Modification of suppressor/cytotoxic and helper subsets in lentil lectin-pretreated mice.

Abstract

The effect of lentil lectin (LCA) on various lymphocyte subpopulations in the spleen, lymph nodes and thymus of CBA mice was studied. The most marked effect after five 1-mg LCA doses was observed in the spleen. LCA caused a drop in both the total and relative number of cells carrying all the markers examined, i.e., Thy 1, L3/T4a, Lyt 2, and sIg, so that large numbers of lymphocytes did not express any of them. A dramatic decrease in the Thy 1-positive cell number is mainly due to depletion of the L3/T4a (helper) T cell subpopulation, whereas the Lyt 2+ (suppressor/cytotoxic) cells are less affected. The decrease in the Thy 1+, Lyt 1+ and L3/T4a+ cell numbers in the thymus and lymph nodes is smaller, the percentage of Lyt 2+ cells is even increased after LCA treatment. Our results indicate that two mechanisms play a role in the induction of allotransplantation tolerance by LCA: 'depletion' of helper T cells and a relative increase in the regulatory (suppressor) cell ratio, which may support allograft survival.