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[Serological foundation for the persisting circulation of influenza viruses A(HON1) and A(H2N2) among children].

Examinations by the HI test of 652 sera from children aged from 9 months to 13 years revealed antibodies to A/Singapore/1/57 (H2N2) in 0.9% and A/PR/8/34 (H0N1) in 1.2% of the children. The specific nature of the activity of the sera was proved by neutralization tests and by treatment of the sera with Staphylococcus aureus adsorbing IgG class antibodies. Antineuraminidase antibodies to these viruses were also detected. Examinations of 247 paired sera from children revealed seroconversion to hemagglutinin and neuraminidase of A/Singapore/1/57 and A/PR/8/34 in 2% and 0.4%, respectively. These results testify to continuing circulation in the human population of influenza A virus subtypes of no current epidemiological importance.

Adsorption↗
PubMed1971

Immunological surveys of arbovirus infections in South-East Asia, with special reference to dengue, chikungunya, and Kyasanur Forest disease.

Serological surveys have been widely used in South-East Asia to determine the presence and activity of arboviruses. The haemagglutination-inhibition test has been most frequently employed but complement-fixation and neutralization tests have also been used in some investigations.Although virus isolations provide the most conclusive evidence, they can be carried out in a few specialized centres only, and serological surveys are very important for studying the distribution of arboviruses.The surveys have shown that group B arboviruses (principally all four types of dengue, Japanese encephalitis, and West Nile) are widely prevalent. Dengue and Japanese encephalitis viruses are more widespread than West Nile virus, which was not known previously to extend east of India although recent survyes have shown that its range extends to Burma. Japanese encephalitis is frequent in most of South-East Asia but in India is found mainly in eastern and south-eastern parts of the country. Kyasanur Forest disease (KFD) and Langat viruses are the only tick-borne group B arboviruses definitely known to occur in the region, the former in India, the latter in Malaysia. KFD virus has been isolated only from a small focus in Mysore, although human and animal sera containing neutralizing antibodies to this virus have been found sporadically in widely scattered areas. Among the group A arboviruses, chikungunya and Sindbis have been detected in serological surveys, but the former has not yet been found in Malaysia.

Adolescent↗
PubMed1985

Isolation of human pathogenic viruses from clinical material on CaCo2 cells.

The use of the epidermal-like cell line CaCo2 and the efficient propagation of viruses from clinical material for diagnostic purposes are reported. Virus replication was observed by cytopathic effects and/or immunofluorescence. The following viruses replicate in CaCo2 cells: enteroviruses (coxsackie B1-B6, poliovirus types 1-3, most echoviruses and coxsackie A viruses), adenoviruses, herpes simplex types 1 and 2, measles, respiratory syncytial, parainfluenza type 2 viruses, and to a lesser extent rubella and mumps viruses. CaCo2 cells were used in neutralization tests for the diagnosis of enteroviral infections.

Cell Line↗
PubMed1977

[Test of an attenuated viral strain of TGE as a vaccine].

A live vaccine was produced using a local strain P of the virus of the transmissive gastroenteritis, arrenuated in cell cultures. The vaccinated pregnant sows had high-titer serum and colostrum virus-neutralizing antibodies. In the first days following farrowing there were in the colostrum ummunoglobulins of the Igg class that prevailed, however, IgA and IgM proved more effective in the virus-neutralizing test. Newborn pigs acquired passive immunity at about the 24th hour after the intake of colostrum. They withstood a challenge with a virulent virus.

Animals↗
PubMed1991

Mouse protection test as a predictor of the protective capacity of synthetic foot-and-mouth disease vaccines.

