Yamanaka N, Faden H
Department of Otolaryngology, Sapporo Medical College, Japan.
J Pediatr. 1993 Feb;122(2):212-8. doi: 10.1016/s0022-3476(06)80115-0.
One of the major outer membrane proteins of nontypeable Haemophilus influenzae, P6, is highly conserved among strains, serves as a target for bactericidal antibody, and has been proposed as a possible vaccine candidate. The serum antibody response to P6 was studied in otitis-prone and normal children by an enzyme-linked immunosorbent assay. Of 20 otitis-prone children, 12 (60%) had a serum IgG antibody response to P6 after otitis media; however, the mean acute antibody level for the group, 4.6 micrograms/ml, was not significantly different from the convalescent level, 5.4 micrograms/ml. Anti-P6 antibody levels were also measured longitudinally for 10 to 25 months in 30 otitis-prone and 13 healthy children. Antibody levels increased sevenfold in the normal group compared with less than three-fold for the otitis-prone group and were significantly higher in the normal children after the age of 18 months (p < 0.05). Finally, otitis-prone children who had two or more episodes of otitis media with nontypeable H. influenzae did not have an anamnestic antibody response to P6. The failure to recognize P6 as a specific immunogen may account for recurrent infections. Moreover, the data suggest that otitis-prone children may not respond adequately to a vaccine containing P6.
不可分型流感嗜血杆菌的主要外膜蛋白之一P6，在菌株间高度保守，是杀菌性抗体的靶点，并已被提议作为一种可能的疫苗候选物。通过酶联免疫吸附测定法研究了易患中耳炎儿童和正常儿童对P6的血清抗体反应。在20名易患中耳炎的儿童中，12名（60%）在患中耳炎后对P6有血清IgG抗体反应；然而，该组的平均急性期抗体水平为4.6微克/毫升，与恢复期水平5.4微克/毫升无显著差异。还对30名易患中耳炎儿童和13名健康儿童进行了10至25个月的纵向抗P6抗体水平测量。正常组抗体水平增加了7倍，而易患中耳炎组不到3倍，且18个月后正常儿童的抗体水平显著更高（p<0.05）。最后，患有两次或更多次由不可分型流感嗜血杆菌引起的中耳炎的易患中耳炎儿童对P6没有回忆性抗体反应。未能将P6识别为特异性免疫原可能是反复感染的原因。此外，数据表明易患中耳炎儿童可能对含P6的疫苗反应不佳。
