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PubMedDate not supplied

Differences in the induction of urate deposition of specific-pathogen-free chicks inoculated with avian nephritis virus passaged by five different methods.

The G-4260 strain of avian nephritis virus (ANV) was passaged using five different methods as follows: method 1, passage three times in chorioallantoic membrane (CAM) of 11-day-old embryonated eggs (CAM3); method 2, passage twice in CAM and further passage once in yolk sac (YS) of 6-day-old embryonated eggs (CAM2-YS1); method 3, passage 11 times in CAM (CAM11); method 4, passage 10 times in CAM and further passage twice in YS (CAM10-YS2); method 5, passage as in Method 4 and then passage three times in chicken kidney cell culture (CAM10-YS2-CK3). CAM11 and CAM10-YS2 were each inoculated orally into 25 one-day-old specific-pathogen-free (SPF) chicks. Seven chicks in the CAM11-inoculated group and six chicks in the CAM10-YS2-inoculated group died or were killed because they were moribund; all had either nephrosis or urate deposition. CAM3, CAM2-YS1, CAM10-YS2, and CAM10-YS2-CK3 were each inoculated intraperitoneally into 15 one-day-old SPF chicks. No chicks inoculated with CAM3 or CAM2-YS1 died, but wo chicks inoculated with CAM10-YS2 and three inoculated with CAM10-YS2-CK3 died with urate deposition. At 14 postinoculation, plasma urate values of the CAM10-YS2- and CAM10-YS2-CK3-inoculated chicks were significantly higher than those of CAM3- and CAM2-YS1-inoculated chicks and control chicks (P less than 0.01). However, interstitial nephritis was observed in most of the ANV-inoculated birds.

Animals↗
PubMed1978

Modification of Trichoplusia ni nuclear polyhedrosis virus passaged in vivo.

A designated strain of plaque-purified Trichoplusia ni nuclear polyhedrosis virus (NPV) was used to initiate a serial passage series in vivo. The virulence of polyhedra inclusion bodies (PIB) and the distribution of MP (many PIB) and FP (few PIB) strains in hemolymph were monitored. When virus was passaged per os as PIB, there was no major change in virulence after 15 passes in insects. Plaque analysis of hemolymph from the infected insects indicated that there was no selection for the FP strain of virus. There was little overall change in the infectivity of nonoccluded virus (NOV) after 16 passes by injection into T. ni larvae; however, plaque analysis of the hemolymph from the infected insects indicated progressive selection of FP virus. It is postulated that when PIB are the vehicles of virus transmission, there is no progressive accumulation of noninfectious FP PIB; however, when NOV are the vehicles of virus transmission, FP NOV production displaces MP virus synthesis. This may result from a growth advantage of the FP NOV over the MP NOV as shown in vitro and from the noninfectious nature of FP PIB.

Animals↗
PubMed2004

Sequence analysis of the variable VP2 gene of infectious bursal disease viruses passaged in Vero cells.

Korean field infectious bursal disease viruses (IBDVs) were isolated from IBDV suspected commercial chickens. A previous study revealed that these IBDV field isolates were virulent or very virulent IBDVs. The isolates were passaged three times in the chorioallantoic membrane of specific-pathogen-free embryonated chicken eggs and four times in Vero cells. After passage, viral RNAs were isolated and purified to determine the genetic changes. The hypervariable regions of the VP2 gene were amplified by reverse transcriptase-polymerase chain reaction (RT-PCR). To confirm the genetic changes, PCR products were cloned, sequenced and compared to the sequences of the parental IBDVs and published IBDV strains. By sequencing analysis, the passaged IBDVs had amino acid changes at positions 253 (Q --> H), 279 (D or N --> N) and 284 (A --> T) which were commonly found in the attenuated IBDV strains. Two serines in the serine-rich heptapeptide (residue 326-332) were substituted into other amino acids which were similar to the IBDV vaccine strains.

Amino Acid Sequence↗
PubMed1980

Most sequence differences between the genomes of the Akv virus and a leukemogenic Gross A virus passaged in vitro are located near the 3' terminus.

