Sunflower seed oil containing ginseng stem-leaf saponins (E515-D) is a safe adjuvant for Newcastle disease vaccine.

Vaccination is an effective method to prevent Newcastle disease (ND) in chickens. Marcol 52 and #10 white oil are mineral-based adjuvants and can be found in commercial inactivated ND virus vaccines. The present study demonstrated that a vegetable origin oil E515-D had lower polycyclic aromatic hydrocarbons and higher flash point than the commercial products Marcol 52 and #10 white oil. E515-D could be mixed with an aqueous phase containing ND virus antigen to form a stable water-in-oil vaccine emulsion and exhibited more potent adjuvant effects on the immune response than Marcol 52 and #10 white oil. Moreover, the absorption of E515-D-adjuvanted vaccine was faster than absorption of Marcol 52- and #10 white oil-adjuvanted vaccines when ND virus vaccines were injected in broilers. Therefore, E515-D was safe and could be a suitable adjuvant used in vaccines for food animals. In addition，E515-D is not easy to be flammable during shipping and storage owing to its higher flash point.

Regulatory aspects of quality and safety for live recombinant viral vaccines against infectious diseases in Japan.

Recombinant viral vaccines expressing antigens of pathogenic microbes (e.g., HIV, Ebola virus, and malaria) have been designed to overcome the insufficient immune responses induced by the conventional vaccines. Our knowledge of and clinical experience with the new recombinant viral vaccines are insufficient, and a clear regulatory pathway is needed for the further development and evaluation of recombinant viral vaccines. In 2018, the research group supported by the Ministry of Health, Labour and Welfare, Japan (MHLW) published a concept paper to address the development of recombinant viral vaccines against infectious diseases. Herein we summarize the concept paper-which explains the Japanese regulatory concerns about recombinant viral vaccines-and provide a focus of discussion about the development of recombinant viral vaccines.

Progress on the research and development of human enterovirus 71 (EV71) vaccines.

Enterovirus 71 (EV71) infections, which can cause severe complications, have become one of the serious public health issues in the Western Pacific region and China. To date, a number of pharmaceutical companies and institutes have initiated the research and development of EV71 vaccines as a countermeasure. As is the case with innovative vaccine development, there are several critical bottlenecks in EV71 vaccine development that must be overcome before the clinical trials, including the selection of vaccine strain, standardization of the procedure for quantifying neutralizing antibody (NTAb) and antigen, establishment and application of a reference standard and biological standards, development of animal models for the evaluation of protective efficacy, and identification of the target patient population. To tackle these technical obstacles, researchers in Mainland of China have conducted a series of studies concerning the screening of vaccine strains and the establishment of criteria, biological standards and detection methods, thereby advancing EV71 vaccine development. This review summarizes recent worldwide progress on the quality control and evaluation of EV71 vaccines.

Adsorption of colostral antibodies against classical swine fever, persistence of maternal antibodies, and effect on response to vaccination in baby pigs.

OBJECTIVE: To determine kinetics of antibody absorption, persistence of antibody concentrations, and influence of titers on vaccination of baby pigs with a vaccine against classical swine fever (CSF). ANIMALS: 15 sows and their litters. PROCEDURE: Farrowings were supervised. Initial time of suckling was recorded. In the first experiment, blood samples were collected at farrowing, 2 and 4 hours after suckling, and hourly until 10 hours after initial suckling. Samples were assayed for CSF antibodies, using a serum neutralizing (SN) test. A second experiment included 33 baby pigs vaccinated as follows: 10 prior to ingestion of colostrum, 18 between 1 and 4 hours after ingestion of colostrum, and 5 at 12 hours after ingestion of colostrum. Fourteen pigs were vaccinated when 7 weeks old, and 15 pigs were not vaccinated. At 10 weeks of age, pigs were challenge-exposed with virulent CSF virus. Blood samples were collected and assayed for CSF antibodies and p125 antigen and p125 antibodies. RESULTS: CSF antibodies were detected in pigs beginning 2 hours after suckling. Colostral antibodies persisted for > 7 weeks (half-life, 79 days). Vaccination of pigs before suckling provided effective protection from severe disease after challenge-exposure. However, vaccination of neonates with antibody titers was not effective, because 19 of 23 (82%) pigs succumbed after challenge-exposure. All pigs vaccinated when 7 weeks old resisted challenge-exposure, whereas all unvaccinated control pigs succumbed. CONCLUSIONS AND CLINICAL RELEVANCE: Vaccination before ingestion of colostrum conferred good protection against CSF in baby pigs. Vaccination of 7-week-old pigs that had decreasing concentrations of passively acquired antibodies was efficacious.

