Lymphocyte expression of a 90 kD brush border antigen

Area of Science:

• Immunology
• Nephrology
• Cell Biology

Background:

• Renal brush border (BB) antigens are crucial in kidney function and disease.
• Heymann's nephritis involves a 330 kD BB antigen, offering insights into epimembranous glomerulonephritis.
• Understanding antigen expression on lymphocytes is key to immune system research.

Purpose of the Study:

• To analyze the expression of six renal brush border (BB) antigens on rat lymphocytes.
• To identify specific BB antigens present on the surface of T and B cells.
• To compare the expression levels of these antigens across different lymphocyte populations.

Main Methods:

• Utilized a panel of monoclonal antibodies to define six BB antigens.
• Performed immunochemical studies, including SDS-PAGE, to analyze protein migration.
• Conducted quantitative binding analysis to determine antigen site numbers on lymphocytes.

Main Results:

• A 90 kD protein (gp 90), synthesized by BB and glomeruli, was detected on the surface of rat T and B lymphocytes.
• Other BB antigens, including the 330 kD protein associated with Heymann's nephritis, were not found on lymphocytes.
• gp 90 and a related thymocyte membrane protein showed co-migration in SDS-PAGE.
• Antigenic site numbers for gp 90 were comparable on thymocytes, spleen, bone-marrow lymphocytes, and pre-B/pre-T cell lines, but lower on helper T cells.

Conclusions:

• Rat lymphocytes express a specific renal brush border antigen, gp 90.
• gp 90 represents a potential link between renal antigens and lymphocyte surface markers.
• The differential expression of gp 90 suggests distinct roles in immune cell populations.