ATTENUATION OF THE NYCBH VACCINE STRAIN OF VACCINIA

I期研究确定了使用分子生物学的可行性。 从NYCBH疫苗株衍生稳定减毒的方法 免疫效力不变的突变体。 在本第二阶段建议中， 将研究在毒性NYCBH-IH分离物中产生的突变体， 确定其毒力参数和免疫保护能力。 一个 在正常和免疫功能低下患者中的毒力参数的详尽研究 小鼠将包括颅内和鼻内LD 50、生长和 从接种部位的传播，以及痘疮的程度 形成划痕的皮肤。 突变体的免疫保护能力 将根据其保护外国人的能力进行评估 病原体通过表达单一中和抗原。 上述研究是为了实验方便而进行的， NYCBH的高毒力实验室分离物。 此信息将 用于在纯化的低毒力噬菌斑中产生特定突变 来自为NIH生产的Wyeth疫苗种子库（NYCBH-W）的分离株 在良好生产规范下。 将评估NYCBH-W突变体 毒力参数，以及保护免受 通过表达单一中和抗原来抑制外源病原体。 这 数据将用于设计第一代候选疫苗 含有单一突变。 随后，突变的组合将 用于确认第二代候选疫苗。

The Phase I studies established the feasibility of using molecular approaches to derive from the NYCBH vaccine strain, stable attenuated mutants of unaltered immune efficacy. In this Phase II proposal selected mutants generated in the virulent NYCBH-IH isolate will be studied to determine their virulence parameters and immune protective capacity. An exhaustive study of virulence parameters in normal and immunocompromised mice will include, intracranial and intranasal LD50s, growth and dissemination from the site of inoculation, and the extent of pock formation on scarified skin. The immune protective capacity of mutants will be assessed by their ability to confer protection against a foreign pathogen by the expression of a single neutralizing antigen. The studies described above were performed for experimental convenience in a high virulence laboratory isolate of NYCBH. This information will be used to create specific mutations in a low virulence plaque purified isolate form the Wyeth vaccine seed stock (NYCBH-W) produced for the NIH under good manufacturing practice. The NYCBH-W mutants will be assessed for virulence parameters, and ability to confer protection against a foreign pathogen by the expression of a single neutralizing antigen. This data will be used to design first generation vaccine candidate(s) containing single mutations. Subsequently, combinations of mutations will be used to conform second generation vaccine candidate(s).