ABSTRACT
Lymph node cell proliferation has so far formed the basic paradigm of the local lymph node assay (LLNA) for the identifi cation of contact allergenic potential of small mole cular weight chemicals. Since the activation of specifi c effector lymphocytes and the formation of immunological memory are the hallmarks of a specifi c immune response depending on clonal expansion of specifi c lymphocytes, cell proliferation in the lymph nodes (LN) was consequently seen as an indicator of the sensitizing potential of a chemical. However, there is accumulating evidence on irritating chemicals, which cause false-positive results in the LLNA by inducing proliferative events in the skin-draining lymph nodes [1-6]. The complex mechanisms leading to irritant-related cell proliferation in the LN are not completely understood, but the phenomenon itself may lead to a reconsideration of the basic principles of generation and evolution of specifi c immune responses induced by chemicals with the potential to form hapten-carrier-conjugates.
