Chronic lymphocytic leukemia: demonstration of cell surface structural heterogeneity by lectin affinity chromatography of cell extracts

Interaction of soybean agglutinin with leukemic T-cells and its use for their in vitro separation from normal lymphocytes by lectin-affinity chromatography

A procedure for separation of leukemic T-cells from normal lymphocytes, using lectin-affinity column chromatography, is described. CNBr-activated Sepharose 6MB was used as a non-mobile phase. The gel was covalently coupled with soybean agglutinin (SBA), then served as an affinity probe for fractionation of mixture of normal lymphocytes and leukemic cells. Leukemic cell lines, derived from acute lymphoblastic leukemia (Jurkat, MOLT-4, RPMI-8402), were tested. The elution of normal lymphocytes was carried out by PBS(-). The leukemic T-cells, interacting with SBA, were removed by N-acetyl-D-galactosamine or low-concentration acetic acid. The type and viability of the separated cell fractions were analyzed by flow cytometry and fluorescent microscopy, using adequate fluorescent antibodies. The interaction of leukemic T-cells with free SBA, as well as with SBA-conjugated Sepharose beads, was examined fluorimetrically and visualized by fluorescent microscopy, using FITC-SBA as a marker. The rate of cell elution on SBA-affinity column decreased in order: normal > leukemic T-cells. Both normal lymphocytes and leukemic T-cells were removed in a mixture from SBA-free Sepharose 6MB by PBS(-) and were not fractionated discretely. The leukemic T-cells specifically interacted with SBA as well as with SBA-affinity adsorbent. In contrast, the normal lymphocytes did not interact with free SBA as well as with SBA-conjugated Sepharose beads in the concentrations applied. The method potentially combines a discrete cell fractionation with manifestation of a specific target cytotoxicity of SBA against leukemic T-cells, without any influence on normal lymphocytes.

Interaction of the hemolytic lectin, CEL-III, with cultured human leukemic cell lines

We studied interaction of CEL-III with cultured human leukemic cell lines and lymphocytes from normal adults by evaluating the extent of cytotoxicity and cytoagglutination. Among acute T lymphoblastic leukemia (T-ALL) cell lines, CEL-III displayed increased toxicity against different acute lymphoblastic leukemia (ALL) cell lines as a function of increasing differentiation stage. In the case of acute B lymphoblastic leukemia (B-ALL) cell lines, CEL-III showed strong cytotoxicity against relatively immature cell lines. We found that CEL-III was more toxic for ALL cell lines than leukocytes obtained from peripheral blood of healthy adults. Strong influence of the additional amount of calcium ion on the extent of cytotoxicity was observed. In addition, we describe a new way to evaluate the extent of cytoagglutination in "% of agglutinated cells". These findings make CEL-III a promising candidate in research for lectins which bind to and destroy only the targeted leukemic cells.

Expression of leucocyte-common antigen and large sialoglycoprotein on leukemic cells in B-cell chronic lymphocytic leukemia and non-Hodgkin's lymphoma

Patterns of leucocyte-common antigen (L-CA) and large sialoglycoprotein (LSGP) expression on leukemic peripheral blood lymphocytes of 13 patients with chronic lymphocytic leukemia (CLL), 17 with non-Hodgkin's lymphoma (NHL) in leukemic phase and one with hairy cell leukemia (HCL) have been examined by means of surface labelling and electrophoresis in 5% polyacrylamide gels. The 13 CLL, 10 of the 11 diffuse NHL and the six nodular poorly differentiated lymphocytic lymphoma (PDLL) patients fell into three groups according to expression of 210, 198 and 185k forms of L-CA. Group 1 (210 less than 198 less than 185k L-CA) included eight CLL and one diffuse NHL; Group 2 (210 greater than or equal to 198 and 185k L-CA) included four CLL, three diffuse NHL and four nodular PDLL; Group 3 (mainly 210k L-CA) included one CLL, six diffuse NHL and two nodular PDLL. A patient with diffuse large cell lymphoma and the HCL patient both had patterns of multiple, diffuse, very high Mr labelled glycoproteins. LSGP on these cells varied from nil to very high and levels were not related to L-CA patterns. Lymph node cells from five patients were also studied and were found to express larger numbers of L-CA forms and less LSGP than corresponding peripheral blood lymphocytes. Possible relationships of L-CA forms and LSGP to lymphocyte function and disease patterns are discussed.