Comparison between different rabbit antisera against the glucocorticoid receptor.

Area of Science:

• Biochemistry
• Immunology
• Molecular Biology

Background:

• The glucocorticoid receptor (GR) is a crucial nuclear receptor involved in various physiological processes.
• Understanding the specificity of antibodies against GR is essential for its study.

Purpose of the Study:

• To characterize seven antisera raised against rat liver glucocorticoid receptor (GR).
• To evaluate their binding affinity, cross-reactivity with different species, and specificity for other steroid receptors.

Main Methods:

• Enzyme-linked immunosorbent assay (ELISA) was used to determine antibody titers.
• Protein A purification was employed for antibody isolation.
• Limited proteolysis (alpha-chymotrypsin, trypsin) was used to assess antigenic determinant stability.
• Cross-reactivity was tested against GR from human, chick, mouse, and rabbit, as well as other steroid receptors.

Main Results:

• All seven antisera recognized the rat GR, with titers ranging from 1:100 to 1:320.
• Antigenic determinants in the non-ligand-binding domain remained intact after proteolysis.
• Two antisera showed cross-reactivity with human and chick GR, while four cross-reacted with mouse and rabbit GR.
• No cross-reactivity was observed with estrogen, progestin, androgen, or mineralocorticoid receptors.

Conclusions:

• The generated antisera recognize specific domains of the rat GR.
• Antibody binding does not impede GR ligand or DNA interaction.
• Significant species-specific differences exist in GR antigenicity.
• These antisera are specific for GR and do not cross-react with other major steroid receptors.