The induction of a protective immunity against Jembrana disease in cattle by vaccination with inactivated tissue-derived virus antigens.

The ability to induce a protective immunity against Jembrana disease, an acute lentivirus disease of Bali cattle (Bos javanicus) present in Indonesia, was investigated. A protective immune response was induced in cattle by vaccination with virus-containing plasma and spleen tissue derived from acutely affected cattle. The virus was inactivated with Triton X-100 and emulsified in either incomplete Freund's adjuvant or a mineral oil adjuvant (MOA). The vaccination procedure suppressed the duration and severity of the disease but did not completely prevent the development of disease in animals challenged with 100 infectious doses of virus.

Shedding of porcine reproductive and respiratory syndrome virus in mammary gland secretions of sows.

OBJECTIVE: To document shedding of porcine reproductive and respiratory syndrome (PRRS) virus in mammary gland secretions of experimentally inoculated sows, to evaluate effects of vaccination during gestation on virus shedding during the subsequent lactation, and to evaluate shedding of PRRS virus in milk of sows in commercial herds. ANIMALS: 6 sows seronegative for PRRS virus were used for experiment 1, and 2 sows were retained for experiment 2. For experiment 3, 202 sows in commercial herds were used. PROCEDURE: In experiment 1, 2 sows were inoculated with PRRS virus, 2 sows were vaccinated with modified-live PRRS virus vaccine, and 2 sows served as control pigs. Mammary gland secretions were assayed for PRRS virus. In experiment 2, pregnant vaccinated sows from experiment 1 were vaccinated with another modified-live PRRS virus vaccine. Mammary gland secretions were assayed in the same manner as for experiment 1. For experiment 3, milk collected from 202 sows in commercial herds was assayed for PRRS virus. RESULTS: In experiment 1, PRRS virus was detected in mammary gland secretions of both vaccinated and 1 of 2 virus-inoculated sows. In experiment 2, virus was not detected in samples from either vaccinated sow. In experiment 3, all samples yielded negative results. CONCLUSIONS AND CLINICAL RELEVANCE: Naïve sows inoculated late in gestation shed PRRS virus in mammary secretions. Previous vaccination appeared to prevent shedding during the subsequent lactation. Results for samples obtained from sows in commercial herds suggested that virus shedding in mammary gland secretions of such sows is uncommon.

Ascorbic acid supplementation improved antibody response to infectious bursal disease vaccination in chickens.

