Contact sensitivity to dinitrofluorobenzene and oxazolone in mice: in vitro cell-electrophoretic assay

Prevalent techniques for the assessment of cell-mediated immunity (CMI) in vitro are time consuming and may lack specificity. Deriving from the earlier observation of reduction in mean electrophoretic mobility (EPM) of lymphocytes following the development of humoral immune response, the possibility of using this electrokinetic method for the assessment of contact sensitivity in vitro was tested. CBA mice epicutaneously sensitized to dinitrofluorobenzene and 2-phenyl 4-ethoxy oxazolone showed a marked and reproducible reduction in the mean EPM of their lymph node cells (LNC). The specificity of this alteration in surface charge density was established by the enhancement in the EPM of contact sensitized LNC upon subsequent incubation in vitro with the specific antigen only. The profiles of time kinetics of changes in the EPM of LNC before and after incubation with antigen were virtually parallel to those of in vivo delayed hypersensitivity (DH) reaction as measured by the ear-swelling method. The coefficients of correlation between the reduction in EPM and in vivo DH response for DNFB and oxazolone were 0.89 and 0.86 respectively. EPM measurements may thus provide a sensitive, rapid, and quantitative parameter for the assessment of CMI in vitro.