Primary immunization of lymph node cells in millipore chambers by exposure to homograft antigen.

Normal Dutch rabbit lymph node and spleen minces, lymph node cell suspensions, and residues from lymph node cell suspensions were cultured in Millipore chambers with slices of autologous or homologous (New Zealand) ear skin. for varying time intervals. Lymphoid cells exposed to New Zealand ear skin for more than 4 days were found capable of producing typical "transfer reactions" in the specific New Zealand ear skin donor, similar in every way to reactions produced by cells from lymph nodes sensitized in the intact Dutch animal. Heat-killed cells and cells exposed to New Zealand ear skin for less than 4 days (in chambers or in the intact animal) or to Dutch ear skin for any period of time were incapable of eliciting such reactions. It is concluded that normal lymphoid tissues undergo primary sensitization when exposed to homografts in Millipore chambers for suitable periods of time.