Inactivated Porcine Parvovirus Research Articles

Assessment of Immunological Response and Impacts on Fertility Following Intrauterine Vaccination Delivered to Swine in an Artificial Insemination Dose.

To protect the health of sows and gilts, significant investments are directed toward the development of vaccines against infectious agents that impact reproduction. We developed an intrauterine vaccine that can be delivered with semen during artificial insemination to induce mucosal immunity in the reproductive tract. An in vitro culture of uterine epithelial cells was used to select an adjuvant combination capable of recruiting antigen-presenting cells into the uterus. Adjuvant polyinosinic:polycytidylic acid (poly I:C), alone or in combination, induced expression of interferon gamma, tumor necrosis factor alpha, and select chemokines. A combination adjuvant consisting of poly I:C, host defense peptide and polyphosphazene (Triple Adjuvant; TriAdj), which previously was shown to induce robust mucosal and systemic humoral immunity when administered to the uterus in rabbits, was combined with boar semen to evaluate changes in localized gene expression and cellular recruitment, in vivo. Sows bred with semen plus TriAdj had decreased γδ T cells and monocytes in blood, however, no corresponding increase in the number of monocytes and macrophages was detected in the endometrium. Compared to sows bred with semen alone, sows bred with semen plus TriAdj showed increased CCL2 gene expression in the epithelial layer. These data suggest that the adjuvants may further augment a local immune response and, therefore, may be suitable for use in an intrauterine vaccine. When inactivated porcine parvovirus (PPV) formulated with the TriAdj was administered to the pig uterus during estrus along with semen, we observed induction of PPV antibodies in serum but only when the pigs were already primed with parenteral PPV vaccines. Recombinant protein vaccines and inactivated PPV vaccines administered to the pig uterus during breeding as a primary vaccine alone failed to induce significant humoral immunity. More trials need to be performed to clarify whether repeated intrauterine vaccination can trigger strong humoral immunity or whether the primary vaccine needs to be administered via a systemic route to promote a mucosal and systemic immune response.

Water-soluble N-2-Hydroxypropyl trimethyl ammonium chloride chitosan enhanced the immunogenicity of inactivated porcine parvovirus vaccine vaccination on sows against porcine parvovirus infection

Porcine parvovirus (PPV) is one of the most common and important virus causes of infectious infertility in swine throughout the world. Inactivated PPV vaccine is broadly used, however, there is no appropriate immunomodulatory adjuvant for enhancing present vaccines and developing new ones. Therefore, in this study, the water-soluble N-2-Hydroxypropyl trimethyl ammonium chloride chitosan (N-2-HACC) was synthesized, the adjuvant potential of chitosan derivative was evaluated in inactivated PPV vaccine. Twenty adult healthy sows were assigned to four groups and vaccinated with synthesized PPV/N-2-HACC, commercial inactivated vaccine, N-2-HACC adjuvant and PBS. After insemination, all sows were challenged with the homologous PPV-H strain. In vivo immunization showed that sows immunized with the PPV/N-2-HACC induced more long-lasting HI antibodies and strong immune responses. Importantly, immunization of PPV/N-2-HACC significantly protected sows from homologous PPV-H strain infection. However, immunization of PPV/N-2-HACC didn't change the level of IL-2, IL-4 and IFN-γ and the production of CD4+, CD8 + T lymphocyte. The results indicated that PPV/N-2-HACC protect PPV infection mainly through enhancing the humoral immunity rather than cellular immunity. In addition, the mummified fetuses were observed from the control groups, but neither of the two vaccine groups. In conclusion, these results suggest that N-2-HACC can be exploited as an effective adjuvant for vaccine development, and the PPV/N-2-HACC are potent immunization candidates against PPV infection.

