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Characterization of major structural proteins of measles virus with monoclonal antibodies
Abstract:
We have prepared and characterized monoclonal antibodies against five major structural proteins, i.e. the HA, P, NP, F and M proteins, of measles virus. At least three non-overlapping antigenic sites were delineated on the HA protein, three on the P, four on the NP, four on the F and five on the M proteins by competitive binding assays. Antigenic sites on the HA and F proteins roughly represented functional domains defined by serological tests. The reactivity of monoclonal antibodies with various measles virus strains including those from subacute sclerosing panencephalitis (SSPE) and other members of the morbillivirus family was studied by immunofluorescence. A monoclonal antibody or set of monoclonal antibodies to each of the antigenic sites showed a characteristic pattern of cross-reactivity with heterologous strains. The HA and NP proteins were antigenically the most variable, followed by the F and M proteins, while the P protein was relatively stable. None of the 14 anti-M monoclonal antibodies reacted with non-virus-producing SSPE cells, strongly suggesting the absence of M protein in these cells.
Insights
Researchers developed monoclonal antibodies targeting key measles virus proteins (HA, P, NP, F, M). They mapped antigenic sites and found HA and NP proteins are most variable, while P protein is stable, offering insights into measles virus evolution.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Measles virus (MeV) poses a significant global health challenge.
- Understanding the antigenic properties of MeV structural proteins is crucial for vaccine development and diagnostics.
- Previous studies have provided limited information on the antigenic diversity of MeV proteins.
Purpose of the Study:
- To generate and characterize monoclonal antibodies against five major MeV structural proteins: Hemagglutinin (HA), Phosphoprotein (P), Nucleoprotein (NP), Fusion (F), and Matrix (M).
- To delineate and map distinct antigenic sites on these proteins using competitive binding assays.
- To investigate the cross-reactivity patterns of these antibodies with various MeV strains, including those from subacute sclerosing panencephalitis (SSPE), and other morbilliviruses.
Main Methods:
- Production and characterization of monoclonal antibodies against purified MeV structural proteins (HA, P, NP, F, M).
- Competitive binding assays were employed to identify and map non-overlapping antigenic sites on each protein.
- Immunofluorescence assays were utilized to assess the reactivity of monoclonal antibodies with diverse MeV strains and morbilliviruses.
Main Results:
- Multiple antigenic sites were identified on each protein: at least three on HA, three on P, four on NP, four on F, and five on M.
- Antigenic sites on HA and F proteins correlated with functionally defined domains.
- Significant antigenic variability was observed in HA and NP proteins, moderate in F and M, and low in P.
- Absence of M protein in non-virus-producing SSPE cells was indicated by negative reactivity with anti-M monoclonal antibodies.
Conclusions:
- The study successfully mapped antigenic sites on key MeV structural proteins, revealing their distinct antigenic profiles.
- Measles virus HA and NP proteins exhibit the highest antigenic variability, suggesting rapid evolution.
- The findings provide valuable data for understanding MeV diversity, strain differentiation, and potentially for improving MeV diagnostics and vaccine strategies.