Antibody to Viruses Affecting Cattle in Commercial Tissue Culture Grade Fetal Calf Serum

Commercial fetal calf serum (FCS) for tissue culture use was tested for neutralizing activity against several viruses which affect cattle. Certain lots of FCS contained no neutralizing activity, whereas other lots contained neutralizing activity to several viruses. It was concluded that the neutralizing activity found in certain lots of sera was due to specific antibody and that its presence could be most easily explained by the contamination of the FCS with serum from postcolostral bovine serum. A nonantibody inhibitor to vesicular stomatitis virus was also found at low levels in most lots of serum. Because those sera which had antibody had antibody to several viruses, it was suggested that the use of the micro-serum neutralization test with a few bovine viruses which are widespread in the bovine population should be satisfactory to detect FCS which was contaminated with postcolostral bovine serum.     

Insertion of primary syncytium-inducing (SI) and non-SI envelope V3 loops in human immunodeficiency virus type 1 (HIV-1) LAI reduces neutralization sensitivity to autologous, but not heterologous, HIV-1 antibodies.

The aim of the study was to investigate the influence of V3 loops from naturally occurring viruses on the neutralization sensitivity of a molecularly cloned virus. A selection of well-defined syncytium-inducing (SI) and non-SI V3 loops of a single human immunodeficiency virus type 1-infected individual (H594) and the V3 regions of two SI laboratory strains were inserted in an infectious molecular clone of human immunodeficiency type 1 LAI. Neutralization was performed with a heterologous serum pool and autologous patient serum, using the virus reduction neutralization assay and peripheral blood lymphocytes as target cells. High sensitivity of the chimeric viruses containing the laboratory strain V3 regions to neutralization by H594 sequential sera as well as the heterologous serum pool was found. A statistically significant correlation between the sensitivities of these viruses was seen. In contrast, insertion of the primary isolate NSI and SI envelope V3 loops significantly reduced the neutralization by autologous serum but not by the heterologous serum pool. No correlation was found between the neutralization of the viruses with laboratory strain-derived V3 regions and the viruses with primary isolate V3 domains. We conclude that heterologous antibodies are able to neutralize infectious molecular clones with V3 loops of both SI and NSI viruses, regardless of whether they originated from laboratory strains or primary isolates. However, serum of patient H594 discriminated between the two types of viruses and showed reduced neutralization of the viruses with the autologous NSI and SI primary isolate V3 loops. These results indicated that the neutralization sensitivity of the viruses depended on the capacity of the V3 region to influence the conformation of the virus envelope. These V3-dependent conformational changes partially explain the neutralization sensitivity of laboratory strains and the relative neutralization resistance of primary isolates.     

A novel pathogenic mechanism of highly pathogenic avian influenza H5N1 viruses involves hemagglutinin mediated resistance to serum innate inhibitors

In this study, the effect of innate serum inhibitors on influenza virus infection was addressed. Seasonal influenza A(H1N1) and A(H3N2), 2009 pandemic A(H1N1) (H1N1pdm) and highly pathogenic avian influenza (HPAI) A(H5N1) viruses were tested with guinea pig sera negative for antibodies against all of these viruses as evaluated by hemagglutination-inhibition and microneutralization assays. In the presence of serum inhibitors, the infection by each virus was inhibited differently as measured by the amount of viral nucleoprotein produced in Madin-Darby canine kidney cells. The serum inhibitors inhibited seasonal influenza A(H3N2) virus the most, while the effect was less in seasonal influenza A(H1N1) and H1N1pdm viruses. The suppression by serum inhibitors could be reduced by heat inactivation or treatment with receptor destroying enzyme. In contrast, all H5N1 strains tested were resistant to serum inhibitors. To determine which structure (hemagglutinin (HA) and/or neuraminidase (NA)) on the virus particles that provided the resistance, reverse genetics (rg) was applied to construct chimeric recombinant viruses from A/Puerto Rico/8/1934(H1N1) (PR8) plasmid vectors. rgPR8-H5 HA and rgPR8-H5 HANA were resistant to serum inhibitors while rgPR8-H5 NA and PR8 A(H1N1) parental viruses were sensitive, suggesting that HA of HPAI H5N1 viruses bestowed viral resistance to serum inhibition. These results suggested that the ability to resist serum inhibition might enable the viremic H5N1 viruses to disseminate to distal end organs. The present study also analyzed for correlation between susceptibility to serum inhibitors and number of glycosylation sites present on the globular heads of HA and NA. H3N2 viruses, the subtype with highest susceptibility to serum inhibitors, harbored the highest number of glycosylation sites on the HA globular head. However, this positive correlation cannot be drawn for the other influenza subtypes.     