Porcine parvovirus VP1/VP2 on a time series epitope mapping: exploring the effects of high hydrostatic pressure on the immune recognition of antigens

Porcine parvovirus (PPV) is a DNA virus that causes reproductive failure in gilts and sows, resulting in embryonic and fetal losses worldwide. Epitope mapping of PPV is important for developing new vaccines. In this study, we used spot synthesis analysis for epitope mapping of the capsid proteins of PPV (NADL-2 strain) and correlated the findings with predictive data from immunoinformatics. The virus was exposed to three conditions prior to inoculation in pigs: native (untreated), high hydrostatic pressure (350 MPa for 1 h) at room temperature and high hydrostatic pressure (350 MPa for 1 h) at − 18 °C, and was compared with a commercial vaccine produced using inactivated PPV. The screening of serum samples detected 44 positive spots corresponding to 20 antigenic sites. Each type of inoculated antigen elicited a distinct epitope set. In silico prediction located linear and discontinuous epitopes in B cells that coincided with several epitopes detected in spot synthesis of sera from pigs that received different preparations of inoculum. The conditions tested elicited antibodies against the VP1/VP2 antigen that differed in relation to the response time and the profile of structurally available regions that were recognized.

The Humoral and Cellular Immune Response Characteristic of Propolis Flavonoid Used as Adjuvant to Inactivated PPV Vaccine in Sows

The present study was conducted to assess the effects of propolis flavonoid used as adjuvant on the immune response of Landrace-Yorkshire hybrid sows immunized with an inactivated vaccine of porcine parvovirus (PPV). Thirty Landrace-Yorkshire hybrid sows were randomly assigned to one of 3 groups, and the sows in two adjuvant groups were intramuscular injected PPV vaccine with 2.0 mL propolis flavonoid adjuvant (PA) or oilemulsion adjuvant (OA), respectively. After that, serum hemagglutination inhibition antibody titers, specific IgM, IgA and IgG subclasses were measured to estimate the humoral immunity for the adjuvant effects of propolis flavonoid, as well as peripheral lymphopoiesis activity, and lymphocyte factor concentrations of Th1 and Th2 for cellular immune responses. Results indicated in a significant enhancing effect of PA on concentrations of IgM, IgG2, IgG3, IL-2 and IFN-γ comparing to OA. Especially in improving the effect of Th1 cellular immune response, the PA was superior to OA. These findings suggested that PA can significantly enhance the immune responses against PPV vaccine and could be exploited to a new PPV vaccine in sows.

The adjuvanticity of ophiopogon polysaccharide liposome against an inactivated porcine parvovirus vaccine in mice

In this study, the adjuvant activity of ophiopogon polysaccharide liposome (OPL) was investigated. The effects of OPL on the splenic lymphocyte proliferation of mice were measured in vitro. The results showed that OPL could significantly promote lymphocyte proliferation singly or synergistically with PHA and LPS and that the effect was better than ophiopogon polysaccharide (OP) at most of concentrations. The adjuvant activities of OPL, OP and mineral oil were compared in BALB/c mice inoculated with inactivated PPV in vivo. The results showed that OPL could significantly enhance lymphocyte proliferation, increase the proportion of CD4+ and CD8+ T cells, improve the HI antibody titre and specific IgG response, and promote the production of cytokines, and the efficacy of OPL was significantly better than that of OP. In addition, OPL significantly improved the cellular immune response compared with oil adjuvant. These results suggested that OPL possess superior adjuvanticity and that a medium dose had the best efficacy. Therefore, OPL can be used as an effective immune adjuvant for an inactivated PPV vaccine.

Effects of oral deoxynivalenol exposure on immune-related parameters in lymphoid organs and serum of mice vaccinated with porcine parvovirus vaccine

