Experimental studies of immunologically mediated enteropathy. II. Role of natural killer cells in the intestinal phase of murine graft-versus-host reaction.

This study has investigated whether natural killer (NK) cells play a protective or an effector role in unirradiated mice with graft-versus-host reaction (GvHR). Treatment of (CBA X BALB/c)F1 mice with anti-asialo GM1 (ASGM1) antibody produced a profound depletion of resting NK-cell activity and also inhibited the normal enhancement of NK activity found after induction of a GvHR with CBA spleen cells. Compared with normal hosts, mice treated with anti-AsGM1 developed less splenomegaly in GvHR and did not show the crypt hyperplasia normally found in this model of GvHR. Anti-AsGM1 also produced a small but significant reduction of intraepithelial lymphocyte (IEL) numbers in the jejunum of control mice. We conclude that intestinal NK cells are an essential component of the local delayed-type hypersensitivity (DTH) reaction which is responsible for the intestinal phase of GvHR in unirradiated mice.