Adjuvant effects of L. acidophilus LW1 on immune responses to the foot-and-mouth disease virus DNA vaccine in mice

The combination of vaccines and adjuvants to prevent the occurrence of high incidence of infectious diseases in bovine

As the global population grows, the demand for beef and dairy products is also increasing. The cattle industry is facing tremendous pressures and challenges. The expanding cattle industry has led to an increased risk of disease in cattle. These diseases not only cause economic losses but also pose threats to public health and safety. Hence, ensuring the health of cattle is crucial. Vaccination is one of the most economical and effective methods of preventing bovine infectious diseases. However, there are fewer comprehensive reviews of bovine vaccines available. In addition, the variable nature of bovine infectious diseases will result in weakened or even ineffective immune protection from existing vaccines. This shows that it is crucial to improve overall awareness of bovine vaccines. Adjuvants, which are crucial constituents of vaccines, have a significant role in enhancing vaccine response. This review aims to present the latest advances in bovine vaccines mainly including types of bovine vaccines, current status of development of commonly used vaccines, and vaccine adjuvants. In addition, this review highlights the main challenges and outstanding problems of bovine vaccines and adjuvants in the field of research and applications. This review provides a theoretical and practical basis for the eradication of global bovine infectious diseases.

Immunomodulatory effects of probiotic Lactobacillus casei on GM-CSF-adjuvanted influenza DNA vaccine

Aim: This study investigates the protective efficacy of influenza DNA vaccine combined with a granulocyte macrophage-colony stimulating factor (GM-CSF) adjuvant, and probiotic Lactobacillus casei, an oral immunomodulator, in a BALB/c mice. Materials & methods: The mice were immunized with HA1 DNA vaccine along with GM-CSF and probiotic twice within a one-week interval. Results: The results showed that both adjuvants exert a synergistic effect in enhancing the humoral and cellular immune responses of the DNA vaccine. This combination also deceased IL-6 and IL-17A levels in the lung homogenates. The protection patterns were closely associated with influenza virus-specific splenocyte proliferative and serum IgG antibody (Ab) responses. Conclusion: The Findings demonstrate L. casei modulate balanced Th1/Th2 immune responses toward HA1 DNA vaccine adjuvanted by GM-CSF.

Isolation and characterization of porcine monoclonal antibodies revealed two distinct serotype-independent epitopes on VP2 of foot-and-mouth disease virus

Pigs are susceptible to foot-and-mouth disease virus (FMDV), and the humoral immune response plays an essential role in protection against FMDV infection. However, little information is available about FMDV-specific mAbs derived from single B cells of pigs. This study aimed to determine the antigenic features of FMDV that are recognized by antibodies from pigs. Therefore, a panel of pig-derived mAbs against FMDV were developed using fluorescence-based single B cell antibody technology. Western blotting revealed that three of the antibodies (1C6, P2-7E and P2-8G) recognized conserved antigen epitopes on capsid protein VP2, and exhibited broad reactivity against both FMDV serotypes A and O. An alanine-substitution scanning assay and sequence conservation analysis elucidated that these porcine mAbs recognized two conserved epitopes on VP2: a linear epitope (²KKTEETTLL¹⁰) in the N terminus and a conformational epitope involving residues K63, H65, L66, F67, D68 and L81 on two β-sheets (B-sheet and C-sheet) that depended on the integrity of VP2. Random parings of heavy and light chains of the IgGs confirmed that the heavy chain is predominantly involved in binding to antigen. The light chain of porcine IgG contributes to the binding affinity toward an antigen and may function as a support platform for antibody stability. In summary, this study is the first to reveal the conserved antigenic profile of FMDV recognized by porcine B cells and provides a novel method for analysing the antibody response against FMDV in its natural hosts (i.e. pigs) at the clonal level.

Protective effect of the probiotic Lactobacillus acidophilus ATCC 4356 in BALB/c mice infected with Toxocara canis