Mice were exposed to deoxynivalenol (DON) via drinking water at a concentration of 2 mg/L for 36 days. On day 8 of treatment, inactivated porcine parvovirus vaccine (PPV) was injected intraperitoneally. The relative and absolute weight of the spleen was significantly decreased in the DON-treated group (DON). Antibody titers to parvovirus in serum were 47.9 ± 2.4 in the vaccination group (Vac), but 15.2 ± 6.5 in the group treated with DON and vaccine (DON + Vac). The IgA and IgG was not different in the DON, Vac an,d DON + Vac groups. IgM was significantly lower only in the DON + Vac group. However IgE was significantly increased in the Vac and DON + Vac group, but no change was observed between the Vac and DON + Vac groups. The concentrations of IL-2, IL-4, GM-CSF, MCP-1 and Rantes in serum, and IL-1α in mesenteric lymph node and MIP-1β in spleen were significantly increased by DON treatment compared to control. The concentrations of IL-2, IL-5, IL-6, IL-9, IL-12, IL-13 and Rantes in thymus, of IL-2 in spleen, and of IL-1α, IL-1β, IL-3, IL-5, IL-10, IL-17, G-CSF, GM-CSF and MCP-1 in mesenteric lymph nodes were significantly decreased in mice compared to those in the Vac group, while concentrations of IL-1α, IL-2, IL-9, IL-13,G-CSF, GM-CSF, IFN-γ, MCP-1, MIP-1α and TNF-α were significantly increased in serum compared to the Vac group. In conclusion, the results presented here indicate that exposure to DON at 2.0 mg/L via drinking water can disrupt the immune response in vaccinated mice by modulating cytokines and chemokines involved in their immune response to infectious disease.

Zearalenone Affects Immune-Related Parameters in Lymphoid Organs and Serum of Rats Vaccinated with Porcine Parvovirus Vaccine

Rats were administered zearalenone (ZEA) via gavage at dosages of 0, 1, 5, and 30 mg/kg for 36 days. On treatment day 8, inactivated porcine parvovirus vaccine (Vac) was injected intraperitoneally. Antibody production against porcine parvovirus was then measured as a function of ZEA treatment. Compared to the vaccine alone, ZEA treatment, with or without Vac, decreased the serum level of IgG. The level of IgM decreased in all ZEA groups at day 22, but the decrease was sustained only in the medium-dose ZEA group at day 36. The level of IgA was unchanged in the Vac only and ZEA groups at day 22, but was decreased in the 5 mg/kg ZEA plus Vac group compared to the Vac only group at day 36. The level of IgE was decreased by all doses of ZEA at day 22, but was unaffected in ZEA plus Vac groups compared to the Vac only group. The levels of IL-1 in the thymus and spleen; INF-γ in serum; IL-2, IL-6, and IL-10 in the thymus; and IL-10 and IFN-γ in the spleen decreased after ZEA administration. Furthermore, the levels of IL-1β in the spleen and mesenteric lymph node, IL-1β in the thymus, IL-2 in the thymus and spleen, IL-6 in the thymus, IL-10 and IFN-γ in the spleen, and GM-CSF and TNF-α in the thymus decreased after vaccination in rats exposed to ZEA. In conclusion, these results suggest that ZEA exposure via drinking water can cause an immunosuppressive effect by decreasing immunoglobulins in serum and cytokines in lymphoid organs.

Enhancing immune responses to inactivated porcine parvovirus oil emulsion vaccine by co-inoculating porcine transfer factor in mice

Inactivated porcine parvovirus (PPV) vaccines are available commercially and widely used in the breeding herds. However, inactivated PPV vaccines have deficiencies in induction of specific cellular immune response. Transfer factor (TF) is a material that obtained from the leukocytes, and is a novel immune-stimulatory reagent that as a modulator of the immune system. In this study, the immunogenicity of PPV oil emulsion vaccine and the immuno-regulatory activities of TF were investigated. The inactivated PPV oil emulsion vaccines with or without TF were inoculated into BALB/c mice by subcutaneous injection. Then humoral and cellular immune responses were evaluated by indirect enzyme-linked immunosorbent assays (ELISA), fluorescence-activated cell sorter analyses (FACS). The results showed that the PPV specific immune responses could be evoked in mice by inoculating with PPV oil emulsion vaccine alone or by co-inoculation with TF. The cellular immune response levels in the co-inoculation groups were higher than those groups receiving the PPV oil emulsion vaccine alone, with the phenomena of higher level of IFN-γ, a little IL-6 and a trace of IL-4 in serum, and a vigorous T-cell response. However, there was no significant difference in antibody titers between TF synergy inactivated vaccine and the inactivated vaccine group (P>0.05). In conclusion, these results suggest that TF possess better cellular immune-enhancing capability and would be exploited into an effective immune-adjuvant for inactivated vaccines.

