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At least 1,621 records · Page 90Linked to original sources
PubMed1988

Partial characterization of a bovine group A rotavirus with a short genome electropherotype.

A group A rotavirus (ID isolate) recovered from a diarrheic beef calf possessed a short genome electropherotype. This short genome electropherotype was a stable characteristic of the ID isolate as it remained unchanged through 3 passages in gnotobiotic calves or through 19 passages in MA104 cell cultures. Subgroup analysis with monoclonal antibodies in an enzyme-linked immunosorbent assay established that the isolate was a subgroup 1 rotavirus. Neutralization tests demonstrated that this isolate was a distinct serotype from the human group A rotavirus S2 isolate (short genome electropherotype) and the turkey group A rotavirus 174 isolate (semi-short genome electropherotype). The ID isolate was pathogenic for 5- to 21-day-old gnotobiotic calves, inducing diarrhea within 48 h postinoculation.

Animals↗
PubMed1981

Assay of avian leukosis viruses by indirect immunoperoxidase method.

Chick embryo fibroblast cells (CEF) infected with avian leukosis viruses were stained selectively by the indirect immunoperoxidase method. Good results were obtained by the use of a successive combination of periodate-lysine-paraformaldehyde fixation and diaminobenzidine reaction mixture. Viral antigens were detected type-specifically on infected cells. Type-specific antisera determined by the neutralization test were absorbed by the homologous type of virus-infected CEF, but not by the heterologous type of these cells. This test was more effective for detecting virus infectivity than the resistance-inducing factor test. Viral antigen was observed 2 days after inoculation with a large amount of the virus. The minimum infective dose of the virus for the antigen detection was 100 resistance-inducing units (RIU) per plate 4 days after infection, or 1 RIU per plate in CEF after two passages.

Animals↗
PubMed1999

Update on the prevalence of serum antibodies (IgG and IgM) to adeno-associated virus (AAV).

In view of presumed non-pathogenicity, tumor suppressive properties, and site-specific integration of the viral genome the human parvovirus, adeno-associated virus (AAV) has gained great interest as a gene transduction vector. Data on the seroprevalence of antibodies to AAV vary between reports, probably due to the different serological methods used. In order to understand better the immune response to AAV during natural infection, sera from different age groups and various geographical regions were compared for AAV antibodies using an ELISA. The data show that the prevalence of antibodies to AAV is similar in Europe (Germany, France, and Switzerland), Brazil, and Japan, indicating worldwide infection. It was confirmed that infection takes place during childhood. However, declining seropositivity thereafter and a second increase of seropositivity after 30 years of age suggests reinfection or reactivation of latent virus in particular as the prevalence of IgM antibodies in adults is relatively high. Furthermore, pregnant women were found to be significantly more frequently seropositive than non-pregnant controls, hinting at a reactivation of persistent AAV (up to 80% of women carry AAV in genital tissue) in specific hormonal conditions, e.g., pregnancy. Cross-reaction of serum antibodies with the different AAV types (defined by complement fixation) was observed by ELISA and neutralization tests confirming earlier results. The results suggest an unstable AAV antibody response allowing lifelong reinfection or reactivation of persisting virus possibly due to partial immunotolerance after an infection in utero, at delivery or during early infancy.

Adolescent↗
PubMedDate not supplied

[Properties of influenza virus strains causing the influenza epidemic in Moscow in 1972-3].

The antigenic and some biological properties of influenza virus strains isolated during 1972-1973 epidemic were studied. Altogether 114 strains were isolated from sick infants of the first months of life beginning from neonatality. The strains under study were found to have high adaptation and elution activity, to be highly sensitive to inhibitors and to produce polymorphous allantoic population in the adaptation period. The hemagglutinating and neuraminidase components were shown to be fairly closely related to those of the membrane of the reference A2/Hong Kong/1/68 strain (H3N2). At the same time, a low neutralizing activity of the antisera for this strain against Moscow strains of 1972-1973 in biological neutralization tests in chick embryos was observed, explaining very high susceptibility of the population to influenza type A infection in the winter of 1972-1973. The strains under study were antigenically homogenous and most closely related to the reference A2/England/42/72 (H3N2) strain.

