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At least 1,207 records · Page 67Linked to original sources
PubMed1996

Prevalence of antibodies to mosquito-borne encephalitis viruses in residents of the Coachella Valley, California.

Sera from 19 (2.6%) and 118 (16.4%) of 719 outpatients attending clinics in the southeastern Coachella Valley, California during 1993 and 1994 exhibited IgG antibodies to western equine encephalomyelitis and St. Louis encephalitis (SLE) viruses, respectively, using enzyme immunoassays. However, only seven (1.0%) and 36 (5.0%) outpatients were positive by plaque-reduction neutralization tests (PRNTs), and seven (1.0%) and 84 (11.7%) outpatients were positive by sera hemagglutination inhibition assays, respectively. None were positive for IgM antibodies indicative of recent infection or were diagnosed clinically with central nervous system disease. Prevalence of PRNT antibody to SLE increased as a function of patient age, but did not vary significantly in relation to years of residence, sex, race, postal zip code, occupation, or month of collection.

Adolescent↗
PubMed1981

[Immunochemical methods of determining myoglobin in blood and urine].

An immunological method for determining myoglobin in biological liquids has been developed. Application of tritiated myoglobin in radioimmunoassay (RIA) opens up an opportunity to create a Soviet long stored RIA kit. The use of the antibody neutralization test to detect hypermyoglobulinemia and myoglobinuria in myocardial infarction patients is characterized by simplicity, little time consuming, and may be used in practical medicine as a preliminary test in timely diagnosis of myocardial infarction.

Adult↗
PubMed1980

Seroepidemiology of human syncytial virus: antibody prevalence in the Pacific.

A seroepidemiological survey of the human syncytial (foamy) virus was done by means of an indirect immunofluorescence test on 1,717 sera from nine different Pacific island territories. The specificity of the reaction was verified by neutralization tests. The study indicated that the virus is ubiquitous in this part of the world, with no region being entirely free of antibody. The antibody prevalence ranged from a low of 1.2% in Ponape to a high of 15.6% in the Cook Islands. The average prevalence for the nine insular communities was 6.9%.

Antibodies, Viral↗
PubMed1985

Modoc-like virus isolated from wild deer mice (Peromyscus maniculatus) in Alberta.

Small mammals were trapped in northeastern Alberta, Canada during 1976. Blood samples from these animals were tested for virus by inoculation of suckling mice. Blood clots from two deer mice yielded isolates of the same virus. The virus was related antigenically to a number of flaviviruses which have been isolated from mammals in Central America and North America and was related most closely to Modoc virus. Physical, chemical, and biological properties of the virus were similar also to those of Modoc virus. It did not produce illness or death in deer mice inoculated in the laboratory. Neutralization tests indicated that 1/38 (3%) red squirrels (Tamiasciurus hudsonicus), 3/35 (9%) least chipmunks (Eutamius minimus), 13/109 (12%) deer mice, and 3/50 (6%) humans were infected naturally. This is the first reported evidence of infection of red squirrels and chipmunks with a Modoc-like virus. These data extend the range of Modoc-like viruses northward by 1,500 km and comprise the first isolate from mammals in the boreal forest of Canada.

Alberta↗
PubMed1985

Neutralization of yellow fever virus studied using monoclonal and polyclonal antibodies.

Monoclonal and polyclonal antibodies with known specificity for either the 54K envelope glycoprotein or the 48K non-structural glycoprotein of yellow fever (YF) virus-infected cells were studied in plaque reduction neutralization tests. Viruses employed in the tests comprised wild-type and vaccine strains of YF and a selection of other flaviviruses. Of 17 monoclonal antibodies examined, six of the 54K-specific antibodies neutralized at least one YF preparation. Both vaccine and wild-type YF viruses varied in their susceptibility to neutralization and there were also differences between individual 17D vaccine strains. The monoclonal antibodies produced a range of titres with the different viruses, the most potent, 864, leaving no non-neutralizable fraction. Addition of anti-globulin, complement or other antibodies did not affect the results. YF-neutralize antibodies which bound to other flaviviruses did not necessarily neutralize them; hence, neutralization could be defined as either homotypic, heterotypic or both homotypic and heterotypic. A polyclonal antiserum and a broadly reacting monoclonal antibody produced almost identical neutralization results in tests with wild-type YF viruses. In contrast, the polyclonal antiserum produced higher titres with vaccine strains of YF. In mouse passive protection experiments on the other hand, the monoclonal antibody did not differentiate between these viruses.

