The distribution of feline immunodeficiency virus in tissue compartments of feral domestic cats
The distribution of feline immunodeficiency virus in tissue compartments of feral domestic cats
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DOI：
10.1007/s00705-010-0598-z
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发表时间：
2010-03-01
影响因子：
2.7
通讯作者：
Rodrigo, Allen G.
中科院分区：
文献类型：
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作者：
Hayward, Jessica J.;Rodrigo, Allen G.
家猫（Felis catus）中猫免疫缺陷病毒（FIV）的患病率和亚型研究已进行彻底。然而，FIV 的宿主内动力学研究较少。在这里，我们确定了从自然感染野猫的多个组织中分离出的 FIV env V3-V6 序列的多样性。使用巢式 PCR，从腘淋巴结中具有可扩增的前病毒 FIV DNA 的 16 只猫中的 8 只的非淋巴组织中扩增出 FIV。总的来说，我们发现宿主内 FIV 多样性较低，但有证据表明一只猫存在组织分隔。猫免疫缺陷病毒是一种慢病毒，与人类免疫缺陷病毒（HIV）密切相关，可引起猫科动物免疫缺陷[17]。 FIV 已在多种组织类型中检测到，包括淋巴组织、中枢神经系统 (CNS)、骨髓、肠道、肝脏和肺 [2,4,15,22]。区室化是病毒在不同组织或细胞类型之间运动的限制[14]。对 HIV-1 的研究表明，与同一个体的外周血相比，其在泌尿生殖道、中枢神经系统和肺部存在区室化 [1, 10–12]。最近的两项研究表明，实验性感染后不久，FIV 就会在中枢神经系统中发生区室化 [9, 13]。迄今为止，还没有证据表明 FIV 的活动受到广泛限制，也没有涉及自然 FIV 感染的证据。本文对自然感染野猫不同组织中 FIV 的多样性进行了研究，旨在寻找区室化的证据。从 2004 年至 2005 年被困在新西兰 (NZ) 两个地点的 16 只猫身上解剖了七种组织（淋巴结、舌头、肝脏、肺、肾脏、睾丸、脑干）。如前所述提取基因组 DNA 并扩增 env V3-V6 区域 [7]。 PCR 产物直接测序以确认每个组织中 FIV 的存在。尽管本研究中采样的所有 16 只猫通过淋巴结 PCR 检测均为 FIV 阳性，但我们只能从 8 只猫的至少一种其他组织中扩增 FIV（表 1）。非淋巴组织产生 FIV 的八只猫组的平均淋巴结前病毒载量显着高于非淋巴组织中缺乏 FIV 的猫（Student’st= 2.72，p\0.05，df= 14）。之前的一项 HIV-1 研究发现，非淋巴组织中的高前病毒载量与晚期感染之间存在明显的相关性 [5]。这些结果可以解释为什么本研究中的许多组织样本都无法扩增FIV，也就是说，未发现非淋巴FIV的猫可能处于FIV感染的早期阶段。这已在 HIV-1 中得到记录，在临床潜伏期，该病毒在淋巴组织中大量存在，并且随着疾病的进展，溢出到血液中并侵入其他组织 [16, 30]。 FIV 也可能存在于组织中，但水平低于本研究的检测限，或存在于组织样本的其他部分 [5]。使用端点稀释测序来获得每个组织 10 个序列的目标 [7, 21]。所有 FIV 序列
Prevalence and subtype studies of feline immunodeficiency virus (FIV) in the domestic cat (Felis catus) have been conducted thoroughly. However, the intrahost dynamics of FIV have been less well studied. Here, we determine the diversity of FIV env V3–V6 sequences isolated from multiple tissues of naturally infected feral cats. Using nested PCR, FIV was amplified from non-lymphoid tissues from eight of sixteen cats that had amplifiable proviral FIV DNA in the popliteal lymph node. In general, we found low intrahost FIV diversity, but there was evidence of tissue compartmentalization in one cat. Feline immunodeficiency virus is a lentivirus, closely related to human immunodeficiency virus (HIV), which can cause immunodeficiency in F. catus [17]. FIV has been detected in a number of tissue types, including lymphoid tissue, central nervous system (CNS), bone marrow, intestine, liver and lung [2, 4, 15, 22]. Compartmentalization is the restriction of virus movement between different tissues or cell types [14]. Studies on HIV-1 have shown compartmentalization in the genitourinary tract, CNS and lung when compared to peripheral blood in the same individuals [1, 10–12]. Two recent studies have shown FIV compartmentalization in the CNS soon after experimental infection [9, 13]. To date, there has been no demonstration of an extensive restriction of movement of FIV and no evidence involving natural FIV infections.Here, the diversity of FIV in different tissues of naturally infected feral cats is investigated, with the aim to look for evidence of compartmentalization. Combinations of seven tissues (lymph node, tongue, liver, lung, kidney, testis, brain stem) were dissected from sixteen cats trapped at two New Zealand (NZ) locations in 2004–2005. Genomic DNA was extracted and the env V3–V6 region was amplified as described previously [7]. PCR products were directly sequenced to confirm the presence of FIV in each tissue. Although all sixteen cats sampled in this study were FIV-positive by PCR from lymph node, we were able to amplify FIV from at least one other tissue from eight cats only (Table 1). The group of eight cats from which nonlymphoid tissues yielded FIV had a significantly higher mean lymph node proviral load than those cats that lacked FIV in non-lymphoid tissue (Student’st= 2.72, p\0.05, df= 14). A previous HIV-1 study found a clear correlation between high proviral load in non-lymphoid tissues and advanced stage of infection [5]. These results could explain the inability to amplify FIV from many of the tissues sampled in the present study, that is, the cats from which non-lymphoid FIV was not found might be in the early stages of FIV infection. This has been documented for HIV-1, where the virus is found in high numbers in lymphoid tissue during clinical latency and, as disease progresses, spills over into the blood and invades other tissues [16, 30]. It is also possible that FIV is present in the tissues, but at a level below the detection limits of this study, or in other parts of sampled tissue [5]. Endpoint dilution sequencing was used to obtain a target of ten sequences per tissue [7, 21]. All FIV sequences