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講座大師 - 第二十二屆 |
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| Tilahun Yilma |
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Live Recombinant Vaccines and Strategies for Enhancing their Safety and Efficacy
活性重組疫苗和增加其安全性及功效的策略 |
We have developed a number of live recombinant vaccines for a number of viral diseases including for rinderpest, peste des petit ruminants, vesicular stomatitis, simian immunodeficiency, smallpox, and Rift Valley fever. The safety and efficacy of these live recombinant vaccines were highly variable. Thus, we have taken a number of approaches to improve both the safety and efficacy of these recombinant vaccines for use in humans and animals. These include: choice of the strain of vaccinia virus (VACV) used as a vector, insertional inactivation of virulence and immunoregulatory genes of VACV, and expression of cytokine genes that attenuate the vector by more than a million-fold without reduction in immunogenicity. Additionally, we have exploited the advantages of recombinant vaccines and developed diagnostic kits that permit one to distinguish between vaccinated and infected individuals. We constructed rVACVs expressing an interferon gamma (IFNγ) and lacking the immune-modulating genes B8R, B13R, and B22R. IFNγ is a Cytokine with potent Immunoregulatory, antineoplastic, and antiviral properties. These rVACVs replicated to high titers in tissue culture, yet were avirulent in both immunocompromised and immunocompetent mice with no detectable viral replication in these animals. A single immunization elicited potent humoral, T-helper, and cytotoxic T-cell immune responses in mice despite the absence of any detectable virus replication in vivo. IFNγ co-expression and the inactivation of one or more VACV immune-modulating genes provide an optimized method for increasing the safety while maintaining the efficacy of rVACV vaccines for use in humans and animals.
我們已經發展出一系列活性重組疫苗，用於預防多種病毒性疾病，包括牛瘟、反芻獸瘟疫、水皰性口炎、猴類免疫缺陷、天花，和裏夫特谷熱(獸疫性肝炎)。然而這些活性重組疫苗，各自具有不同的安全性和功效。因此我們採用許多不同的方法，來改進這些活性重組疫苗的安全性和功效，以便用在人類和動物身上。這些方法包括：選用痘瘡病毒(Vaccinia Virus，VACV)的病毒株作為載體、在VACV嵌入鈍化的致病和免疫調解基因、表現細胞激素基因去減弱病毒載體一百萬倍但不降低免疫性。此外，我們利用活性重組疫苗的有利特性去發展診斷工具，藉以辨識已接種疫苗或受感染的個體。
我們以基因工程技術建構了一系列重組痘瘡病毒(rVACV)，使其能表現加瑪干擾素(IFNγ)，並欠缺數個免疫調解基因（B8R、B13R、和B22R）。IFNγ是一種細胞激素，具有強效的免疫調解、抗惡性腫瘤、和抗病毒的功能。這些重組痘瘡病毒，雖然可以在組織培養中增殖至高效價，但在免疫功能不足和免疫能力強的老鼠體內，卻測不到這些重組病毒的複製，顯示其作為疫苗的非致病性。單一次的接種，就能在受試老鼠體內引起強效的體液型、T輔助細胞、和細胞毒性型T細胞的免疫反應，同樣在活體內測不出此重組病毒的複製。綜上所述，IFNγ的共同表現結合一個或多個VACV免疫調解基因的鈍化，可成為一個優化的疫苗建構方法，適用於人類和動物，不僅增加安全性，也可同時維持重組痘瘡病毒(rVACV)作為疫苗的功效。
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Transfer of Technologies in Molecular Biology to Developing Countries: Development of Recombinant Vaccines and Rapid Diagnostic Kits.
移轉分子生物科技至發展中國家：重組型疫苗和快速診斷工具的發展 |
The International Laboratory of Molecular Biology (ILMB) met its obligations in the realm of technology transfer with a very active program of training in biotechnology. International scientists have trained at the ILMB on projects related to the laboratory’s major goals of vaccine and rapid diagnostic kit development. We established a molecular biology laboratory in Egypt in 1994 through USAID funding; it is operational with a staff of Egyptians scientists that were trained at the ILMB. Additional laboratories have been set up in Ethiopia, Kenya, and Senegal. In November 2001, Senegalese scientists that were trained at the ILMB conducted a two-week long technology workshop in Dakar for participants from more than 30 countries in Africa, and successfully taught the participants to prepare and use the iELISA kit for livestock diseases such as rinderpest. The test uses the nucleoprotein antigen of the rinderpest virus, which can be abundantly and inexpensively produced in baculovirus expression vectors.
