ANTIBODIES TO STEROIDS FROM A SMALL HUMAN NAIVE IGM LIBRARY

Human antibodies specific for digoxigenin, estradiol, testosterone and progesterone have been isolated from a small combinatorial IBM repert oire (4 X 10(7)) of single chain antibodies (scFv). The affinities of both the anti-estradiol and antiprogesterone scFv were approximately 1 0(8) M-1, Naive IgM genes appeared to be highly represented, since onl y the heavy chain variable domain of the anti estradiol antibody conta ined differences to corresponding germline sequences, The light chain variable domain of the progesterone receptor was also identical to a g ermline sequence, showing that it is possible for completely naive ant ibodies to bind steroids with affinities comparable to those obtained after a secondary immune response, (C) 1997 Federation of European Bio chemical Societies.