A passive immunity test (MPT) in suckling mice for the quantification of protective anti-foot-and-mouth disease virus (FMDV) antibodies in serum is described. Comparisons with titres obtained using conventional serum neutralization tests show that for cattle given synthetic peptide vaccines this in vivo assay is a better indicator of protection, while for convalescent animals and virus-vaccinates both tests are equally valid predictors of immune status. Cleavage of Fc fragments from anti-virus or anti-peptide IgG results in a marked decrease in MPT titres although binding to virus in ELISA is unaffected, indicating that intact antibodies are required for in vivo clearance of FMDV. Cross-protection studies demonstrate that anti-peptide sera, while less potent than anti-viral sera in conferring passive immunity against FMDV challenge, have a wider protective range than anti-viral sera within the O serotype and also between O and A serotypes. Possible qualitative differences between anti-viral and anti-peptide sera are discussed in the light of these findings.

Animals↗
PubMed1986

Antigenic analysis of rotavirus isolates using monoclonal antibodies specific for human serotypes 1, 2, 3 and 4, and SA11.

Five neutralizing monoclonal antibodies produced against human rotavirus (HRV) serotypes 1, 2, 3 and 4 and the simian rotavirus (SA11) were used to study 59 rotavirus isolates of human, simian and feline origin previously serotyped using polyclonal antisera. In neutralization tests, 19 of 26 HRV serotype 1 isolates, both strains of HRV serotype 2, 14 of 24 HRV serotype 3 isolates and all of seven serotype 4 isolates were neutralized by the homologous serotype-specific monoclonal antibodies. Use of the panel of monoclonal antibodies revealed antigenic differences between strains within serotypes 1 and 3 and, in the case of the serotype 3 strains, each variant had a unique RNA electropherotype. An enzyme immunoassay (EIA) which utilized the monoclonal antibodies essentially confirmed the neutralization results. Preliminary results show that direct serotyping in faecal extracts by EIA using these monoclonal antibodies is specific but lacks sensitivity.

Antibodies, Monoclonal↗
PubMed1975

Neutralization of Sindbis virus by antisera to antigens of vector mosquitoes.

Sindbis virus harvested from infected cultures of Vero cells and from Aedes aegypti mosquitoes was used in neutralization tests with sera obtained from guinea pigs immunized with ground A. aegypti and from guinea pigs repetitively bitten by mosquitoes. Employing these antisera, more mosquito-propagated virus was neutralized than was virus grown in cultures of Vero cells. The neutralizing activity resided in the immune globulin fraction and may reflect the production of antibody to vector antigens on the viral envelope.

Aedes↗
PubMed1976

Cell-mediated immunity in Aujeszky disease virus infected pigs. I. Lymphocyte stimulation.

The appearance of cell-mediated immunity was studied in Aujeszky diseased pigs with the aid of the in vitro stimulation of sensitized lymphocytes. The first cell-mediated immunity reaction of lymphocytes occurred 4 days after infection. From day 7 to 35, the latest day tested, the reactions were most marked with lymphocytes from lymph nodes and spleen, whereas blood and thymus lymphocytes reacted less frequently; bone marrow lymphocytes showed no response. Reinfection did not considerably enhance lymphocyte reactivity. Humoral immunity was demonstrated a few days later than cell-mediated immunity. Neutralizing antibodies were first detected at day 7, reaching optimal titers at day 14. Complement fixing antibodies were detected from day 14 onward. Reinfection caused a very weak booster effect only on neutralizing antibody production. The sensitivity of the neutralization test could be enhanced up to sixfold by the addition of fresh guinea pig complement. It is concluded that cell-mediated immunity influences the early stage of infection with Aujeszky disease virus when humoral immunity is not yet demonstrable or yet rather low. Lymph nodes and spleen are apparently of special importance for the appearance of ADV-reactive lymphocytes.

Animals↗
PubMed1978

Immunoglobulin-specific radioimmunoprecipitation assays for quantitation of nasal secretory antibodies to hemagglutinin of type A influenza viruses.

