Christopher-Hennings J, Nelson E A, Nelson J K, Rossow K D, Shivers J L, Yaeger M J, Chase C C, Garduno R A, Collins J E, Benfield D A
Animal Disease Research and Diagnostic Laboratory, South Dakota State University, Brookings 57007-1396, USA.
Vet Pathol. 1998 Jul;35(4):260-7. doi: 10.1177/030098589803500404.
Previous studies have indicated that porcine reproductive and respiratory syndrome virus (PRRSV) can be identified in and transmitted through boar semen. However, the site(s) of replication indicating the origin of PRRSV in semen has not been identified. To determine how PRRSV enters boar semen, five vasectomized and two nonvasectomized PRRSV-seronegative boars were intranasally inoculated with PRRSV isolate VR-2332. Semen was collected three times weekly from each boar and separated into cellular and cell-free (seminal plasma) fractions. Both fractions were evaluated by reverse transcriptase nested polymerase chain reaction (RT-nPCR) for the presence of PRRSV RNA. Viremia and serostatus were evaluated once weekly, and boars were euthanatized 21 days postinoculation (DPI). Tissues were collected and evaluated by RT-nPCR, virus isolation (VI), and immunohistochemistry to identify PRRSV RNA, infectious virus, or viral antigen, respectively. PRRSV RNA was identified in semen from all vasectomized and nonvasectomized boars and was most consistently found in the cell fraction, within cells identified with a macrophage marker. Viral replication as determined by VI was predominately found within lymphoid tissue. However, PRRSV RNA was widely disseminated throughout many tissues, including the reproductive tract at 21 DPI. These results indicate that PRRSV can enter semen independent of testicular or epididymal tissues, and the source of PRRSV in semen is virus-infected monocytes/macrophages or non-cell-associated virus in serum. PRRSV-infected macrophages in semen may result from infection of local tissue macrophages or may originate from PRRSV-infected circulating monocytes or macrophages.
先前的研究表明，猪繁殖与呼吸综合征病毒（PRRSV）可在公猪精液中被检测到并通过其传播。然而，精液中表明PRRSV来源的复制位点尚未明确。为了确定PRRSV如何进入公猪精液，对5头输精管结扎的和2头未进行输精管结扎的PRRSV血清阴性公猪经鼻接种PRRSV毒株VR-2332。每周从每头公猪采集3次精液，并分离为细胞成分和无细胞成分（精浆）。通过逆转录巢式聚合酶链反应（RT-nPCR）评估这两种成分中PRRSV RNA的存在情况。每周评估一次病毒血症和血清状态，接种后21天（DPI）对公猪实施安乐死。采集组织并通过RT-nPCR、病毒分离（VI）和免疫组织化学分别鉴定PRRSV RNA、传染性病毒或病毒抗原。在所有输精管结扎和未结扎的公猪精液中均检测到PRRSV RNA，且最常出现在细胞成分中，存在于用巨噬细胞标志物鉴定的细胞内。通过VI确定的病毒复制主要发生在淋巴组织中。然而，在21 DPI时，PRRSV RNA广泛分布于许多组织中，包括生殖道。这些结果表明，PRRSV可独立于睾丸或附睾组织进入精液，精液中PRRSV的来源是病毒感染的单核细胞/巨噬细胞或血清中的非细胞相关病毒。精液中PRRSV感染的巨噬细胞可能源于局部组织巨噬细胞的感染，也可能源于PRRSV感染的循环单核细胞或巨噬细胞。