Human toxocariasis consists of chronic tissue parasitosis that is difficult to treat and control. This study aimed to evaluate the action of the probiotic Lactobacillus acidophilus ATCC 4356 on larvae of Toxocara canis and the effect of IFN-γ cytokine on parasite-host in vivo (1.10⁹ CFU) and in vitro (1.10⁶, 1.10⁷, 1.10⁸, 1.10⁹ CFU) interactions. Four groups of six BALB/c mice were formed: G1 - L. acidophilus supplementation and T. canis infection; G2 - T. canis infection; G3 - L. acidophilus supplementation; and G4 - PBS administration. Mice were intragastrically suplemented with probiotics for 15 days before inoculation and 48 h after inoculation with 100 T. canis eggs. The inoculation of T. canis was also perfomed intragastrically. The recovery of larvae took place through digestion of liver and lung tissues; the evaluation of IFN-γ gene transcription in leukocytes was performed by qPCR. The in vitro test consisted of incubating the probiotic with T. canis larvae. The supplementation of probiotics produced a reduction of 57.7% (p = 0.025) in the intensity of infection of T. canis larvae in mice, whereas in the in vitro test, there was no larvicidal effect. In addition, a decrease in the IFN-γ gene transcription was observed in both, T. canis-infected and uninfected mice, regardless of whether or not they received supplementation. The probiotic L. acidophilus ATCC 4356 reduced T. canis infection intensity in mice, however, the probiotic did not have a direct effect on larvae, demonstrating the need of interaction with the host for the beneficial effect of the probiotic to occur. Yet, the proinflammatory cytokine IFN-γ did not apparently contributed to the observed beneficial effect of probiotics.

Synergistic Therapeutic Effects of Probiotic Lactobacillus casei TD-2 Consumption on GM-CSF-Induced Immune Responses in a Murine Model of Cervical Cancer

We perceive the potential of combined immunotherapy for the synergistic treatment of human papillomavirus (HPV)-associated tumors. So, the tumor inhibiting effects of combination of L. casei TD2a and GM-CSF on the TC-1 growth were evaluated In Vivo using lymphocyte proliferation, lymphocyte cytotoxicity, splenocyte, and tumor cytokine assays. The results showed that tumor inhibition in transplanted mice in the GM-CSF combined with probiotic L. casei group was significantly higher than that observed in the other groups excluding GM-CSF group whose tumor inhibition effect was considerable. The findings also indicated that the combined group could generate tumor-specific cytolytic and splenocyte proliferative responses. The levels of IFN-γ, IL-4, and IL-12 after treating with GM-CSF combined with probiotic L. casei were significantly higher than those of other groups. The intratumoral Tumor Necrosis Factor Related Apoptosis-Inducing Ligand (TRAIL) was also significantly increased in the combined group. Tumor analysis further showed that the combined group decreased the accumulation of IL-10 in the tumor microenvironment of treated mice. Furthermore, tumor volume analysis demonstrated that combination group and even GM-CSF suppress tumor growth. Our findings showed that the combination of GM-CSF and probiotic results in improved tumor suppression against HPV-associated tumors and stimulates enhancement of specific antitumor immune responses.

Recombinant Lactobacillus acidophilus expressing S1 and S2 domains of porcine epidemic diarrhea virus could improve the humoral and mucosal immune levels in mice and sows inoculated orally

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The recombinant L. acidophilus expressing S₁ and S₂ domains of PEDV were generated.

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The oral vaccines for PED were based on a swine-origin L. acidophilus.

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The oral L. acidophilus vaccines induced humoral and mucosal immunity in mice.

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The L. acidophilus-S₁ vaccine induced humoral and mucosal immunity in sows.

Porcine epidemic diarrhea (PED) is a highly contagious intestinal infectious disease caused by porcine epidemic diarrhea virus (PEDV), which is characterized by a high mortality rate in piglets. Since 2012, a remarkable growth in PED outbreaks occurred in many pig farms in China, landing a heavy blow on the pig industry. In order to develop a new effective vaccine for the current PEDV, oral vaccines were generated by transferring eukaryotic expression recombinant plasmids carrying the S₁ and S₂ (antigenic sites of the S protein) epitopes of PEDV into a swine-origin Lactobacillus acidophilus (L. acidophilus). After oral immunization of the BALB/c mice, higher levels of anti-PEDV specific IgG and SIgA antibodies and cellular immune responses were detected in mice orally administered with the recombinant L. acidophilus-S₁ compared to the L. acidophilus-S₂. Furthermore, L. acidophilus-S₁ was used to inoculate the pregnant sows orally and the results showed that the recombinant L. acidophilus-S₁ could elicit a specific systemic and mucosal immune response. In summary, our study demonstrated that oral immunization with L. acidophilus-S₁ could improve the humoral and mucosal immune levels in sows and would be a promising candidate vaccine against PEDV infection in piglets.

Immune enhancing effects of Lactobacillus acidophilus on Newcastle disease vaccination in chickens

INTRODUCTION AND PURPOSE

Despite the various vaccination programs for protection against New Castle disease, it remains an important threat to the poultry industry. The ability of the probiotic bacteria to improve the immune system in both animals and humans supports their use as immune adjuvants for vaccination. The aim of the present study was to examine the effects of Lactobacillus acidophilus in ND vaccination.

