Co-administration of chicken IL-7 or NK-lysin peptide 2 enhances the efficacy of Eimeria elongation factor-1α vaccination against Eimeria maxima infection in broiler chickens.

This study was conducted to develop a recombinant Eimeria elongation factor-1α (EF-1α)-vaccination strategy against Eimeria maxima (E. maxima) infection by co-administering with chicken IL-7 (chIL-7) or chicken NK-lysin peptide 2 (cNK-2) in commercial broiler chickens. Chickens were divided into the following 5 groups: control (CON, no Eimeria infection), nonimmunized control (NC, PBS plus Montanide ISA 78 VG), Vaccination 1 (VAC1, 100 µg of recombinant EF-1α plus Montanide ISA 78 VG), Vaccination 2 (VAC2, VAC1 plus 1 µg of chIL-7), and Vaccination 3 (VAC3, VAC2 plus 5 µg of cNK-2 peptide). The first immunization except the cNK-2 injection was performed intramuscularly on day 4, and the secondary immunization was given with the same concentration of components as the primary immunization 1 wk later. All chickens except the CON group were orally inoculated with freshly prepared E. maxima (1.0 × 104 oocysts per chicken) oocysts on Day 19. The results of the in vivo vaccination trial showed that chickens of all groups immunized with recombinant EF-1α antigen (VAC1, VAC2, and VAC3) showed higher serum antibody levels to EF-1α, and co-injection with chIL-7 further increased the serum IL-7 level in the VAC2 and VAC3 groups. Chickens in the VAC2 group showed significantly (P < 0.01) higher body weight gains at 6 and 9 d post-E. maxima challenge infection (dpi) with reduced gut lesions in the jejunum at 6 dpi. The VAC3 group showed reduced fecal oocyst shedding compared to the nonimmunized and infected chickens (NC). At 4 dpi, E. maxima infection significantly (P < 0.05) up-regulated the expression levels of proinflammatory cytokines (IL-ß and IL-17F) and type Ι cytokines (IFN-γ and IL-10) in the jejunum (NC), but the expression of these cytokines was significantly (P < 0.05) down-regulated in the VAC1, VAC2, and VAC3 groups. Furthermore, E. maxima challenge infection significantly (P < 0.05) down-regulated the expressions of jejunal tight junction (TJ) proteins (Jam2 and Occludin) at 4 dpi, but their expression was up-regulated in the VAC2 and VAC3 groups. Collectively, these results show the protective effects of the EF-1α recombinant vaccine, which can be further enhanced by co-injection with chIL-7 or cNK-2 peptide against E. maxima infection.

Analysis of adipose tissue immune gene expression after vaccination of rainbow trout with adjuvanted bacterins reveals an association with side effects.

Most existing fish vaccines are presented in the form of oil-based emulsions delivered by intraperitoneal injection. Whilst very effective they are frequently associated with inflammatory responses that can result in clinically significant side-effects often involving the adipose tissue that is in direct contact with the vaccine. To explore the potential of immune gene expression changes in the adipose tissue of fish to be markers of vaccination efficacy or development of side-effects we have studied the response to a bacterial (Aeromonas salmonicida) vaccine administered with two different adjuvants. The first adjuvant was Montanide™ ISA 763A VG, thought to induce a mostly humoral response, and the second was Montanide™ ISA 761 VG that gives a more balanced humoral and cell mediated response. Following vaccination tissue samples were collected at days 3, 14 and 28 for RTqPCR analysis. Fifty immune genes were studied with a focus on a) pro-inflammatory associated molecules and b) adaptive immune response related molecules linked with possible Th1, Th2, Th17 and T-regulatory pathways, with the expression data analysed for associations with Speilberg post-vaccination side effect scores. The results showed that the adipose tissue is a particularly sensitive and discriminatory tissue for studying adjuvant effects. A clear upregulation of many immune genes occurred in response to both vaccine groups, which persisted over time and overlapped with the appearance of visible adhesions. Our analysis revealed a relationship between adipose tissue immune function and the development of vaccine-induced adhesions giving the potential to use immune gene expression profiling in this tissue to predict the side-effects seen.

