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A new protein (J1-31 antigen, 30 kD) is expressed by astrocytes, Müller glia and ependyma
R Predy1, D Singh, R Bhatnagar
1Department of Pathology, University of Alberta, Edmonton, Canada.
Abstract:
Monoclonal antibody (MAb) J1-31 raised using human brain homogenate as immunogen in mice can be used as a cell type marker for certain types of CNS macroglia, namely astrocytes, Müller cells and tanycytes as well as ciliated ependymal cells. Except for the ciliated ependymal cells, these types of macroglia express glial fibrillary acidic protein (GFAP). J1-31 antigen is an intracellular protein which has a MW of 30 kD under reducing conditions for gel electrophoresis (Singh et al., 1986). This protein is distinct from GFAP (MW 50 kD) and vimentin (MW 55 kD), the two core proteins of 10 nm IFs known to be expressed in the above types of macroglia. This conclusion is based on several criteria including temporal differences in the onset of expression of GFAP and J1-31 antigen during development of the rat cerebellum. Also, there is no detectable (by immunofluorescence microscopy) expression of J1-31 antigen in the prenatal CNS or outside the CNS where vimentin has been reported to be abundant. The most direct evidence that J1-31 antigen and GFAP are distinct proteins comes from studies on the mature ciliated ependymal cells which do not express GFAP and yet show intense immunostaining for J1-31 antigen.
Insights
Monoclonal antibody J1-31 identifies specific CNS macroglia and ciliated ependymal cells. This antibody targets a distinct 30 kD protein, separate from GFAP and vimentin, aiding cell type identification.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Background:
- Glial fibrillary acidic protein (GFAP) and vimentin are key intermediate filament proteins in macroglia.
- Identifying specific CNS cell types requires precise molecular markers.
Purpose of the Study:
- To characterize the J1-31 monoclonal antibody as a cell type marker.
- To determine if the J1-31 antigen is distinct from GFAP and vimentin.
Main Methods:
- Immunization of mice with human brain homogenate to generate monoclonal antibody (MAb) J1-31.
- Gel electrophoresis to determine the molecular weight of the J1-31 antigen.
- Immunofluorescence microscopy to assess antigen expression during development and in different cell types.
- Comparison of J1-31 expression with GFAP and vimentin expression.
Main Results:
- MAb J1-31 identifies astrocytes, Müller cells, tanycytes, and ciliated ependymal cells in the CNS.
- The J1-31 antigen is an intracellular protein with a molecular weight of 30 kD, distinct from GFAP (50 kD) and vimentin (55 kD).
- Expression patterns of J1-31 antigen and GFAP differ during development, and J1-31 is present in GFAP-negative ciliated ependymal cells.
Conclusions:
- MAb J1-31 is a valuable cell type marker for specific CNS macroglia and ciliated ependymal cells.
- The J1-31 antigen represents a novel molecular target distinct from established glial markers.
- This antibody facilitates the differentiation of glial cell populations within the central nervous system.