MATERIALS AND METHODS

A total of 170 one day old chicks were divided in 5 groups. In groups A, B and C chicks were received L. acidophilus (5 × 10⁹, 3 × 10⁹ and 2 × 10⁹) and also vaccinated with inactivated and attenuated ND vaccines. In group D, chicks only vaccinated without bacterial inoculation and group E was negative control with neither vaccine nor bacteria. Then IgG and HI NDV antibody titers were measured in all tested groups.

RESULTS

IgG and HI NDV antibody levels were significantly higher in Lactobacillus treated groups especially in group A with 5 × 10⁹ bacteria, than only vaccinated and negative control groups. Also antibody levels against NDV increased during the vaccination period especially in probiotic treated groups.

CONCLUSION

In conclusion, L. acidophilus can use for improving immunogenicity of NDV vaccination programs.

Selection of new lactic acid bacteria strains bearing probiotic features from mucosal microbiota of healthy calves: Looking for immunobiotics through in vitro and in vivo approaches for immunoprophylaxis applications

From the birth, since their mucosal microbiota and immune system are not fully developed, newborn calves are susceptible to several mucosal pathogenic microorganisms. Operating through humoral and non-humoral mechanisms in the host, several lactic acid bacteria strains bearing probiotic features are often employed in livestock as food supplement, improving animal production performance, promoting health and reducing the severity of mucosal infections. Accordingly, we isolated, species-level identified and screened for their probiotic potentials seventy lactic acid bacteria strains from upper airway, vaginal and intestinal mucosa of healthy calves. Based on in vitro approaches, we selected three strains: Lactobacillus fermentum V3B-08 isolated from upper airway mucosa, Weissella hellenica V1V-30 isolated from vaginal mucosa and Lactobacillus farciminis B4F-06 isolated from intestinal mucosa were used to mono-colonize germ-free mice in the same site in which these strains were isolated, aiming to characterize their immunomodulatory features. These strains were able to colonize germ-free mice mucosa and trigger sIgA synthesis at a local level, in addition to stimulating, in different ways, adaptive immune responses at a systemic level.

Assessment of antioxidant activity, lipid profile, general biochemical and immune system responses of Wistar rats fed with dairy dessert containing Lactobacillus acidophilus La-5

The viability and survival of Lactobacillus acidophilus La5 under in vitro simulated gastrointestinal in probiotic dairy dessert was assessed. In addition, the effects of regular consumption of the dessert (5g/day) on the lipid profile, immune system, and antioxidant/biochemical status of Wistar rats were also evaluated after 2weeks of treatment. Adequate counts of L. acidophilus La-5 were observed regards the viability and gastrointestinal conditions. The probiotic dairy dessert was efficient in reducing the LDL-cholesterol, triacylglycerol and increased the HDL-cholesterol in serum. Aspartate amino transferase, alanine aminotransferase, total protein, albumin, heat shock proteins, immune system responses, and blood-cells counts (monocyte, lymphocyte, neutrophil and leucocyte) were not affected (p>0.05) after 15days of treatment. Overall, the probiotic dairy dessert may be a viable alternative to enhance the blood lipid profile and could be used to improve the antioxidant defenses.

Characterization of a new Lactobacillus salivarius strain engineered to express IBV multi-epitope antigens by chromosomal integration

To obtain adhesive and safe lactic acid bacteria (LAB) strains for expressing heterologous antigens, we screened LAB inhabitants in intestine of Tibetan chickens by analyzing their adhesion and safety properties and the selected LAB was engineered to express heterologous antigen (UTEpi C-A) based on chromosomal integration strategy. We demonstrated that a new Lactobacillu salivarius TCMM17 strain is strongly adhesive to chicken intestinal epithelial cells, contains no endogenous plasmids, is susceptible to tested antimicrobials, and shows no toxicities. In order to examine the potential of TCMM17 strain as heterogenous antigen delivering vehicle, we introduced a UTEpi C-A expression cassette in its chromosome by constructing a non-replicative plasmid (pORI280-UUTEpi C-AD). The recombinant TCMM17 strain (∆TCMM17) stably was found to keep the gene cassette through 50 generations, and successfully displayed EpiC encoded by the cassette on its surface. This work provides a universal platform for development of novel oral vaccines and expression of further antigens of avian pathogens.