The 70S genomic RNA of nonleukemogenic AKR(Akv) virus was compared to that of an in vitro passaged, cloned, leukemogenic Gross A virus by fingerprint and sequence analysis. Fifty-seven of the large ribonuclease T1-resistant oligonucleotides of each virus have the same electrophoretic mobility and sequence. Thirteen large ribonuclease T1 oligo nucleotides are unique to the Gross A virus, whereas five are unique to Akv. Four of the oligonucleotides unique to each virus are related by one or two simple base changes. Five of the differences in oligonucleotides are located in the region of the genome that codes for the gag and pol genes. Eight of the differences are located near the 3' poly(A) terminus of the virus. The origins and biological consequences of these differences are discussed.

AKR murine leukemia virus↗
PubMedDate not supplied

Newcastle disease virus passage in MDBK cells as an aid in detection of a virulent subpopulation.

Newcastle disease virus strains (NDV) La Sota, Texas GB (GB), and mixtures of the two strains were serially passaged in embryonated chicken eggs or the MDBK cell line, a more restrictive culture system than eggs for NDV. The two culture systems were compared by evaluating culture harvests for pathogenicity in inoculated chickens; the harvests were identified by hemagglutination-inhibition tests against monoclonal antibodies that can differentiate La Sota and GB cultures. Both viruses, inoculated alone or as mixtures, were propagated by passage in chicken eggs. La Sota strain failed to propagate by continuous passage in MDBK cells, and only GB was identified in culture harvests propagated in MDBK cells that had been inoculated with GB or mixtures of GB and La Sota. The results indicate that the MDBK cell line is a more selective substrate than chicken eggs and suggest that passage in MDBK cells may aid in selecting for more virulent subpopulations of NDV in a mixed culture. Other reference NDV strains, pigeon NDV isolates, and recent lentogenic NDV isolates from chickens were also passaged in MDBK cells; all strains except those that are classified as lentogens like La Sota could be serially propagated in MDBK cells.

Animals↗
PubMedDate not supplied

Antigenic variability of porcine reproductive and respiratory syndrome (PRRS) virus isolates. Influence of virus passage in pig.

In order to study the antigenic variability of porcine reproductive and respiratory syndrome virus (PRRSV), 18 European and Canadian field isolates were analysed with a panel of 15 monoclonal antibodies (MAbs) raised against five different European and one Canadian PRRSV isolates. The antigenic pattern of these isolates was used to infer their phylogenetic relationships. Isolates which had the same reactivity pattern were gathered together so that five antigenic profiles were analysed. The pairwise distances between these groups were defined based on antigenic pattern differences. Two main antigenic groups were obtained, discriminating between the European and the Canadian populations, as illustrated by the great distance observed between European and Canadian isolates (D = 0.5619 +/- 0.0625) compared to the distance between European isolates (D = 0.1524 +/- 0.0735). The distance matrix allowed also the construction of a tree diagram. Bootstrap analysis was performed to test the confidence in the branching. The tree diagram confirmed the distinction between the European and the Canadian PRRSV populations. Antigenic variability between an isolate and its progeny recovered after one or two passages in vivo was examined on six isolates. It was restricted to the GP3 protein of the virus.

Animals↗
PubMedDate not supplied

Modification of three avian viruses passaged in Chinese hamster lung cells (Don) in pathogenicity to chicken embryo.

The Beaudette 42 strain of avian infectious bronchitis virus, Sato strain of Newcastle disease virus, and Uchida strain of avian reovirus were passaged in Chinese hamster lung cells (Don), and some properties were examined. The Don-passaged strains showed a difference in replication in Don and chicken embryo kidney cells in one-step growth curve examinations and a partial modification in pathogenicity to chicken embryos; nevertheless, neutralization tests revealed no serological alteration.

Animals↗
PubMed1992

Comparison of the sequence of the gene encoding African swine fever virus attachment protein p12 from field virus isolates and viruses passaged in tissue culture.

Comparison of the amino acid sequence of the African swine fever virus attachment protein p12 from different field virus isolates, deduced from the nucleotide sequence of the gene, revealed a high degree of conservation. No mutations were found after adaptation to Vero cells, and a polypeptide with similar characteristics was present in an IBRS2-adapted virus. The sequence of the 5' flanking region was conserved among the isolates, whereas sequences downstream of the gene were highly variable in length and contained direct repeats in tandem that may account for the deletions found in different isolates. Protein p12 was synthesized in swine macrophages infected with all of the viruses tested.

