THE COMBINED EFFECT OF PASTEURELLA MULTOCIDA AND MYXOVIRUS PARAINFLUENZA-3 UPON CALVES.
Explore the source record for details and available documents.
Animals↗
SEARCH · Search PubMed
Results for “Neutralization Tests”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
[STUDY OF THE INTERACTION AMONG THE "TRANSITIONAL STRAINS" OF THE INFLUENZA VIRUS A2 AND THAT IN THE SERA OF NORMAL GUINEA PIGS CONTAINING INHIBITOR].
Explore the source record for details and available documents.
Animals↗
Isolation of etiological agent of hydropericardium syndrome in chicken embryo liver cell culture and its serological characterization.
The virus causing hydropericardium syndrome was isolated in chicken embryo liver (CEL) cell culture from livers obtained from naturally infected broilers. The cytopathic effects characterized by rounding and degeneration of cells were visible 36 hr post infection in first passage. At 4th passage level, the infectivity titre was 5.24 log10 TCID50/ml. In May-Grunwald and Giemsa stained cells, basophilic intranuclear inclusions ('bird eye' inclusion), typical of aviadenovirus infection, were observed. The specificity of inclusion was confirmed by indirect immunofluorescence. Various serological tests, such as agar gel precipitation test, counter immuno electrophoresis, micro serum neutralization test and enzyme linked immunosorbent assay were also standardized to confirm the isolation of etiological agent of hydropericardium syndrome in CEL cell culture and to diagnose the disease in poultry.
Adenoviridae Infections↗
[Prevalence for seropositivity for HIV, hepatitis B and hepatitis C in blood donors].
Despite utilizing different actions to render blood safe for transfusions, we continue to have the risk of transmitting some viral infections. For this reason, it is important to determine prevalence of infections due to HIV and hepatitis B and hepatitis C viruses in blood donors. Previous studies from Mexico indicate that HIV prevalence is 0.01 to 0.13%, while it is 0.11 to 1.22% for hepatitis B, and for hepatitis C, prevalence is 0.47 to 1.47%. We are checking the results of the screening tests (ELISA 3rd generation and chemiluminescent immunoassays) from blood donors studied at the Central Blood Bank (Banco Central de Sangre) at the Mexican Institute of Social Security's (IMSS) Twentieth First Century National Medical Center in Mexico City from 1995 to 2002. Reactive results were studied by confirmatory tests, Western Blot for HIV, AgHBs neutralization test for hepatitis B, and RIBA-HCV3.0 for hepatitis C. Reactive results from 513,062 blood donors confirmed for HV were 0.07%, reactive results and confirmation of hepatitis B from 511,733 blood donors were 0.13%, and reactive results and confirmation of hepatitis C from 511,115 blood donors were 0.31%. Rates obtained are low when compared with results of previous studies in Mexico for HIV, hepatitis B, and hepatitis C. It may be possible than these low rates indicate the positive impact obtained from preventive actions, better strategies of detection of blood donors with high risk, and the advantage of working with a fully automated test system with state-of-the-art technology.
Blood Donors↗
Comparison of commercially available and novel West Nile virus immunoassays for detection of seroconversion in pig-tailed macaques (Macaca nemestrina).
We report the assessment and validation of an NS1 epitope-blocking enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to West Nile virus (WNV) in macaques. Sera from naturally infected Macaca nemestrina were tested by ELISA and plaque reduction neutralization test (PRNT). Results were correlated with hemagglutination inhibition (HAI) data. Our results demonstrate that the blocking ELISA rapidly and specifically detects WNV infection in M. nemestrina. In addition, the diagnostic value of 7 commercially available immunoassays (PanBio immunoglobulin [Ig] M ELISA, PanBio IgG ELISA, PanBio immunofluorescence assay (IFA), InBios IgG ELISA, InBios IgM ELISA, Focus Diagnostics IgG ELISA, and Focus Diagnostics IgM ELISA) in M. nemestrina was evaluated and compared with that of the epitope-blocking ELISA. The PanBio IgG ELISA was found to effectively diagnose WNV exposure in M. nemestrina. Further, PanBio IFA slides are fast and reliable screening tools for diagnosing flaviviral exposure in M. nemestrina.
