イベント・セミナー詳細

専門家

水曜会(第690回)

情報公開日:2015年5月19日 (火曜日)

日時

平成27年5月27日(水曜日)13時30分~

場所

国立研究開発法人 農業・食品産業技術総合研究機構
動物衛生研究所 講堂
茨城県つくば市観音台3-1-5 交通案内/会場案内(建物3)
Tel: 029-838-7707(企画管理部 業務推進室 交流チーム)
Fax: 029-838-7907

今回は、サルモネラの感染制御とワクチン開発に関する一般演題2題を予定しております。
参加希望者の事前登録は不要、当日参加も可能です。多数のご来聴をお待ちしております。

内容

座長:江口 正浩(動衛研)

Functional analysis of Salmonella-specific monoclonal antibody (20分)

Swarmistha Devi Aribam 1.2, Yohsuke Ogawa 1, Yoshihiro Shimoji 1, Masahiro Eguchi 1 ( 1 Bacterial and Parasitic Disease Research Division, National Institute of Animal Health, 2 Japan Society for the Promotion of Science (JSPS))

Salmonella enterica serovar Typhimurium (S. Typhimurium) is an invasive enteric pathogen that causes zoonotic food-borne infectious disease. Infection by Salmonella has a substantial impact on the health of livestock, and even leads to death of animals. An important aspect in designing strategies against Salmonella infection is to develop vaccines for livestock that can counteract Salmonella infection. For the development of an efficacious vaccine, proper understanding of the protective immune responses to Salmonella infection is required. Salmonella-specific antibodies were shown to protect mice against Salmonella infection, but the underlying defense mechanisms remain less clearly defined. This study focuses on understanding the role of antibodies in mediating immunity to the host against Salmonella infection. By using a novel monoclonal antibody (mAb) that was developed using a mutant strain of S. Typhimurium, we have shown that Salmonella-specific antibodies have the potential to provide protection to mice against Salmonella infection. In addition, the functional role of the novel mAb in mediating protection to the host was also investigated via in vitro infection studies. S. Typhimurium generally has the ability to survive and replicate within macrophages through escape from the host’s antibacterial functions. In our study, we found that the novel mAb opsonizes the bacteria for enhanced bacterial uptake by the macrophage, and mediated activation of the macrophage. The antibacterial functions of the macrophage are subsequently induced that resulted in killing of intracellular bacteria. This study therefore suggests an important mechanism of antibody in mediating protection against Salmonella infection, and will be an aid in developing antibody-based vaccines or therapeutic agents.

座長:江口 正浩(動衛研)

Development of a live attenuated vaccine against chicken salmonellosis (20分)

Marta Elsheimer Matulova 1.2 ( 1Bacterial and Parasitic Disease Research Division,National Institute of Animal Health, 2 Japan Society for the Promotion of Science (JSPS))

Salmonellosis is one of the most prevalent infectious diseases in humans worldwide. As humans are mainly infected through a food chain from eggs and poultry products, one of the effective measures to reduce salmonellosis in chickens - and subsequently in humans - is vaccination. However, inactivated vaccines confer low protection and older live vaccines consisting of random auxotroph mutants such as aroA mutants are not well described. Generally, efficient vaccination against salmonellosis in chickens is difficult due to their natural resistance to Salmonella infection. In our studies we therefore focused on a construction of a safe, genetically defined, efficient live vaccine against salmonellosis specifically designed for poultry. We have tested several Salmonella Enteritidis mutants with deletions in various virulence factors such as frequently used aroA and phoP mutants, or Salmonella pathogenicity island (SPI) mutants. Results showed that SPI1 mutant protects chickens the best against salmonellosis. By introducing two additional mutations we have constructed a potential vaccine, in which a) the strain can be easily differentiated from field strains, and b) chickens vaccinated with this strain can be differentiated from infected chickens using a commercial ELISA kit. Furthermore, by adding two different serovars we produced a composite vaccine, which might be effective against a broad spectrum of Salmonella serovars infecting chickens. Nevertheless, further testing of the vaccine in a larger scale by a pharmaceutical company revealed several problems, which will also be shortly discussed. In order to induce a protective immunity in chickens, a development of chicken immune system, interactions with Salmonella and microbiota must be also taken into consideration. In our second project we therefore focused on a chicken response to Salmonella infection in the spleen, intestine and leukocyte subpopulations. Most of the genes identified in our studies were not associated with Salmonella infection before. We used the most up-regulated ones as markers of inflammation to compare vaccination with different deletion mutants. Together with data on age-dependent resistance of chickens to Salmonella infection, we will be able to adjust vaccination scheme to better protect chickens against salmonellosis.

法人番号 7050005005207