Antigens, Viral↗
PubMed1994

Neutralizing antibodies to phocine distemper virus in Atlantic walruses (Odobenus rosmarus rosmarus) from Arctic Canada.

The first evidence of phocine distemper virus (PDV) infection in Atlantic walruses (Odobenus rosmarus rosmarus) from Nottingham Island, Northwest Territories, Canada, is reported. Blood samples were collected from three male walruses killed by Inuit hunters in the fall of 1990. Differential virus neutralization test for each animal yielded higher titers against PDV than against other members of the Morbillivirus genus including canine distemper, peste des petits ruminants, rinderpest and measles viruses. Thus, PDV infection may be enzootic in walruses of the eastern Canadian Arctic.

Animals↗
PubMed1997

[Outbreak of Coxsackievirus B5 meningoencephalitis in Cuba, 1995].

An increase in the reported cases of viral meningoencephalitis (VME) was detected in October and November, 1995, compared with the same period of 1994. 43 stock specimens from children with this diagnosis were received at the Laboratory of Enterovirus from the "Pedro Kourí" Institute of Tropical Medicine. 23 isolations (53.4%) were obtained and identified as Coxsackievirus B5. Besides, in 43 matched sera investigated by the neutralization test against some Enteroviruses, 21 proved to be positive (48.8%) to the isolated agent. This allowed us to affirm, supported by the clinical picture and by epidemiology, that we are in the presence of an VME outbreak produced by Coxsackievirus B5.

Animals↗
PubMed2003

Isolation of a new flavivirus related to cell fusing agent virus (CFAV) from field-collected flood-water Aedes mosquitoes sampled from a dambo in central Kenya.

Cell fusing agent virus (CFAV) is an RNA insect virus that was isolated from a line of Aedes aegypti mosquito cells and has been assigned to the family Flaviviridae, genus Flavivirus. We report here the first isolation of a CFA-like virus from field-collected mosquitoes. Mosquito larvae and pupae were sampled from flooded dambos in Central Province, Kenya during the short rain season of 1999. Specimens were reared to adults, identified and pooled by species and were tested for the presence of virus. Two virus isolates were obtained from two pools of Aedes macintoshi mosquitoes. The virus isolates replicated only in invertebrate cells in culture and not in vertebrate cells or in mice. The virus isolates did not antigenically cross-react with known arboviruses but were identified to family by reverse-transcriptase polymerase chain reaction (RT-PCR) performed using primers specific to alphaviruses, bunyaviruses and flaviviruses; only the flavivirus-specific primers produced a DNA fragment of the expected size. Nucleic acid sequencing of this fragment showed the two isolates to be nearly identical. Comparison of sequences to the GenBank database using BLAST identified the virus as most closely related to CFAV. Results from cross-neutralization tests suggested that, although the BLAST search indicated homology to CFAV, the virus isolated represented a new insect flavivirus. Detailed characterization of this new virus, described in Crabtree et al. [7], further supports this finding. We propose this new flavivirus be designated Kamiti River virus (KRV). This is the first isolation of a CFA-like virus from field-collected mosquitoes and indicates the presence of this group of viruses in nature.

Aedes↗
PubMed1974

Swine vesicular disease: comparative studies of viruses isolated from different countries.

Seven viruses isolated from outbreaks of swine vesicular disease in various countries between 1966 and 1973 were compared in pigs and infant mice. All produced a similar disease and virus excretion pattern in the pig, although the Italy/66 virus was considerably less virulent than the other viruses. The results of cross neutralization tests of convalescent pig sera and the response of 5-day-old mice to intraperitoneal inoculation indicated minor differences between some viruses. The Italy/66, Hong Kong/71 and France/73 viruses differed from each other and also from the Italy/72, England/72, Austria/73 and Poland/73 group of viruses.

Animals↗
PubMed1983

Characterization of a herpes simplex virus type 2 75,000-molecular-weight glycoprotein antigenically related to herpes simplex virus type 1 glycoprotein C.

