacillus plantarum with an invasive effect was constructed, and it expressed the TA4-AMA1 protein of E. tenella. After oral immunization with recombinant L. plantarum, specific humoral and mucosal immune levels were measured by indirect ELISA, and the differentiation of T cells was analysed by flow cytometry. After challenge with sporulated oocysts, the body weight, oocyst shedding and cecum lesions of the chicken were evaluated. The results indicated that chickens immunized with recombinant invasive L. plantarum produced higher levels of specific antibodies in the serum than did the non-immunized controls, and the secretory IgA (sIgA) levels were increased in the intestinal washes compared to those of the controls (P < 0.05). Flow cytometry showed that recombinant invasive L. plantarum significantly stimulated T cell differentiation compared to the PBS group (P < 0.01, P < 0.001), and a higher proportion of CD4+ and CD8+ T cells were detected in peripheral blood. Moreover, the lesion scores and histopathological caecum sections showed that immunizing chickens with recombinant invasive L. plantarum can significantly relieve pathological damage in the cecum (P < 0.01), and the relative body weight gain was 89.64 %, which was higher than the 79.83 % gain in the chickens immunized with non-invasive L. plantarum. After the challenge, faeces from ten chickens in each group were collected between 4 and 7 days, and the oocysts per gram (OPG) was determined by the McMaster technique. The data indicated that oocysts in the faeces of chickens immunized with the recombinant invasive L. plantarum were significantly lower than those of the controls (P < 0.01). The results suggest that recombinant invasive L. plantarum effectively activated immune responses against E. tenella infection and can be used as a candidate vaccine against E. tenella infection.

Aeromonas veronii is one of the main pathogens causing freshwater fish sepsis and ulcer syndrome. More and more cases have shown that it has become an important zoonotic and aquatic agent. In this study, a A. veronii TH0426 mutant strain (ΔlamB) with an in-frame deletion removed nucleotides 10-1,296 of the lamB gene was firstly constructed to investigate its functions. The results showed that the LD50 value of the mutant ΔlamB to zebrafish and mice was 13.7-fold and 5.6-fold higher than those of the wild-type strain, respectively. The toxicity of wild-type strain to EPC cells was 2.1-fold and threefold higher than those of ∆lamB when infected for 1 and 2 hr. Furthermore, the ability of biofilm formation and the adhesion and invasion to EPC cells of ∆lamB significantly decreased for 5.6-fold and 1.8-fold separately. In addition, motility detection result indicated that ∆lamB lost the swimming ability. The results of flagellar staining and TEM demonstrated that the flagella of ∆lamB were shed. In general, the deletion of lamB gene caused a significant decrease in the virulence and adhesion of A. veronii TH0426, and it can be known that the lamB gene of A. veronii plays a crucial role in the pathogenesis.

To investigate the effect of Trichinella spiralis infection on dectin-2 expression on dendritic cells (DC) in mice.Seventy-two female BABL/c mice were randomized into experimental and control groups (n=36 in each), and received intragastric administration of 200 muscle larvae of Trichinella spiralis and PBS respectively. Six animals were each sacrificed on days 7, 14, 21, 28, 35 and 42 after administration. The spleen and mesenteric lymph nodes (MLN) were dissected and single cell suspensions were prepared. The expression of dectin-2 on DC in the spleen and MLN was examined by flow cytometry. In another experiment, bone marrow was obtained from C57BL/6 mice, and was treated with granulocyte-macrophage colony-stimulating factor and interleukin 4 to induce bone marrow-derived dendritic cells (BMDC) in vitro. Then 100 μg/ml T. spiralis excretory/secretory (ES) antigen or the same volume of PBS was added. The expression of dectin-2 was determined by flow cytometry at 6, 12, 24, 36 and 48 h.The flow cytometry results showed a significant decrease of dectin-2 expression［（7.0±0.7）%］ on spleen DC compared with that of the control group［（15.1±1.6）%］（P0.01） on day 7, and significant increase of dectin-2 on MLNDC compared with that of the control on days 7, 21 and 28 ［（11.1±3.5）% vs. （6.6±0.4）%, （12.4±1.4）% vs. （4.9±0.4）%, （6.9±1.0）% vs. （4.0±1.4）%］ （P0.05） after infection. In vitro results showed that dectin-2 expression was （9.4±2.2）%, （6.9±1.8）%, （6.9±0.7）%, （9.1±1.9）%, and（15.9±1.9）% respectively at 6, 12, 24, 36, and 48 h after ES stimulation on BMDC. The expression at 6, 12, 24 and 36 h decreased significantly in comparison to that of the PBS group［（21.3±6.3）%］（P0.01).Trichinella infection can induce changes of dectin-2 expression on DC of mice.

Research on cysticercosis has been stimulated by the rapid development of genomics, proteomics and bioinformatics and the emergence of molecular biological and immunological technologies. In this review, we attempt to discuss the research development on genomics of Taenia solium and candidate vaccines and antigens for cysticercosis. This will provide a new perspective for studying genomics of Taenia solium and for cysticercosis prevention and treatment, and provide a wealth of informative data for the development of novel and highly efficient vaccines against cysticercosis or diagnostic antigen molecules for cysticercosis.