The immune enhancement of propolis adjuvant on inactivated porcine parvovirus vaccine in guinea pig

Two experiments were carried out. In immune response test, the immune enhancement of propolis, oilemulsion and aluminium salt were compared in guinea pig vaccinated with inactivated porcine parvovirus (PPV) vaccine. The result showed that three adjuvants could enhance antibody titer, T lymphocyte proliferation, IL-2 and IL-4 secretion of splenic lymphocyte. The action of propolis was similar to that of oilemulsion and superior to that of aluminium salt, especially in early period of vaccination propolis could accelerate antibody production. In immune protection test, the effects of three adjuvants on PPV infection were compared in guinea pig vaccinated with PPV vaccine then challenged with PPV. The result showed that propolis and oilemulsion could enhance the antibody titer, IL-2 and IL-4 content in serum and decrease the PPV content in blood and viscera. In the effect of improving cellular immune response, the propolis was the best. These results indicated that propolis possessed better immune enhancement and would be exploited into a effective adjuvant of inactivated vaccine.

Parvovirus Antibodies in Vaccinated Gilts in Field Conditions – Results with HI and ELISA tests

This study was conducted to determine the antibody response for porcine parvovirus (PPV) of 39 gilts in field conditions after vaccination. Gilts from four herds endemically infected with PPV were injected twice with a commercial vaccine of inactivated PPV and Erysipelothrix rhusiopathiae. The PPV antibodies were analysed both with haemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA) in order to study the agreement between these methods. The possible association between high-antibody titres and reproductive failure (repeat breeding, culling for infertility, < or = 6 piglets born alive) was also investigated. In these study herds, endemically infected by PPV, most gilts (84.6%) had not seroconverted by the age of 6 months. On-field vaccination resulted in a consistent increase of humoral immunity not exceeding the antibody level of 1 : 512 in the majority of gilts in all herds examined. The agreement between ELISA and HI tests was moderate (Spearman's rho = 0.87, kappa = 0.63). The seroconversion over the level >1:512 by mid-pregnancy was not associated with reproductive failure.

Ginseng and aluminium hydroxide act synergistically as vaccine adjuvants

The dry extract prepared from the Panax ginseng C.A. Meyer-root (total ginseng (T-ginseng)) contain ginsenosides (G-des) which were shown to have adjuvant properties as demonstrated by: (a) injecting guinea pigs with a mixture of T-ginseng and inactivated porcine parvovirus (PPV) as a conventional vaccine; (b) injecting PPV-antigen and T-ginseng simultaneously but separately at different sites on the animal and (c) injecting only the T-ginseng 1 or 2 weeks prior to immunisation with the PPV-antigen. Using a haemagglutination inhibition (HI) test in the antibody titration, it was found that the mean HI-titre for the animals injected with PPV-antigen only was 320±0. By comparison, the mean titre value was 2026±1206 for the sera from the animals injected with the same vaccine but adjuvanted with 4 mg of T-ginseng, while the antibody titre induced by a vaccine containing Al(OH) 3-gel was 2986±1596. Interestingly, the T-ginseng and Al(OH) 3 acted synergistically and further improved the antibody response to the PPV-antigen to 6826±2413, i.e. more than 20 times the HI titre of the non-adjuvanted PPV-vaccine. Immunisations using PPV-vaccines adjuvanted with single purified G-des demonstrated that the ginseng fractions Rb1 and Rg1 are potent adjuvants inducing higher or similar antibody titres than the vaccine adjuvanted with Al(OH) 3, e.g. Rb1 tested at a concentration of 830 μg per dose induced a significantly ( P=0.009) higher antibody titre than the one adjuvanted with Al(OH) 3. Nevertheless, different than the mixture Al(OH) 3–T-ginseng; Rb1 and Rg1 act antagonistically and partially inhibit each other. The G-des adjuvanted vaccines induced significantly ( P=0.0011) higher titres of IgG2 antibodies compared with IgG1.

A novel non-mineral oil-based adjuvant. II. Efficacy of a synthetic sulfolipopolysaccharide in a squalane-in-water emulsion in pigs.