A preliminary study on viral decontamination of chicken serum using gamma-irradiation

A preliminary experiment was carried out to determine whether a decontamination procedure using gamma irradiation, similar to that adopted in the European guideline for bovine serum contaminated by pestivirus, could be applied to chicken serum. Chicken sera spiked with known amounts of enveloped and non-enveloped chicken viruses were gamma irradiated. The remaining live viruses were then measured by titration and the virus reduction capacity of the irradiation process was established for both enveloped and non-enveloped virus models. In parallel with the irradiation procedure, a classical in vivo extraneous agent test was also evaluated in order to see if it has the capacity to detect low enough levels of live viruses to be used for testing irradiated serum. The results suggest that the principles of the bovine serum decontamination procedure may be applied to chicken serum. Further studies are required to determine if this process would provide an acceptable solution for the viral ‘decontamination’ of chicken serum.     

Serological relationships of five herpesviruses isolated from salmonid fishes

The five herpesviruses isolated from salmonid fishes were compared for their serological relatedness by serum cross-neutralization studies with polyclonal rabbit serum. The five viruses fell into two major groups. The three viruses from fishes in Japan, Oncorbyncbus mason virus (OMV), yamame tumor virus (YTV) and nerka virus (NeVTA) were closely related. They however, differed considerably from two viruses from salmonid fishes in North America, Herpesvirus salmonis (HPV) and the steelhead herpesvirus (SHV). The latter two viruses were also closely related. This study indicated that the viruses in the two countries are serologically distinct and are not a result of transfers of infected fish or eggs between continents.     

Immunogenicity and protection efficacy of replication-deficient influenza A viruses with altered NS1 genes

We explored the immunogenic properties of influenza A viruses with altered NS1 genes (NS1 mutant viruses). NS1 mutant viruses expressing NS1 proteins with an impaired RNA-binding function or insertion of a longer foreign sequence did not replicate in murine lungs but still were capable of inducing a Th1-type immune response resulting in significant titers of virus-specific serum and mucosal immunoglobulin G2 (IgG2) and IgA, but with lower titers of IgG1. In contrast, replicating viruses elicited high titers of serum and mucosal IgG1 but less serum IgA. Replication-deficient NS1 mutant viruses induced a rapid local release of proinflammatory cytokines such as interleukin-1beta (IL-1beta) and IL-6. Moreover, these viruses also elicited markedly higher levels of IFN-alpha/beta in serum than the wild-type virus. Comparable numbers of virus-specific primary CD8(+) T cells were determined in all of the groups of immunized mice. The most rapid onset of the recall CD8(+)-T-cell response upon the wild-type virus challenge was detected in mice primed with NS1 mutant viruses eliciting high levels of cytokines. It is noteworthy that there was one NS1 mutant virus encoding NS1 protein with a deletion of 40 amino acids predominantly in the RNA-binding domain that induced the highest levels of IFN-alpha/beta, IL-6 and IL-1beta after infection. Mice that were immunized with this virus were completely protected from the challenge infection. These findings indicate that a targeted modification of the RNA-binding domain of the NS1 protein is a valuable technique to generate replication-deficient, but immunogenic influenza virus vaccines.     

Reproducible Plaquing System for Rabies, Lymphocytic Choriomeningitis, and Other Ribonucleic Acid Viruses in BHK-21 / 13S Agarose Suspensions

BHK21/13S-agarose suspension cultures provide an excellent plaquing system for rabies and lymphocytic choriomeningitis viruses. The system has facilitated accurate and reproducible assay of serum neutralization and cloning of these viruses. Rubella, reo, and Kern Canyon viruses may also be assayed by this technique.     

Point Mutations in the Paramyxovirus F Protein That Enhance Fusion Activity Shift the Mechanism of Complement-Mediated Virus Neutralization

Parainfluenza virus 5 (PIV5) activates and is neutralized by the alternative pathway (AP) in normal human serum (NHS) but not by heat-inactivated (HI) serum. We have tested the relationship between the fusion activity within the PIV5 F protein, the activation of complement pathways, and subsequent complement-mediated virus neutralization. Recombinant PIV5 viruses with enhanced fusion activity were generated by introducing point mutations in the F fusogenic peptide (G3A) or at a distal site near the F transmembrane domain (S443P). In contrast to wild-type (WT) PIV5, the mutant G3A and S443P viruses were neutralized by both NHS and HI serum. Unlike WT PIV5, hyperfusogenic G3A and S443P viruses were potent C4 activators, C4 was deposited on NHS-treated mutant virions, and the mutants were neutralized by factor B-depleted serum but not by C4-depleted serum. Antibodies purified from HI human serum were sufficient to neutralize both G3A and S443P viruses in vitro but were ineffective against WT PIV5. Electron microscopy data showed greater deposition of purified human antibodies on G3A and S443P virions than on WT PIV5 particles. These data indicate that single amino acid changes that enhance the fusion activity of the PIV5 F protein shift the mechanism of complement activation in the context of viral particles or on the surface of virus-infected cells, due to enhanced binding of antibodies. We present general models for the relationship between enhanced fusion activity in the paramyxovirus F protein and increased susceptibility to antibody-mediated neutralization.     

