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At least 991 records · Page 55Linked to original sources
PubMed1990

[Study on natural infection of epidemic haemorrhagic fever virus in Leptotrombidium scutellare].

Leptotrombidium (L.) scutellare was considered to be the suspected vector of epidemic haemorrhagic fever (EHF). In order to clarify the relationship between this mite and EHF, from Oct to Nov 1988 and Oct of 1989, the larvae of this mite were collected from rats in areas with constantly high incidence of EHF in Shanxi Province and larvae with only small quantity of meal were selected and for more than 15 days before isolation of EHFV. Six strains of virus were isolated. The viruses isolated were identified to be EHFV by serum test, immunofluorescent blocking test as well as neutralization test. The above results further demonstrate this mite can naturally be infected by EHFV and therefore serve as vector of EHF.

Animals↗
PubMed1986

[Erythrocyte diagnostic agents for detecting bacterial antigens of the genus Citrobacter].

Citrobacter antigenic and antibody erythrocyte diagnosticums, serogroups 1, 2, 3, 4, 5, 6, 7, 8, 11, 12, 13, and 22, have been developed. Tests with the use of these diagnosticums have proved to be highly sensitive and mainly group-specific. The antigen in the cellular form is best detected by means of the passive hemagglutination test and in the molecular form, by means of the neutralization test. The antibody-binding and agglutinating activities of strictly group-specific and cross-reacting O-antigenic determinants differ in their sensitivity to heating and to treatment with phenol. In the study of fecal samples taken from patients the above method for the detection of Citrobacter antigens has been shown to have high resolution.

Animals↗
PubMed1987

[Specificity of the serological diagnosis of dysentery using erythrocytic reagents].

The serological specificity of the diagnosis of dysentery, made by different methods with the use of antigenic and antibody erythrocyte diagnostic agents under the conditions of the circulation of different Shigella species and subspecies in a given locality, has been compared. The method for the determination of the diagnostic titer of the total serum antibody activity has proved to be the least specific. The methods for the detection of Shigella antigens, especially over time, in patients' excretions and for the determination of serum antibody activity show complete specificity. The combination of specificity and sensitivity makes the detection of Shigella antigens in feces by means of the passive hemagglutination test and the antibody neutralization test the method of choice for the diagnosis of dysentery.

Antibodies, Bacterial↗
PubMed1985

[Development of a numerically additive combined vaccine against tetanus and smallpox].

Mandatory vaccination against smallpox was abolished on the account of smallpox-eradication proclaimed by the WHO and the postvaccinal complications detected after smallpox vaccination. At the same time vaccine banks with the vaccinia virus strain "Elstree" were organized. Should mass vaccinations with this vaccinia virus strain be carried out in a case of emergency, severe postvaccinal diseases and complications can arise in overaged and immunosuppressed vaccinees after primovaccination. Therefore attenuated vaccinia virus strains should be used for vaccine banks, which cannot be activated, or increase in virulence in impaired vaccinees after primovaccination. For these individuals the vaccinia virus strain "MVA", among other attenuated vaccinia strains, is recommended. The MVA virus strain can be applied parenterally without complications. From the scientific and field-relevant point of view it was tried to combine the vaccinia virus strain "MVA" with tetanus toxoid and to develop a combination vaccine "tetanus-smallpox". In immunization experiments using mice, piglets and monkeys, safety and efficacy of the vaccine were investigated. Efficacy was demonstrated by means of postvaccinal antibody determination and by the mouse protection test. Tetanus antitoxin was measured by ELISA and indirect hemagglutination test, antibody levels to vaccinia virus were investigated employing the neutralization test and hemagglutination inhibition test. No significant differences in potency could be demonstrated between the combination vaccine and the corresponding monovalent vaccines in mice, piglets and monkeys. The combination vaccine consisted of 12 Lf tetanus toxoid and 10 TCID50 vaccinia virus "MVA" preserved with gelatine and glucosamine. The double intramuscular immunization of monkeys stimulated average tetanus antitoxin titers of 1:310 and average vaccinia virus titers of 1:195 2 weeks p. revacc. Similar results were obtained in mice and piglets. Side reactions were not observed in mice and piglets. Except for occasional local reactions of short duration at the injection site of the monkeys, similarly no adverse reactions were observed after intramuscular vaccination with the combination vaccine.

Adjuvants, Immunologic↗
PubMed1988

[Interserovar antitoxic immunity to Vibrio cholerae toxins].

