The local lymph node assay has been proven to be a common test for ide
ntification of contact sensitizing chemicals and for investigation the
influence of immunomodulatory substances. In the present study are mo
dified the kinds of counting the transformed cells by using a cell sor
ter FACS-Scan. 3, 4 and 5 days after DNFB painting auricular lymph nod
es of sensitized (only!) or sensitized and drug treated guinea pigs we
re removed and prepared to determine the frequency of large pyroninoph
ilic blasts. The data obtained by microscopic evaluation and the data
of FACS-Scan analysis are absolutely comparable. Cyclophosphamide had
a strong suppressive effect, the new synthesized immunomodulator AWD 1
00-041 a stimulatory activity.