The adjuvanticity of a sulfolipopolysaccharide (SLP) incorporated into a squalane-in-water emulsion (SLP/S/W) was compared with that of a mineral oil-in-water (O/W) adjuvant currently used in commercial porcine vaccines. Groups of pigs were immunized twice with vaccines comprising either inactivated influenza virus (iFlu3 containing strains A/Swine, MRC-11 and X-79), inactivated pseudorabies virus (iPRV), live pseudorabies virus (PRV) or inactivated porcine parvovirus (iPPV) as antigen and SLP/S/W or O/W as adjuvant. Antibody titres in serum 2 or 3 weeks after the second immunization were measured by haemagglutination inhibition (HI) or serum neutralization (SN) assays. Both adjuvants significantly augmented the antibody responses against the antigens tested. Mean factors of increase obtained by SLP/S/W and O/W were: 315 and 91, respectively, for A/Swine; 478 and 137 for MRC-11; 362 and 128 for X-79; 69 and 49 for iPRV; and 23 and 7 for live PRV. Increased humoral immunity against live PRV was affirmed by reduced levels and duration of virus excreted by pigs after challenge with virulent PRV. Immunization of pigs with iPPV plus adjuvant SLP/S/W gave 36-fold higher titres than with O/W. It was concluded that SLP/S/W is more effective than O/W in stimulating humoral immunity against the viral antigens examined and that the two constituents SLP and S/W interact synergistically. Advantages of SLP/S/W over O/W include stronger adjuvanticity, better biocompatibility and lower doses of active substances.

Outbreaks of porcine parvovirus disease in Panama.

The first recorded isolation of porcine parvovirus (PPV) in Panama is described. The outbreaks of PPV disease were characterised by a high prevalence of mummified foetuses, stillborn and weak pigs and a common source of exposure. Diagnosis was based on virus isolation and by demonstrating viral antigen in lungs of affected foetuses. Six farms in four different provinces were involved. Rapid control of the epizootic was achieved through the use of an inactivated PPV vaccine in the affected farms.

Development of a vaccine preventing parvovirus‐induced reproductive failure in pigs

An inactivated porcine parvovirus (PPV) vaccine for the prevention of PPV-induced reproductive failure in pigs was developed, using virus grown in cell culture, inactivated with beta-propiolactone and adjuvanted with aluminum hydroxide. The vaccine was tested for safety by subcutaneous injection into pregnant gilts. There were no signs of abnormal reactions nor evidence of PPV infection in the gilts or their foetuses when they were sacrificed 6 weeks after vaccination. To demonstrate that the vaccine was immunogenic, pigs were immunised either once or twice with 4 weeks between doses. Resulting antibody titres (haemagglutination inhibition - HAI) ranged from less than 8 to 64 (geometric mean of 30) after one dose of vaccine, and from 128 to 512 (geometric mean 256) after two doses. To demonstrate that the vaccine was protective, antibody-negative gilts were vaccinated twice, with 4 weeks between doses, joined after the second dose, and were then infected with virulent PPV 40 to 50 days after joining. In litters from 10 vaccinated gilts, none of 93 foetuses showed evidence of PPV infection. In contrast, in litters from two unvaccinated gilts, all 13 foetuses showed evidence of PPV infection and 10 of these were mummified. The average number of live piglets per litter was 9.2 from vaccinated gilts and 1.5 from unvaccinated gilts. The vaccine was therefore considered to be effective in preventing PPV reproductive failure in susceptible gilts.

Efficacy of an Inactivated Porcine Parvovirus (PPV) Vaccine under Field Conditions

Dose response experiments were carried out by vaccinating groups of seronegative gilts (7 months of age) and groups of gilts with residual maternal serum antibodies to PPV (5 months of age). PPV vaccines containing different amounts of inactivated virions were used. Vaccinations were carried out twice with 3 weeks intervals. It was demonstrated, that a single vaccination even with a vaccine with low antigen content elicited an antibody response to PPV in seronegative gilts. The titer values increased after the 2nd vaccination. When the gilts had residual maternal serum antibodies at the time of vaccination the antibody response was generally lower. In some animals the titer values decreased after the 1st vaccination, but except for 2 gilts vaccinated with vaccines with a low antigen content an increase of titer values followed after the 2nd vaccination. During a field trial performed in a herd with enzootic PPV infection all the gilts were vaccinated with PPV vaccine before mating. Blood samples were examined for HI antibodies before and after vaccination and at weaning time of each of the resulting 5 litters. In total 24 batches of gilts comprising 326 animals mated during a 2 year period were examined. It was demonstrated, that the applied vaccine preparations used under field conditions gave a relatively high and long lasting antibody response, even when the gilts were vaccinated as early as at about 5 months of age.