The immunochemical affinity of V. cholerae enterotoxins, serovars Inaba and Ogawa, has been shown in animal experiments on cross antitoxic immunity in the small intestine, the passive hemagglutination test and the toxin neutralization test. However, antitoxic interaction with both enterotoxins is characteristic only for antibodies to V. cholerae of serovar Inaba, while in animals immune to Ogawa toxin the choleragenic effect of enterotoxins produced by V. cholerae of both serovars in retained. The possible mechanisms of one-sided cross interserovar antitoxic immunity in cholera are discussed.

Animals↗
PubMed1979

[Serological method of detecting antirabies antibodies].

The possibility of the determination of rabies antibodies by the serological method has been demonstrated, involving the use of culture rabies virus, strain Vnukovo-32, concentrated and purified by high speed centrifugation, for the sensitization of anserine erythrocytes. The neutralization test in mice and the passive hemagglutination test showed a correlation in rabies antibody titers in the sera of animlas immunized with rabies vaccines. The advantages of the passive hemagglutination test consist in the rapidity of obtaining the results, in a simple and economic method of carrying out the test.

Animals↗
PubMed1970

A new influenza A virus infection in turkeys. VI. Artificial immunization against the malignant virus strain turkey-Ontario 7732-66.

The immune reaction of turkeys and chickens to inactivated preparations of a virulent strain of avian influenza A virus has been examined. In both species any level of antibody detectable by the hemagglutination inhibition or serum neutralization tests was protective against the challenge exposure. However, some vaccinated birds were protected in the absence of detectable antibody. Chickens responded with higher and longer lasting antibody titers than turkeys to identical antigen preparations. Whereas the vaccine induced protection in chickens for at least 84 days, the immune protection in turkeys barely lasted 42 days. Immune birds responded to the live virus challenge with a marked rise in serologic titers which suggest that they were still susceptible to subclinical infection. These findings are discussed in their relationship to available data on classical fowl plague and influenza in mammals.

Animals↗
PubMedDate not supplied

[Antigenic determinants in the makeup of the hemagglutinins of influenza virus type A (H3N2) isolated in 1977--1978].

Antigenic composition of hemagglutinins (HA) of influenza A viruses isolated during the epidemic of 1977--1978 was studied. Three antigenic determinants of H3.1, H3.5 and H3.7, identical to the determinants of HA of the viruses isolated in 1975, were detected in HA of the viruses isolated in 1977--1978 by means o the HAI test with inhibitor-free and monoreceptor sera. A/South Australia/1/77 virus was an exception in this group of viruses, and its HA contained only two determinants, H3.5 and H3.7, common with the HA of the viruses circulating in 1975. Neither the HAI test nor the biological neutralization tests showed H3.1 in A/South Australia/1/77 virus.

Epitopes↗
PubMed1984

[Antitumor activity of schizophyllan (SPG) against syngeneic ACI/N rat tumor, AMC-60 fibrosarcoma and BC-47 bladder cancer].

The antitumor activity of schizophyllan (SPG) against syngeneic ACI/N rat tumor, AMC-60 fibrosarcoma and BC-47 bladder cancer was investigated. Intramuscular injection of SPG caused a marked suppression of AMC-60 tumor growth. Results obtained with cytotoxicity tests in vitro and lymphoblastogeneic response in vitro suggest the association of enhanced macrophage cytostasis and high reactivity of lymphoid cells with the resistance of the host to AMC-60 tumor. Moreover, SPG showed pronounced antitumor activity against BC-47 bladder cancer. The highest therapeutic effectiveness was obtained when SPG injection was started at an advanced stage of the tumor, 4 out of 15 rats treated being completely cured of cancer. Cytotoxicity tests in vitro and neutralization tests in vivo indicated the important role of cytotoxic lymphocytes as well as activated macrophages in the host defence mechanism against BC-47 cancer. This, taken together with the fact that the rats cured completely by SPG therapy acquired transplantation resistance to BC-47 cancer, shows that SPG may promote tumor immunity in the host.

Animals↗
PubMed1981

[Adaptation of an isolate of bovine enteritic coronavirus to serial growth in cell culture and characterization of the virus (author's transl)].

