In vitro evaluation on contact sensitivity from DNCB and DNBS using lymphocyte blastogenesis response test

To assess the contact allergic potential of sensitizers, an in vitro predictive model was developed. First of all, guinea pigs were sensitized by 1-chloro-2-4,dinitrobenzene (DNCB), and lymph node cells from sensitized and control guinea pigs were cultured in the presence of DNCB, 2,4-dinitrobenzene sulfonic acid sodium salt (DNBS), DNCB plus epidermal cell (DNCB + EC), DNBS + EC and epidermal cell modified hapten (dinitrophenyl-EC, DNP-EC) at 3 x 10(5), 5 x 10(5) and 8 x 10(5) cells/well, respectively. Lymphocyte blastogenesis responses were assessed by uptake of 5H-thymidine. The results indicated that lymphocytes from sensitized guinea pigs responded to the foregoing antigens in vitro to a greater degree than those from control guinea pigs and the blastogenesis response by DNBS was the highest among the challenges of DNBS, DNCB, DNCB + EC, DNBS + EC and DNP-EC. When the number of lymphocytes was sufficient, the blastogenesis response of lymphocytes could be in vitro challenged successfully not only by DNBS, DNCB + EC, DNBS + EC and DNP-EC, but also DNCB alone. There was a cross sensitivity between DNCB and DNBS for in vivo and in vitro challenges. Moreover, significant relationships were observed between lymphocyte blastogenesis response and doses of DNBS used in vitro assay at 5 x 10(5) and 8 x 10(5) cells/well. The results indicate that this assay is an useful in vitro predictive model of contact sensitivity and cross sensitivity of sensitizers.