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PubMedDate not supplied

[Human infection by Hantavirus in southern and southeastern Brazil].

The results of serological investigation on Hantavírus antibodies carried out between February 1986 and August 1990 in human populations of the States of São Paulo and Paraná, Brazil, which had close contact with urban rats or wild rodents and others small mammals are described. OBJECTIVE--To identify the human infection caused by Hantavíruses, which are the etiological agents of Hemorrhagic fever with renal syndrome. METHODS--Sera from 1063 persons were tested by enzyme immunoassay (ELISA) to Hantaan, Seoul and Puumala antigens. Plaque reduction neutralization test to the same antigens and indirect immunofluorescent test to Hantaan antigen were performed in the positive sera. RESULTS--Antibodies to Hantaan, Seoul or Puumala viruses were detected in 32 persons by enzyme immunoassay (ELISA) and immunofluorescent test. Plaque reduction neutralization test performed in these 32 sera were positive in 5 (3 for Puumala and 2 for Seoul viruses). One serum reacted with high titer to Seoul virus in all tests. It was from a male resident in the rural area of Ribeira Valley, State of São Paulo, where he was born and has always lived. He had only travelled inside the State of São Paulo. CONCLUSION--There are serological evidences of Hantavírus infections in residents of the rural areas of the Amparo Island, Paranaguá Bay, State of Paraná and the Ribeira Valley, State of São Paulo; in employees of the port of Paranaguá, State of Paraná and in patients of the Emílio Ribas Hospital, São Paulo, State of São Paulo, who had a presumptive diagnosis of leptospirosis.

Adult↗
PubMed1995

Properties of statistical tests of neutrality for DNA polymorphism data.

A class of statistical tests based on molecular polymorphism data is studied to determine size and power properties. The class includes Tajima's D statistic as well as the D* and F* tests proposed by Fu and Li. A new method of constructing critical values for these tests is described. Simulations indicate that Tajima's test is generally most powerful against the alternative hypotheses of selective sweep, population bottleneck, and population subdivision, among tests within this class. However, even Tajima's test can detect a selective sweep or bottleneck only if it has occurred within a specific interval of time in the recent past or population subdivision only when it has persisted for a very long time. For greatest power against the particular alternatives studied here, it is better to sequence more alleles than more sites.

Computer Simulation↗
PubMed1975

Immunity to transmissible (coronaviral) enteritis of turkeys (bluecomb).

Turkey flocks recovering from natural and laboratory induced coronaviral enteritis developed lifelong immunity. Virus neutralization tests indicated that neutralization capacity of serums from recovered turkeys was low. One-way cross challenge test using turkeys inoculated with various bluecomb isolates revealed close antigenic relationship or antigenic identity among bluecomb isolates. The controlled application of intestinal preparations containing coronavirus as a vaccination procedure had value in developing active lasting immunity but it has limitations in areas that are attempting to eliminate the disease by a depopulation program. Killed vaccines injected parenterally did not produce a detectable immunity.

Animals↗
PubMed1998

[Introduction to a study of specific antibodies (IgG and IgM) detection with ELISA in the diagnosis of poliomyelitis].

Samples of single sera collected from 38 patients with different clinical diagnosis were studied in order to perform ELISA techniques with the purpose of detecting poliomyelitis IgG and IgM antibodies. The résults were compared through antibody titration by neutralization test. 21 pairs of sera from infants suffering from acute flaccid paralysis were studied by ELISA-IgM, ELISA-IgG and neutralization test. Stool samples were collected from 20 of the latter patient. Wild poliovirus type 1 was isolated in 8 cases. ELISA-IgM technique was positive in 14 cases. The true positive poliomyelitis diagnosis was based on the persistence of flaccid paralysis 60 days after the onset and on wild poliovirus isolation with significant increase in antibody level. 16 cases were classified as poliomyelitis, 2 cases as non poliomyelitic paralysis and 3 cases as undetermined. 16 out of the 18 well established diagnosis were in agreement (88.8%) with the detection or not of IgM antibodies by ELISA. The specificity of these IgM ELISA antibodies was examined by studying 11 cases of lymphocytic meningitis. Cross reaction in serological responses between polioviruses and coxsackieviruses was observed. These cross reactions should be evaluated by studying a greater number of cases. The poliovirus ELISA-IgM is a sensitive, economical and rapid method to be used in poliomyelitis diagnosis to complete the neutralizing test and virus isolation.