Coronaviruses are known to behave as pathogens in a variety of animal species. Their multiplication in the differentiated enterocytes of the intestinal tract induces a severe diarrheic syndrome which may lead to death. To study these viruses and to progress in the development of prophylactic and diagnostic methods, it is essential to succeed in adapting the agents to serial growth in cell culture. In spite of several attempts adaptation to primary cell cultures could be obtained in the past only for two isolates. The present work describes the methodology which enabled us to succeed in the adaptation of a bovine enteric coronavirus isolated in France to primary calf kidney cells, and reports results on the characteristics of this virus. Adaptation to serial growth was realized at 34 degrees C in the following way: 3 passages each lasting 8 to 10 days followed by 16 passages each lasting 6 days. From the 20th passage on the duration of incubation was reduced to 4 days. Virus growth was checked using an indirect immunofluorescence test. During the first passages only a few dispersed positive cells could be observed but later on small foci of immunofluorescent cells did appear. By the 35th passage infective titers did not exceed 1 x 10(5) TCID50/ml and cytopathic effects were always very discrete. When the susceptibility of different cell-types to this coronavirus strain (G110) was checked we found that only bovine cells and the human HRT18 cell-line were able to replicate the virus. In HRT18 cells titers as high as 5 x 10(7) TCID50/ml could be obtained at the first passage of G110 strain, previously adapted to primary calf kidney cells. As regards the antigenic properties of G110 virus no difference could be established between this strain and the Nebraska isolate (NCDCV) neither by indirect immunofluorescence test nor by indirect neutralization test. The G110 strain agglutinates rat and mouse erythrocytes. The density of purified virions in mouse gradients is 1.19 and the morphology of the particles is characteristic of a coronavirus.

Animals↗
PubMed1994

Viremia and serological responses in adult chickens infected with western equine encephalomyelitis and St. Louis encephalitis viruses.

Adult hens, similar to those used for arbovirus surveillance, were experimentally infected with western equine encephalomyelitis (WEE) and St. Louis encephalitis (SLE) viruses to describe the viremia response, to compare serological testing methods, and to evaluate a new method of collecting whole blood onto filter paper strips from lancet pricks of the chicken comb. Young (19 weeks), but not old (38 weeks), hens developed a low-titer, transient viremia for a 1-day period. Immunoglobulin G (IgG) was detected by days 10 and 14 after infection with WEE and SLE viruses, respectively, by indirect fluorescent antibody tests, hemagglutination inhibition tests, and plaque reduction neutralization tests on sera and in direct enzyme immunoassays (EIA) on both sera and eluates from filter paper samples. Immunoglobulin M (IgM) was first detected in sera 2 and 3 days before IgG, respectively, but IgM could not be detected reliably in eluates from dried blood. Sera and dried blood samples collected from naturally infected sentinel chickens gave comparable results when tested by an EIA for IgG.

Animals↗
PubMedDate not supplied

[The interrelationship of the capacity for the expression of different serovariants of the Yersinia pestis capsular antigen with the degree of reduction of the lipopolysaccharide of the bacterial cells].

The immunochemical study of the expression of different serovariants of Y. pestis capsular antigen in Escherichia coli HB 101, Salmonella minnesota R595 and Y. pestis EV recipient strains with different degrees of LPS reduction was made. Plasmids pFS1, pFBK7 and pFBK10 coding initial and serologically atypical variants of the capsular antigen were introduced into microbiol cells. Altered LPS structures were shown to have no influence on the serological specificity of the capsular antigen. Immunochemical activity was determined in the diffuse precipitation test, the passive hemagglutination test and the antibody neutralization test. Changes in the structure of LPS were shown to produce no effect on the serological activity of the capsular antigen coded by intact fra operon (plasmid pFS1). The transfer of hybrid plasmids pFBK7 and pFBK10 to recipient microorganisms led to the synthesis of serovariant Fl1 in recombinant strains with O-LPS, which was immunochemically different from serovariant Fl2 synthesized in strains with R-LPS.

Antigens, Bacterial↗
PubMed1996

Prevalence of antibodies to bluetongue, bovine herpesvirus 1 and bovine viral diarrhea/mucosal disease viruses in water buffaloes in Minas Gerais State, Brazil.

A serological survey to detect water buffaloes with antibodies to bluetongue virus (BTV), bovine herpesvirus 1 (BHV 1) and bovine viral diarrhea/mucosal disease virus (BVD/MDV) was performed in Minas Gerais State, Brazil. Precipitating antibodies against BTV were detected by the agar gel immunodiffusion test (AGID) in 54.4% of the serum samples tested. Microplate serum-neutralization tests revealed that 14.7% and 52.7% of the water buffaloes had antibodies to BHV 1 and BVD/MDV, respectively. The prevalence of antibodies to BTV in water buffaloes under two years old was significantly lower than in adults.