Trichinella spiralis is an intestinal nematode parasite that can cause trichinellosis in humans and animals worldwide. The most important known hosts of T. spiralis are pigs, horses, dogs and cats. Pork and its products are the main sources of infection in human trichinellosis. Vaccines against these infections are urgently needed. In this study, the genes encoding the 43-kDa or 45-kDa glycoprotein present in the excretory-secretory (ES) products from T. spiralis muscle larvae (ML) were cloned into the eukaryotic expression vector pVAX1, resulting plasmids pVAX1-Ts43 and pVAX1-Ts45, respectively. Then BALB/c mice were intramuscularly immunized with the DNA vaccine pVAX1-Ts43, pVAX1-Ts45, or both to evaluate their immunogenicity and host protective potential. After the third immunization, mice of each group were challenged with 300 T. spiralis ML. The results showed that the mice immunized with the DNA vaccine pVAX1-Ts43 or pVAX1-Ts45 developed significant numbers of FAS+PNA+ B220+ B cells indicating the formation of the germinal centers (GCs), IFN-γ-secreting (mesenteric lymph nodes, MLN) cells, and IL-4-, and IL-10-secreting splenocytes. Mice immunized with the pVAX1-Ts43 or pVAX1-Ts45 vaccine elicited partial protective immunity against challenge infections with T. spiralis as shown by significant reduction in ML. Most notably, the combined immunity of pVAX1-Ts43 and pVAX1-Ts45 induced better immune responses than either of the DNA vaccines given alone and provided as high as 75.9% reductions in muscle larval burden. These results suggest that the plasmid DNA encoding the 43-kDa or 45-kDa glycoprotein could be considered as a potential vaccine candidate against T. Spiraling infection.

Toxoplasma gondii is a zoonotic protozoan of almost all species of mammals and birds. However, no information is available about seroprevalence of the pathogen in stray dogs in seven cities from Inner Mongolia, Jilin, Liaoning province, China. Using the indirect hemagglutination antibody (IHA) test with a cutoff titer of 1:64, 129 (14.05 %) out of 918 stray dogs were surveyed to be T. gondii seropositive. Analysis of the risk factor showed that there was no statistical difference of seroprevalence of T. gondii between males (13.46 %) and females (14.54 %) (P > 0.05). The seropositive rates of T. gondii infection in stray dogs among the seven cities in northern China were significant statistically different (P = 0.005). Moreover, seroprevalence of T. gondii in dogs were varied from 11.01 % (95 % CI 6.94-15.09) to 16.86 % (95 % CI 12.27-21.46) among different age groups, and the difference was statistically significant (P = 0.03). More importantly, T. gondii seropositive in stray dogs has a declining tendence from 2011 to 2015 (P = 0.004). The results of the present study showed that stray dogs in Inner Mongolia, Jilin, Liaoning province, China are exposed to T. gondii, for the first time, and could also provide a foundation data for prevent and control T. gondii infection in dogs, other animals and humans.

Highlights • The S protein of PDEV was displayed on the surface of a recombinant Lactobacillus plantarum NC8 strain. • NC8-pSIP409-pgsA'-S-DCpep promoted DC activation in the LP. • IgG and sIgA were significant increased in mice orally administered with the NC8-pSIP409-pgsA'-S-DCpep. • The expression of specificity cytokines IFN-γ, IL-4 and IL-17A of MLNs was enhanced in mouse treated with the NC8-pSIP409-pgsA'-S-DCpep. • NC8-pSIP409-pgsA'-S-DCpep might mediate B cell response in mouse., Porcine epidemic diarrhea virus (PEDV) is one of the most important causative pathogens of swine diarrhea, which is widely prevalent throughout the world and is responsible for significant economic losses in the commercial pig industry, both domestic and abroad. The spike (S) protein in the PEDV capsid structure can carry the major B lymphocyte epitope, which induces production of neutralizing antibodies and provides immunoprotective effects. Moreover, the conserved region encoded by the S gene can be considered a target for establishing a new diagnostic method and is a new candidate for vaccine design. In this study, use of anchorin pgsA' allowed the fusion protein of S-DCpep to express on the surface of recombinant Lactobacillus plantarum (NC8-pSIP409-pgsA'-S-DCpep) NC8 strain. Mice were immunized by lavage administration of the recombinant NC8-pSIP409-pgsA'-S-DCpep, which was observed to induce DC activation and high production of sIgA and IgG antibodies in experimental animals, while also eliciting production of significantly more IgA+B220+ B cells. More importantly, secretion of cytokines IFN-γ, IL-4 and IL-17 in mice that were vaccinated with NC8-pSIP409-pgsA'-S-DCpep was remarkably increased. The results of our study suggest that NC8-pSIP409-pgsA'-S-DCpep potently triggers cellular and humoral immune responses. The obtained experimental results can provide a theoretical basis that lays the foundation for production of a novel oral vaccine against PED.