Muhsen M, Lee P
Acta Virol. 2018;62(3):333-336. doi: 10.4149/av_2018_228.
Homologous interference in vitro is defined as the ability of primary viral infection to prevent secondary homologous superinfection. Non-cytopathic bovine viral diarrhea virus (ncp BVDV) has been classified according to the exaltation of Newcastle disease phenomenon (END) as END positive (E+) and END negative (E-) strains. Simultaneous inoculation of MDBK-SY cell monolayers with BVDV/E- virus and a three log higher amount of BVDV RK13/E+ virus, leads to acquisition of the BVDV/E- feature of blocking Newcastle disease virus (NDV) infection in cells. BVDV/E- strains, particularly at a high titre and MOI ≥1.25, can exert and impose their effects in BVDV/E+ infected cells; however, if BVDV/E- MOI is reduced to MOI below 0.625, the BVDV/E+ effect can be restored leading to cytopathic effects (CPE) induction by NDV reciprocal to the titre of the BVDV RK13/E+ strain. Moreover, blocking and prevention of induced CPE by NDV or vesicular stomatitis virus (VSV) occurs even when BVDV/E- superinfects primary BVDV/E+ infected cells, indicating a defective homologous interference between BVDV/E+ and BVDV/E- strains. Taken together, BVDV/E- strains have a strong competitive potency and mediate a fast acting (i.e. within 60 min) influence against BVDV/E+ activity. This may be relevant in vivo where BVDV/E- and BVDV/E+ combinations are frequently isolated from infected individuals.
体外同源干扰被定义为原发性病毒感染阻止继发性同源超感染的能力。非细胞病变性牛病毒性腹泻病毒（ncp BVDV）已根据新城疫现象增强（END）分为END阳性（E+）和END阴性（E-）毒株。用BVDV/E-病毒和数量高三个对数的BVDV RK13/E+病毒同时接种MDBK-SY细胞单层，会导致细胞获得阻止新城疫病毒（NDV）感染的BVDV/E-特性。BVDV/E-毒株，特别是在高滴度和MOI≥1.25时，可在BVDV/E+感染的细胞中发挥并施加其作用；然而，如果BVDV/E-的MOI降至低于0.625，BVDV/E+的作用可恢复，导致NDV诱导产生与BVDV RK13/E+毒株滴度呈反比的细胞病变效应（CPE）。此外，即使BVDV/E-对原发性BVDV/E+感染的细胞进行超感染，也会发生对NDV或水疱性口炎病毒（VSV）诱导的CPE的阻断和预防，这表明BVDV/E+和BVDV/E-毒株之间存在缺陷的同源干扰。综上所述，BVDV/E-毒株具有很强的竞争能力，并对BVDV/E+的活性介导快速作用（即60分钟内）的影响。这在体内可能具有相关性，因为在感染个体中经常分离到BVDV/E-和BVDV/E+的组合。