一株广谱中和抗原性出血热病毒株的发现

一株分离自杭州市褐家鼠的出血热病毒Gou_3株的免疫血清对10株I型病毒的中和滴度除二株为160外均为320,而对4株Ⅱ型病毒的滴度为320—640,说明Gou_3株免疫血清对两型毒株中和效价大多数无差异或只差2倍,是一株中和抗原广谱的毒株。用I型和Ⅱ型毒株免疫血清对Gou_3株进行型别检定结果表明Gou_3株是Ⅱ型病毒。     

Douglas and Tinaroo viruses: two Simbu group arboviruses infecting Culicoides brevitarsis and livestock in Australia

Two Australian members of the Simbu group, Douglas and Tinaroo viruses, were found to be distinct, by virus-neutralization tests, from three previously known Simbu group viruses isolated in Australia, namely Akabane, Aino and Peaton viruses. A low-titre, two-way, cross-reaction was noted between Akabane and Tinaroo viruses. Antibody to Tinaroo and Douglas viruses was detected in serum from cattle, buffalo, sheep, goats and deer but not in humans, pigs, kangaroos and wallabies. The results for horses were inconclusive. The distribution of antibodies to each virus falls mainly within the geographical distribution of the biting midge Culicoides brevitarsis, an insect from which each virus has been isolated.     

Comparison of rotavirus strains by hemagglutination inhibition.

Rotaviruses have been shown to be of importance as aetiologic agents of gastroenteritis in infants and in domestic animals of several species. Hemagglutinins were prepared from two Canadian isolates of bovine rotavirus and from one isolate of a simian rotavirus. A United Kingdon isolate of bovine rotavirus was shown not to possess hemagglutinating activity, indicating a strain difference between a Canadian and United Kingdom bovine rotavirus. In hemagglutination-inhibition (HAI) tests a rabbit hyperimmune (two injections) serum, prepared to one of the bovine rotaviruses, was not helpful in distinguishing the two bovine viruses because of cross-reactions between the viruses. However, it was possible to distinguish the bovine viruses from the simian virus with this serum. When guinea pig immune sera were prepared to the four rotavirus strains and tested with the three hemagglutinins in the HAI test, antigenic differences between the four strains of rotavirus were demonstrated. Hyperimmune guinea pig serum prepared to a strain of human rotavirus did not inhibit any of three hemagglutinins indicating that the human strain is different from the three rotavirus strains which gave hemagglutinins.     

Specific Inhibition of Mammalian Ribonucleic Acid C-Type Virus Deoxyribonucleic Acid Polymerases by Rat Antisera

Inhibition of the ribonucleic acid (RNA)- and deoxyribonucleic acid (DNA)-dependent DNA polymerase activities of mammalian C-type viruses was obtained with sera from rats bearing murine leukemia virus-induced transplant tumors. Polymerase activities of nonmammalian (viper) C-type virus and murine mammary tumor virus were not inhibited by such sera nor by serum from a rat immunized with the DNA polymerase of feline leukemia virus purified by isoelectric focusing. The latter serum appeared to inhibit preferentially the DNA-dependent DNA polymerase activity of mammalian C-type viruses showing no inhibition of RNA-dependent DNA synthesis.     

Detection of rabies virus antibodies in fruit bats (Eidolon helvum) from Nigeria

Fruit bats (Eidolon helvum) were collected from three different localities in Western Nigeria: Oti, Ibadan and Idanre. Fifty serum samples were analyzed using a modified rapid fluorescent focus inhibition technique against rabies, Mokola, Lagos bat and Duvenhage viruses. Twenty-five brain samples were screened for rabies and related lyssavirus antigens by direct fluorescent antibody microscopy and by an indirect fluorescent antibody technique with rabies anti-nucleocapsid monoclonal antibodies. All brain samples were negative. Two serum samples had relatively high anti-rabies activity; no neutralizing activity was detected against Mokola, Lagos bat or Duvenhage viruses.     

Non-invasive in vivo monitoring of trackable viruses expressing soluble marker peptides

Noninvasive methods are needed to study the kinetic properties of viruses in living organisms. Oncolytic viruses are used increasingly for cancer therapy but there is currently no satisfactory way to measure efficiency of tumor transduction, changing levels of viral gene expression or the timing of virus elimination. We therefore generated trackable oncolytic measles viruses expressing inert (nonimmunogenic, nonfunctional and accurately measurable) soluble marker peptides. The marker peptides did not compromise virus replication. Ex vivo and in vivo kinetics of the trackable viruses could be easily followed by measuring the concentrations of virally encoded marker peptides in culture supernatant or in serum. When mice bearing human tumor xenografts were challenged with the trackable viruses, distinct kinetic profiles of marker-gene expression could be correlated with distinct therapeutic outcomes. Oncolytic viruses expressing inert soluble marker polypeptides should greatly facilitate the rational development of effective, individually tailored cancer virotherapy.     

