frozen cell culture of rat b lymphocyte hybridoma cells r1e4 also referred to as 84 1c as described in m baniyash et al mol immunol 25 705 1988 is thawed and expanded as described above about 10 u00d7 10 6 cells are injected into nude mice charles river wilmington mass as described above the mice are primed seven days in advance with 1 ml intraperitoneal injection of pristane r1e4 antibody is purified as described above about 2 mg ml solution of r1e4 antibody is added to a spectra por molecular porous tubing membrane molecular weight cut off 12 000 14 000 and sealed with spectrum clips spectrum medical industries inc los angeles calif the solution is changed to about 0 1 m sodium carbonate ph 8 6 by dialysis versus 1 l of this buffer at 4 u00b0 c for 18 hours with 3 changes the r1e4 antibody is derivatized with biotin by mixing 2 ml dialyzed antibody at 2 mg ml with 400 u03bcl sulfo nhs biotin pierce chemical co rockford ill dissolved at 1 mg ml in water the antibody plus nhs biotin reacted at ambient temperature for 2 hours the unreacted biotin is removed by placing the reaction mixture in a spectra por dialysis bag 14 000 mw cutoff and dialyzed against 1 liter phosphate buffered saline pbs the dialysis solution is changed 3 times over an 18 hour period at 4 u00b0 c biotinylated r1e 4 is stored at.