Department of Cell Biology, University of São Paulo School of Medicine, Ribeirão Preto, Brazil.
Intervirology. 2017;60(1-2):56-60. doi: 10.1159/000480014. Epub 2017 Sep 5.
Syncytia formation is the hallmark of the cytopathic effect caused by human respiratory syncytial virus (HRSV), which is the most important viral respiratory pathogen in children. This article reports methodological improvements in primary HRSV isolation and the importance of syncytia formation and mRNA levels of F protein for the progeny yield, using clinical isolates of HRSV.
The A and B strains of HRSV were isolated in HEp-2 cell cultures from fresh and frozen nasopharyngeal aspirates. The formation of syncytia was evaluated using 2 different assays. Levels of F protein mRNA were quantified by real-time PCR while HRSV progeny titration was done by plaque assay.
HRSV was primarily isolated from 238 of 312 (90.7%) samples, and 13 of these (12 HRSV-A and 1 HRSV-B) were continuously passaged in vitro. The quantity and size of syncytia formed by 6 pure HRSV-A clinical isolates were different, as were the levels of F protein mRNA.
There is a direct correlation of quantities of syncytia and inoculum size, but not with mRNA levels of HRSV-A F protein. Importantly, levels of F protein mRNA were directly related to progeny production.
合胞体形成是人类呼吸道合胞病毒（HRSV）引起的细胞病变效应的标志，它是儿童最重要的病毒性呼吸道病原体。本文报道了在使用临床分离株的情况下，用于原发性 HRSV 分离的方法学改进，以及合胞体形成和 F 蛋白 mRNA 水平对后代产量的重要性。
使用新鲜和冷冻的鼻咽抽吸物，在 HEp-2 细胞培养物中分离 A 和 B 株 HRSV。使用 2 种不同的测定法评估合胞体的形成。通过实时 PCR 定量 F 蛋白 mRNA 的水平，而通过噬斑测定进行 HRSV 后代滴定。
HRSV 主要从 312 个样本中的 238 个（90.7％）中分离出来，其中 13 个（12 株 HRSV-A 和 1 株 HRSV-B）在体外连续传代。6 株纯 HRSV-A 临床分离株形成的合胞体的数量和大小不同，F 蛋白 mRNA 水平也不同。
合胞体的数量与接种物的大小直接相关，但与 HRSV-A F 蛋白的 mRNA 水平无关。重要的是，F 蛋白 mRNA 水平与后代产量直接相关。
