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The objective of this pilot study was to determine the efficacy of inactivated (1 or 2 dose) and live-attenuated chimeric porcine circovirus (PCV)1-2 vaccines in sows using the PCV2-spiked semen model. Thirty-five sows were randomly divided into 6 groups: negative and positive controls, 1 dose inactivated PCV1-2 vaccine challenged (1-VAC-PCV2), 2 dose inactivated PCV1-2 vaccine challenged (2-VAC-PCV2), 1 dose live-attenuated PCV1-2 vaccine unchallenged (1-LIVE-VAC), and 1 dose live-attenuated PCV1-2 vaccine challenged (1-LIVE-VAC-PCV2). The inactivated PCV1-2 vaccine induced higher levels of PCV2-specific antibodies in dams. All vaccination strategies provided good protection against PCV2 viremia in dams, whereas the majority of the unvaccinated sows were viremic. Four of the 35 dams became pregnant: a negative control, a positive control, a 2-VAC-PCV2 sow, and a 1-LIVE-VAC-PCV2 sow. The PCV2 DNA was detected in 100%, 67%, and 29% of the fetuses obtained from the positive control, inactivated vaccinated, or live-attenuated vaccinated dams, respectively. The PCV2 antigen in hearts was only detectable in the positive control litter (23% of the fetuses). The PCV1-2 DNA was detected in 29% of the fetuses in the litter from the 1-LIVE-VAC-PCV2 dam. Under the conditions of this pilot study, both vaccines protected against PCV2 viremia in breeding age animals; however, vertical transmission was not prevented.L’objectif de cette étude pilote était de déterminer l’efficacité de vaccins inactivés (1 ou 2 doses) et vivants atténués chimériques du circovirus porcin (PCV)1-2 chez des truies en utilisant le modèle de semence inoculée avec PCV2. Trente-cinq truies ont été réparties de manière aléatoire en six groupes : témoins négatif et positif, 1 dose de vaccin PCV1-2 inactivé et challengé (1-VAC-PCV2), 2 doses de vaccin PCV1-2 inactivé et challengé (2-VAC-PCV2), 1 dose de vaccin PCV1-2 vivant atténué non-challengé (1-LIVE-VAC), et 1 dose de vaccin PCV1-2 vivant atténué et challengé (1-LIVE-VAC-PCV2). Le vaccin PCV1-2 inactivé a induit des niveaux plus élevés d’anticorps anti-PCV2 spécifiques chez les truies. Toutes les stratégies de vaccination ont entrainé une bonne protection contre une virémie par PCV2 chez les truies, alors que la majorité des truies non-vaccinées étaient virémiques. Quatre des 35 truies sont devenues gestantes : une truie témoin négatif, une truie témoin positif, une truie 2-VAC-PCV2, et une truie 1-LIVE-VAC-PCV2. L’ADN du PCV2 a été détecté chez, respectivement, 100 %, 67 %, et 29 % des fœtus obtenus des truies témoin positif, vaccin inactivé ou vaccin vivant atténué. L’antigène PCV2 dans le cœur n’était détectable que dans les portées des témoins positifs (23 % des fœtus). L’ADN de PCV1-2 a été détecté chez 29 % des fœtus dans la portée d’une truie 1-LIVE-VAC-PCV2. Dans les conditions de cette étude pilote, les deux vaccins étaient protecteurs contre une virémie par PCV2 chez des animaux en âge de se reproduire; toutefois ils n’empêchaient pas la transmission verticale.(Traduit par Docteur Serge Messier).

The present invention provides a novel chimeric porcine circovirus infectious DNA clone and live attenuated chimeric virus with the PCV2, preferably of subtype PCV2b, capsid gene integrated into a non-pathogenic PCV1 virus genome. In a particular embodiment, the PCV2 capids gene is of subtype PCV2b, the predominant subtype circulating in pigs worldwide. The attenuated chimeric virus, designated PCV1-2b, effectively protects pigs from PCV2b challenges, and can be used as a live vaccine, as well as an inactivated (killed) vaccine, that provides protection and cross protection against PCV2b and PCV2a subtypes infection. The live attenuated vaccine of the present invention is also effective protecting pigs from porcine circovirus-associated disease (PCVAD).

The present invention provides a novel chimeric porcine circovirus infectious DNA clone and live attenuated chimeric virus with the PCV2, preferably of subtype PCV2b, capsid gene integrated into a non-pathogenic PCV1 virus genome. In a particular embodiment, the PCV2 capids gene is of subtype PCV2b, the predominant subtype circulating in pigs worldwide. The attenuated chimeric virus, designated PCV1-2b, effectively protects pigs from PCV2b challenges, and can be used as a live vaccine, as well as an inactivated (killed) vaccine, that provides protection and cross protection against PCV2b and PCV2a subtypes infection. The live attenuated vaccine of the present invention is also effective protecting pigs from porcine circovirus-associated disease (PCVAD).

The present invention provides a novel chimeric porcine circovirus infectious DNA clone and live attenuated chimeric virus with the PCV2, preferably of subtype PCV2b, capsid gene integrated into a non-pathogenic PCV1 virus genome. In a particular embodiment, the PCV2 capids gene is of subtype PCV2b, the predominant subtype circulating in pigs worldwide. The attenuated chimeric virus, designated PCV1-2b, effectively protects pigs from PCV2b challenges, and can be used as a live vaccine, as well as an inactivated (killed) vaccine, that provides protection and cross protection against PCV2b and PCV2a subtypes infection. The live attenuated vaccine of the present invention is also effective protecting pigs from porcine circovirus-associated disease (PCVAD).