The rainbow trout (Salmo gairdneri Richardson) granular leukocytes and mast-cells system versus the human one. Cytomorphometrical and cytochemical characters in these two species philogenetically poles apart.

In man, circulating granular leukocytes constitute a cellular system and are able to migrate in the tissues to take part in the immune reactions. This study was to characterize the granular leukocytes and the eventual existence of mast-cells of a low vertebrate, rainbow trout (Salmo gairdneri R.) in order to compare it with man. The blood smears and tissues sections have been tested whit panoptic methods, cytochemistry and toluidine blue. White blood cell count, leukocytes formula and cytomorphometric characterization was performed using an image analyser. Scanning of tissues sections in order to identify mast-cells has been also performed. In this model the granular leukocytes are all neutrophilic like; no eosinophilic, no basophilic no tissue mast-cells, basically existing in allergic and anaphylactic reactions, were found.