Peppoloni S, Pizza M, De Magistris M T, Bartoloni A, Rappuoli R
IRIS Research Institute, Biocine Spa, Siena, Italy.
Physiol Chem Phys Med NMR. 1995;27(4):355-61.
Whooping cough, an acute respiratory disease affecting over sixty million infants, can be prevented by vaccination. The vaccine currently used, composed of killed bacterial cells, however, has been associated with many side effects. An improved vaccine against the disease should contain pertussis toxin (PT), a major virulent factor of Bordetella pertussis (B. pertussis). In order to be included in the vaccine, PT needs to be detoxified and the chemical methods used so far are not completely satisfactory, since they give a product with reduced immunogenicity and possible residual toxicity. To avoid this problem, we have used recombinant DNA technologies to clone the PT gene, express it in bacteria, map the B and T cell epitopes of the molecule and identify the amino acids that are important for the enzymatic activity and toxicity. Based on this information, the gene coding for PT was mutated to produce an inactive protein. This genetically modified PT was non toxic, highly immunogenic and able to protect mice from intracerebral challenge with virulent B. pertussis. The mutant was included as a main component of an acellular pertussis vaccine which has been shown in numerous clinical trials to be more safe and immunogenic than the old cellular vaccine.
百日咳是一种影响超过六千万婴儿的急性呼吸道疾病，可通过接种疫苗预防。然而，目前使用的由灭活细菌细胞组成的疫苗已出现许多副作用。一种改进的针对该疾病的疫苗应包含百日咳毒素（PT），它是百日咳博德特氏菌（B. pertussis）的主要致病因子。为了能被纳入疫苗，PT需要进行解毒，而目前使用的化学方法并不完全令人满意，因为它们产生的产物免疫原性降低且可能存在残留毒性。为避免这个问题，我们利用重组DNA技术克隆了PT基因，并在细菌中表达，绘制该分子的B细胞和T细胞表位图谱，鉴定对酶活性和毒性重要的氨基酸。基于这些信息，编码PT的基因发生突变以产生无活性蛋白。这种基因改造后的PT无毒、免疫原性高，并且能够保护小鼠免受强毒性B. pertussis的脑内攻击。该突变体被用作无细胞百日咳疫苗的主要成分，在众多临床试验中已表明其比旧的细胞疫苗更安全且免疫原性更强。
