Properties of the Dengue Virion
The initial filtration experiments by Ashburn and Craig (1907) and Cleland et al. (1919) were refined by Manoussakis (1928) who found that dengue virus, in the form of infectious human serum, could pass Chamberland L II filters, indicating a relatively small size of the viral particles. Later estimates of the particle diameter determined by the gradocol membrane technique and infectivity of the filtrate for human volunteers were reported as 13–23 nm by Toda and Nakagawa (1943, 1944) and 17–25 nm or less by Sabin (1952a). More recent electron microscopic evidence indicates that these values are too low, at least for the enveloped, complete virions. One may suggest three alternative explanations of this apparent discrepancy: (a) defects of the filters or the filtration procedures or their interpretation, (b) distortion of the enveloped virions during filtration, (c) infectiousness of naked viral cores for experimental human subjects. Passage of infectious mouse-adapted dengue-2 virions through Millipore filters of 50 nm average pore diameter has been reported by Casals (1968b).
KeywordsSucrose Gradient Dengue Hemorrhagic Fever Protamine Sulfate Immune Seron Sindbis Virus
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