Lectin staining of carbohydrates of haemic cells; the cells of normal blood and bone marrow and of the myeloid leukaemias

Lectin histochemistry of human bone marrow: investigation of trephine biopsy specimens in normal and reactive states and neoplastic disorders

The lectin binding pattern of bone marrow cells in normal and reactive states and in various neoplastic disorders was investigated using trephine biopsy specimens taken from the iliac crest. The tissue samples were routinely processed (fixed in formalin and embedded in paraffin wax) and subjected to mild decalcification with EDTA. The following results were obtained. (1) More than half of the 23 fluoresceinated lectins used reacted with normal blood cells and/or their neoplastic derivatives. Inhibition tests with the appropriate sugars confirmed the specificity of binding for the majority, but not all, of the lectins. (2) WGA, Con A, PSA, STA and RCA60 and RCA120 produced a particularly intense reaction with normal, reactive and neoplastic myeloid cells. Erythroblasts exhibited weak staining in a few cases by a few lectins (WGA producing the strongest staining), while megakaryocytes nearly always remained unstained. Neoplastic lymphoid cells in various lymphoproliferative disorders and plasmacytoma cells generally reacted with the same lectins as the myeloid cells. (3) Since neoplastic myeloid cells in various myelodysplastic and myeloproliferative disorders exhibited a lectin binding pattern similar to that of myeloid cells in normal and reactive bone marrow, it is unlikely that lectin histochemistry of the bone marrow will prove of great value in the diagnosis of myelodysplastic-myeloproliferative disorders.

Cellular carbohydrate components in human, rabbit and rat lacrimal gland. Studies using fluorescein and peroxidase labelled lectins

Orbital lacrimal glands from adult male and female rabbits, rats and humans were examined for the presence of intracellular receptors of four lectins: concanavalin-A agglutinin, lutus tetragonolobus agglutinin, ricinus comunis-60 agglutinin and wheat-germ agglutinin using fluorescein-conjugated lectin and peroxidase labelling methods for fluorescence and electron microscopy, respectively. Lectins were used as specific probes to detect carbohydrate moiety of the lacrimal gland. The pattern of labelling with the lectins suggests that N-acetyl-glucosamine, N-acetyl-D-galactosamine, D-galactose, D-mannose, sialic acid and L-fucose are contained in the lacrimal gland of the three species. The significance of these findings is discussed.

Physiological and pathobiological significance of ocular glycoproteins. I. Studies using fluorescein labelled glycine max

Cell surface carbohydrates play an important role in several biological, immunological, and neoplastic phenomena including development, growth regulation, cellular locomotion, receptor activation, and tumour metastasis. Fluorescein labelled lectins which bind to specific carbohydrate residues in glycoproteins and glycolipids are being increasingly used as chemical probes to study cell components. Several different preparations of ocular tissues from human, rabbit, and rat were examined for the distribution of N-acetyl-D-galactosamine (D-gal NAc) by means of fluorescein-labelled lectin from soybean (glycine max). A very strong fluorescence was observed in the corneal epithelium; Descemet's membrane and corneal endothelium were also strongly fluorescent. The conjunctival epithelium similarly showed a strong reaction, as did the goblet cells. The iris epithelium and the dilator pupillae were only weakly fluorescent, but the ciliary body showed strong fluorescence, as did the blood vessels. As compared with lens fibres the lens epithelium was strongly fluorescent. The outer retina, that is, the photoreceptors, the pigment epithelium, and Bruch's membrane, showed a very strong reactivity. The optic nerve showed moderate fluorescence, but reaction with extraocular muscles was variable. The skin of the upper and lower eyelids, hair follicles, and blood vessels showed strong lectin binding. Sections of retinoblastoma and malignant melanoma showed no reaction. The physiological and pathological significance of these findings is discussed.

The lectin binding affinity of Reed-Sternberg cells

Reed-Sternberg cells from ten cases of Hodgkin's disease were examined by the direct immunofluorescence technique, for their affinity for nine lectins. The surrounding lymphocytes and monocytes of HD tissue were also assessed for their ability to bind lectins. RS cells showed considerable heterogeneity of reaction. Overall, there was a marked decrease in the binding of most of the lectins studied in HD cases as compared to normal peripheral blood mononuclear cells. This was particularly evident for RCA, PHA and PNA binding. It is suggested that there is a defect in carbohydrate metabolism, with fewer lectin-binding sites on both RS cells and on the mononuclear cell populations in Hodgkin's disease. Further quantitative work is required to verify this.

