Brown E W, Yuhki N, Packer C, O'Brien S J
Biological Carcinogenesis and Development Program, Program Resources, Inc./DynCorp, Frederick, Maryland 21702-1201.
J Virol. 1994 Sep;68(9):5953-68. doi: 10.1128/JVI.68.9.5953-5968.1994.
Feline immunodeficiency virus (FIV) is a novel lentivirus that is genetically homologous and functionally analogous to the human AIDS viruses, human immunodeficiency virus types 1 and 2. FIV causes immunosuppression in domestic cats by destroying the CD4 T-lymphocyte subsets in infected hosts. A serological survey of over 400 free-ranging African and Asian lions (Panthera leo) for antibodies to FIV revealed endemic lentivirus prevalence with an incidence of seropositivity as high as 90%. A lion lentivirus (FIV-Ple) was isolated by infection of lion lymphocytes in vitro. Seroconversion was documented in two Serengeti lions, and discordance of mother-cub serological status argues against maternal transmission (in favor of horizontal spread) as a major route of infection among lions. A phylogenetic analysis of cloned FIV-Ple pol gene sequences from 27 lions from four African populations (from the Serengeti reserve, Ngorongoro Crater, Lake Manyara, and Kruger Park) revealed remarkably high intra- and interindividual genetic diversity at the sequence level. Three FIV-Ple phylogenetic clusters or clades were resolved with phenetic, parsimony, and likelihood analytical procedures. The three clades, which occurred not only together in the same population but throughout Africa, were as divergent from each other as were homologous pol sequences of lentivirus isolated from distinct feline species, i.e., puma and domestic cat. The FIV-Ple clades, however, were more closely related to each other than to other feline lentiviruses (monophyletic for lion species), suggesting that the ancestors of FIV-Ple evolved in allopatric (geographically isolated) lion populations that converged recently. To date, there is no clear evidence of FIV-Ple-associated pathology, raising the possibility of a historic genetic accommodation of the lion lentivirus and its host leading to a coevolved host-parasite symbiosis (or commensalism) in the population similar to that hypothesized for endemic simian immunodeficiency virus without pathology in free-ranging African monkey species.
猫免疫缺陷病毒（FIV）是一种新型慢病毒，在基因上与人类艾滋病病毒1型和2型（HIV - 1和HIV - 2）同源，功能上类似。FIV通过破坏受感染宿主中的CD4 T淋巴细胞亚群，导致家猫免疫抑制。一项针对400多头非洲和亚洲野生狮子（ Panthera leo ）进行的FIV抗体血清学调查显示，地方性慢病毒流行，血清阳性率高达90%。通过体外感染狮子淋巴细胞分离出一种狮子慢病毒（FIV - Ple）。在两只塞伦盖蒂狮子身上记录到了血清转化，母狮与幼狮血清学状态的不一致表明，母源传播（支持水平传播）并非狮子间主要的感染途径。对来自非洲四个种群（塞伦盖蒂保护区、恩戈罗恩戈罗火山口、马尼亚拉湖和克鲁格公园）的27头狮子的克隆FIV - Ple pol基因序列进行系统发育分析，结果显示在序列水平上个体内和个体间存在显著的高遗传多样性。通过表型、简约和似然分析程序解析出三个FIV - Ple系统发育簇或进化枝。这三个进化枝不仅在同一群体中共同出现，而且在整个非洲都有分布，它们彼此之间的差异程度与从不同猫科动物物种（美洲狮和家猫）分离出的慢病毒的同源pol序列之间的差异程度相同。然而，FIV - Ple进化枝彼此之间的关系比与其他猫科慢病毒的关系更为密切（狮子物种单系），这表明FIV - Ple的祖先在最近才汇聚的异域（地理隔离）狮子种群中进化。迄今为止，尚无明确证据表明FIV - Ple会引发病理学变化，这增加了一种可能性，即狮子慢病毒与其宿主在历史上发生了基因适应，从而在种群中形成了一种共同进化的宿主 - 寄生虫共生关系（或共生现象），类似于在非洲野生猴类中无病理学表现的地方性猿猴免疫缺陷病毒的假设情况。
