scholarly journals Quantal and graded dose-responses of bluetongue virus: a comparison of their sensitivity as assay methods for neutralizing antibody

1966 ◽  
Vol 64 (2) ◽  
pp. 231-244 ◽  
Author(s):  
Sven-Eric Svehag
Keyword(s):  
Poisson Distribution ◽  
Bluetongue Virus ◽  
Neutralizing Antibody ◽  
Survival Times ◽  
Response Curves ◽  
Virus Particles ◽  
The Best Approximation ◽  
Graded Responses ◽  
Quantal Responses ◽  
Random Variation

The sensitivity of quantal and graded responses to mouse-adapted bluetongue virus for the detection of neutralizing antibody was compared using probit and rankit analysis. The graded response, based on survival times, allowed the demonstration of antibody in highly dilute serum, in which antibody was not detected by the quantal response recording percentage death.Quantal responses to bluetongue virus variants were compared with theoretical dose-response curves constructed according to the Poisson distribution for the random variation of virus particles in inocula. Of these theoretical curves the first term in the Poisson distribution gave the best approximation to the experimental data but the fit to normal distribution curves was better. The quantal responses to bluetongue virus did not appear to reflect the random variation of one-or-more infectious virus particles in inocula.In graded responses to bluetongue virus, a rectilinear relationship was observed between reciprocal harmonic means of survival times and log virus dilutions.

Exposure of protein VP7 on the surface of bluetongue virus

1990 ◽  
Vol 48 (3) ◽  
pp. 600-601
Author(s):  
A.D. Hyatt
Keyword(s):  
Bluetongue Virus ◽  
Structural Proteins ◽  
Major Constituent ◽  
Outer Coat ◽  
Virus Particles ◽  
Antibody Recognition ◽  
The Core ◽  
The Family ◽  
Electron Microscopical ◽  
Physical Accessibility

Bluetongue virus (BTV) is the type species os the genus orbivirus in the family Reoviridae. The virus has a fibrillar outer coat containing two major structural proteins VP2 and VP5 which surround an icosahedral core. The core contains two major proteins VP3 and VP7 and three minor proteins VP1, VP4 and VP6. Recent evidence has indicated that the core comprises a neucleoprotein center which is surrounded by two protein layers; VP7, a major constituent of capsomeres comprises the outer and VP3 the inner layer of the core . Antibodies to VP7 are currently used in enzyme-linked immunosorbant assays and immuno-electron microscopical (JEM) tests for the detection of BTV. The tests involve the antibody recognition of VP7 on virus particles. In an attempt to understand how complete viruses can interact with antibodies to VP7 various antibody types and methodologies were utilized to determine the physical accessibility of the core to the external environment.

scholarly journals Bluetongue Virus Particles as Nanoreactors for Enzyme Delivery and Cancer Therapy

2021 ◽  
Author(s):  
Eva C. Thuenemann ◽  
Duc H. T. Le ◽  
George P. Lomonossoff ◽  
Nicole F. Steinmetz
Keyword(s):  
Cancer Therapy ◽  
Bluetongue Virus ◽  
Virus Particles ◽  
Enzyme Delivery

scholarly journals Analysis and phylogenetic comparisons of full-length VP2 genes of the 24 bluetongue virus serotypes

2007 ◽  
Vol 88 (2) ◽  
pp. 621-630 ◽  
Author(s):  
S. Maan ◽  
N. S. Maan ◽  
A. R. Samuel ◽  
S. Rao ◽  
H. Attoui ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Full Length ◽  
Molecular Diagnostic ◽  
Mammalian Host ◽  
Reading Frame ◽  
Diagnostic Assays ◽  
Primary Determinant ◽  
Serotype Identification

The outer capsid protein VP2 of Bluetongue virus (BTV) is a target for the protective immune response generated by the mammalian host. VP2 contains the majority of epitopes that are recognized by neutralizing antibodies and is therefore also the primary determinant of BTV serotype. Full-length cDNA copies of genome segment 2 (Seg-2, which encodes VP2) from the reference strains of each of the 24 BTV serotypes were synthesized, cloned and sequenced. This represents the first complete set of full-length BTV VP2 genes (from the 24 serotypes) that has been analysed. Each Seg-2 has a single open reading frame, with short inverted repeats adjacent to conserved terminal hexanucleotide sequences. These data demonstrated overall inter-serotype variations in Seg-2 of 29 % (BTV-8 and BTV-18) to 59 % (BTV-16 and BTV-22), while the deduced amino acid sequence of VP2 varied from 22.4 % (BTV-4 and BTV-20) to 73 % (BTV-6 and BTV-22). Ten distinct Seg-2 lineages (nucleotypes) were detected, with greatest sequence similarities between those serotypes that had previously been reported as serologically ‘related’. Fewer similarities were observed between different serotypes in regions of VP2 that have been reported as antigenically important, suggesting that they may play a role in the neutralizing antibody response. The data presented form an initial basis for BTV serotype identification by sequence analyses and comparison of Seg-2, and for development of molecular diagnostic assays for individual BTV serotypes (by RT-PCR).

