THE PROTEOGLYCAN SKELETON OF THE KURLOFF BODY EVIDENCED BY CUPROLINICBLUE STAINING

This study deals with the ultrastructure of the chondroitin sulphate p roteoglycans of the Kurloff body, a large lysosome organelle, metachro matic towards Toluidine Blue, of a blood cell unique to the guinea pig and called the Kurloff cell. Splenic Kurloff cell from oestrogen-trea ted guinea pig cells were examined after staining with Cuprolinic Blue , a cationic phthalocyanine-like dye, in the presence of MgCl2 in a cr itical electrolyte concentration method. Better results were obtained when the fixation-staining by the glutaraldehyde Cuprinolinic Blue MgC l2 mixture was preceded by a glutaraldehyde pre-fixation. On light mic roscopy, Kurloff bodies generally exhibited an overall pink and glassy metachromasia, sometimes with additional darker metachromatic small d ots at their peripheries. At the ultrastructural level, the metachroma tic central matrix of the Kurloff body usually exhibited, as a major f eature, a typical network pattern of ribbon-like or stellate electron- dense precipitates suggesting the presence of a skeleton of Cuprolinic Blue-reactive filamentous structures. Taking into account their high anionicity (as shown by the stability of the dye binding in the presen ce of 0.3 M MgCl2) and their susceptibility to chondroitinase ABC, the se anionic structures were assumed to be related to the proteochondroi tin-4-sulphate previously characterized as the only major sulphated gl ycoconjugate of the Kurloff cell.