peptides were cleaved from the resin with simultaneous side chain protecting group removal by exposure to anhydrous hydrogen fluoride for 40 min at 0 4 u00b0 c in the presence of 10 anisole v v after removal of hydrogen fluoride by water aspiration the resin was washed with anhydrous ethyl ether to remove the anisole the peptide was washed from the resin with sequential washes of dimethylformamide 50 dimethylformamide 10 acetic acid 10 acetic acid and distilled water the combined washings were lyophilized purification of the peptides was accomplished by reverse phase high performance liquid chromatography hplc using a preparative column whatman partisil 10 ods 3 magnum 20 2 2 u00d7 50 cm the desired peptide was eluted during gradient development of the chromatogram the elution program ranged from 95 solvent a 0 1 trifluoroacetic acid 5 acetonitrile water and 5 solvent b 0 1 trifluoroacetic acid acetonitrile to 50 a and 50 b over 65 minutes a portion of each purified peptide was hydrolyzed in 6 0n hcl pierce at 110 u00b0 c for 24 hours and amino acid compositions were determined using a beckman amino acid analyzer model 121m using the geysen technique of peptide synthesis described previously 157 octapeptides were synthesized in duplicate on polyethylene rods or 34 pins 34 each peptide represents an 8 mer made by moving one amino acid at a time through the sequence of rifn u03b2 a solution of 175 u03bcl of each neutralizing mab at an appropriate dilution was mixed with each of the peptide pins overnight at 4 u00b0 c each peptide pin was mixed with.