Animals↗
PubMed1998

(E)-5-(2'-bromovinyl)-2'-deoxyuridine inhibition of macropodid herpesvirus 1 in vitro.

Herpesviruses have caused the death of kangaroos and wallabies in European and North American zoos. Eight antiherpetic purine or pyrmidine nucleoside compounds were tested in plaque reduction neutralization tests for in vitro inhibition of macropodid herpesvirus 1, a virus that has been associated with illness in captive macropods in Australia. The virus was most susceptible to inhibition by (E)-5-(2'-bromovinyl)-2'-deoxyuridine (BVDU) and 5'-iodo-2'-deoxycytidine. Because BVDU effectively inhibits macropodid herpesvirus 2 in vitro, it may be the drug of choice for experimental therapy in herpesvirus infections in captive macropodids.

Animals↗
PubMed2006

Immunologic analysis induced by DNA vaccine encoding E protein of Beijing-1 strain derived from Japanese encephalitis virus.

OBJECTIVE: We have compared the gene expression and DNA immunization efficacy encoding prME and E proteins of a different strain (JaGAr-01) derived from Japanese encephalitis virus. This study aimed to construct a recombinant encoding E protein of the Beijing-1 strain derived from Japanese encephalitis virus and analyze the humoral, cellular and protective immunity induced by the above recombinant. METHODS: The recombinant pJBE containing E (1,500 bps) gene from the Beijing-1 strain of Japanese encephalitis virus was constructed and then transfected into the HepG2 cell line by liposome fusion. The expression of E (about 53 kD) protein in transfected cells was analyzed by Western blot using a specific anti-JEV-E antibody. BALB/c mice were vaccinated with 3 microg of pJBE by the gene-gun technique. JaGAr-01 and Beijing-1 strains (10(5) PFU/100 microl) of Japanese encephalitis virus were given to BALB/c mice by intraperitoneal injection 3 weeks after double DNA immunization with a lethal virus challenge. BALB/c mice were observed for 21 days after challenge. An 80% plaque reduction neutralization test was performed to titrate the neutralization antibody before and after viral challenge. A lactate dehydrogenase activity release test was used to examine cytotoxic T lymphocyte activity after double DNA immunization. RESULTS: The expression of about 53 kD protein associated with pJBE was determined in transfected HepG2 cells with specific anti-JEV-E antibody. A higher level of neutralization antibodies and the cytotoxicity effect were induced with pJBE immunization using the gene-gun technique, and were similar to those induced with inactivated vaccine derive from the Beijing-1 strain of Japanese encephalitis virus. Balb/c mice immunized with pJBE survived the challenge with the different strains of Japanese encephalitis virus; however, Balb/c mice immunized with inactivated vaccine did not survive the challenge with the JaGAr-01 strain of Japanese encephalitis virus at all. CONCLUSIONS: DNA vaccine containing the E protein gene derived from Japanese encephalitis virus can provide not only better efficacy including humoral and cellular immunity, but also cross-protection against infection with homologous and heterologous Japanese encephalitis virus.

Animals↗
PubMed1968

Hemagglutinating activity of enteroviruses recovered in two primary cell lines and a stable line.

A microhemagglutination technique was used to detect hemagglutinating properties of enteroviruses recovered in two primary cell lines, monkey kidney (MK) and human amnion (HAm), and in a continuous cell line, human embryonic lung (HEL). During a 3-year period, 1,528 isolations of enteroviruses were tested for hemagglutinating activity and hemagglutination inhibition response; 96.3% of the viruses were also identified by virus neutralization tests. Enteroviruses recovered in HEL were far less likely to develop hemagglutinins than viruses isolated in MK or HAm. Of the enteroviruses known to agglutinate human type O cells, 77.8% of the primary viral isolates from MK, 62.1% of the isolates from HAm, and 20.3% of the isolates from HEL exhibited this property. An additional 8.1% of the isolations obtained in HEL hemagglutinated human cells after a single passage in MK. The microhemagglutination technique using microtiter equipment was simple to perform, saved time and valuable typing sera, and helped to obtain identifications rapidly.

Child↗