Kurloff cell ultrastructure after combined formaldehyde-cetylpyridinium chloride fixation and high-iron diamine staining

Abstract

This study deals with the ultrastructure of the chondroitin sulphate proteoglycans of the Kurloff body, a large lysosomal organelle that stains metachromatically with Toluidine Blue and which is present in Kurloff cells (a blood cell unique to the guinea pig). Splenic tissues were fixed with 1% cetylpyridinium chloride (CPC) added to 4% paraformaldehyde and examined either after Spicer's high-iron diamine staining for sulphated anionic sites followed by post-fixation with ferrocyanide-osmium tetroxide or after a simple post-fixation with ferrocyanide-osmium tetroxide. CPC-precipitated sulphated sites were preferentially located at the periphery of the Kurloff body but, unexpectedly, were absent in the central matrix. Although their electron opacity was lower, these anionic sites were readily observable in the absence of HID-staining after sole post-fixation by ferrocyanide-reduced osmium. CPC-precipitated sulphated anionic sites were either associated with the myelin figures or constituted unexpected structures. They contained (i) tightly-stacked lamellae, with a very regular 4 nm periodicity, and (ii) groups of 2, 3, 4 short dense lines with a 3-5 nm periodicity. By taking into account the susceptibility of these HID-reactive structures towards chondroitinase ABC, these different sulphated components were assumed to be related to the proteochondroitin-4-sulphate previously characterized as the only major sulphated glycoconjugate of the Kurloff cell. Their colocalization with phospholipidic structures was suggested following observation of sections treated by a chloroform-methanol mixture.

Kurloff cell lysosomal arylsulphatases: Presence of both cationic and highly anionic isoforms of the sole B class

“…Since the desulphatation of commercial chondroitin-4-sulphate by partially purified KC Asase has been attested by the loss of their methachromatic properties, KC Asase themselves may constitute good candidates to be responsible for this desulphatation process. Moreover the previously described [15,18,21] proteochondroitin-4-sulphate of Kurloff body may, thus, constitute potential physiological substrates for Asase IIB in KC. Asase liB have indeed similar physiological substrates in other models [7,13].…”

Anatomical features for an adequate choice of experimental animal model in biomedicine: II. Small laboratory rodents, rabbit, and pig

“…The presence of Kurloff (Foa-Kurloff) cells is unique to guinea pigs. These cells are mononuclear leukocytes with natural killer activity that are found in the circulating blood, splenic sinusoids, bone marrow, and thymus (Pouliot et al, 1996;Landemore et al, 1993).…”