Studies of the antibody nature of the rheumatoid factor: Reaction of the rheumatoid factor with human specific precipitates and with native human gamma globulin

The reaction of the RF with diphtheria toxoid‐human antitoxin precipitates was studied. All the RF activity from different rheumatoid sera was absorbed to the specific precipitates. This absorption was not markedly inhibited by even a large excess of added serum gamma globulin. The reaction of the RF with the specific precipitates was found to be reversible. The dissociation reaction was studied quantitatively by using I 131 ‐labeled rheumatoid serum.