scholarly journals Bluetongue virus in a Nigerian dairy cattle herd: 1. Serological studies and correlation of virus activity to vector population

1983 ◽  
Vol 90 (2) ◽  
pp. 177-193 ◽  
Author(s):  
K. A. J. Herniman ◽  
J. P. T. Boorman ◽  
W. P. Taylor
Keyword(s):  
Bluetongue Virus ◽  
Light Trap ◽  
Survival Rates ◽  
Virus Transmission ◽  
Neutralizing Antibody ◽  
Decay Rates ◽  
Vector Population ◽  
Virus Activity ◽  
Serological Studies ◽  
Trap Catches

SUMMARYNewborn calves were bled at monthly intervals and examined for serum antibodies to bluetongue virus (BTV). Maternal immunity persisted for 3 months and it was possible to calculate decay rates for virus neutralizing antibody. Calves were subclinically infected with BTV within a few months of becoming susceptible and neutralization tests were used to deduce the serotype responsible. A profile of virus activity was built up over a 12 month period. Frequent light trap catches were used to examine the population dynamics of suspected Culicoides vector species. Two species, imicola and schultzei were present throughout the wet and dry seasons and survival rates were sufficiently long to account for virus transmission at any time of the year.

scholarly journals CD8 T Cell Responses to an Immunodominant Epitope within the Nonstructural Protein NS1 Provide Wide Immunoprotection against Bluetongue Virus in IFNAR−/−Mice

2018 ◽  
Vol 92 (16) ◽  
Author(s):  
Alejandro Marín-López ◽  
Eva Calvo-Pinilla ◽  
Diego Barriales ◽  
Gema Lorenzo ◽  
Alejandro Brun ◽  
...  
Keyword(s):  
T Cell ◽  
Bluetongue Virus ◽  
Neutralizing Antibodies ◽  
Nonstructural Protein ◽  
T Cell Responses ◽  
Neutralizing Antibody ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Cell Responses ◽  
N Terminus

ABSTRACTThe development of vaccines against bluetongue, a prevalent livestock disease, has been focused on surface antigens that induce strong neutralizing antibody responses. Because of their antigenic variability, these vaccines are usually serotype restricted. We now show that a single highly conserved nonstructural protein, NS1, expressed in a modified vaccinia Ankara virus (MVA) vector can provide multiserotype protection in IFNAR−/−129 mice against bluetongue virus (BTV) that is largely dependent on CD8 T cell responses. We found that the protective antigenic capacity of NS1 resides within the N terminus of the protein and is provided in the absence of neutralizing antibodies. The protective CD8 T cell response requires the presence of a specific peptide within the N terminus of NS1, since its deletion ablates the efficacy of the vaccine formulation. These data reveal the importance of the nonstructural protein NS1 in CD8 T cell-mediated protection against multiple BTV serotypes when vectorized as a recombinant MVA vaccine.IMPORTANCEConventional vaccines have controlled or limited BTV expansion in the past, but they cannot address the need for cross-protection among serotypes and do not allow distinguishing between infected and vaccinated animals (DIVA strategy). There is a need to develop universal vaccines that induce effective protection against multiple BTV serotypes. In this work we have shown the importance of the nonstructural protein NS1, conserved among all the BTV serotypes, in CD8 T cell-mediated protection against multiple BTV serotypes when vectorized as a recombinant MVA vaccine.

scholarly journals Dose-response relationships in a microneutralization test for foot-and-mouth disease viruses

1978 ◽  
Vol 80 (1) ◽  
pp. 31-42 ◽  
Author(s):  
J. C. Booth ◽  
M. M. Rweyemamu ◽  
T. W. F. Pay
Keyword(s):  
Dose Response ◽  
Foot And Mouth Disease ◽  
Neutralizing Antibody ◽  
Mouth Disease ◽  
Antibody Activity ◽  
Response Curves ◽  
Susceptibility To Infection ◽  
Foot And Mouth ◽  
Antibody Titres ◽  
Microneutralization Test

