Study of guinea pig and human antibodies to toluene diisocyanate

Antibodies to toluene diisocyanate (TDI) have previously been reported in both sensitized guinea pigs and industrial workers. Detection of antibodies to TDI is difficult because the ability of TDI to self-polymerize and cross-link carrier proteins causes problems in preparing satisfactory hapten-protein conjugate antigens. Use of monoisocyanate analogues of TDI for antigen preparation eliminates the problem. This study compared 3 tolyl monoisocyanate isomers with TDI for haptenic ability to detect antibodies to TDI in sensitized guinea pigs and humans. Using the gel-diffusion technique, antibodies from guinea pigs reacted with ortho-, meta- and para-tolyl monoisocyanate haptens and with a TDI hapten. In the guinea pigs, reactions appeared to be strongest with the TDI hapten and weakest with meta-tolyl isocyanate hapten. On the other hand, antibodies in TDI-sensitized workers, as determined by radioallergosorbent testing, reacted comparably with each of the haptens.