Fieldsteel A H, Cox D L, Moeckli R A
Infect Immun. 1981 May;32(2):908-15. doi: 10.1128/iai.32.2.908-915.1981.
In a series of seven experiments, the virulent Nichols strain of Treponema pallidum was shown to attach and replicate on the surface of tissue culture cells of cottontail rabbit epithelium (Sf1Ep) growing in conventional monolayer cultures under an atmosphere of 1.5% oxygen. Five days after inoculation of 10(6)T. pallidum, the number of treponemes had increased to between 8 x 10(6) and 2.59 x 10(7). The viability of harvested organisms ranged from 86 to 97%. The number of T. pallidum continued to increase, generally reaching a plateau between days 9 and 12 of incubation, with increases ranging up to 100-fold and averaging 49-fold. There appeared to be a ceiling of multiplication of about 2 x 10(8) irrespective of the inoculum, which ranged from 10(6) to 10(8)T. pallidum. Concurrent deoxyribonucleic acid assays were performed on the cultures containing T. pallidum to obtain further evidence of replication. Significant increases in treponemal deoxyribonucleic acid were observed when the inocula ranged from 10(6) to 10(7), with the greatest increases, as might be expected, being in the former group. There was also excellent correlation in the amount of deoxyribonucleic acid per treponeme; the averages for the 10(6), 2.5 x 10(6), and 10(7) groups were 3.46 x 10(-14), 3.28 x 10(-14), and 2.79 x 10(-14) g per treponeme, respectively (3.14 +/- 0.72 x 10(-14) g per treponeme). In each experiment, organisms were harvested from the group inoculated with 10(6)T. pallidum after 7 days of incubation to test for virulence. In all instances, the organisms were virulent; erythematous, indurated, treponeme-containing lesions were produced from an average of six to seven organisms. Scanning electron microscopy revealed that during the course of replication many microcolonies of treponemes formed on the surface of the cells.
在一系列七个实验中，梅毒螺旋体强毒株Nichols株被证明可在1.5%氧气环境下常规单层培养生长的棉尾兔上皮组织培养细胞（Sf1Ep）表面附着并复制。接种10⁶梅毒螺旋体五天后，螺旋体数量增加到8×10⁶至2.59×10⁷之间。收获的生物体活力在86%至97%之间。梅毒螺旋体数量持续增加，通常在培养的第9天至12天之间达到平稳期，增加幅度高达100倍，平均为49倍。无论接种量如何，似乎都存在约2×10⁸的增殖上限，接种量范围为10⁶至10⁸梅毒螺旋体。对含有梅毒螺旋体的培养物进行了同步脱氧核糖核酸检测，以获得复制的进一步证据。当接种量从10⁶至10⁷时，观察到螺旋体脱氧核糖核酸有显著增加，正如预期的那样，前一组增加幅度最大。每个螺旋体的脱氧核糖核酸量也有很好的相关性；10⁶、2.5×10⁶和10⁷组的平均值分别为每个螺旋体3.46×10⁻¹⁴、3.28×10⁻¹⁴和2.79×10⁻¹⁴克（每个螺旋体3.14±0.72×10⁻¹⁴克）。在每个实验中，培养7天后从接种10⁶梅毒螺旋体的组中收获生物体以检测毒力。在所有情况下，生物体都具有毒力；平均六到七个生物体可产生含螺旋体的红斑、硬结性病变。扫描电子显微镜显示，在复制过程中，细胞表面形成了许多螺旋体微菌落。