Animals↗
A study of the immuno-suppressive activity of Herpes simplex virus type 2 and the tumor enhancing potential of the virus on Yoshida sarcoma.
The relative delays of Yoshida sarcoma (YS) tumor induction were used as indicator for the immunosuppressive potential caused by the subcutaneous infection of Sprague-Dawley rats with approximately 10(7) TCD50 HSV-2. The tumor formation is clearly accelerated and the number of tumors is increased as compared to sham injected rats. The impairment of immunity is at its maximum when the virus and the YS cells are applied simultaneously, whereas virus given after the tumor is of no consequence. The adoptive neutralization test of Winn showed that the neutralization potential of spleen cells originating from HSV-2 infected donors is decreased from day 8 to day 11 post infection but rturns back to normal a week later. The stimulation of spleen cells with PHA is reduced up to 50% of control values on day 6 to 8 post virus infection but PFC and RFC values are not noticeably affected and neither are the hemagglutination titres. The implications of the immuno-suppressive faculty of HSV-2 for human genital malignancies are discuss.ed.
Animals↗
Antibody response in pigs inoculated with transmissible gastroenteritis virus and cross reactions among ten isolates.
Groups of two or three day old pigs were inoculated intravenously with cell culture grown transmissible gastroenteritis virus. A single or a multiple dosage schedule was used. The magnitude of immune response was measured in terms of serum neutralization indices. A single dose of relatively attenuated virus caused mild clinical signs of transmissible gastroenteritis infection in the pigs and induced a low level of antibody in the serum by the seventh day after inoculation. Repeated injections of virus at seven day intervals stimulated little increase in antibody titers. However, high serum antibody titers were obtained for all pigs if the time interval between injections was extended to 15 days. Sera obtained early after exposure to live transmissible gastroenteritis virus contained mainly IgM antibody whereas sera obtained later after exposure contained mainly IgG antibody. Ten plaque purified isolates of transmissible gastroenteritis virus, comprising eight American isolates, one Japanese isolate and one British isolate were indistinguishable by means of reciprocal plaque reduction neutralization tests.
Animals↗
[The role of Hantaan virus serotypes in the etiology of hemorrhagic fever with renal syndrome in the Far East of the USSR].
The employment of two serological tests (indirect fluorescence antibody technique and neutralization test) demonstrated the leading role of Hantaan virus serotype 1 strains isolated from field mice in the pattern of the incidence of hemorrhagic fever with renal syndrome (HFRS). Proofs of the etiological importance of strains of serotypes 3 and 5 occurring in brown rats and Cl. rufocanus were obtained. No data on any association of human HFRS cases with strains of serotype 4 isolated from reed voles could be demonstrated.
Animals↗
[An arbovirus study of pregnant women in Southern Moravia].
The authors revealed by means of the haemagglutination-inhibition test (HIT) and the plaque reduction neutralization test (PRNT) that in 1983 to 1985 pregnant women in the Breclav district became infected with the Tahyna virus. HI antibodies against the virus were detected in 96 (28.4%) women from a total of 338 examined. A new infection was proved in 15 (4.4%) women. The majority of infections was contracted in August to October. Positive results were supported by the PRNT. Antibodies against arboviruses Sindbis, Calovo, West Nile, tick-borne encephalitis, Bhandza were not detected in any of the women.
Adolescent↗
Serological relationship among ten strains of avian infectious bronchitis virus.
Ten strains of avian infectious bronchitis virus (IBV) were studied serologically by cross-neutralization test using rabbit and chicken immune sera. With the chicken sera all 10 IBV strains were antigenically related. In particular, anti-KH serum neutralized all heterologous strains except of the Ishida strain; Nerima strain was neutralized by all antisera except of anti-Ishida serum. Most cross-reactions were less or more heterologous, thus all 10 IBV strains seemed to belong to one serological type. Using rabbit sera, all strains except of Connecticut A-5968, cross-reacted with certain other strains. Most cross-reactions were partially heterologous showing one-way-relationship; heterologous relations were observed less frequently than with chicken sera.