Radioimmunoprecipitation (RIP) assays were developed to selectively quantitate class-specific antibodies to purified hemagglutinins (HA) of type A influenza virus in nasal secretions. Rabbit anti-human secretory piece of immunoglobulin A (IgA) and rabbit anti-human IgG were used as second antibodies. A third antibody, goat anti-rabbit IgG, was incorporated into the system to separate immune complexes formed between iodinated HA, nasal wash test specimen, and second antibody. The utilization of this reagent avoided the need for large quantities of IgA and IgG antibody-negative carrier secretions. Nasal was specimens obtained from 14 adults immunized with an inactivated type A influenza virus vaccine were evaluated by RIP and viral neutralization assays. Significant homologous postvaccination secretory IgA and IgG antibody levels were demonstrable in 13 (93%) of individuals by RIP, whereas only 5 (36%) exhibited rises by viral neutralization tests. Moreover, the geometric mean IgA and IgG antibody levels were at least 20- and 37-fold greater than the neutralizing antibody titer. The pattern of heterologous immunoglobulin-specific antibody responses tended to be similar to those observed with the homologous HA subunit.

Adult↗
PubMed1990

Antitumor activity of T cells in lymphoid organs induced by interferon in tumor-bearing mice.

Administration of human hybrid interferon-alpha A/D (IFN) for 5 consecutive days induced antitumor activity in spleen of Meth A fibrosarcoma-bearing mice 9-10 days after cessation of IFN administration. Antitumor activity assayed by the in vivo neutralization test was found in the spleen of responding mice but not in that of progressive mice. This activity was T-cell-dependent and tumor-selective. However, tumor-neutralizing activity was not found in spleen recovered as early as 3 days after cessation of IFN administration when many tumor cells are still surviving in tumor nodules and being attacked by the host. Instead, T-cell-dependent and tumor-selective tumor-neutralizing activity was found in the lymph node of tumor-bearing mice at this early stage. Furthermore, the tumor-neutralizing activity was already detected in the lymph nodes during the course of IFN administration, although there was no difference in the cell composition of the lymph nodes of IFN- and placebo-administered mice. Since IFN-alpha is apparently not a direct modifier of T cells, these results indicate that IFN probably did not directly increase the number of antitumor T cells but instead modified the host-tumor interaction in such a way that, as an early event, the enhanced T-cell response to tumor cells occurred, resulting in an increase in the antitumor T-cell population in lymph nodes. We supposed that, as the tumor regressed, these antitumor T cells would eventually leave the lymph node and migrate to the spleen.

Animals↗
PubMed1987

Irreproducibility of neutralization of herpes simplex virus under conditions where antibody is not in excess.

Neutralizing activity against herpes simplex virus was significantly reduced if initial virus titers were greater than 10(6) PFU/ml; there was no significant neutralization when initial virus titers approached 10(8) PFU/ml. This was a result of utilization of all available antibody by virus particles and 'free' virus antigen and emphasizes the importance of conducting virus neutralization tests under conditions of antibody excess.

Antibodies, Viral↗
PubMed1993

Isolation of Batai virus (Bunyaviridae:Bunyavirus) from the blood of suspected malaria patients in Sudan.

From August through November 1988, 77,500 patients with fever presented to the municipal hospital and to eight government health centers in Kassala, a town of approximately 400,000 individuals in eastern Sudan. A diagnosis of malaria, based primarily on clinical presentation, was made in 14,395 individuals during this four-month period; fevers of unknown origin were diagnosed in 29 patients. A Bunyavirus that was antigenically similar or identical to Batai virus by complement fixation and plaque-reduction neutralization tests was recovered from two of 196 sera collected from patients with acute fever admitted to the municipal hospital in Kassala in October 1988. IgM antibody against this virus was detected by enzyme-linked immunosorbent assay in 7% of the sera from patients with acute fever tested and IgG antibody was detected in 61%.

Adult↗
PubMed2003

Passive acquired immunity against measles in infants born to naturally infected and vaccinated mothers.