Evidence is presented that the herpes simplex virus type 2 glycoprotein previously designated gF is antigenically related to herpes simplex virus type 1 gC (gC-1). An antiserum prepared against type 1 virion envelope proteins immunoprecipitated gF of type 2 (gF-2), and competition experiments revealed that the anti-gC-1 component of the antiserum was responsible for the anti-gF-2 cross-reactivity. An antiserum prepared against fully denatured purified gF-2, however, and three anti-gF-2 monoclonal antibodies failed to precipitate any type 1 antigen, indicating that the extent of cross-reactivity between gC-1 and gF-2 may be limited. Several aspects of gF-2 synthesis and processing were investigated. Use of the enzymes endo-beta-N-acetylglucosaminidase H and alpha-D-N-acetylgalactosaminyl oligosaccharidase revealed that the fully processed form of gF-2 (about 75,000 [75K] apparent molecular weight) had both complex-type N-linked and O-linked oligosaccharides, whereas newly synthesized forms (67K and 69K) had only high-mannose N-linked oligosaccharides. These last two forms were both reduced in size to 54K by treatment with endo-beta-N-acetylglucosaminidase H and therefore appear to differ only in the number of N-linked chains. Neutralization tests and radioiodination experiments revealed that gF-2 is exposed on the surfaces of virions and that the 75K form of gF-2 is exposed on cell surfaces. The similarities and differences of gF-2 and gC-1 are discussed in light of recent mapping results which suggest collinearity of their respective genes.

Antigens, Viral↗
PubMedDate not supplied

Plaque dissociation of herpes simplex viruses: biochemical and biological characters of the viral variants.

Polycaryocytogenic (P) and non-polycaryocytogenic, or aggregating (A), stable variants were selected from a herpes simplex virus type 1 (HSV-1) and from a herpes simplex virus type 2 (HSV 2) which had not been deliberately exposed to known mutagenic agents. The P variant of HSV-1 (FP) differed from the A variant (FA) in polypeptides and glycoprotein patterns, but no gross differences were evident between the two variants of HSV-2 (GP and GA). Each P variant proved more 'specific' than each A variant in immune neutralization tests. At high multiplicity, GP produced polycaryocytes but FP did not. Virulence tests in mice showed FP to be much more virulent than FA but GA to be more virulent than GP. Finally, A and P variants of each type could not be differentiated with respect to thermal resistance of virons, capacity to grow at high temperature, and buoyant density of DNA.

Cell Line↗
PubMed1982

Congenital factor VII deficiency. Clinical and laboratory characteristics of a newly discovered kindred.

Four generations of a newly discovered kindred suffering from congenital factor VII deficiency have been studied. The abnormality was transmitted as an autosomal recessive character and resulted in homozygotes with less than 1% factor VII procoagulant activity. Antibody neutralization tests using a monospecific rabbit anti-human factor VII antibody demonstrated the presence of factor VII antigen in excess of factor VII procoagulant activity. The disorder has therefore resulted from the presence of a functionally abnormal factor VII molecule and not from a true deficiency of this factor. When the plasmas from the homozygotes were tested in the prothrombin time test using human, rabbit and ox tissue thromboplastins, a progressive diminution in the ability of these reagents to detect the factor VII procoagulant deficiency was observed. These differences were however small and the complete insensitivity of ox brain thromboplastins that characterizes the factor VII Padua abnormality was not observed.

Adolescent↗
PubMed1981

Herpes simplex type 2 neutralization antibodies in patients with cancers of urinary bladder, prostate, and cervix.

In the blood samples obtained from a total of 68 patients with cancers of the urinary bladder, prostate, and cervix, who applied to the Departments of Urology, Obstetrics, and Gynecology of Hacettepe Medical Faculty, neutralizing antibodies were sought for against herpes simplex type 2 by neutralization test. The same test was applied to 35 control patients with no known malignancies. In contrast to the presence of the antibody in 62.86% of the control subjects, this ratio was 90.70% in patients with cancer of the urinary bladder, 87.50% in those with prostatic carcinoma, and 88.89% in those with cancer of the cervix.

Adult↗
PubMed1988

Isolation and characterization of caliciviruses from dogs with vesicular genital disease.

