HUMAN MONOCLONAL-ANTIBODIES AGAINST THE RHESUS-D ANTIGEN FROM WOMEN WITH SEVERE RH IMMUNIZATION SUBMITTED TO HIGH-DOSE INTRAVENOUS IMMUNOGLOBULIN TREATMENT

The pre- and postpartum maternal serum anti-D concentrations of 28 wom en with severe Rh(D) immunization who received high-dose intravenous i mmunoglobulin treatment has been determined. In all cases, including 1 in which the newborn was D negative, a sharp increment in the anti-D titer was observed after delivery. The specific immunoglobulin concent ration rose to levels ranging from 4.7 to 204.0 mu g/ml and, in 20% of the patients, increments of fifty times or greater were observed. Hum an monoclonal antibodies (hmAb) have been produced from Epstein-Barr v irus-transformed lymphoblastoid B cell lines derived from 1 of these n aturally hyperimmunized patients whose serum contained an anti-D-categ ory DVT antibody. Four anti-D-secreting cell lines (97.E3.39.214, 44.E 4.R1.257, E7.R1.126.83.115 and E11V.117.63; hereafter referred to as 2 14, 257, 115 and 63) have been established and maintained in continuou s culture for periods ranging from several months to 3 years, without loss of antibody production capacity. Antibodies 115 and 214 recognize all D-u samples tested at the same level as the polyclonal positive c ontrol. Antibodies 63 and 257 show a significantly lower reaction stre ngth with some of the D-u samples. Studies with D category cells showe d that the D-VI category was recognized only by hmAb 214. The reactivi ty pattern of this antibody is that of an anti-epD4, although the reac tion strength varied greatly with different D-IVa cell samples. Result s obtained with hmAb 257 and 115 using papain-treated D category cells suggest that booth react as anti-epD6/7. Antibody 63 reacts as anti-e pD1, although it shows only weak re activity with the single sample of D-VII cells tested. A mixture of hmAb 214 and 115 should thus be capa ble of identifying most weak and partial D erythrocytes by an appropri ate method.