Antiviral activity of oxidized polyamines

Summary. Polyamines, oxidized by serum amine oxidase, yield aminoaldehydes and hydrogen peroxide. Acrolein may be formed from the aminoaldehydes by a spontaneous β-elimination process. These oxidation products “oxidized polyamines” inhibit bacterial growth and exhibit anticancer activity. The antimicrobial activity of oxidized polyamines is not limited to bacteria; and the inactivation of bacterial viruses, plant viruses and animal viruses, was also reported. Bacteriophages of the T-odd series are permeable and were inactivated by oxidized polyamines. The inactive phages absorb to their bacterial host and injected their DNA, which formed a stable inactive complex with the aminoaldehydes. Aminoaldehydes, synthesized chemically, also inactivated viruses. The growth of the plant viruses: Tobacco mosaic virus, Potato virus X and Alfalfa mosaic virus was also inhibited by oxidized polyamines. The animal viruses, which were inactivated by oxidized polyamines included Myxoviruses (influenza and Newcastle disease viruses), West Nile, vaccinia and Sindbis viruses. These findings may have practical implications.     

Important factors for testing barrier materials with surrogate viruses.

This study evaluated bacteriophages phi X174, T7, PRD1, and phi 6 as possible surrogates for pathogenic human viruses to challenge barrier materials and demonstrated some important factors for their use. Chemical incompatibility with test material was demonstrated when lipid-enveloped phi 6 was inactivated by an aqueous eluate of vinyl gloves, but 0.5% calf serum protected phi 6 from the eluate. Low concentrations (2%) of calf serum also prevented the exaggerated binding of the bacteriophages to filters. Recovery of viruses from surfaces decreased with increasing time before recovery. Penetration through punctures displayed different types of kinetics. The combined data indicate that (i) some bacteriophages may serve as surrogate viruses, (ii) experimental conditions determine whether a particular virus is appropriate as a challenge, and (iii) phi X174 is an excellent choice as a surrogate virus to test barrier materials. The data further indicate that before barrier materials are challenged with viruses, adequate tests should be performed to ensure that the virus is compatible with the test material and test conditions, so that meaningful data will result.     

Important factors for testing barrier materials with surrogate viruses.

This study evaluated bacteriophages phi X174, T7, PRD1, and phi 6 as possible surrogates for pathogenic human viruses to challenge barrier materials and demonstrated some important factors for their use. Chemical incompatibility with test material was demonstrated when lipid-enveloped phi 6 was inactivated by an aqueous eluate of vinyl gloves, but 0.5% calf serum protected phi 6 from the eluate. Low concentrations (2%) of calf serum also prevented the exaggerated binding of the bacteriophages to filters. Recovery of viruses from surfaces decreased with increasing time before recovery. Penetration through punctures displayed different types of kinetics. The combined data indicate that (i) some bacteriophages may serve as surrogate viruses, (ii) experimental conditions determine whether a particular virus is appropriate as a challenge, and (iii) phi X174 is an excellent choice as a surrogate virus to test barrier materials. The data further indicate that before barrier materials are challenged with viruses, adequate tests should be performed to ensure that the virus is compatible with the test material and test conditions, so that meaningful data will result.     

Evaluation of the human host range of bovine and porcine viruses that may contaminate bovine serum and porcine trypsin used in the manufacture of biological products

Current U.S. requirements for testing cell substrates used in production of human biological products for contamination with bovine and porcine viruses are U.S. Department of Agriculture (USDA) 9CFR tests for bovine serum or porcine trypsin. 9CFR requires testing of bovine serum for seven specific viruses in six families (immunofluorescence) and at least 2 additional families non-specifically (cytopathicity and hemadsorption). 9CFR testing of porcine trypsin is for porcine parvovirus. Recent contaminations suggest these tests may not be sufficient. Assay sensitivity was not the issue for these contaminations that were caused by viruses/virus families not represented in the 9CFR screen. A detailed literature search was undertaken to determine which viruses that infect cattle or swine or bovine or porcine cells in culture also have human host range [ability to infect humans or human cells in culture] and to predict their detection by the currently used 9CFR procedures. There are more viruses of potential risk to biological products manufactured using bovine or porcine raw materials than are likely to be detected by 9CFR testing procedures; even within families, not all members would necessarily be detected. Testing gaps and alternative methodologies should be evaluated to continue to ensure safe, high quality human biologicals.