Animals↗
[The results of using an immunoenzyme method in an epizootiologic survey of natural Siberian foci of plague].
The approbation of the enzyme immunoassay in the study of diverse field material (corpses of animals, ectoparasites, soil, feces of birds of prey, etc.) for the presence of Yersinia pestis contamination has shown the advantages of this assay over the existing serological tests: the passive hemagglutination test and the antigen (or antibody) neutralization test. The use of the immunoperoxidase preparation obtained on the basis of staphylococcal protein A makes it possible to detect antibodies to Y. pestis in animals of various species known to be the main carriers, as well as less important ones, in the natural foci of plague in Siberia. The enzyme immunoassay is recommended for use in the study of not only active natural foci, but also territories, dangerous with respect to plague, as well as for controlling the state of such territories after the realization of relevant sanitation measures.
Animals↗
[Guinea pig resistance to infection by the spores of the tetanus causative agent at various levels of tetanus antitoxin and delayed hypersensitivity].
Comparative experimental investigations on guinea pigs immunized against tetanus, carried out with the use of different methods for the determination of immunity to tetanus, have demonstrated the existence of a relationship between the results of the tests used in these investigations (the neutralization test, the passive hemagglutination test and the allergic skin test) and the resistance of the animals to challenge with C. tetani spores in Dcl and Dlm50. The mechanisms of not only humoral, but also cell-mediated immunity play an important role in protection from tetanus infection. The possibility of using, on principle, the allergic skin test with tetanin for the evaluation of immunity to tetanus in individual patients with the aim of differential approach to protection against tetanus in traumas has been shown.
Allergens↗
[Comparison of EBL cells and ELISA in the culture and serological diagnosis of rhinitis atrophicans in swine].
Pasteurella multocida isolates from 271 nasal swabs of pigs were tested in EBL cell culture for toxin production. Mixed bacteria cultures of the same swabs were examined in the P. multocida toxin ELISA K462 (Dakopatts). In the ELISA 114 swabs reacted positive, whereas toxigenic P. multocida were detected by the EBL cell test in 86 swabs. In a neutralization test (SNT) combined with EBL cell culture and with the ELISA 111 sera were examined for P. multocida antitoxin. The toxin had to be more concentrated for the ELISA than for the cell culture; therefore the SNT with EBL cells was more sensitive. Whereas 101 sera had titres of 1:4 or higher in the cell culture, 68 of these sera were positive in the ELISA.
Animals↗
In vitro tests for the measurement of clostridial toxins, toxoids and antisera. II. Titration of Clostridium perfringens toxins and antitoxins in cell culture.
The usefulness of cytopathic indicators for the titration of Cl perfringens beta and epsilon toxins has been investigated. Neutralization experiments with monoclonal antibodies have shown that the entities responsible for the lethal and dermonecrotic effects of Cl perfringens beta toxin preparations are identical. However, the cytopathic effects of the same preparations are caused by other entities. Therefore, titrations based upon lethal and dermonecrotic indicators of beta toxin are equally valid but those based on cytopathic effects are not. Similar experiments with Cl perfringens epsilon preparations have shown that their lethal, dermonecrotic and cytopathic activities are all caused by the same entity. It follows that all three activities can be valid indicators for toxin neutralization tests. Cell culture titrations of Cl perfringens epsilon antitoxin performed on rabbit sera at the levels of test prescribed by the European Pharmacopoeia have produced consistent results which agree closely with the dermonecrotic test. This test has, in turn, been shown to reflect the results of the mouse lethal test accurately. Titrations of cattle and sheep sera at lower levels of test have also produced results in close agreement with the in vivo test. It is concluded that cell culture titration offers a valid in vitro alternative to the use of mouse lethal and guinea-pig dermonecrotic indicators for the titration of sera generated in the course of potency tests and field trials of Cl perfringens epsilon vaccines.
