目的调查献血者人群中H抗原缺失血型的表型频率，研究其血清学和遗传学特征。

Objective Survey the frequency of H deficient phenotype in blood donor population and analyze the serological and genetic characteristics of these individuals.

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目的：对炭疽毒素保护性抗原（PA）的不同结构域进行了缺失突变，以期找到免疫原性降低而功能变化不大的PA蛋白突变体。

Objective:To find protective antigen(PA) defective mutants of anthrax toxin with the same function as PA but with low immunogenicity, different domains of PA were mutated.

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目的：研究O抗原“缺失”的宋内志贺菌其它生物学性状的变化情况。

Objective:To study the other properties of Shigella sonnei with "no" O antigen.

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