Our accomplishments in transferring technology to developing countries have been widely acknowledged and reported in a number of scientific journals, including Nature (Stevens, Vol. 355, p. 194: 16 January 1992) and Science ( 237:1289-1291, 1987--War on Cattle Disease Divides the Troops). With our many successes in research, training, and transfer of technologies in molecular biology to developing countries, we have grown and become better integrated into the international scientific community. We have established joint activities and extensive collaborative efforts with a number of national and international organizations and private firms, e.g., the National Institutes of Health (NIH), United States Department of Agriculture (USDA), United States Agency for International Development (USAID), International Atomic Energy Agency (IAEA), Food and Agriculture Organization (FAO), and the African Union (AU). Working within the guidelines of these organizations, the ILMB was broadly concerned with development of biotechnology programs for animal production and animal health, training of scientists from developing countries, transfer of biotechnology information and techniques to these countries, and formation of a network of laboratories dealing with specific biotechnology issues. The ILMB was also active in the University of California System-wide Biotechnology Research and Education Program. This research and training program in biotechnology provided resources for training highly qualified graduate students and postdoctoral fellows in the area of vaccine development and viral pathogenesis. In addition, challenges and constrains encountered during our effort to transfer technologies in molecular biology to developing countries will be discussed.
國際分子生物學實驗室(International Laboratory of Molecular Microbiology，ILMB) 為了履行其職責，以積極主動的生物科技教育訓練，進行相關技術轉移。各國科學家因此至ILMB接受訓練，參加旨在發展疫苗接種和快速診斷工具的計畫。此教育訓練計畫獲得美國國際開發署(United States Agency for International Development，USAID)的經費贊助，於1994年在埃及成立分子生物實驗室，其運作人員由在ILMB訓練出的埃及科學家擔任。另外，在衣索比亞、肯亞、和塞內加爾也設立了同樣的實驗室並提供教育訓練。2001年11月，曾在ILMB接受訓練的塞內加爾科學家，在達卡舉辦了為期兩週的工作坊。與會人員來自非洲三十多個國家，成功地傳授如何針對以牛瘟為例的家畜疾病，製備和使用以間接酵素連結免疫分析法(Indirect Enzyme-Linked Immunosorbent Assay，iELISA)為主的分析檢驗工具。這個免疫測試以牛瘟病毒的核蛋白為抗原，可以大量且便宜地在桿狀病毒載體中製造。
我們如此將科技轉移給發展中國家的成就，曾獲得一些頂尖科學期刊的公認和報導，例如:自然(Stevens, Vol. 355, p. 194: 16 January 1992)，和科學 (237:1289-1291, 1987--War on Cattle Disease Divides the Troops )。隨著我們在研究、訓練、以及移轉分子生物技術給發展中國家的諸多成功，我們已經成長並且融入了國際科學社群。我們也和一些國家、國際組織，以及私人機構，共同舉辦活動或合作，例如:美國國家衛生研究院(National Institutes of Health，NIH)、美國農業部(United States Department of Agriculture ，USDA)、美國國際開發署(United States Agency for International Development，USAID)、國際原子能總署(International Atomic Energy Agency，IAEA)、聯合國糧食及農業組織(Food and Agriculture Organization，FAO)、和非洲聯盟(African Union)，AU)等。在這些組織的規範與指導下，ILMB廣泛地關注許多議題: 為增加畜牧動物生產和動物健康的生物科技發展計畫、為發展中國家訓練科學家、將資訊和技術轉移給這些國家、並為特定生物技術議題建構實驗室交流網路。ILMB也積極參與由加州大學系統主導的生物科技研究和教育計畫。這項計畫提供資源，用於訓練在疫苗開發和病毒致病性等領域研修的頂尖研究生和博士後研究員。另外，在致力於將分子生物科技轉移給發展中國家的過程中，我們所遭遇的挑戰和限制，也將在演講中論述。
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