Antibody Specificity↗
PubMed1982

Immunological relationship among human adenoviruses of subgenus D.

Antigenic relationships between adenoviruses of subgenus D were determined by neutralization tests in HeLa cell cultures by CPE inhibition. For cross-testing, several antisera of the same species were tested against the prototype viruses. 39 wild strains belonging to 12 different virus species were also studied. Marked variation in the degree of cross-neutralization between individual sera of the same species was often observed. However, virus strains within a species mostly showed identical serological reactions. Hence, antigenic specificity appears to be a fairly constant property of any one species. Strong cross-neutralizations between species are presumably due to a relationship of the hexon (hexon) antigen, whereas weak cross-neutralizations found between viruses related by hemagglutination-inhibition are due to the gamma (fiber) antigen. Viruses related to adenovirus 15 (Mastadenovirus h 15) showed a variety of cross-reactions in neutralization tests. In view of the new species definitions of adenoviruses and to facilitate identification, changes in the classification of Ad 15, 25, 29, and 15/H9 are proposed. The prototypes of Ad 13, 15, 25, 29, and 30 have been cloned by terminal dilution.

Adenoviruses, Human↗
PubMed1985

Characterization of adenovirus 15/H9 intermediate strains.

17 adenovirus strains from various parts of the United States and Europe were characterized by immunological and biochemical methods. They were antigenically related to adenovirus 15 (Ad15) in neutralization tests. In hemagglutination-inhibition tests, a relationship was seen to Ad9, but not to Ad15. These strains were named Ad15/H9 intermediate strains. The relatedness of prototypes Ad15 and Ad29 in neutralization tests and of Ad9 and Ad8 in hemagglutination-inhibition tests was also found in the strains studied. The DNAs of these strains were analyzed by use of restriction endonucleases. After cleavage with the enzymes BamHI, BglII, BstEII, HindIII, and SmaI, fragment patterns of Ad15/H9 strains were found to be different from the prototypes and were more closely related to Ad9 than to Ad15. Furthermore, the 17 strains could be classified into six different genome types, a-f.

Adenoviruses, Human↗
PubMed1981

Guamá-group virus activity in Surinam.

From October 1972 through December 1973 entomological surveys were carried out in both a savannah and coastal area in Surinam. Attempts were made to isolate arboviruses from the captured mosquitoes. The results have been published elsewhere (Panday and Digoutte, 1979). The present paper deals with the further typing of the obtained Guamá-group viruses. Preliminary typing was done by means of complement-fixation test. By performing the neutralization test in mice, the unknown Guamá-group viruses were tested against reference hyperimmune mouse ascitic fluids with neutralizing antibodies against Guamá, Bimití, Catú and Moyú virus, respectively. It turned out that only Guamá, and Catú strains were isolated. In the coastal area four strains of Guamá type were isolated from pools of Coquillettidia venezuelensis (Theobald), and one from a pool of Culex spp. In the savannah area four strains of Catú type were obtained from pools of Culex portesi Senevet and Abonnenc.

Animals↗
PubMed1980

Determination of tetanus antitoxin levels in hyperimmunized volunteers.