Two virus isolates, one from lesions of the vagina of a Bearded Collie and the other from the penis and prepuce of a Black Labrador, were partially characterized. The two viruses possessed the physicochemical properties, size and morphology of viruses belonging to the family Caliciviridae. The two isolates were shown by cross neutralization tests to be distinct from previously reported canine and feline caliciviruses. The viruses, isolated four years apart, are antigenically related. Additional studies are necessary to determine whether they are two distinct viruses or strains of another serotype belonging to the caliciviruses of the canine species.

Animals↗
PubMed2004

Seroprevalence of IgG specific for dengue virus among adults and children in Santo Domingo, Dominican Republic.

The seroprevalence of dengue (DEN) virus-specific IgG was determined by enzyme-linked immunosorbent assay among 1,008 adults recruited at blood banks and among 201 children less than 10 years old visiting a hospital in Santo Domingo, Dominican Republic. Most (98%, 987 of 1,008) of the adults and 56% (113 of 201) of the children were positive for DEN virus-specific IgG. Among adults, there were no significant differences in the prevalence by age, sex, and residential area of the participants. Among children, the prevalence of DEN virus-specific IgG increased with age (1-2 years old, 0-5%; 3-6 years old, 25-65%; and >/=7 years old, 76-92%). The prevalence in 50% of those less than one year of age was probably due to maternal antibody transfer. Neutralization tests of adult samples indicate that DEN virus infections with different serotypes have occurred sequentially or simultaneously among the inhabitants of Santo Domingo.

Adolescent↗
PubMed1977

Neutralization kinetics studies with type SAT 2 foot-and-mouth disease virus strains.

A comparison of homologous and heterologous rates of neutralization demonstrated that antigenic relationships of foot-and-mouth disease virus strains could be differentiated quantitatively by the kinetics of neutralization method described previously (Rwysed this way gave R values which were similar to those obtained with other neutralization test methods but which were generally smaller than those obtained with complement fixation test results. It was demonstrated that there were wide differences between the vaccine strains tested as demonstrated by R value relationships. An examination of r values, however, demonstrated that antisera to the Moz 1/70 strain were highly reactive with most of the virus strains from Central and Southern Africa. The selection of FMD virus strains with a wide serological range for vaccine production is discussed.

Animals↗
PubMed1978

Antigenic relatedness of 17 strains of human cytomegalovirus.

A 10 minute kinetic neutralization test was used to assess antigenic relatedness among 17 strains of human cytomegalovirus. Hyperimmune guinea pig sera exhibited extensive cross-reactivity. However, the data did suggest that there may be four antigenic groups represented in this collection of CMV strains. Available epidemiologic data for these strains do not provide any discernible basis for this grouping.

Animals↗
PubMed1999

Monoclonal antibodies to an Indian strain of type A foot-and-mouth disease virus.

A set of five neutralizing monoclonal antibodies (MAbs) to an Indian strain (IND17/77) of type A (subtype A22) foot-and-mouth disease (FMD) virus (FMDV) was used in the study. Four of the MAbs (27S, 37S, 85S, and 143S) identified a trypsin-sensitive (TS) epitope(s) and were specific for VP1, while the remaining MAb (145S) reacted with a trypsin-resistant (TR) epitope and was specific for VP3 in Western blot analysis. Both the epitopes (TS and TR) were conformation-independent in nature. Results obtained in MAb-competition enzyme-linked immunosorbent assay (ELISA), and profiling of the (MAb) neutralization-escape mutants in ELISA and cross-neutralization test revealed two overlapping TS epitopes (27S/37S and 85S/143S) on the virus. Variation at both these epitopes was observed in some field isolates of serotype A. Comparison of deduced amino acid sequence in the VP1 region (aa 140-213) between the parent virus and the mutants identified Gly148 and Arg153 as critical for the formation of both the TS epitopes. Substitution of R153 by Gly or Ser was observed in mutants with no reactivity for the MAbs 85S/143S. However, these mutants maintained partial reactivity with MAbs 27S/37S, and substitution of Gly148 by Glu eliminated both the epitopes. No amino acid substitution was observed in the VP1 region of aa 200-213. Efficient neutralization of the MAb neutralization escape mutants (MAb-resistant (MAR) mutants) by bovine vaccinate serum (BVS) indicated involvement of other epitopes on the virion surface in eliciting neutralizing antibodies following vaccination.

Amino Acid Substitution↗