MOLECULAR DETERMINANTS OF MACROPHAGE TROPISM AND VIRAL PERSISTENCE - IMPORTANCE OF SINGLE AMINO-ACID CHANGES IN THE POLYMERASE AND GLYCOPROTEIN OF LYMPHOCYTIC CHORIOMENINGITIS VIRUS
MOLECULAR DETERMINANTS OF MACROPHAGE TROPISM AND VIRAL PERSISTENCE - IMPORTANCE OF SINGLE AMINO-ACID CHANGES IN THE POLYMERASE AND GLYCOPROTEIN OF LYMPHOCYTIC CHORIOMENINGITIS VIRUS
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DOI：
10.1128/jvi.67.12.7340-7349.1993
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发表时间：
1993-12-01
影响因子：
5.4
通讯作者：
AHMED, R
中科院分区：
文献类型：
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作者：
MATLOUBIAN, M;KOLHEKAR, SR;AHMED, R
本研究证明，免疫抑制淋巴细胞脉络丛脑膜炎病毒（LCMV）变体克隆13在体内和体外均表现出对巨噬细胞增强感染的特异性偏好，并且病毒聚合酶和糖蛋白中单个氨基酸的改变是巨噬细胞趋向性的原因。变异克隆13和亲本Armstrong株之间的生长差异是对巨噬细胞特异性的，因为克隆13和Armstrong株在成纤维细胞中生长得同样好，都不能有效地分离感染淋巴细胞。克隆13基因组的完整测序和遗传分析表明，聚合酶（K- >Q在1079位）的单个氨基酸变化是巨噬细胞病毒产量的主要决定因素。通过比较亲本病毒和重组病毒的序列，这一点得到了明确的证明，除了聚合酶基因的单一突变外，它们在所有位点上都是相同的。这一发现进一步得到证实，表明该位点的赖氨酸（Q—>K）的逆转导致巨噬细胞趋向性丧失。此外，一种独立衍生的LCMV嗜巨噬细胞变体，克隆28b，在同一位置发生K- >N突变。因此，这些结果表明，在聚合酶的残基1079上用中性氨基酸（Q或N）取代带正电的氨基酸K可增强巨噬细胞中的病毒复制。除了聚合酶的改变外，糖蛋白的突变也与巨噬细胞的嗜性有关。糖蛋白（F- >L在260位）的单氨基酸变化不影响每个巨噬细胞的病毒产量，但对确定感染的巨噬细胞数量至关重要。我们之前的研究表明，聚合酶和糖蛋白中同样的两种突变对于在成年小鼠中建立慢性感染是必不可少的。由于相同的突变赋予巨噬细胞向性和在体内持续存在的能力，这些研究提供了令人信服的证据，证明巨噬细胞感染是病毒持续存在和免疫抑制的关键决定因素。
This study documents that the immunosuppressive lymphocytic choriomeningitis virus (LCMV) variant, clone 13, shows a specific predilection for enhanced infection of macrophages both in vitro and in vivo and that single amino acid changes in the viral polymerase and glycoprotein are responsible for macrophage tropism. The growth difference seen between variant clone 13 and the parental Armstrong strain was specific for macrophages, since both clone 13 and Armstrong grew equally well in fibroblasts and neither isolate infected lymphocytes efficiently. Complete sequencing of the clone 13 genome, along with genetic analysis, showed that a single amino acid change in the polymerase (K-->Q at position 1079) was the major determinant of virus yield in macrophages. This was proven unequivocally by comparing the sequences of parental and reassortant viruses, which were identical at all loci except for the single mutation in the polymerase gene. This finding was further strengthened by showing that reversion at this site back to lysine (Q-->K) resulted in loss of macrophage tropism. In addition, an independently derived macrophage-tropic variant of LCMV, clone 28b, had a K-->N mutation at the same position. Thus, these results show that substitution of the positively charged amino acid K with a neutral amino acid (either Q or N) at residue 1079 of the polymerase resulted in enhanced viral replication in macrophages. In addition to the polymerase change, a mutation in the glycoprotein was also associated with macrophage tropism. This single amino acid change in the glycoprotein (F-->L at position 260) did not affect virus yield per macrophage but was critical in determining the number of macrophages infected. Our previous studies have shown that the same two mutations in the polymerase and glycoprotein are essential for establishing a chronic infection in adult mice. Since the same mutations confer macrophage tropism and ability to persist in vivo, these studies provide compelling evidence that infection of macrophages is a critical determinant of viral persistence and immune suppression.