The purpose of the present study was to determine if supplementation of ascorbic acid (AA) to the diet would have a beneficial effect on infectious bursal disease (IBD) vaccination of chickens for protection against infectious bursal disease virus (IBDV) infection. Two hundred forty specific pathogen-free (SPF) chickens were divided into eight experimental groups. A 2 x 2 x 2 factorial arrangement in a completely randomized design was used; AA supplementation at 1,000 ppm in the diet, vaccination, and challenge were the main effects. Prior to challenge and 10 d after challenge, serum AA concentration, serum corticosterone concentration, ELISA antibody titer to IBDV, body weight, bursa-to-body weight (B:B) ratio, and bursal histological score (BHS) were determined. Nonvaccinated chickens fed a diet supplemented with AA did not exhibit clinical signs or mortality following challenge, whereas AA-unsupplemented counterparts had 100% cumulative morbidity and 30% cumulative mortality. Serum AA levels of AA-supplemented and vaccinated chickens were significantly (P < 0.05) higher than AA-unsupplemented and vaccinated chickens. Fourteen days following vaccination, significantly (P < 0.05) higher ELISA titers to IBDV were observed in vaccinated chickens supplemented with AA as compared to AA-unsupplemented counterparts. Ascorbic acid-supplemented chickens, especially those also vaccinated, had higher body weight gains as compared to the AA-unsupplemented chickens. Ascorbic acid-supplemented chickens challenged with IBDV did not show any clinical signs or mortality. The results suggest that supplementation of AA at 1,000 ppm in the diet has beneficial effects on antibody response to IBD vaccination and body weight gain.

Natural transmission of bovine leukemia virus in dairy and beef cattle.

Many potential routes of bovine leukemia virus (BLV) transmission are reviewed in this article. Vertical transmission, in utero, or through colostrum and milk, accounts for a relatively small proportion of infections. Iatrogenic horizontal transmission, through procedures permitting the transfer of blood between cattle, has been shown to be a major route of transmission in most settings. Contact transmission stems from a mixture of natural sources of blood, exudates, and tissues that enter the body through mucosal surfaces or broken skin. Careful analysis of management procedures and environmental conditions present in individual dairy and beef herds affords the greatest opportunity to develop effective BLV prevention programs.

Experience with veterinary vaccines in warm climates.

After a short description of the African laboratories manufacturing veterinary vaccines, the authors explain the main constraints for the use, in the field, of veterinary vaccines in warm climates. The need to respect the cold chain from the supplier of vaccines to the recipient animal is emphasised. In the Ivory Coast, during national vaccination campaigns, it has been proved that the quality of the rinderpest and contagious bovine pleuropneumonia vaccines is satisfactory when there is no disruption in the cold transport services. The data of this survey are exposed. In the framework of a project entitled "Thermostable rinderpest Vaccine, Transfer of Technology", a thermostable vaccine has been developed. It is manufactured in different African laboratories and integrated in some Pan African Rinderpest Campaign (PARC) vaccination programmes. On the other hand, the prospects offered by new thermotolerant attenuated vaccines against Newcastle disease are exposed. Finally, the authors present an outlook on the development of thermoresistant veterinary vaccines, such as those produced by genetic engineering, in particular with pox virus vectors.

Single-radial-immunodiffusion as an in vitro potency assay for human inactivated viral vaccines.

Single-radial-immunodiffusion (SRID) assays have been used to determine the potency of all human inactivated influenza virus vaccines licensed by the Food and Drug Administration for use in the United States since 1978. SRID replaced less reliable tests which were based on the aggregation of erythrocytes by the hemagglutinins of influenza viruses. Similar SRID assays have been used experimentally to determine the potency of inactivated polio and rabies vaccines. In each case, the assays are based on the diffusion of viral antigen into an agarose gel containing specific antibodies to the antigen being measured. For influenza and rabies, disruption of the virions with a detergent is necessary to permit the diffusion of the appropriate antigens, where as with polio, intact virions are allowed to diffuse. The interaction between antigen and antibody produces a zone of precipitation whose size is directly proportional to the amount of antigen applied. A potency value for unknowns is obtained by comparing the sizes of zones produced by unknown preparations to the sizes of zones obtained with a calibrated reference of known antigen content. Once the specific reference antigens and antibodies are prepared and the test standardized, it is a remarkably simple technique which unlike agglutination assays is very reproducible, relatively unaffected by minor variations in test conditions and is far less time consuming and cumbersome than in vivo assays for potency such as those done by inoculating mice or monkeys. More importantly, clinical studies demonstrate that standardization of influenza vaccines by SRID provides a better correlate of human immunogenicity than previous methods.