Briles D E, Hollingshead S K, King J, Swift A, Braun P A, Park M K, Ferguson L M, Nahm M H, Nabors G S
Departments of Microbiology and Pediatrics, University of Alabama at Birmingham, AL 35294, USA.
J Infect Dis. 2000 Dec;182(6):1694-701. doi: 10.1086/317602. Epub 2000 Nov 8.
Pneumococcal surface protein A (PspA), a cross-reactive protein expressed by all pneumococci, is known to elicit an antibody in animals that can passively protect mice from infection with Streptococcus pneumoniae. A phase I trial with recombinant PspA showed the protein to be immunogenic in humans. Pre- and postimmune serum samples from this trial were examined, and human antibody to PspA could protect mice from pneumococcal infection. The serum samples of subjects immunized twice with 125 microg of PspA had >100 times as much antibody per milliliter as was required to consistently protect mice from fatal infection (1.3 microg/dose). At least 98% of PspAs fall into PspA sequence/serologic families 1 or 2. Human antibodies elicited by a family 1 PspA protected against infection with S. pneumoniae expressing either family 1 or 2 PspAs and with strains of all 3 capsular types tested: 3, 6A, and 6B. These studies suggest that PspA may have efficacy as a human vaccine.
肺炎球菌表面蛋白A（PspA）是所有肺炎球菌表达的一种交叉反应蛋白，已知它能在动物体内引发抗体，这种抗体可被动保护小鼠免受肺炎链球菌感染。一项关于重组PspA的I期试验表明该蛋白在人体中具有免疫原性。对此次试验的免疫前和免疫后血清样本进行了检测，发现人体针对PspA的抗体可保护小鼠免受肺炎球菌感染。用125微克PspA免疫两次的受试者血清样本，每毫升所含抗体量比持续保护小鼠免受致命感染所需量（1.3微克/剂量）高出100倍以上。至少98%的PspA属于PspA序列/血清学家族1或2。由家族1的PspA引发的人体抗体可抵御表达家族1或2的PspA以及所有3种受试荚膜类型（3、6A和6B）菌株的肺炎链球菌感染。这些研究表明PspA可能作为一种人类疫苗具有疗效。
