Lipton H L, Twaddle G, Jelachich M L
Division of Neurology, Evanston Hospital, Illinois.
J Virol. 1995 Apr;69(4):2525-33. doi: 10.1128/JVI.69.4.2525-2533.1995.
Theiler's murine encephalomyelitis virus (TMEV) produces a persistent central nervous system infection and chronic, inflammatory demyelinating disease in susceptible mice. TMEV antigen(s) and RNA genome have been detected in astrocytes, oligodendrocytes, and macrophages during persistence. Whether there is a predominant cell type in which TMEV persists has not been resolved. Since TMEV-induced demyelinating lesions are infiltrated with macrophages and a number of other persistent viruses show near-exclusive tropism for these phagocytic cells, we used two-color immunofluorescent staining with conventional and confocal microscopy to colocalize TMEV to cells that stain with monoclonal antibodies (MOMA-2) [unknown antigen], Mac-1 [CD11b], FA-11 [CD66], and 2F8 [scavenger receptor]) to macrophages in BeAn-infected SJL mice. A predominant virus antigen burden within macrophages infiltrating demyelinating lesions was seen. A dichotomy of cells staining for virus antigen(s) was found with infected cells containing either a large or small virus antigen load. Ninety percent of cells with a large virus antigen load were large phagocytes (20 to 50 microns) that were readily detected at low power (5x objective). Cells with smaller amounts of virus antigen(s) turned out to be either these same large phagocytic cells or much smaller cells, approximately equal to 10 microns in diameter. Forty percent of cells with a small virus antigen load were macrophages. The unidentified approximately equal to 10-microns cells that are virus antigen positive and macrophage negative in this study could still be macrophages, or they may be oligodendrocytes. The fact that virus was detected in the cytoplasm and not phagolysosomes of macrophages and the sheer mass of fluorescently stained virus proteins in some macrophages suggest that TMEV persists in these phagocytic cells by active virus replication.
泰勒氏鼠脑脊髓炎病毒（TMEV）可在易感小鼠中引发持续性中枢神经系统感染以及慢性炎性脱髓鞘疾病。在病毒持续感染期间，已在星形胶质细胞、少突胶质细胞和巨噬细胞中检测到TMEV抗原和RNA基因组。TMEV持续存在的主要细胞类型尚未明确。由于TMEV诱导的脱髓鞘病变中有巨噬细胞浸润，并且许多其他持续性病毒对这些吞噬细胞表现出近乎排他性的嗜性，我们使用双色免疫荧光染色结合传统显微镜和共聚焦显微镜，将TMEV与用单克隆抗体（MOMA - 2 [未知抗原]、Mac - 1 [CD11b]、FA - 11 [CD66]和2F8 [清道夫受体]）染色的细胞共定位，以研究BeAn感染的SJL小鼠中巨噬细胞内的TMEV。在浸润脱髓鞘病变的巨噬细胞中可见主要的病毒抗原负荷。发现病毒抗原染色细胞存在二分法，即感染细胞的病毒抗原负荷要么大要么小。病毒抗原负荷大的细胞中有90%是大吞噬细胞（20至50微米），在低倍镜（5倍物镜）下很容易检测到。病毒抗原量较少的细胞结果要么是这些相同的大吞噬细胞，要么是直径约为10微米的小得多的细胞。病毒抗原负荷小的细胞中有40%是巨噬细胞。本研究中病毒抗原呈阳性而巨噬细胞呈阴性的未鉴定的约10微米细胞仍可能是巨噬细胞，也可能是少突胶质细胞。在巨噬细胞的细胞质而非吞噬溶酶体中检测到病毒，以及一些巨噬细胞中大量荧光染色的病毒蛋白，这一事实表明TMEV通过活跃的病毒复制在这些吞噬细胞中持续存在。