A method is described using double diffusion with a perspex template for determining tetanus antitoxin levels in the plasma of volunteers who have been hyperimmunized with tetanus toxoid for the purpose of producing human tetanus immune globulin. This test is simple to perform, economical, sentitive, reproducible and is in excellent agreement with the standard toxin neutralization test in mice. Comparisons with the in vivo toxin neutralization test are presented for this test, the passive hemagglutination, radial immunodiffusion and counter electrophoresis methods.

Counterimmunoelectrophoresis↗
PubMed1977

Immunodiffusion test in avian encephalomyelitis. II. Detection of precipitating antibody in infected chickens in comparison with neutralizing antibody.

The sensitivities of double-immunodiffusion (DID) and neutralization tests to detect avian encephalomyelitis (AE) antibody in chickens were studied. Two antigens were employed in the tests. Concentrated antigen gave a higher titer of antiserum than crude antigen, which reacted only to serum having a neutralization log-index (NI) of 3.4approximately4.0 or more. Antibody responses were examined in four growing chick groups inoculated with AE virus by the intracerebral, subcutaneous and oral routes by the DID test with concentrated antigen and by the neutralization test for 1 or over 2 years after inoculation. When concentrated antigen was used, most sera having an NI of over 1.0 were positive for precipitating antibody. Therefore, the sensitivity of the DID test was nearly equal to that of the neutralization test. The DID test was considered to be applicable to the diagnosis of AE and an antibody survey in the field.

Age Factors↗
PubMed1976

Identification of paramyxovirus-specific haemolysis-inhibiting antibodies separate from haemagglutinating-inhibiting and neuraminidase-inhibiting antibodies. 2. NDV and mumps virus haemolysis-inhibiting antibodies.

Egg-grown Newcastle disease (NDV) and mumps virus were used for preparation of rabbit hyperimmune sera against purified whole virus and projectionless virus particles. These sera and convalescent sera after natural NDV and mumps infections in chickens and human subjects, respectively, were studied in haemolysis-inhibition (HLI), haemagglutination-inhibition (HI) and neuraminidase-inhibition (NI) tests both before and after absorption with Tween 80-ether (TE) treated virus preparations. In addition, neutralization tests using the different sera were carried out. HI and NI antibodies and the major population of neutralizing antibodies in convalescent sera were removed by absorption with TE treated virus material without changing the titre of non-HI HLI antibodies. Rabbit hyperimmune sera directed against projectionless virus particles exhibited HLI antibody titres in marked excess of HI and NI antibody titres, whereas this was not found in sera against whole virus. Absorption with TE treated virus material resulted in removal of all demonstrable antibody activities in sera against whole virus. The corresponding absorption of sera against projectionless particles eliminated HI antibodies without changing the titre of non-Hi HLI antibodies. In rabbit hyperimmune sera, HI antibodies were of primary importance in neutralization tests. After addition of anti-gamma globulin to the test, an efficient neutralization was observed if mumps non-HI HLI antibodies were used whereas this was not found if NDV non-HI HLI antibodies were used.

Animals↗
PubMed1977

Clinical and serologic study of four smallpox vaccines comparing variations of dose and route of administration. Basic study and laboratory standardization.

The present four-center collaborative study was undertaken in an attempt to define the best vaccine and/or vaccination procedure for use in areas of the world that are free of smallpox. The study was designed to compare the effect of different vaccinial strains, viral concentrations, and routes of administration on the morbidity and antibody response associated with primary vaccination and standard challenge revaccination. Primary vaccinations were performed on 1,585 children; 49.6% of the children were vaccinated by the percutaneous route, and 50.4% received vaccine subcutaneously. The overall age and sex distributions of percutaneous and subcutaneous vaccinees were comparable, but there were marked differences in participants among the four study centers. Vaccines in Kentucky had a greater mean age; the greatest number of Negroid children were enrolled in St. Louis, and more of them were vaccinated by the subcutaneous route; and the dropout rate was much greater in San Diego and Colorado. An analysis of comparative interlaboratory serologic procedures with the use of 20 coded duplicate samples of serum revealed good agreement in the hemagglutination-inhibition test; results of neutralization tests had greater variability of mean titers. On duplicate samples of serum from study participants there was generally good correlation between each of the four study centers and the Center for Disease Control's reference laboratory in titers of hemagglutination-inhibiting antibody. In contrast, 38% of the neutralization titers determined at the four study centers were greater than or equal to 0.67 log10 higher than the respective titers noted at the Center for Disease Control.

