Cytochemical analysis of mast cell phenotypes in the lymph nodes of allogeneic tumor-grafted mice and in the thymus

Variations in mast cell (MC) phenotype have been investigated from morphological, biochemical, immunological and functional points of view. Histologically, the MC heterogeneity is easily shown by use of the sequential staining of Alcian blue followed by safranin. This allows to currently discriminate between the alcianophilic (blue) mucosal mast cells (MMCs) and the safraninophilic (red) connective tissue-type mast cells (CTMCs). This staining reaction has been used to study the MC response to fibrosarcoma graft in mice. It was shown that MC number was increased in the graft-draining lymph nodes (LNs). However, most of the MCs appeared red in syngeneic tumor-draining LNs, whereas they were blue in allogeneic tumor-draining LNs. To define the phenotypes of these MC subpopulations, we have compared their tinctorial properties to those of peritoneal MCs (CTMCs) and of instestinal MCs (MMCs) by use of several cytochemical reactions. We have also studied the thymus MCs in irradiated mice (lymphoma induction) as in irradiated bone marrow-grafted mice (lymphoma inhibition).