The simultaneous use of two prostaglandin E radioimmunoassays employing two antisera of differing specificity I. Determination of prostaglandin content in sera and culture medium of simian virus 40 transformed cells

Two antisera produced by employing a PGE₁ or PGE₂ protein conjugate have been titered and tested for crossreactivity with PGE₁ and PGE₂. These antibodies revealed marked differences in PGE₁ versus PGE₂ specificity. Anti-PGE₁ displayed only a low level of crossreactivity with PGE₂ (20%), while anti-PGE₂ was capable of detecting both PGE₁ and PGE₂ in known mixtures of PGs. These two antisera have been utilized to measure the same serum and culture medium samples. The differing values obtained with the two PGE antisera are a reflection of the known differences in PGE specificity. These results stress the fact that antisera with only partial crossreactivity with PGE₂ have only limited use in assessing experimental fluctuations in PGE level.