Jin R, Day B W, Karol M H
Department of Environmental and Occupational Health, University of Pittsburgh, Pennsylvania 15238.
Chem Res Toxicol. 1993 Nov-Dec;6(6):906-12. doi: 10.1021/tx00036a023.
To investigate the process of toluene diisocyanate (TDI) sensitization, studies were conducted to identify TDI-protein adducts in the bronchoalveolar lavage (BAL) fluid of guinea pigs exposed to a sensitizing atmosphere of the commercially used 4:1 mixture of 2,4- and 2,6-TDI. Animals were exposed to 2 ppm TDI for 3 h. Immediately thereafter lungs were lavaged. TDI-modified proteins in the lavage fluid were identified by immunologic staining with a highly sensitive and specific rabbit antiserum raised to a TDI-keyhole limpet hemocyanin (TDI-KLH) conjugate. The sensitivity of the antiserum was demonstrated by its ability to identify TDI-guinea pig serum albumin (GSA) adducts with as few as 0.7 mol of TDI/mol of protein. The antiserum did not react with GSA nor with a GSA adducted with another aromatic diisocyanate, diphenylmethane 4,4'-diisocyanate. TDI-protein adducts in the BAL fluid were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by immunoblotting with use of the rabbit anti TDI-KLH antiserum. At least 5 protein bands were recognized by the antiserum. Electrophoretic mobilities indicated molecular sizes equivalent to 10.5, 38, 45, 66, and 148 kDa. Employing a murine anti-GSA antibody in immunoaffinity chromatography, one of the proteins in the 66-kDa band was identified as serum albumin. Attempts to purify the TDI-albumin adduct using a Cibacron-Sepharose column were unsuccessful. Studies with a model TDI0.7-GSA conjugate (which contained an average of 0.7 mol of TDI/mol of GSA) indicated that the TDI-albumin was not retained by the triazine dye column unless the adducted protein was first reduced by incubation with mercaptoethanol.(ABSTRACT TRUNCATED AT 250 WORDS)