Black or African American↗
PubMed1989

Experimental infection of bulls with a genital isolate of bovine herpesvirus-4 and reactivation of latent virus with dexamethasone.

Five 13- to 18-month old Belgian Blue bulls were used in this experiment. Four bulls (Nos. 2, 3, 4 and 5) were inoculated intratesticularly with 10(5) plaque-forming units of bovine herpesvirus-4 (BHV-4) in each testicle (Day 0). The challenge BHV-4 strain was previously isolated from testicle cells of a bull exhibiting orchitis and azoospermia. The fifth bull (No. 1) was used as a control and received the same volume of uninfected cell culture supernatant. For 5 days, beginning on Day 51 post-infection, two bulls (Nos. 4 and 5) and the control bull (No. 1) received 0.1 mg kg-1 of dexamethasone. Unilateral castrations were then performed at regular intervals for viral examination. Treatment with dexamethasone reactivated latent BHV-4, but no clinical signs were observed in treated bulls until the end of the experiment (Day 93). Only Bull 3 showed conjunctivitis and temporary azoospermia. The virus was recovered from various samples showing that: (i) BHV-4 can be present in a latent state in the testicles and mononuclear blood cells; (ii) dexamethasone reactivates the virus; (iii) the virus is excreted by nasal and ocular routes. Each infected bull seroconverted and a booster antibody response appeared after dexamethasone treatment as shown by immunofluorescence. Neutralizing antibodies were detected in each bull by complement-dependent neutralization test with titres higher than those obtained by a classical neutralization test. No booster response of neutralizing antibodies was observed after dexamethasone treatment. The antigenically relevant envelope BHV-4 proteins were identified by Western blotting using sera samples from the animals. DNA restriction endonuclease profiles of viruses reisolated after primary infection and reactivation showed only small differences.

Animals↗
PubMed1985

[Use of the immunofluorescence reaction for evaluating the immunological transformation in those inoculated with a chemical typhus vaccine].

The results of the serological examination of persons immunized with chemical typhus vaccine (CTV) are presented. The examination was carried out by means of the complement fixation test (CFT), the passive hemagglutination test (PHAT), the toxin neutralization test (TNT) and the immunofluorescence test (IFT). The acetone-fixed live culture of Rickettsia prowazekii, strain Breinl, served as antigen in IFT. If persons immunized with CTV showed positive titers in CFT, TNT and PHAT, the results of IFT were highly correlated with the CFT titers. In 6-12 months after immunization with CTV the titers of CFT, TNT and PHAT became negative, while the IFT titers remained positive for several subsequent years.

Antibodies, Bacterial↗
PubMed1988

Detection of antibody to pseudorabies virus in swine sera by indirect immunoperoxidase plaque staining.

A new method for the detection of pseudorabies antibody in swine sera was developed by use of the indirect immunoperoxidase plaque staining test. The indirect immunoperoxidase plaque staining test demonstrated serologic responses in pigs that were subcutaneously infected with pseudorabies virus. The test had a sensitivity and a specificity comparable to those of the complement-dependent neutralization test and appeared to be somewhat more sensitive than the neutralization test and the enzyme-linked immunosorbent assay. The test was simple to perform, and the results could be read with the unaided eye under ordinary light, making the test particularly suitable for the routine testing of large numbers of serum samples.

Animals↗
PubMed1984

Analysis of antigenicity of Clostridium botulinum type C1 and D toxins by polyclonal and monoclonal antibodies.

