Studies on Newcastle Disease Virus

Bang, Frederik B.

doi:10.1084/jem.88.2.251

Cited by 34 publications

(10 citation statements)

References 9 publications

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“…Our Bang, 1946Bang, , 1947Bang, , 1948), but our latest observations support our earlier views of the morphology of the virus . We found none of the gross pleomorphism evident in micrographs of centrifuged concentrates of the virus.…”

Section: Discussionsupporting

confidence: 89%

“…This was particularly the case with Newcastle-disease virus, where purified preparations showed particles of similar size but of widely differing structure. The variability of Newcastle-disease virus preparations has been noted by other workers (Cunha, Weil, Beard, Taylor, Sharp & Beard, 1947;Bang, 1946Bang, , 1047Bang, , 1948. There is another objection to the isolation of viruses by centrifugation; it yields a limited range of particle sizes for study.…”

Section: Injluertxa and Related Viruses 299mentioning

confidence: 90%

“…Does it represent a variable virus structure, or is it largely induced by excessive manipulqtion of the virus during purification? Investigation of the effects of various electrolyte concentrations on the dispersion of Newcastledisease virus by Bang (1947Bang ( , 1948 and our own observations on purified…”

Section: The Adsorption Of Injuenza Virusesmentioning

confidence: 92%

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The Investigation of Influenza and Related Viruses in the Electron Microscope, by a New Technique

Dawson

Elford

1949

Journal of General Microbiology

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SUMMARY:Influenza and related viruses were studied by a new method in which virus is adsorbed on the membranes of laked fowl red cells for examination in the electron microscope. The numbers of virus particles adsorbed per unit area of red-cell membrane were estimated from direct counts in micrographs of palladium-shadowed and unshadowed specimens. There was a definite saturation level of adsorption for each strain of virus, the value varying also according to the particular batch of cells and their age after storage at 0". For subsaturation conditions the number of particles adsorbed was proportional to the concentration of virus and the concentration of cells, and a function both of time of contact and temperature. The relationships were complicated by the fact that elution began before adsorption was complete.The comparative data for the size and variation of these viruses were obtained from micrographs of preparations directly adsorbed from infective allantoic fluid and thus not subjected to harsh methods of purification. The mean sizes (mp) found for the dried virus were : influenza A virus, 90 11.5 ; influenza 13 virus, 103 k 8 ; fowl-plague virus, 101 f 16 ; Pu'ewcastle-disease virus, 193 f 28 ; and mumps virus, 179 f 28.The occurrence of long forms associated with influenza B virus was confirmed and filamentous structures were demonstrated for the first time in preparations of a strain of fowl-plague virus.

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Section: Discussionsupporting

confidence: 89%

Section: Injluertxa and Related Viruses 299mentioning

confidence: 90%

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The Investigation of Influenza and Related Viruses in the Electron Microscope, by a New Technique

Dawson

Elford

1949

Journal of General Microbiology

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“…Specific infectivity (also referred to as plating efficiency) was among the earliest established parameters of virus characterization and has been generally expressed as some unit of physical quantitation of virus (e.g., grams of protein or nucleic acid, number of capsids, or number of genomes) per unit of virus infectivity (e.g., PFU, 50% lethal/infectious dose [LD 50 (44)(45)(46). High particle-to-PFU ratios are common and reflect the fact that some viral particles in a given preparation are defective and incapable of initiating or Cell-free ME or ME-T was plated on fibroblast or epithelial cell cultures in the presence of anti-UL130 and anti-UL131 antibodies, and the number of resultant plaques was determined.…”

Section: Discussionmentioning

confidence: 99%

Human Cytomegalovirus gH/gL/gO Promotes the Fusion Step of Entry into All Cell Types, whereas gH/gL/UL128-131 Broadens Virus Tropism through a Distinct Mechanism

