ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694950

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694951

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Antibody profile responses elicited against foot‐and‐mouth disease virus nonstructural proteins, under various experimental and field conditions, were detected by means of highly sensitive immunoenzymatic approaches. On the basis of the results obtained, useful inferences were made for proper interpretation of seroepidemiologic surveys in the determination of residual viral activity in an animal population, regardless of its vaccination condition, and for import/export testing. In this work several considerations on survey strategy and assay approaches are discussed.

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694952

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Cattle which have been infected with foot‐and‐mouth disease (FMD) virus can be differentiated from those that have been vaccinated on the basis of the detection of antibody to one or more of the non‐structural (NS) proteins of the virus. Cattle which have been protected by vaccination can become persistently infected with FMD virus (FMDV) without ever showing clinical signs. Vaccinated, protected cattle which are persistently infected cannot be distinguished from animals that merely have been vaccinated on the basis of serological tests for antibody to the structural proteins of FMDV. Sera were collected from groups of cattle for varying periods after exposure to infection under experimental conditions. On the basis of isolation of virus from probang samples collected during the course of the experiments it was possible to classify the cattle according to the following criteria; naive, infected and eliminated the virus (convalescent), infected and persistently infected with FMDV (carriers), vaccinated alone, vaccinated and either convalescent or carrier. Sera were examined for antibody to the NS proteins Lb, 2C, 3A, 3D, and 3ABC by an indirect profiling ELISA usingE. coli‐expressed fusion proteins as antigens. Considerable variation was observed in the antibody response to NS proteins of both naive and vaccinated animals following infection. The extent of individual variation was so great that convalescent animals could not be differentiated from carrier animals on the basis of their antibody response to any of the NS proteins examined. The majority of vaccinated, protected animals showed an antibody response to NS proteins, particularly 3ABC, following exposure to infection. However, the carrier state was demonstrated in some vaccinated, protected animals in which no antibody response to any of the NS proteins could be detected. The detection of antibody to NS proteins can therefore be used on a group, or herd, basis to detect circulation of virus in a vaccinated population but further investigations in the field are required to determine the sampling level necessary for statistical acceptance. On an individual animal basis, however, freedom from antibody to NS proteins in a vaccinated animal, or an animal of unknown history, does not necessarily imply that the animal is free from infection with FMD virus and, furthermore, the titre of antibody to NS proteins is not a useful predictive measure of whether or not an infected animal has successfully eliminated the virus.

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694953

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

We had shown in preliminary studies with a small number of animals that antibodies against 2C could be detected in cattle and pigs which had been infected with FMDV but not in animals which had been vaccinated against the disease. To determine whether this test was generally applicable, seta from several hundred animals which had been vaccinated with different products in many countries have been tested in an ELISA using baculovirus expressed 2C. Our results show that only 1–2% of the sera gave a positive reaction by this method. In contrast, 100% of sera from convalescent animals gave a positive reaction.

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694954

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Four groups of ten nine‐month‐old Nelore heifers were used for this study. Each group received one of four foot‐and‐mouth disease (FMD) trivalent vaccines for the duration of the experiment. The four vaccine formulations (Normal, 2X, 4X and 8X) differed in 140S content to determine the serological reactivities to FMD virus (FMDV) nonstructural proteins 2C, 3ABC and 3D. Vaccination was by the intramuscular administration of vaccine on day 0, 180 and 360. Bleedings were done at 30 days post vaccination (dpv), 90 dpv, 30 days post revaccination (dpr), 90 dpr, and 30 days post third administration (dprr). There was a general tendency to have higher mean 3D responses with increased vaccine application but not with increased concentration of antigen. With 2C and 3ABC this tendency was not seen, neither with repeated application of vaccine nor with increased antigen concentration. All individual animal observations to 2C and 3ABC remained within three standard deviations of the average observed for naive bovids.

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694955

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694956

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper summarises the development of monoclonal antibody (Mab)‐based immunoassays measuring antibodies to non‐structural proteins of FMDV to differentiate infection from vaccination.

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694957

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

An indirect enzyme‐linked immunosorbent assay (I‐ELISA) capable of detecting foot‐and‐mouth disease virus (FMDV)‐specific antibodies in sera from animals with previous viral exposure was developed, as an alternative tool to the enzyme‐linked immunoelectrotransfer blot (EITB) test previously described (Bergmannet al., 1993). Out of the 5 recombinant DNA‐derived FMD nonstructural viral antigens used in the EITB assay, 3ABC was selected, as a serologic probe for the I‐ELISA. High sensitivity for detection of acute as well as of subclinical infection, even at late stages of the persistent status, was indicated by the results for sera from naive animals following experimental infection, or following exposure to the virus under natural conditions. The ability of the test to identify FMDV persistently infected animals subjected to systematic vaccination was also demonstrated. High specificity was revealed by evaluating sera from cattle in FMD‐free regions without vaccination, including samples from cattle infected with a variety of bovine viruses. Analysis of sera from animals in FMD‐free areas under regular vaccination campaigns, including cattle with multiple immunization cycles showed that, ocasionally, antibodies against 3ABC are elicited. The data presented herein indicate that, in agreement with results obtained with the EITB test, the I‐ELISA detected FMDV‐specific antibodies, also at late stages of the persistent infection, maintaining nonspecific reactions at low levels, even in regions under systematic vaccination. Use of the I‐ELISA is suitable as a sensitive, safe, rapid, reproducible and economic test for the detection of previous virus exposure. A combination of screening by the I‐ELISA together with confirmation of suspect serum samples by the more specific EITB assay is proposed for large scale epidemiological surveillance.

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694958

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

ELISA's for antibodies to non‐structural proteins of foot‐and‐mouth disease developed to date use recombinant proteins as antigens. To compare the antibody response to recombinant antigen and native antigen we developed an antigen capture ELISA for foot‐and‐mouth protein 3A. The concentration of 3A protein in virus cultures was significantly higher in the cell debris than in the supernatant, which made it possible to use proteins directly eluted from cells separated from a virus culture using Filteraid. The antigen was trapped between one monoclonal antibody coated to the plate, and a second monoclonal antibody conjugated with horseradish peroxidase. The reaction of the second (conjugated) monoclonal antibody could be blocked by several post‐infection sera. Further research has to be performed to determine whether or not this method can result in a reproducible serological test.

ISSN:0165-2176    

DOI:10.1080/01652176.1998.9694959

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor