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Indirect complement fixation test with foot-and-mouth disease virus antigen concentrated by polyethylene glycol
Abstract:
To a BHK-21 cell culture fluid infected with the O, A, or Asia 1 type of foot-and-mouth disease (FMD) virus was added polyethylene glycol 16000 to a concentration of 10% (w/v). Then the fluid was concentrated to one-tenth of the original volume. The resulting concentrated virus antigens showed a complement fixation (CF) titer ranging from 12 to 14. The rate of recovery of CF activity was in a range of 40 approximately 80%. Each antigen was applied to the indirect complement fixation (ICF) test with serum from cattle infected experimentally with the respective type of virus to estimate antibody titers. When antibody was examined for a rise and fall, it began to be detected 4 approximately 7 days after inoculation and was detectable even 63 days after inoculation. It showed a tendency to exhibit a rise and fall parallel with that of neutralizing antibody, although it was always lower in titer than this antibody. ICF antibody corresponding to one type of virus was type-specific, presenting little crossing with a heterologous antigen. As a result, it was clarified that such antigen as prepared from an infected cell culture fluid after concentration with polyethylene glycol was applicable to the ICF test for the estimation of the titer of antibody against FMD virus.
Insights
This study developed a method using polyethylene glycol to concentrate foot-and-mouth disease virus (FMDV) antigens for antibody detection. The indirect complement fixation (ICF) test proved effective for quantifying FMDV antibodies in cattle.
Area of Science:
- Veterinary Virology
- Immunodiagnostics
Background:
- Foot-and-mouth disease virus (FMDV) poses a significant threat to livestock globally.
- Accurate and efficient diagnostic methods are crucial for FMDV surveillance and control.
Purpose of the Study:
- To develop and evaluate a method for preparing FMDV antigens for use in the indirect complement fixation (ICF) test.
- To assess the utility of ICF test for estimating antibody titers against different FMDV serotypes in cattle.
Main Methods:
- BHK-21 cell cultures infected with FMDV (types O, A, Asia 1) were treated with 10% polyethylene glycol 16000.
- Virus-infected fluids were concentrated to one-tenth of the original volume.
- Prepared antigens were used in ICF tests with experimentally infected cattle sera.
Main Results:
- Concentrated FMDV antigens exhibited complement fixation (CF) titers of 12-14 with 40-80% recovery of CF activity.
- Antibodies were detected 4-7 days post-inoculation and remained detectable for up to 63 days.
- ICF antibody titers correlated with neutralizing antibody titers but were lower, and demonstrated type-specific reactivity.
Conclusions:
- Polyethylene glycol concentration is an effective method for preparing FMDV antigens from infected cell culture fluids.
- The ICF test is a valuable tool for estimating antibody titers against FMDV in cattle.
- The developed antigen preparation method supports type-specific antibody detection for FMDV surveillance.