African Swine Fever↗
PubMed1978

Excess of interfering over infectious particles in herpes simplex virus passaged at high m.o.i. and their effect on single-cell survival.

The capacity of herpes simplex virus to kill cells and to form both infectious centres and progeny virus was studied in cell culture. Two virus stocks were compared at various m.o.i.: (i) a standard virus stock and (ii) a stock which contained interfering virus particles (I particles). The formation of infectious progeny virus as well as of infectious centres appeared to be reduced by the action of I particles. In the examined virus stock I particles exceeded infectious particles by at least a factor of 5 to 10. More than 50% of cells which could be demonstrated to be hit by I particles survived and formed colonies.

Cell Line↗
PubMed2000

Association of structural changes in the V2 and V3 loops of the gp120 envelope glycoprotein with acquisition of neutralization resistance in a simian-human immunodeficiency virus passaged in vivo.

The in vivo passage of a neutralization-sensitive, laboratory-adapted simian-human immunodeficiency virus (SHIV-HXBc2) generated a pathogenic, neutralization-resistant virus, SHIV-HXBc2P 3.2. SHIV-HXBc2P 3.2 differs from SHIV-HXBc2 only in 13 amino acid residues of the viral envelope glycoproteins. Here we used antibody competition analysis to examine the structural changes that occurred in the SHIV-HXBc2P 3.2 gp120 exterior envelope glycoprotein. The relationships among the antibody epitopes on the conserved gp120 core of SHIV-HXBc2 and SHIV-HXBc2P 3.2 were similar. The third variable (V3) loop was more closely associated with the fourth conserved (C4) region and CD4-induced epitopes on the gp120 core in the HXBc2P 3.2 gp120 glycoprotein compared with the HXBc2 gp120 glycoprotein. Rearrangements of the second variable (V2) loop with respect to the CD4 binding site and associated epitopes were evident in comparisons of the two gp120 glycoproteins. Thus, the in vivo evolution of a neutralization-resistant virus involves conformational adjustments of the V2 and V3 variable loops with respect to the conserved receptor-binding regions of the gp120 core.

Animals↗
PubMed1996

The equine herpesvirus 1 IR6 protein is nonessential for virus growth in vitro and modified by serial virus passage in cell culture.

The IR6 protein of different plaque isolates from three passages of the equine herpesvirus 1 strain Rac was investigated. Southern blot and DNA sequence analyses revealed that plaque isolates from the 12th passage (RacL11 and RacL22) retained both copies of the IR6 gene, whereas two different genotypes were observed by the 185th passage: RacM24 still harbored both copies of the IR6 gene, whereas RacM36 deleted one of the two copies. In the 256th passage (RacH), both copies of the IR6 gene were absent. As compared to the wild-type IR6 protein, both the RacM24 and RacM36 IR6 protein displayed amino acid exchanges at positions 34, 42, 110, and 134 of the 272 amino acid polypeptide. It is shown that (i) the IR6 protein is nonessential for virus growth in vitro. (ii) In RacL11-infected equine and rodent cells, the typical rod-like appearance of the IR6 protein could be detected from 6 hr p.i., whereas in RacM24- and RacM36-infected cells formation of these structures was not observed. (iii) The RacL11 IR6 gene product was present in both the nuclei and cytoplasmic fraction of infected cells. In contrast, the IR6 protein of both RacM24 and RacM36 colocalized with cytoplasmic membrane vesicles. (iv) The RacL11 and RacL22 IR6 protein is present in viral nucleocapsids, whereas that of RacM24 and RacM36 is not incorporated into virions. (v) The RacL11 IR6 gene product aggregated to disulfide-linked oligomers, whereas the RacM24 and RacM36 IR6 protein showed only marginal oligomerization. (vi) In COS7 cells transfected with constructs expressing either the full-length RacL11-IR6 protein or a truncated form lacking the 81 carboxyterminal amino acids, the formation of rod-like structures was observed, indicating that another viral protein is not necessary for aggregation of the IR6 protein. In contrast, the IR6 protein expressed from constructs derived from either RacM24 or RacM36 failed to form these structures. (vii) Analyses of chimeric RacL11-RacM24 IR6 proteins suggest a crucial role for amino acid Leu-134 in the ability of the IR6 protein to form the rod-like structures.

Amino Acid Sequence↗