Comparative effects of levamisole, Staphylococcus, and Freund's adjuvant on rat immunization with excretory and secretory antigens of Trichinella spiralis muscle larvae

Protective efficacy of intranasal inactivated pseudorabies vaccine is improved by combination adjuvant in mice

Pseudorabies virus (PRV) not only causes great economic loss to the pig industry but also seriously threatens the biosafety of other mammals, including humans. Since 2011, PRV mutant strains have emerged widely in China, and the classical Bartha-K61 vaccine cannot confer complete protection for pigs. PRV mainly infects pigs via the respiratory tract. Intranasal immunization with PRV has received more attention because intranasal vaccination elicits systemic and mucosal immune responses. To induce systemic and mucosal immune responses against PRV, we developed a combination adjuvant as a delivery system for intranasal vaccine, which was formulated with MONTANIDE™ Gel 01 and CVCVA5. In comparison to naked antigen of inactivated PRV, single Gel 01 adjuvanted inactivated antigen and single CVCVA5 adjuvanted inactivated antigen, intranasal inactivated PRV vaccine formulated with the combination adjuvant induced greater mucosal IgA immunity and serum antibody responses (IgG, IgG1, and IgG2a). Furthermore, the production of the Th1-type cytokine IFN-γ and the Th2-type cytokine IL-4 indicated that the cellular and humoral responses to the intranasal vaccine were improved by the combination adjuvant. In addition, the intranasal vaccine formulated with the combination adjuvant induced long-term T lymphocyte memory with increased central (CD62L⁺CD44⁺) and effector (CD62L^–CD44⁺) memory subsets of both CD4 and CD8 T cells in nasal-associated lymphoid tissue. Intranasal challenge with virulent PRV in mice showed that the protective efficacy of the intranasal PRV vaccine was improved by the combination adjuvant compared with the other single-adjuvanted vaccines. In summary, these data demonstrated that Gel 01 combined with the CVCVA5 adjuvant induced a synergistic effect to improve mucosal immunity and protective efficacy of the intranasally inactivated PRV vaccine in mice. It represents a promising vaccination approach against PRV infection.

Kinetics of Eosinophils during Development of the Cellular Infiltrate Surrounding the Nurse Cell of Trichinella spiralis in Experimentally Infected Mice

We study the kinetics of eosinophils during the development of the cellular infiltrate surrounding the nurse cell of Trichinella spiralis (T. spiralis) in experimentally infected mice. Male CD1 mice were experimentally infected with 50 viable muscle larvae of the MSUS/MEX/91/CM-91 T. spiralis strain. Tongues and diaphragms were obtained daily from days 13 to 39 post infection. Diaphragms were compressed and subjected to Giemsa stain. Tongues were histologically sectioned and stained with erythrosine B or hematoxylin and eosin. The cellular infiltrate and the nurse cell-larva complex were detected by optical microscopy since day 16 post infection. The size of the larva increased exponentially during the course of the infection. The kinetics of eosinophils showed a multimodal trend, with a bimodal predominance. The maximum peaks were reached on days 21 and 27 post infection. The results of this study demonstrate that eosinophils occur abundantly in two transcendent moments of the T. spiralis life cycle: first, when the stage 1 larva invades the myocyte and second when the nurse cell-larva complex has been fully developed. These results help one to understand the immunobiology of T. spiralis, highlighting the importance of eosinophils in the survival of the larva in skeletal muscle. Further studies are needed to characterize the cell populations that comprise the cellular infiltrate during the development of the mother cell.

Statistical approach to Trichinella infection in horses handled by rural slaughterhouses across five distinctive socioeconomic regions in Mexico

This work aimed to investigate the prevalence of Trichinella infection in horses (Equus ferus caballus) handled by rural slaughterhouses across five distinctive socioeconomic regions in Mexico. Serum samples were obtained by non-probabilistic convenience sampling in the Eastern, Southern Central and Western regions (100 samples of each). Additionally, muscle tissue samples were collected from the East (n=45), Southeastern (n=88), Southern Central (n=39) and Southwestern (n=11) regions. Antibodies were determined by Western blot and the muscle tissue was examined by artificial digestion. A global antibody prevalence of 2% was obtained. Regionally, a prevalence of 5% was observed in the East and 1% in the Southern Central region. No antibodies were detected in the West region and no larvae were found in the muscle tissue samples. These findings support the low presence of Trichinella in Mexican horses, which can positively impact the Mexican horse meat trade.

Influence of levamisole and Freund's adjuvant on mouse immunisation with antigens of adults of the liver fluke Fasciola hepatica Linnaeus, 1758

We have studied the influence of both levamisole (AL) and Freund's adjuvant (AF) on the immunisation of mice with the secretory antigens of adults of the liver fluke Fasciola hepatica Linnaeus, 1758. Total IgG antibodies were detected in all groups where the F. hepatica antigen was administered, been levels of IgG1 increased respect to IgG2a antibodies. During immunisation, IL-4 and IFN-γ were only detected in AL and AF groups, but after infection, IL-4 boosted in all groups. IFN-γ increased two fold in AF and AL groups compared to the saline solution (AS) group. Worm recovering was of 32-35% in groups administered without antigen whereas in AS, AL and AF groups recovering was of 25%, 12% and 8%, respectively. Macroscopical lesions in the liver were scarce in AL and AF groups. Our data suggest that immunisation of mice with antigens of F. hepatica enhances the immune response avoiding both liver damage and worm establishment after challenge infection. The murine model of fasciolosis has appeared to be useful to elucidate the mechanism by which the parasite modulates immune responses toward a Th2 type but also the development of Th1 type-inducing vaccines.