• 한국동물위생학회지
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• 제46권3호
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• pp.193-202
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• 2023

Porcine epidemic diarrhea is an infectious intestinal disease caused by the porcine epidemic diarrhea virus (PEDV). Especially, when suckling piglets are infected, the mortality rate is close to 100%. PEDV is classified into G1 and G2 types based on genetic differences. The G2 type PEDV outbreak in the United States in 2013 was highly pathogenic and contagious, and it has spread worldwide and caused continuous economic losses. Most commercial vaccines used are G1 type vaccines, and existing vaccines do not fully protect piglets due to genetic differences. In this study, we evaluated the safety of the newly developed G2 type attenuated HSGP vaccine strain by inoculating it into piglets and testing whether the vaccine virus spreads to the non-vaccinated, negative pigs and whether the vaccine reverts to its virulence during serial passage experiments. Each experiment lasted for 7 days for each passage, and fecal viral titers, clinical symptoms, and weight gain were measured daily. After the experiment, necropsy was performed to measure intestinal virus titer and pathological evaluation. As a result of the first passage, no transmission of the vaccine virus to negative pigs co-housed with vaccinated pigs was observed. In addition, after four consecutive passage experiments, the clinical symptoms and small intestine lesions were gradually alleviated, and no virus was detected in the feces in the fourth passage experiment. Therefore, it was concluded that the vaccine was safe without virulence reversion in accordance with the guidelines of the current licensing authority. However, further studies are needed on the genetic changes and biological characteristics of the mutant virus that occur during successive passages of the attenuated vaccine since the replication and clinical symptoms of the virus increased until the third passage during successive passages of the vaccine virus. Based on this study, it was concluded that virulence reversion and safety evaluation of attenuated vaccines through serial passage in target animals can be useful to evaluate the safety of attenuated viruses.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1996년도 제4회 추계심포지움
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• pp.115-120
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• 1996

Vaccination has been considered to be the most effective way to control infectious diseases. Currently, many vaccines used in humans are live-attenuated or killed microorganisms. Polio, mumps, and measles vaccines are live-attenuated. Killed vaccines include cholera and pertussis vaccines, These conventional vaccines, however, suffer from some problems. In the case of live-attenuated vaccines, reversion to virulence is observed in a small but significant number of clinical cases each year. In killed vaccines, due to the possible hazard to employees working with live pathogens, the cost of preparation is high. Killed vaccines also need to be given in multiple doses, Furthermore, both live-attenuated and killed vaccines have possible presence of cellular materials leading to side effects. Moreover, there are diseases such as malaria and hepatitis for which conventional attenuated and killed vaccines are not available because the pathogens cannot be grown in sufficient amounts to allow the classical methods to be used.

• 미생물학회지
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• 제50권2호
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• pp.108-113
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• 2014

녹농균(Pseudomonas aeruginosa)과 비브리오 불니피쿠스균(Vibrio vulnificus)은 그람 음성의 병원균들로써, quorum sensing(QS) 기전을 통해 병원성을 발현하는 세균들이다. 이들 병원균의 감염은 많은 경우 생물막 형성에 의해 매개된다고 알려져 있는데, 이에 본 연구에서는 P. aeruginosa와 V. vulnificus를 대상으로 QS 기전의 유무에 따른 생물막 형성의 시간적 추이를 분석해 보았다. 그 결과 P. aeruginosa의 경우 QS 기전이 결핍된 균주가 야생형에 비해 초기 부착은 더 잘 하였으나, 이후 생물막 구조의 성숙 능력은 야생형에 비해 현저히 떨어짐을 알 수 있었다. 이러한 특성 때문에 야생형과 QS 결핍 균주의 생물막 형성을 시간의 추이에 따라 정량적으로 비교해 보면 초기 10시간 정도 까지는 QS 결핍 균주가 더 많은 생물막을 형성하다가, 이후 야생형이 더 많이 생물막을 형성하는 역전 현상이 관찰되었다. V. vulnificus는 P. aeruginosa와는 달리 QS 결핍 균주가 야생형보다 더 많은 생물막을 형성한다고 보고된 균주이다. 이 균주에서 같은 방식으로 생물막 형성을 조사해 본 결과, 108시간의 장시간 동안에도 항상 QS 결핍 균주가 야생형 보다 더 많은 생물막을 형성하여, 역전 현상은 관찰되지 않았다. 이 결과는 P. aeruginosa의 경우에는 QS 기전이 초기 부착은 저해하는 방향으로, 성숙과정은 촉진시키는 방향으로 작용하며, V. vulnificus에서는 일관되게 생물막 형성을 저해하는 방향으로 작용함을 보여주는 것이다. 따라서 생물막 제어를 위한 타겟으로 QS기전을 이용할 때에는 제어하고자 하는 생물막 형성 단계와 세균 종을 함께 고려하여야 한다고 제안한다.