A mechanism for the depression of contact sensitivity with B-cell mitogens.

LPS or DxS impair contact sensitivity to oxazolone in mice, evaluated as ear thickness and DNA synthesis of regional lymph node cells in vitro. Lymphoid cells from LPS- or DxS-injected and sensitized mice were able to transfer specifically the suppression when injected into animals sensitized immediately before cell transfer. This cell suppressor activity was eliminated by nylon wool filtration. These results suggest that B-cell mitogens may enhance suppressor cell activity of regulatory cells which arise during conventional immunization.