Animals↗
PubMed1987

Studies on the classification of bovine enteroviruses.

Bovine enteroviruses isolated from cattle and other ruminants in various areas of the world were classified into three distinct serotypes by cross-neutralization tests using criteria established for the differentiation of human enteroviruses. According to Western blot analysis, however, immunodominant structural polypeptides VP1 of the viruses tested have common epitopes, recognized by antisera to each of the three serotypes. These findings indicate that non-neutralizing epitopes on VP1 are generally conserved. It is, therefore, conjectured that bovine enteroviruses were derived from a common ancestor.

Animals↗
PubMed1974

Neutralizing antibody response of guinea pigs to lymphocytic choriomeningitis virus.

A 24-h neutralization test that is based on fluorescent cell counting was used for the detection and quantitative determination of serum-neutralizing antibody against lymphocytic choriomeningitis virus. The earliest manifestation of serum-neutralizing antibody in guinea pigs was shown to occur within 1 week after inoculation with lymphocytic choriomeningitis virus. Within 11 weeks, serum-neutralizing antibody increased from 20- to 300-fold. Neutralizing end points of serum samples, obtained from 3 through 11 weeks, were enhanced as much as sevenfold by complement. Anti-guinea pig immunoglobulin G or anti-whole guinea pig serum potentiated the neutralizing activity of serum as much as 20- and 40-fold, respectively.

Animals↗
PubMed1985

Enzyme-linked immunosorbent assay for identification and measurement of antibodies to group A streptococcal bacteriophage.

A sensitive enzyme immunoassay (ELISA) was developed to identify and measure antibodies to group A streptococcal bacteriophage hyaluronidase. With a purified preparation of bacteriophage hyaluronidase as the solid-phase antigen, the ELISA was shown to be as specific as and more sensitive than the standard bacteriophage neutralization test for measurement of antibody to bacteriophage. In rabbits immunized with bacteriophage, the ELISA detected antibody earlier than the neutralization assay (7 vs. 11 days) and was able to distinguish IgG and IgM class antibodies. A strong correlation was demonstrated between antibody titers measured by ELISA and bacteriophage neutralization (r = 0.88; P less than 0.001). Preliminary data using the ELISA, modified to measure human antibody to bacteriophage hyaluronidase, indicated that an antibody response of both IgG and IgM classes occurred in humans after group A streptococcal infection. This ELISA provided a sensitive method for detection and measurement of antibody to a specific bacteriophage antigen, which will be useful in the investigation of the role of bacteriophage in the pathogenesis of group A streptococcal infections.

Animals↗
PubMed1979

Antitoxic immunity against the so-called lung toxin produced by Escherichia coli.

Cross neutralization test with antisera to crude haemolysins produced by some Escherichia coli strains indicated that there were no antigenic differences among the haemolysins tested. These crude preparates showed definite cytotoxicity which could also be cross neutralized by "antihaemolysin" sera. Neutralization experiments were performed in mouse lung test with homologous and heterologous anti-haemolysin sera, and with O and OK sera to the wild type strain and its toxic R mutant. The results showed that the immunity in the mouse lung model is antitoxic and antibacterial.

Animals↗
PubMed1977

Lyophilized combination pools of enterovirus equine antisera: preparation and test procedures for the identification of field strains of 19 group A coxsackievirus serotypes.

This paper describes the preparation of seven combination pools of equine antisera, designated J though P, for identification of 19 coxsackievirus A immunotypes. Each pool is composed of 4 to 6 antisera; the serotypes included are A1-6, 8, 10-15, and 17-22. These pools, unlike the previously prepared A-H enterovirus pools, were lyophilized from volumes of 0.5 ml dispensed into 5-ml vials, and when rehydrated with 5 ml of diluent provide 50-antibody-unit material ready for use in identification tests without further dilution. Procedures for using the antiserum pools are given, and guidance is provided for interpreting the results of serum neutralization tests in identifying field isolates.