SUMMARYTwo-dimensional quantal microneutralization tests on foot-and-mouth disease viruses, in which neutralizing antibody activity was titrated against a serial range of virus doses, demonstrated a variety of dose-response curves some of which were rectilinear, others clearly curvilinear. Moreover, in the case of the non-linear responses obtained with some antisera, the shape of the curve was such that antibody titres recorded with doses of virus ranging from 103–105TCD 50 were closely similar. Studies were carried out on the effect of varying the conditions of the test on the shape of the dose-response curve: significant differences were obtained after treatment of the antiserum–virus mixtures with anti-species globulin, and when the test was assayed in cells of differing susceptibility to infection.

scholarly journals The epidemiology of bluetongue in Malawi

1988 ◽  
Vol 100 (3) ◽  
pp. 493-499 ◽  
Author(s):  
J. M. Haresnape ◽  
W. P. Taylor ◽  
S. A. M. Lungu
Keyword(s):  
Central Region ◽  
Rainy Season ◽  
Bluetongue Virus ◽  
Neutralizing Antibody ◽  
Dry Season ◽  
Virus Activity

SummaryA 4 year survey was undertaken in 1982–6 to examine the seasonal nature of bluetongue virus activity in Malawi. Bluetongue infection at Bwemba in Lilongwe district and Likasi in Mchinji district, both in the Central Region of Malawi, was detected by examining sera taken from calves at each site, at monthly intervals. The proportion of seronegative calves undergoing serocon version each month was used as a measure of virus activity. At both sides bluetongue virus activity was found to be most marked during the rainy season, with no activity detected during the dry season from July to September. Thus the pattern of bluetongue infection in Malawi is highly seasonal. Examination of type-specific neutralizing antibody showed that the prevalent serotypes varied from year to year.

scholarly journals Theoretical Description Of A Reparamatrization of Discrete Two Parameter Poisson Lindley Distribution for Modeling Waiting And Survival Times Data

2016 ◽  
Vol 29 (1) ◽  
pp. 217-222
Author(s):  
Tanka Raj Adhikari
Keyword(s):  
Poisson Distribution ◽  
Method Of Moments ◽  
Research Paper ◽  
Theoretical Description ◽  
Survival Times ◽  
Lindley Distribution ◽  
Two Parameters ◽  
First Four Moments ◽  
Special Case ◽  
Two Parameter

In this research paper, the theoretical description of are paramatrization of a discrete two-parameter Poisson Lindley Distribution, of which Sankaran’s (1970) one parameter Poisson Lindley Distribution is a special case, is derived by compounding a Poisson Distribution with two parameters Lindley Distribution for modeling waiting and survival times data of Shanker et al. (2012).The first four moments of this distribution have derived. Estimation of the parameters by using method of moments and maximum likely hood method has been discussed.

scholarly journals A 24-Hour Cycle in Single Locust and Mantis Photoreceptors

1981 ◽  
Vol 91 (1) ◽  
pp. 307-322 ◽  
Author(s):  
G. A. HORRIDGE ◽  
J. DUNIEC ◽  
L. MARČELJA
Keyword(s):  
Point Source ◽  
Diurnal Rhythm ◽  
Capture Efficiency ◽  
The Other ◽  
Field Size ◽  
Acceptance Angle ◽  
Response Curves ◽  
Spontaneous Breakdown ◽  
Intensity Response ◽  
Quantal Responses

1. When fixed during the night the rhabdom of the locust and mantis is much broader than when fixed during the day. 2. Dark-adapted ommatidia of the locust and mantis by day and night have a zone of vacuoles around the rhabdom tip, but when light-adapted this zone is replaced by cytoplasm rich in mitochondria. 3. Illumination of the rhabdom in the night state causes the microvilli to swell and the rhabdom to break down over the course of about 1 h. 4. A diurnal rhythm is apparent in the spontaneous breakdown of the rhabdom in the morning even though the eye has seen no light for 12 h. 5. Intensity/response curves (peak of the response in mV plotted against log intensity of stimulus) show an increase in sensitivity during the night even though the stimulus is a point source on axis. 6. On the other hand, counts of bumps (quantal responses to individual photons) show no change in photon capture efficiency at night when the stimulus is a point source. 7. Strong illumination of the eye in the night state causes a desensitization which continues for 1 h. 8. Measurements of the acceptance angle in the dark-adapted day and night states show that field size is an indicator of the diameter of the rhabdom tip, but actual fields are larger than those calculated from the anatomical dimensions.

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