Efficacy of porcine parvovirus vaccines.

Three inactivated porcine parvovirus vaccines were tested for efficacy in 66 susceptible gilts. The gilts were challenged with virulent virus on the 40th day of gestation. All the vaccines provided excellent protection against fetal mortality despite insignificant serological responses to one of them. Good protection was obtained with two of the vaccines even when the dose was substantially reduced. Unvaccinated controls had very few viable fetuses.

Radioimmunoassay of adjuvant-associated porcine parvovirus using a monoclonal antibody in a nitrocellulose membrane system

A quantitative and simple indirect radioimmunoassay (IRIA) was developed for porcine parvovirus (PPV), employing a monoclonal antibody directed against PPV adsorbed to nitrocellulose membrane. The IRIA was equally sensitive to live or inactivated PPV. There was a linear relationship between membranebound radioactivity and PPV quantity within a range of 10–80 hemagglutinating (HA) units of virus. Two commercially used adjuvants, aluminum hydroxide (AH) and carboxyvinyl polymer (CP), reduced bound radioactivity in a concentration-dependent manner. At fixed adjuvant concentrations, there were, nevertheless, linear relationships between bound radioactivity and HA units of PPV. Known amounts of PPV were prepared in adjuvants according to commercial vaccine formulations. Using these standards, the PPV content of 16 commercial PPV vaccines was estimated by IRIA. The IRIA may be one practical method of in vitro estimation of antigenic mass in adjuvanted vaccines.

Antibody responses of guinea-pigs, rabbits and pigs to inactivated porcine parvovirus vaccines

Antibody responses were compared in guinea-pigs, rabbits and pigs following vaccination with inactivated porcine parvovirus (PPV) vaccines. Mean PPV hemagglutination inhibition (HI) antibody titers of 52, 56 and 36 at 1 week after first vaccination and 896, 640 and 512 at 2 weeks after second vaccination were detected in guinea-pigs, rabbits and pigs, respectively. PPV vaccines prepared with greater concentrations of virus, as determined by hemagglutination (HA) units, and of aluminum hydroxide gel adjuvant, induced higher HI antibody titers in guinea-pigs. Optimal concentrations for inducing consistently high antibody titers consisted of vaccine virus with a HA titer of 256/0.1 ml and gel adjuvant at a final concentration of 50%. A second vaccination at 4 weeks compared to 2 or 3 weeks after first vaccination resulted in higher mean HI titers. These data provide preliminary information on the use of guinea-pigs or rabbits as laboratory animal models for testing the potency of PPV vaccines.

弱毒日本脳炎生ウイルス-不活化豚パルボウイルス混合試作予防液についての2, 3の試験

mixed vaccine (JP) was prepared tentatively by freeze-drying a mixture of attenuated Japanese encephalitis live virus (JEV) and inactivated porcine parvovirus (PPV). When inoculated with it, guinea pigs and mice presented no abnormal signs, and SPF piglets 10 and 30 days old and pregn ant sows at 40 days of gestation neither abnormal fluctuation in body temperature or leukocyte count, or viremia. An increase in HI antibody titer was noticed 3-4 weeks after inoculation.In field trials-JP was inoculated into 52 and 51 swine negativeboth for antibodies against JEV and PPV in 1975 and 1976, respectively. As a result, the frequency of occurrence of the dead newborn was significantly lower in sows inoculated with JP than in uninoculated controls in each year. In 1975 JP inoculation had a more satisfactory effect to lower this frequency and the rate of parturition of abnormal young than inoculation with JEV vaccine alone.