PDF(Pubmed)
Abstract：
Porcine epidemic diarrhea virus (PEDV) causes a highly contagious enteric disease with major economic losses to swine production worldwide. Due to the immaturity of the neonatal piglet immune system and given the high virulence of PEDV, improving passive lactogenic immunity is the best approach to protect suckling piglets against the lethal infection. We tested whether oral vitamin A (VA) supplementation and PEDV exposure of gestating and lactating VA-deficient (VAD) sows would enhance their primary immune responses and boost passive lactogenic protection against the PEDV challenge of their piglets. We demonstrated that PEDV inoculation of pregnant VAD sows in the third trimester provided higher levels of lactogenic protection of piglets as demonstrated by >87% survival rates of their litters compared with <10% in mock litters and that VA supplementation to VAD sows further improved the piglets\' survival rates to >98%. We observed significantly elevated PEDV IgA and IgG antibody (Ab) titers and Ab-secreting cells (ASCs) in VA-sufficient (VAS)+PEDV and VAD+VA+PEDV sows, with the latter maintaining higher Ab titers in blood prior to parturition and in blood and milk throughout lactation. The litters of VAD+VA+PEDV sows also had the highest serum PEDV-neutralizing Ab titers at piglet post-challenge days (PCD) 0 and 7, coinciding with higher PEDV IgA ASCs and Ab titers in the blood and milk of their sows, suggesting an immunomodulatory role of VA in sows. Thus, sows that delivered sufficient lactogenic immunity to their piglets provided the highest passive protection against the PEDV challenge. Maternal immunization during pregnancy (± VA) and VA sufficiency enhanced the sow primary immune responses, expression of gut-mammary gland trafficking molecules, and passive protection of their offspring. Our findings are relevant to understanding the role of VA in the Ab responses to oral attenuated vaccines that are critical for successful maternal vaccination programs against enteric infections in infants and young animals.
摘要：
猪流行性腹泻病毒(PEDV)是一种高度传染性的肠道疾病,给世界范围内的猪生产带来重大经济损失。由于新生仔猪免疫系统的不成熟以及PEDV的高毒力,提高被动产乳免疫力是保护哺乳仔猪免受致死性感染的最佳途径。我们测试了口服维生素A（VA）补充剂和妊娠和泌乳VA缺陷（VAD）母猪的PEDV暴露是否会增强其初级免疫反应并增强其仔猪对PEDV挑战的被动泌乳保护。我们证明了妊娠晚期VAD母猪的PEDV接种对仔猪的泌乳保护水平更高，表现为仔猪的存活率>87％，而模拟窝的存活率<10％，并且补充VAD母猪的VA进一步将仔猪的存活率提高到>98％。我们在VA充足（VAS）PEDV和VADVAPEDV母猪中观察到PEDVIgA和IgG抗体（Ab）滴度和Ab分泌细胞（ASCs）显着升高，后者在分娩前和整个泌乳期间在血液和乳汁中保持较高的Ab滴度。VADVAPEDV母猪的窝在攻击后第0天和第7天（PCD）的仔猪血清PEDV中和Ab滴度也最高，这与母猪血液和乳汁中更高的PEDVIgAASCs和Ab滴度相吻合。提示VA在母猪中的免疫调节作用。因此，向仔猪提供足够的乳原性免疫的母猪提供了针对PEDV攻击的最高被动保护。怀孕期间的母体免疫（±VA）和VA充足性增强了母猪的初级免疫反应，肠-乳腺运输分子的表达，被动保护他们的后代。我们的发现与了解VA在口服减毒疫苗的Ab反应中的作用有关，这对于成功实施针对婴儿和幼年动物肠道感染的母体疫苗接种计划至关重要。