BACKGROUND: Currently, the majority of newborns in Poland are born to mothers who have been immunized against measles. The aim of this study was to compare the maternal measles antibody titers of infants born to mothers who had been infected by measles wild virus (group I) with those born to mothers who had been vaccinated (group II). MATERIAL/METHODS: Serum samples were tested for measles antibodies from 79 infants in the 7th month of life and from 27 mothers between 17 and 41 years of age. Two commercial enzyme immunoassays (EIA) and a plaque neutralization test (PNT) were used. RESULTS: Only 12.7% of all infants showed measles antibodies in EIA. However, antibodies could be detected by PNT in all the infants, although only 36.6% showed titers of >1:8, which corresponds to protective antibody values of >0.2 IU/ml. The mean geometrical titer was significantly higher among infants from group I than in group II (1:7.16 vs. 1:3.71, p=0.0038). Protective antibody titers were detected in 50% of infants from group I and only 18.2% in group II (p<0.02). CONCLUSIONS: Passive acquired immunity in infants born to mothers who have had measles lasts longer than in infants born to vaccinated mothers. Nearly two thirds of infants (65.4%) in the 7th month of life did not have sufficient maternally derived neutralizing antibodies to protect against measles. Our data suggest that the recommended age for the first dose of measles vaccine during measles epidemics should be lowered to 9 months, with re-vaccination at 12-15 months.

Adolescent↗
PubMed1986

[Experimental and natural infection with the enzootic leukosis virus of cattle].

A trial was performed with heifers at the age of six to seven months. The animals were experimentally infected with the lymphocytes of a virus-productive donor. Infection was produced in all the nine cases, as demonstrated by means of the positive syncytial test. As indicated by the results of the trial, the antibodies to the enzootic bovine leucosis virus (BLV) were produced soon after experimental infection. A high sensitivity of the serum-neutralization test and the ELISA method was demonstrated in this connection: by these methods, the antibodies were identified already two to three weeks after experimental infection whereas by the immunodiffusion test they could be detected only after five weeks. Twenty-four animals were exposed to natural contact infection. Within 270 days of the trial, the disease after contact was recorded only in one heifer out of the four that were in close contact with the experimentally infected animals. In this case, as compared with experimental infection, the antibodies were produced much later--after 85 to 93 days. Leucosis was recorded in none of the remaining animals. The reasons why such a favourable result was obtained were the thorough disinfection of the stables after blood collections and the strict observance of the aseptic conditions. The results of experimental infection in three cows were identical with those obtained in young cattle. In the experimentally infected dairy cows, antibodies in milk were determined by the ELISA method. As found, in milk the antibodies to BLV appear two to three weeks later than they do in serum. The ELISA method of BLV antibody detection can be used for the identification of infected animals in herds where enzootic bovine leucosis occurs.

Animals↗
PubMed1975

Detection and serological identification of adeno-associated virus in avian adenovirus stocks.

Eleven avian adenovirus strains were tested for the presence of avian adeno-associated viruses (AAAV). Six strains contained AAAV. Electron microscopy using rabbit anti-AAAV serum was useful in detecting the satellite virus. The AAAV previously isolated from guail bronchitis virus was related to each of the six new isolates by immunoagglutination, complement fixation, immunodiffusion, and neutralization tests.

Adenoviridae↗
PubMed1979

Pseudorabies: adaptation of the countercurrent immunoelectrophoresis for the detection of antibodies in porcine serum.

A countercurrent immunoelectrophoresis test was developed for the detection of precipitating antibodies to pseudorabies virus in pig serum. The precipitation reaction occurred only between the pseudorables antigen and the homologous porcine antiserum. The sensitivity of the method was compared to that of the serum neutralization test. On the basis of its sensitivity, its specificity and the rapidity with which the results were obtained, the countercurrent immunoelectrophoresis may become a potentially valuable screening method to test large numbers of porcine serum.

Animals↗