The production of monoclonal antibodies against aldosterone.

We have prepared several monoclonal antibodies against aldosterone-3-carboxy-methyloxime-BSA conjugate by fusing spleen lymphocytes from an immunized mouse with the mouse myeloma line HL-1 Friendly. A total of 6 different clones were isolated and expanded. All of the antibodies exhibited low cross-reactivities against most of the compounds tested. Antibodies A5A3, A2E11, and C1E2 exhibited low cross-reactivity with 18-hydroxycorticosterone and 18-hydroxydeoxycorticosterone and showed no detectable displacement of tritiated aldosterone from the antibodies with cortisol, corticosterone, and related steroids. The only steroid that showed moderate cross-reactivity was 3 alpha,5 beta-tetrahydroaldosterone (around 3%). Clone A5H12 antibodies exhibited high cross-reactivity with tetrahydroaldosterone (19.3%) but otherwise was very similar to the above clones. Antibody of clone C1E4 showed high cross-reactivity to tetrahydroaldosterone (41.2%) and 18-hydroxyDOC (2%) with relatively low cross-reactivity to DOC (0.078%). Clone A2G9 antibodies were the only ones for which cortisol and corticosterone displaced tritiated aldosterone with cross-reactivities of 0.0042% and 0.125%, making them unsuitable for a direct radioimmunoassay of plasma aldosterone. The monoclonal antibodies were very sensitive to freezing and thawing. The cross-reactivities of the first three clones' antibodies compare favorably with those polyclonal antibodies that have been described to be suitable for use in direct radioimmunoassays of plasma aldosterone. Their advantage is the reliable supply of an antibody with consistent, predictable properties.