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Differences in bovine parainfluenza 3 virus variants studied by monoclonal antibodies against viral glycoproteins
Abstract:
We previously showed that of three bovine parainfluenza 3 virus strains the M strain, which is neurovirulent for young mice, has an extensive syncytium-inducing activity, whereas avirulent SC and 910N strains are weak in this activity. It was also demonstrated that both M and SC strains have very low hemagglutination and neuraminidase activities, while the 910N strain shows these activities to high levels. In the present study, monoclonal antibodies (Mabs) were raised against the glycoproteins of the 910N strain, and utilized to further characterize these three viral strains. Five Mabs against the hemagglutinin-neuraminidase protein, which were classified into four different epitope-recognizing groups, neutralized the M strain much more effectively than the 910N and SC strains, while the Mabs showed lower hemagglutination inhibition (HI) titers against the M and SC strains than the 910N strain. Three Mabs against the fusion protein neutralized the M strain but not the 910N and SC strains, while they showed no HI activity against any of these strains. These findings suggested that the M strain is considerably different from other strains in the structure of the viral envelope proteins.
Insights
Monoclonal antibodies reveal significant differences in bovine parainfluenza 3 virus envelope proteins. The neurovirulent M strain exhibits distinct glycoprotein structures compared to avirulent strains.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Bovine parainfluenza 3 virus (BPIV3) exhibits varying virulence and biological activities among different strains.
- Previous studies identified neurovirulent M strain with high syncytium-inducing activity and low hemagglutination/neuraminidase activity, contrasting with avirulent SC and 910N strains.
Purpose of the Study:
- To characterize three BPIV3 strains (M, SC, 910N) by raising monoclonal antibodies (mAbs) against the 910N strain's glycoproteins.
- To investigate the structural differences in viral envelope proteins among these BPIV3 strains.
Main Methods:
- Generation of monoclonal antibodies against hemagglutinin-neuraminidase (HN) and fusion (F) proteins of BPIV3 910N strain.
- Neutralization assays and hemagglutination inhibition (HI) tests using the generated mAbs against BPIV3 M, SC, and 910N strains.
Main Results:
- Five anti-HN mAbs effectively neutralized the M strain more than SC and 910N strains, showing lower HI titers against M and SC strains.
- Three anti-F protein mAbs neutralized the M strain but not SC or 910N strains, with no observed HI activity.
- The M strain demonstrated significantly different reactivity patterns with mAbs compared to the SC and 910N strains.
Conclusions:
- The M strain of BPIV3 possesses distinct viral envelope protein structures, particularly HN and F proteins, differentiating it from avirulent SC and 910N strains.
- These structural variations likely contribute to the observed differences in neurovirulence and biological activities among BPIV3 strains.