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Alterations in expression of measles virus polypeptides by antibody: molecular events in antibody-induced antigenic
Abstract:
Six hours after measles virus antibodies bind to the surface of HeLa cells acutely infected with measles virus, the expression of an external polypeptide F1, as well as internal polypeptides P and M are altered. The loss of F1 molecules during antibody-induced antigenic modulation explains the lack of cell-cell fusion and giant cell formation of infected cells cultured in the presence of antibody. The decrease in F1, P, and M viral polypeptides is specific, since the effect is only seen with antibodies directed against measles virus antigens expressed on the cell's surface and not with antibodies directed against nonviral antigens expressed on the surfaces of virus-infected cells. Since the P protein or its analog in other viral systems appears to be associated with transcriptive complex whereas the M protein is associated with nucleocapsid recognition and alignment at the plasma membrane, the alterations in these polypeptides might lead to aberrations in measles virus synthesis and maturation that are hallmarks of persistent measles virus infection.
Insights
Antibodies targeting measles virus on infected cells reduce key viral proteins, hindering cell fusion and potentially causing persistent infections. This study reveals specific molecular changes impacting measles virus replication.
Area of Science:
- Virology
- Cell Biology
- Immunology
Background:
- Measles virus infection can lead to persistent disease.
- Viral protein expression is crucial for measles virus replication and cell-to-cell spread.
- Antibody-mediated immune responses can modulate viral antigen expression.
Purpose of the Study:
- To investigate the effect of measles virus-specific antibodies on viral polypeptide expression in infected cells.
- To determine the impact of these changes on cell fusion and giant cell formation.
- To explore the potential link between altered polypeptide expression and persistent measles virus infection.
Main Methods:
- HeLa cells were acutely infected with measles virus.
- Antibodies against measles virus surface antigens were applied.
- Expression levels of external polypeptide F1 and internal polypeptides P and M were analyzed.
- Cell-cell fusion and giant cell formation were assessed.
Main Results:
- Antibody binding to measles virus-infected HeLa cells altered the expression of external F1 and internal P and M polypeptides.
- Loss of F1 molecules correlated with a lack of cell-cell fusion and giant cell formation.
- The observed decrease in viral polypeptides was specific to measles virus antibodies.
- Alterations in P and M proteins suggest potential impacts on measles virus synthesis and maturation.
Conclusions:
- Antibody-induced antigenic modulation specifically reduces key measles virus polypeptides (F1, P, M).
- This reduction inhibits measles virus spread by preventing cell fusion.
- Altered expression of P and M proteins may contribute to the aberrations seen in persistent measles virus infections.