Animals↗
PubMed1988

[An immunoenzyme test used for the detection of antibodies to rinderpest: the advantage of using a purified virus cultivated in a cell line].

Two types of in vitro assays (enzyme immunoassay and sero-neutralization test) were compared for their ability to detect antibodies to rinderpest virus in field sera from West African bovines. Purified virus grown on Vero cells (Ag/Vero) or bovine kidney cells (Ag/BK), were tested as antigen in enzyme-linked immunoassays (EIA). The results of the comparative evaluation of the two antigens by EIA, prove that Ag/Vero did enhance the sensitivity and the specificity of the test in comparison to Ag/BK and offers a 94% correspondence with seroneutralization.

Animals↗
PubMed1997

Rift Valley fever virus: a seroepidemiologic study of small terrestrial vertebrates in South Africa.

Epizootics of Rift Valley fever (RVF) are often associated with periods of heavy rainfall, which are favorable for mosquito vectors. However, in seasons with normal or low rainfall, enzootic circulation occurs, suggesting the existence of a natural host that can act as a cryptic carrier during interepizootic periods. To confirm the role of heavy rainfall in epizootic circulation, and to identify a possible natural host of RVF virus, serum samples from small terrestrial mammals in the Free State and Northern Cape regions of South Africa were collected before and after the 1988 floods. These areas are known to support epizootic circulation of RVF virus. The samples were tested for the presence of RVF virus-specific IgG using an ELISA and positive sera were confirmed by a neutralization test. Forty-seven (15%) of 312 Aethomys namaquensis (Namaqua rock rat) had antibodies to RVF virus. Of these positive sera, nine (6%) of 141 were collected before the floods of 1988 and 38 (22%) of 171 were collected afterwards (P = 0.001). Naive A. namaquensis were inoculated with RVF virus and developed a viremia, but no clinical symptoms, suggesting that they can act as temporary asymptomatic carriers of the virus. These results suggest a role for A. namaquensis as a cryptic carrier for RVF virus during interepizootic periods and support the results of other studies suggesting an amplifying role for heavy rainfall in the circulation of RVF virus.

Animals↗
PubMed1984

Isolation and serotyping of porcine rotaviruses and antigenic comparison with other rotaviruses.

Seven rotavirus strains were isolated in cell cultures from the intestinal contents of piglets with diarrhea. MA104 cells with pancreatin in the cell culture medium was the host system of choice for virus isolation and replication. A cell culture immunofluorescence test in which MA104 cells were used in microtiter plates was very effective for detecting and assaying rotaviruses. A plaque reduction neutralization test, cross-protection studies in gnotobiotic pigs, and electrophoresis of rotaviral double-stranded RNA were used for comparing viruses. Three strains produced plaques on initial isolation attempts, replicated well in cell cultures, and were antigenically very similar. We suggest that these three strains be considered porcine rotavirus serotype 1, with The Ohio State University (OSU) strain serving as the prototype. The OSU strain was distinct from bovine, simian, canine, and human (Wa and M) rotaviruses by plaque reduction neutralization. Four strains did not produce plaques on initial isolation attempts, were difficult to adapt to cell cultures, and were related to each other but were distinct from the serotype 1 strains. We suggest that the Gottfried (G) strain be tentatively considered as a prototype for porcine rotavirus serotype 2. The G strain was antigenically closely related to canine and simian rotaviruses and less so to human M rotavirus (human rotavirus serotype 3). Canine, simian, and human M rotaviruses were closely related. All seven porcine rotavirus strains caused diarrhea in gnotobiotic pigs. Cell-cultured vaccines of the OSU and G strains caused only mild or no diarrhea in gnotobiotic pigs, and protection occurred when such pigs were challenged with homologous, bur not heterologous, virulent viruses. A survey indicated that 94% of 274 porcine serum samples and 100% of 75 herds were serologically positive to the porcine OSU rotavirus.