Studies of lectin binding to normal and neoplastic lymphoid tissues. I. Normal nodes and Hodgkin's disease

Lectins are proteins which have the ability to interact specifically with carbohydrate residues of glycoproteins and other glycoconjugates. The staining patterns of 10 fluorescein conjugated lectins (F-Con A, F-LCA, F-RCA, F-WGA, F-PHA, F-PWM, F-LTA, F-SBA, F-PNA, F-DB) and a protease inhibitor (F-LA) have been studied in histological sections of 11 normal or reactive lymph nodes and 6 nodes and one skin biopsy involved by Hodgkin's disease. On the basis of the patterns of lectin binding, and current knowledge of their saccharide specificities, we found that within germinal centres there is an orderly carbohydrate rich extracellular matrix which contains a higher concentration of GlcNAc and terminal Gal residues than the surface membranes of component cells. This suggests active secretion rather than simple membrane shedding, and it is possible that this pericellular domain plays a part in the regulation of the proliferative response, or controls migration of lymphocytes in and out of the germinal centre. Lectin binding in Reed-Sternberg cells suggests that the huge nucleoli contain glycoconjugates of diverse structure, which may be linked with their failure to undergo cytokinesis.

Lectin staining of carbohydrates of haemic cells. III. The cells of Hodgkin's disease and other lymphomas

When stained for reactive sialyl groups with fluorescein-labelled Aprotinin (FLA), lymphocytes of three diffuse lymphomas were uniformly faintly fluorescent. The nodules of a nodular lymphocytic lymphoma showed dimly fluorescing lymphocytes surrounded by brightly fluorescing, apparently normal cells. The spleens of eight patients with Hodgkin's disease showed involvement in six cases. With FLA, the two uninvolved spleens contained only brightly fluorescing lymphocytes, whereas the foci of Hodgkin's lesions in the six spleens and in eight involved lymph nodes from a further eight patients contained varying proportions of brightly and dimly fluorescing lymphoid cells. Mononuclear Hodgkin's cells and bi- or multinucleated Reed-Sternberg cells fluoresced faintly. Fluorescein-labelled Ricinus communis agglutinin (FL-RCA) for galactose, and Concanavalin A (FL-Con A) for mannose or glucose, showed eosinophils, reticulin and collagen fibres especially in nodular sclerosing Hodgkin's disease, whereas all lymphocytes, Hodgkin and Reed-Sternberg cells stained faintly with either lectin. The reduction of reactive sialyl groups in malignant lymphocytes of lymphomas and Hodgkin's lesions is similar to that in lymphocytic leukaemias. It is suggested that in Hodgkin's disease these lymphocytes together with the Hodgkin and Reed-Sternberg cells represent the malignant component, whereas the brightly fluorescent normal lymphocytes, together with histiocytes, eosinophils (and neutrophils) represent a reactive component in the lesions. Similarly, the reactive lymphocytes in sarcoid lesions and sinus histiocytosis were brightly fluorescing.

Heterogeneity of concanavalin A binding by mouse peritoneal macrophages

The binding of the lectin concanavalin A (Con A) to the cell surface of monocytes and macrophages collected from the stimulated peritoneal cavity of mice was investigated electron microscopically with horseradish peroxidase-gold as an indirect marker. Individual cells were identified by the cytochemical localization of peroxidatic (PO) activity. In monocytes and monocyte-derived macrophages with PO activity in cytoplasmic granules, the degree of Con A binding was lower than in resident macrophages with PO activity in the rough endoplasmic reticulum and nuclear envelope. An even higher degree of Con A labelling was found on the surface of cells devoid of PO activity. Since the above-mentioned cell populations show a different degree of lectin binding, it is suggested that lectin labelling methods might offer a new tool for quantitative investigation of the differentiation of monocytes and resident macrophages.