Zhou

Lanchy

Ryckman

2015

J Virol

157

214

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Interaction between gH/gL and the fusion protein gB is likely a conserved feature of the entry mechanism for all herpesviruses. Human cytomegalovirus (HCMV) gH/gL can be bound by gO or by the set of proteins UL128, UL130, and UL131, forming gH/ gL/gO and gH/gL/UL128-131. The mechanisms by which these complexes facilitate entry are poorly understood. Mutants lacking UL128-131 replicate well on fibroblasts but fail to enter epithelial/endothelial cells, and this has led to the general assumption that gH/gL/UL128-131 promotes gB-mediated fusion on epithelial/endothelial cells whereas gH/gL/gO provides this function on fibroblasts. This was challenged by observations that gO-null mutants were defective on all of these cell types, suggesting that entry into epithelial/endothelial cells requires both of the gH/gL complexes, but the severe replication defect of the gO mutants precluded detailed analysis. We previously reported that the ratio of gH/gL/gO and gH/gL/UL128-131 in the virion envelope varied dramatically among HCMV strains. Here, we show that strains not only differ in the ratio, but also vary in the total amount of gH/gL in the virion. Cell-type-specific particle-to-PFU ratios of HCMV strains that contained different amounts of gH/gL/gO and gH/gL/UL128-131 were determined. Infection of both fibroblasts and epithelial cells was generally correlated with the abundance of gH/gL/gO, but not with that of gH/gL/UL128-131. The low infectivity of virions rich in gH/gL/UL128-131 but low in gH/gL/gO could be overcome by treatment with the chemical fusogen polyethylene glycol (PEG), strongly arguing that gH/gL/gO provides the conserved herpesvirus gH/gL entry function of promoting gB-mediated fusion for entry into all cell types, whereas gH/gL/UL128-131 acts through a distinct mechanism to allow infection of select cell types. IMPORTANCEThe functions of HCMV gH/gL complexes in entry are unclear. Unlike the well-studied Epstein-Barr virus (EBV), where gH/gL and gH/gL/gp42 complexes both seem capable of promoting gB fusion during entry into different cell types, our studies here suggest that for HCMV, gH/gL/gO promotes gB fusion on all cell types, whereas gH/gL/UL128-131 broadens virus tropism through a distinct, as yet unknown mechanism. To our knowledge, this is the first suggestion of a herpesvirus gH/gL that does not act by promoting gB fusion, which might make HCMV a useful model to study the fundamental mechanisms by which herpesvirus gH/gL regulates gB fusion. Moreover, gH/gL/UL128-131 is a candidate vaccine target. Our findings help to explain the cell-type-dependent virus neutralization exhibited by anti-gH/gL/UL128-131 antibodies and underscore the importance of gH/ gL/gO as another important part of vaccine or therapeutic strategies. P rimary infection of healthy adults by human cytomegalovirus (HCMV) is usually subclinical or mildly symptomatic but leads to lifelong persistent or latent infection. Primary infection or reactivation of HCMV in immunocompromised hosts, such those infected with HIV and t...

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“…In a later paper in this series it is shown that infection and death of the embryo are produced by a very few particles of Newcastle virus (12). By use of the theory of random distribution of particles as outlined in the Poisson theory, it is possible to draw a theoretical curve for the expected number of infectious units needed to produce infection.…”

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confidence: 99%

Studies on Newcastle Disease Virus

Bang¹

1948

Journal of Experimental Medicine

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Electron microscope studies of purified preparations of the virus of Newcastle disease have shown that this virus has a filamentous to sperm-like form when dried from saline suspensions (1, 2). If, however, the virus is suspended in water and then dried from this suspension, it has a roughly spherical form, which corresponds to its appearance in the original allantoic fluid (3). An apparent conversion from the spherical form in water to the filamentous form has been brought about by the addition of saline to make a 0.07 to 0.15 solution (3). The change in shape revealed by electron microscopy was brought about without any detectable change in activity of the suspension. Two questions must be answered before these observations can be assigned any basic significance. (a) Could the lack of a detectable change in activity be merely due to inadequacies in the methods of measuring activity? In other words, might we destroy 95 per cent of the virus by the procedure which changes its shape, and not detect this loss of active virus particles? (b) Does this change in shape on transfer to saline represent a change which occurs within the solution, or is it merely the result of drying from different solvents? Some experimental evidence against this latter possibility was previously mentioned (3), but more work needs to be done.We attempt in this paper to evaluate the methods of determining activity (embryo infectivity) and conclude that the changes in shape of the virus cannot be accounted for on the basis of disintegration.The determination of the 50 per cent mortality or infectivity end-point (4) by means of chick embryos has been in use for a number of years, but very few reports have been made on the accuracy of the method used. Indeed, there is no statistical study available which attempts to estimate the expected probable error with a given number of ~nlmals and a given titration end-point slope.In a limited number of duplicate titrations of Eastern equine encephalomyelitis, a variation of as much as 0.6 log was found between two duplicate titrations (5), using five embryos in each of three dilutions. In a more extensive evaluation of the 50 per cent infectivity measurements for influenza vires in the embryo, Knight (6) found that the chances were 19 out of 20 that differences in end-points of 0.62 logarithmic units were significant.* This means that more than 75 per cent of the infectiousness 1 Five embryos in each dilution. 233 on

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Studies on Newcastle Disease Virus

Cited by 34 publications

References 9 publications

The Investigation of Influenza and Related Viruses in the Electron Microscope, by a New Technique

The Investigation of Influenza and Related Viruses in the Electron Microscope, by a New Technique

Human Cytomegalovirus gH/gL/gO Promotes the Fusion Step of Entry into All Cell Types, whereas gH/gL/UL128-131 Broadens Virus Tropism through a Distinct Mechanism

Studies on Newcastle Disease Virus

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