Animals↗
PubMed1989

[The clinico-laboratory characteristics of cases of diseases connected with viruses of the California encephalitis complex in the inhabitants of Moscow].

To study the role of viruses of the California encephalitis virus complex (the family Bunyaviridae) in infectious pathology, 187 fever patients admitted to the Clinical Infectious Hospital in May-September 1986 were examined. In 10 of these patients the neutralization test revealed the presence of diagnostically significant changes in neutralizing antibodies (neutralization indices), which was indicative of the role played by Tahyna virus or other related viruses belonging to the California encephalitis virus complex in the etiology of the diseases. The analysis of the clinical picture showed that in all patients the disease took an acute course in its initial stage, starting with shivering and characterized by high fever, headache, pronounced toxicosis, the possibility of the formation of intracerebral hypertension and pneumonia.

Acute Disease↗
PubMed1976

Comparative studies of Epstein-Barr virus strains from Ghana and the United States.

A high incidence of oropharyngeal excretion of Epstein-Barr virus (EBV) has been observed in African children with Burkitt's lymphoma (BL) (48%) and matched controls (45%). This compares with an incidence of 77% in American patients with infectious mononucleosis (IM) and 13% in age-matched controls. Cross-neutralization tests between EBV strains derived from BL and IM patients and their sera failed to detect differences in the major neutralizing antigenic components. Cord-blood lymphocytes transformed by American EBV expressed only early viral functions (EBV nuclear and soluble complement-fixing antigens) and produced no detectable transforming activity. By contrast, cord-blood lymphocytes transformed by African EBV strains contained 0.2-0.3% of cells with EBV capsid and early antigen and produced EBV with transforming activity. These cells contained twice as many copies of EBV homologous DNA as the cells transformed by American EBV strains.

Adolescent↗
PubMed1989

Analysis of the roles of bluetongue virus outer capsid proteins VP2 and VP5 in determination of virus serotype.

Analyses of reassortant and parental strains of BTV serotypes 3 and 10, in serum neutralization tests, confirmed the major role of outer capsid protein VP2 in determination of virus serotype and its involvement in serum neutralization. However, a reassortant BTV strain (R70), containing protein VP5 derived from BTV 3 and VP2 derived from BTV 10, cross-neutralized with both parental virus strains (BTV 3 and BTV 10). It is concluded that VP5 also plays some part in serotype determination of these virus isolates, as analyzed by serum-neutralization, but its role may be less significant than that of VP2.

Animals↗
PubMed1977

Persistence of maternal antibody in infants beyond 12 months: mechanism of measles vaccine failure.

A serologic study was made in 34 children immunized against measles at the age of 12 months. Using a sensitive virus neutralization test, it was found that many of the children had pre-existing maternal antibody to measles virus. Children with high pre-existing antibody titers failed to seroconvert. Children with lower pre-existing antibody titers seroconverted, but the resulting antibody titer was significantly lower than in children without pre-existing antibody titer. The results of this study demonstrate a probably mechanism for measles vaccine failure in 12-month-old children and support the recommendation of the Public Health Service Advisory Committee on Immunization Practices to postpone measles vaccination to 15 months of age.

Age Factors↗
PubMed1975

Antigenic and biologic characteristics of Venezuelan encephalitis virus strains including a possible new subtype, isolated from the Amazon region of Peru in 1971.

Nine strains of Venezuelan encephalitis (VE) virus isolated from the Amazon region of Peru in 1971 were identified as antigenic subtype I based on plaque-reduction neutralization tests with four and 20 units of antibody. A tenth strain, 71D1252, was possibly a new subtype, but was related to subtypes I and III. Hemagglutinins of each strain made from infected mouse brains had optimals pHs of 6.2 and 6.4. Nine strains were pathogenic for adult hamsters and adult mice, but strain 71D1252 inapparently infected some adult hamsters and mice inoculated peripherally. Plaques of nine strains in Vero African green monkey kidney cell cultures were intermediate in size between representative epizootic and enzootic strains, but plaques of strain 71D1252 were small like epizootic strains.

Animals↗