Clostridium botulinum type C1 toxin was purified from C-Stockholm (C-ST), and D toxin was purified from D-1873 and D-South African. Polyclonal antibodies against these toxins were prepared in rabbits. Twenty-eight monoclonal antibodies to these toxins were also prepared with BALB/c myeloma cells. The antibodies were analyzed by both enzyme-linked immunosorbent assay (ELISA) and a toxin neutralization test. ELISA was performed with the three purified toxins and heavy-chain (Hc) and light-chain (Lc) components derived from C-ST and D-1873 toxins. A neutralization test was carried out with 11 toxin preparations (7 from type C and 4 from type D cultures). ELISA results indicated that there exists at least one common antigenic determinant on each of the Hc and Lc components of the three purified toxins. The results of the neutralization test also indicated that type C1 and D toxin preparations contain several common antigenic sites in their molecules. Some are common to toxins from several specific cultures, whereas others are common to toxins from a large number of cultures. It was speculated that toxins from two type C strains are composed of Hc and Lc components which are somewhat similar to those of D-1873 and C-ST toxins, respectively.

Animals↗
PubMedDate not supplied

The neutralizing characteristics of strains of infectious bronchitis virus as measured by the constant-virus variable-serum method in chicken tracheal cultures.

The constant-virus variable-serum neutralization test in chicken tracheal organ cultures was employed in cross-neutralization tests with the following infectious bronchitis viruses: Massachusetts 41, Connecticut, Iowa 97, Iowa 609, Holte, JMK, Clark 333, SE 17, Florida, and Arkansas 99. These viruses all proved serologically distinct by this method. Chickens immunized with the Connecticut strain and later challenged with Arkansas 99 were not protected against it.

Animals↗
PubMed1981

Serodiagnosis of La Crosse virus infections in humans.

Serological diagnoses of human infections with California serogroup viruses are usually made by means of complement fixation or hemagglutination inhibition tests or both. An analysis of antibody titers in sera from 128 humans with California (La Crosse) virus infections indicated that exclusive use of the complement fixation tests would have detected only 50% of the actual seroconversions, whereas hemagglutination inhibition and neutralization tests alone would have been sufficient to make the diagnosis in 79.3% and 84.8% of the cases, respectively. These and other results presented demonstrate that the complement fixation test is not sufficiently useful as a primary tool for diagnosis of La Crosse virus infections. We suggest the use of the hemagglutination inhibition test for preliminary screening of sera from individuals with suspect infections caused by California serogroup viruses. The neutralization test should then be used or confirmation and subtype identification. If hemagglutination inhibition and neutralization titers are high and stable, the complement fixation test should then be used as a last, but specific, resort.

Antibodies, Viral↗
PubMed2003

Comparison of assays for the detection of West Nile virus antibodies in chicken serum.

Six tests for the detection of West Nile virus (WNV) antibodies in the serum of experimentally infected chickens were compared. The tests included the hemagglutination-inhibition test (HIT), immunoglobulin M (IgM)-capture enzyme-linked immunosorbent assay (ELISA) with WNV-infected mouse brain antigen, immunoglobulin G (IgG) indirect ELISA with tickborne encephalitis viral antigen, the microtitre virus neutralization test, the standard plaque reduction neutralization test (PRNT), and the microtitre PRNT (micro-PRNT). Thirty adult chickens, intravenously and intramuscularly inoculated with 10(7) plaque-forming units (PFU) of WNV strain Egypt 101, were bled and given a booster of 10(7) PFU at 7,15, and 21 d postinoculation; the final blood collection was on day 28. Although the micro-PRNT is capable of detecting the highest antibody titres during both early and late infection, because of the technical complexity and time requirements of this test a combination of IgM and IgG ELISAs is recommended for serologic screening. Serum samples that give positive results in the ELISAs can then be tested by the micro-PRNT to determine the specificity of antibodies to WNV.

Animals↗