Weinbaum D L, Benner R R, Dowling J N, Alpern A, Pasculle A W, Donowitz G R
Infect Immun. 1984 Oct;46(1):68-73. doi: 10.1128/iai.46.1.68-73.1984.
We have recently shown that Legionella micdadei is ingested, but not killed, by human neutrophils. Herein we investigate the role of human monocytes in defense against this organism. Serum and monocytes from normal donors having no detectable antibody to L. micdadei were used. Egg-passaged L. micdadei organisms multiplied inside these monocytes with a peak growth of 2 log units within 12 h. No growth occurred when monocytes were omitted or when sonicated monocytes were used. Electron microscopy 18 h after infection revealed these organisms to be intracellular in normal-appearing phagosomes. When the input multiplicity of L. micdadei was greater than 1 CFU per monocyte, no intracellular growth occurred. When egg-passaged Legionella pneumophila organisms were used, intracellular organisms were found in phagosomes studded with ribosomes at the same time period. Peak intracellular growth of L. pneumophilia occurred by 48 h. L. micdadei activated the complement system and was opsonized by C3. However the use of complement-depleted (heat-inactivated) serum as the opsonic source had no effect on the bacterium's ingestion or growth in the monocyte. Thus, L. micdadei multiples in human monocytes. This entry and growth is independent of antibody or complement. The intracellular locations of L. micdadei and L. pneumophila differ, suggesting different mechanisms for the survival of these two organisms in the monocyte.
我们最近发现，人类嗜中性粒细胞可摄取米德戴军团菌，但不会将其杀死。在此，我们研究人类单核细胞在抵御这种病原体中的作用。我们使用了来自对米德戴军团菌无可检测抗体的正常供体的血清和单核细胞。经鸡胚传代的米德戴军团菌在这些单核细胞内繁殖，12小时内生长峰值为2个对数单位。若省略单核细胞或使用经超声处理的单核细胞，则不会出现生长现象。感染18小时后的电子显微镜检查显示，这些病原体存在于外观正常的吞噬小体内，呈细胞内寄生状态。当米德戴军团菌的输入复数大于每个单核细胞1个集落形成单位（CFU）时，未出现细胞内生长现象。当使用经鸡胚传代的嗜肺军团菌时，在同一时期可在布满核糖体的吞噬小体中发现细胞内病原体。嗜肺军团菌的细胞内生长峰值在48小时出现。米德戴军团菌激活补体系统并被C3调理。然而，使用补体缺失（热灭活）血清作为调理源对该细菌在单核细胞内的摄取或生长没有影响。因此，米德戴军团菌在人类单核细胞内繁殖。这种进入和生长与抗体或补体无关。米德戴军团菌和嗜肺军团菌在细胞内的定位不同，这表明这两种病原体在单核细胞内存活的机制不同。
