Mendy Awa L, Agbla Schadrac C, Odutola Aderonke A, Antonio Martin, Greenwood Brian M, Sutherland Jayne S, Ota Martin O C
Vaccines & Immunity Theme, Medical Research Council Unit, Fajara, The Gambia.
Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom.
PLoS One. 2017 Oct 5;12(10):e0185824. doi: 10.1371/journal.pone.0185824. eCollection 2017.
The currently used Streptococcus pneumoniae vaccines have had a significant impact on the pneumococcal diseases caused by the serotypes they cover. Their limitations have stimulated a search for alternate vaccines that will cover all serotypes, be affordable and effective in young children. Pneumococcal protein antigens are potential vaccine candidates that may meet some of the shortfalls of the current vaccines. Thus, this study aimed to determine the relationship between antibodies against pneumococcal protein antigens and nasopharyngeal carriage in infants.
One hundred and twenty mother-infant pairs were enrolled into the study. They had nasopharyngeal swabs(NPS) taken at birth and every two weeks for the first eight weeks after delivery, and blood samples were obtained at birth and every four weeks for the first eight weeks after delivery. Nasopharyngeal carriage of S. pneumoniae was determined from the NPS and antibodies against the pneumococcal proteins CbpA, PspA and rPly were measured in the blood samples.
The S. pneumoniae carriage rate in infants increased to that of mothers by eight weeks of age. The odds of carriage in infants was 6.2 times (95% CI: 2.0-18.9) higher when their mothers were also carriers. Bacterial density in infants was lower at birth compared to their mothers (p = 0.004), but increased with age and became higher than that of their mothers at weeks 4 (p = 0.009), 6 (p = 0.002) and 8 (p<0.0001). At birth, the infants' antibodies against CbpA, and rPly pneumococcal protein antigens were similar, but that of PspA was lower (p<0.0001), compared to their mothers. Higher antibody concentrations to CbpA [OR (95% CI): 0.49 (0.26-0.92, p = 0.03)], but not PspA and rPly, were associated with protection against carriage in the infants.
Naturally induced antibodies against the three pneumococcal protein antigens were transferred from mother to child. The proportion of infants with nasopharyngeal carriage and the bacterial density of S. pneumoniae increased with age within the first eight weeks of life. Higher concentrations of antibodies against CbpA, but not PspA and rPly, were associated with reduced risk of nasopharyngeal carriage of S. pneumoniae in infants.
目前使用的肺炎链球菌疫苗对其所覆盖血清型引起的肺炎球菌疾病产生了重大影响。其局限性促使人们寻找能覆盖所有血清型、价格可承受且对幼儿有效的替代疫苗。肺炎球菌蛋白抗原是可能弥补当前疫苗某些不足的潜在疫苗候选物。因此，本研究旨在确定婴儿体内肺炎球菌蛋白抗原抗体与鼻咽部携带情况之间的关系。
120对母婴纳入本研究。在出生时以及出生后前八周每两周采集一次鼻咽拭子（NPS），并在出生时以及出生后前八周每四周采集一次血样。从NPS中确定肺炎链球菌的鼻咽部携带情况，并在血样中检测针对肺炎球菌蛋白CbpA、PspA和rPly的抗体。
婴儿的肺炎链球菌携带率在8周龄时升至母亲的携带率水平。当母亲也是携带者时，婴儿携带肺炎链球菌的几率高出6.2倍（95%可信区间：2.0 - 18.9）。与母亲相比，婴儿出生时的细菌密度较低（p = 0.004），但随年龄增长而增加，并在第4周（p = 0.009）、第6周（p = 0.002）和第8周（p<0.0001）时高于母亲。出生时，婴儿针对CbpA和rPly肺炎球菌蛋白抗原的抗体与母亲相似，但针对PspA的抗体低于母亲（p<0.0001）。较高的CbpA抗体浓度[比值比（95%可信区间）：0.49（0.26 - 0.92，p = 0.03）]与婴儿预防携带肺炎链球菌有关，但PspA和rPly抗体浓度与预防携带无关。
针对三种肺炎球菌蛋白抗原的自然诱导抗体从母亲传递给孩子。在生命的前八周内，鼻咽部携带肺炎链球菌的婴儿比例和肺炎链球菌的细菌密度随年龄增加。较高浓度的抗CbpA抗体与婴儿鼻咽部携带肺炎链球菌风险降低有关，但抗PspA和抗rPly抗体与降低风险无关。