Animals↗
Improvement of African swine fever virus neutralization assay using recombinant viruses expressing chromogenic marker genes.
Antibody neutralization of African swine fever (ASF) virus measured by a plaque reduction assay presents frequent difficulties because of the absence or delay in plaque formation by many strains, especially low-passage viruses. To overcome this problem, a new ASF virus neutralization test has been developed. The new test consists of a conventional plaque reduction assay in which the viral plaques are detected by expression of marker genes. For the development of this neutralization assay 4 mutant viruses were generated by homologous recombination, containing beta-galactosidase or beta-glucuronidase reporter genes inserted into the thymidine kinase locus of the viral genome. These recombinant viruses have the following advantages with respect to parental viruses: (1) the neutralization assay takes less than a third of the time needed using non-recombinant viruses; (2) the small plaques can be detected more accurately by color contrast; and (3) the neutralization-resistant virus clones can be recovered easily post-plaque counting. Additionally, these recombinant viruses permit differentiation by chromogenic staining of individual infected pig macrophages, the natural host cell for ASF virus, facilitating neutralization assays in these primary cultures as described in cell lines.
African Swine Fever Virus↗
Viral aggregation resulting in the failure to correctly identify an unknown rhinovirus.
A seed lot of strain SF 1684 of rhinovirus type 2 prepared in human embryonic lung cells (WI-38) contained aggregates which interfered with its neutralization by homotypic or homologous antisera. The same virus showed no evidence of aggregation at five other passage levels studied. Virus in the seed lot was not identified correctly, and the titer of homologous antiserum was mistakenly considered to be low as a result of neutralization tests conducted with the aggregated virus. Filtration and a more easily effected treatment with sodium deoxycholate (1%) disaggregated the virus and restored its susceptibility to neutralization by homologous and homotypic antiserum.
Animals↗
Triamterene-induced immune haemolytic anaemia with acute intravascular haemolysis and acute renal failure.
Acute intravascular haemolysis and renal failure developed while a patient was taking triamterene. A direct antiglobulin test with a polyvalent reagent was positive. Serum caused agglutination of normal red cells in the presence of triamterene and caused an increase of partial haemolysis of both trypsin-treated erythrocytes and red cells from a patient with paroxysmal nocturnal haemoglobinuria (PNH) in the presence of complement. From the results of antibody-neutralization test and treatment with 2-mercaptoethanol, the presence of IgM antibody with lambda light chain could be demonstrated. The triamterene seemed to bind strongly to the red cells in vitro but in vivo there was no detectable adsorption to red cells. Haptenic inhibition was not demonstrated. From these results, it was assumed that this antibody was found to cross-react with methotrexate which has a structure similar to that of triamterene.
Acute Kidney Injury↗
Ecology of Jamestown Canyon virus (Bunyaviridae: California serogroup) in coastal California.
This paper reports the first isolation of Jamestown Canyon (JC) virus from coastal California and the results of tests for antibody to JC virus in mammals living in coastal California. The virus isolation was made from a pool of 50 Aedes dorsalis females collected as adults from Morro Bay, San Luis Obispo County, California. The virus isolate was identified by two-way plaque reduction-serum dilution neutralization tests done in Vero cell cultures. Sera from the mammals were tested for antibody to JC virus by a plaque-reduction serum dilution neutralization method. A high prevalence of JC virus-specific antibody was found in horses and cattle sampled from Morro Bay. This finding is additional evidence for the presence of a virus antigenically identical or closely related to JC virus in Morro Bay and indicates that the vectors of the virus in Morro Bay feed on large mammals. A high prevalence of virus-specific antibody was also found in horses sampled from Marin and San Diego counties. This finding suggests that viruses antigenically identical or closely related to JC virus are geographically widespread in coastal California.
Aedes↗