Glycoconjugates with Neu5Ac(alpha 2,6)Gal(beta 1,4)GlcNAc sequences: a selective lectin-histochemical property of Kurloff cells in guinea pig thymus.
The Kurloff cell (KC), a natural killer lymphocyte, contains a large (10-microns diameter) periodic acid-Schiff (PAS)-positive lysosome-like inclusion body called the Kurloff body (KB), which exhibits strong acid phosphatase activity. The presence of Sambucus nigra agglutinin (SNA)-reactive Neu5Ac(alpha 2,6)-D-Gal/Gal-NAc(beta 1,4)GlcNAc oligosaccharide sequences and the absence of the corresponding Neu5Ac(alpha 2,3) Maackia amurensis agglutinin (MAA)-reactive sequence in the major 35-kDa N-glycosylproteins of the complex or hybrid type extracted from purified KC were established by Western-lectin-blotting of cytosolic extracts from purified KC. Moreover, these SNA-reactive sequences, or at least part of them, were shown to be borne by sialidase-sensitive KC acid isophosphatases. Thymic sections rich in KC, from estrogenized guinea pigs were examined by affino-histochemistry with these sialic acid-reactive lectins. The SNA-reactivity of thymic sections was quasi-exclusively confined to KC clusters, whereas the whole thymic section was negative for MAA. KC were not SNA-reactive following preincubation and incubation with 200 mM lactose. When submitted to enzymatic or mild chemical desialylation processes, the SNA-reactivity of the KC clusters was enhanced. The SNA-reactivity of KC clusters was completely abolished following prolonged chemical desialylation, whereas the PAS-positivity of KB remained unchanged. Even after a prolonged sialidase treatment, this SNA-reactivity was only reduced. Moreover, after both these desialylation processes, KC developed a heavier Ricinus communis agglutinin-reactivity, thus confirming the presence of penultimate Gal residues in their abundant SNA-reactive oligosaccharide sequences Neu5Ac(alpha 2,6)Gal(beta 1,4)GlcNAc. Such a selective lectin histochemical property provides a marker for detecting KC.
Oulhaj
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Laboratoire d'Histologie, UFR de Médecine, Université de Caen, France.
Letaïef
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SE
Landemore
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G
Izard
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J
D000818:Animals; D002240:Carbohydrate Sequence; D005260:Female; D006001:Glycoconjugates / Q000737:chemistry / Q000378:metabolism*; D006168:Guinea Pigs; D006651:Histocytochemistry; D007694:Killer Cells, Natural / Q000378:metabolism*; D037102:Lectins; D008297:Male; D008969:Molecular Sequence Data; D009439:Neuraminidase; D037121:Plant Lectins; D054788:Ribosome Inactivating Proteins; D013950:Thymus Gland / Q000166:cytology / Q000378:metabolism*
D006001:Glycoconjugates; D037102:Lectins; D037121:Plant Lectins; C050600:Sambucus nigra lectins; D009439:Neuraminidase; D054788:Ribosome Inactivating Proteins