Chang Chia-Yi, Tsai Kuo-Jung, Deng Ming-Chung, Wang Fun-In, Liu Hsin-Meng, Tsai Shu-Hui, Tu Yang-Chang, Lin Nien-Nong, Huang Yu-Liang
School of Veterinary Medicine, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei 10617, Taiwan.
Animal Health Research Institute, Council of Agriculture, Executive Yuan, 376 Chung-Cheng Road, Tansui, New Taipei City 25158, Taiwan.
Animals (Basel). 2023 Jan 21;13(3):368. doi: 10.3390/ani13030368.
Classical swine fever (CSF) is a systemic hemorrhagic disease affecting domestic pigs and wild boars. The modified live vaccine (MLV) induces quick and solid protection against CSF virus (CSFV) infection. Maternally derived antibodies (MDAs) via colostrum could interfere with the MLV's efficacy, leading to incomplete protection against CSFV infection for pigs. This study investigated CSFV transmission among experimental piglets with various post-MLV immune statuses. Nineteen piglets, 18 with MDAs and 1 specific-pathogen-free piglet infected with CSFV that served as the CSFV donor, were cohabited with piglets that had or had not been administered the MLV. Five-sixths of the piglets with MDAs that had been administered one dose of MLV were fully protected from contact transmission from the CSFV donor and did not transmit CSFV to the piglets secondarily exposed through cohabitation. Cell-mediated immunity, represented by the anti-CSFV-specific interferon-γ-secreting cells, was key to viral clearance and recovery. After cohabitation with a CSFV donor, the unvaccinated piglets with low MDA levels exhibited CSFV infection and spread CSFV to other piglets through contact; those with high MDA levels recovered but acted as asymptomatic carriers. In conclusion, MLV still induces solid immunity in commercial herds under MDA interference and blocks CSFV transmission within these herds.
经典猪瘟（CSF）是一种影响家猪和野猪的全身性出血性疾病。改良活疫苗（MLV）能诱导对猪瘟病毒（CSFV）感染的快速且可靠的保护。通过初乳获得的母源抗体（MDA）可能会干扰MLV的效力，导致仔猪对CSFV感染的保护不完整。本研究调查了处于不同MLV免疫状态的实验仔猪之间的CSFV传播情况。19头仔猪，其中18头带有MDA，1头感染CSFV的无特定病原体仔猪作为CSFV供体，与已接种或未接种MLV的仔猪共同饲养。六分之五接种了一剂MLV且带有MDA的仔猪受到完全保护，免受CSFV供体的接触传播，并且没有将CSFV传播给通过共同饲养而二次接触的仔猪。以抗CSFV特异性分泌干扰素-γ的细胞为代表的细胞介导免疫是病毒清除和恢复的关键。与CSFV供体共同饲养后，MDA水平低的未接种疫苗的仔猪出现CSFV感染，并通过接触将CSFV传播给其他仔猪；MDA水平高的仔猪恢复但成为无症状携带者。总之，在MDA干扰下，MLV仍能在商业猪群中诱导可靠的免疫力，并阻止CSFV在这些猪群中传播。
