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Subacute sclerosing panencephalitis: measles virus matrix protein nucleic acid sequences detected by in situ
Abstract:
Subacute sclerosing panencephalitis (SSPE) is characterized by a hyperimmune state toward the polypeptides of measles virus except the matrix (M) protein. Using cloned (3H)-labeled complementary DNA probes for in situ hybridization, we found the M protein and nucleocapsid (NP) protein nucleotide sequences in glial cells and neurons of cryostat sections from two SSPE brains. In one SSPE brain, M protein was lacking, but the other measles polypeptides were present. IgG and IgM antibodies eluted from that brain lacked antibodies to M protein, but antibodies to other measles polypeptides were present. In SSPE brain, the viral M-protein defect is not a deletion of the M gene, but rather a block in gene expression.
Insights
Subacute sclerosing panencephalitis (SSPE) shows a unique immune response to measles virus. Researchers found the measles matrix (M) protein gene is present but not expressed in SSPE brain cells, indicating a gene expression block.
Area of Science:
- Neurology
- Virology
- Immunology
Background:
- Subacute sclerosing panencephalitis (SSPE) is a rare, fatal neurological complication of measles virus infection.
- Patients with SSPE exhibit a hyperimmune state against most measles virus proteins, with a notable exception for the matrix (M) protein.
Purpose of the Study:
- To investigate the presence and expression of measles virus matrix (M) protein in the brains of patients with SSPE.
- To determine the molecular basis for the lack of M protein-specific antibodies in SSPE patients.
Main Methods:
- In situ hybridization using cloned (3H)-labeled complementary DNA probes.
- Analysis of viral protein and nucleotide sequences in glial cells and neurons from SSPE brain tissues.
- Elution and characterization of IgG and IgM antibodies from SSPE brain tissue.
Main Results:
- Nucleotide sequences for M protein and nucleocapsid (NP) protein were detected in glial cells and neurons of two SSPE brains.
- In one SSPE brain, M protein was absent, while other measles polypeptides were present.
- IgG and IgM antibodies eluted from this brain lacked M protein antibodies but contained antibodies against other measles polypeptides.
Conclusions:
- The defect in M protein in SSPE brains is not due to gene deletion but a blockage in gene expression.
- This gene expression block of the measles M protein contributes to the unique immunological profile observed in SSPE.