Influence of carbohydrates on the antigenic structure of gonadotropins: distinction of agonists and antagonists.

The biological properties of glycosylated (native) and deglycosylated gonadotropins are different. The immunological characteristics of antibodies prepared against deglycosylated lutropin and human chorionic gonadotropin were investigated. Distinct antibodies of rabbit polyclonal antisera against deglycosylated lutropin and deglycosylated chorionic gonadotropin were separated by affinity chromatography on divinylsulfonyl-Sepharose-immobilized hormone or antagonist columns, respectively, in successive runs.

Alterations in antigenic structure of gonadotropins following deglycosylation.

Radioimmunological techniques were utilized to probe possible changes in conformation of gonadotropins (human chorionic gonadotropin--hCG; and ovine luteinizing hormone--oLH) following chemical deglycosylation (DG-hCG and DG-LH). All antisera produced in rabbits, rats or mice contained antibodies that were specific to the deglycosylated hormones with the native hormones showing weak and non-parallel cross-reaction (less than 5%), but with rabbit antibodies to native hormones the deglycosylated hormones were fully reactive. Using hCG, asialo-hCG (A-hCG) and DG-hCG, we have shown that removal of sugars internal to sialic acid is required to produce these specific antibodies.