Vaccination with Clostridium perfringens recombinant proteins in combination with Montanide™ ISA 71 VG adjuvant increases protection against experimental necrotic enteritis in commercial broiler chickens.

This study was performed to compare four Clostridium perfringens recombinant proteins as vaccine candidates using the Montanide™ ISA 71 VG adjuvant in an experimental model of necrotic enteritis. Broiler chickens were immunized subcutaneously with purified clostridial recombinant NetB toxin, pyruvate: ferredoxin oxidoreductase (PFO), α-toxin, or elongation factor-Tu (EF-Tu), or with vehicle control, in conjunction with ISA 71 VG, and intestinal lesion scores, body weight gains, NetB toxin and PFO antibody levels, and proinflammatory cytokine and chemokine levels were measured as outcomes of protection following oral co-infection with C. perfringens and Eimeria maxima. Birds immunized with all recombinant proteins plus ISA 71 VG showed significantly reduced gut lesions compared with the ISA 71 VG-only group. Birds immunized with NetB toxin or PFO plus ISA 71 VG exhibited significantly increased body weight gains compared with the ISA 71 VG alone group. Greater NetB toxin antibody titers were observed in the NetB/ISA 71 VG group, and greater PFO antibody titers were evident in the PFO/ISA 71 VG group, each compared with the other three vaccine/adjuvant groups. Finally, decreased levels of gene transcripts encoding interleukin-8, tumor necrosis factor superfamily 15, and LPS-induced TNF-α factor were observed in the intestinal lymphocytes of chickens immunized with NetB toxin, PFO, α-toxin, and/or EF-Tu in the presence of ISA 71 VG compared with ISA 71 VG alone. All parameters evaluated were equal in co-infected chickens given ISA 71 VG alone compared with infected/adjuvant-free birds, indicating that the adjuvant itself did not have a disease protective effect. These results suggest that vaccination with clostridial recombinant proteins, particularly NetB toxin or PFO, in combination with ISA 71 VG enhances protective immunity against experimental necrotic enteritis in broiler chickens.

Efficacy of intranasal and spray delivery of adjuvanted live vaccine against infectious bronchitis virus in experimentally infected poultry.

Live vaccines are widely used in the avian industry. Such vaccines can be either injected or delivered on animal mucosa and are usually not adjuvanted. In this study we show that live vaccines efficacy can be improved by formulation with adjuvants in a model of mucosal delivery of live infectious bronchitis vaccine in chicken. Three adjuvant technologies have been tested using intranasal and spray delivery methods to poultry. Those technologies are water in oil in water emulsion, nanoparticles and polymer adjuvants. Intranasal delivery of polymer and nanoparticles adjuvanted live vaccines improved significantly the antibody titer and protection to challenge observed compared to a commercial non-adjuvanted reference. Moreover, spray delivery of the polymer adjuvanted vaccine showed a significantly higher protection compared to the non-adjuvanted reference. Our data demonstrates that the use of MontanideTM adjuvants in the formulation of live poultry vaccines for mucosal delivery can confer to vaccinated animals a significantly improved protection against pathogens.

Load reduction in live PRRS vaccines using oil and polymer adjuvants.

PRRSV live vaccines are widely used in pig farming practice and are usually not adjuvanted. For safety issues, it would be useful to reduce the antigenic load of such vaccines while preserving their efficacy. In this study we show that the addition of polymer or oil adjuvants in a PRRS live vaccine enhanced the protection to challenge of vaccinated animals compared to a non-adjuvanted commercial reference. Moreover, for both types of adjuvants, despite lower antibody titers, the protection to challenge given by the adjuvanted vaccine containing only 50% of the antigen load was equivalent to the protection given by the non-adjuvanted vaccine. These results demonstrate that the addition of relevant adjuvants can enhance the efficacy of the protection conferred to animals by live vaccines.