Generation of a monoclonal anti-GP70 antibody and characterization of its reactivity with various human cell lines and cells from leukemia-lymphoma patients

Development of a two color immunofluorescence stain and immunolocalization method for N-myc and c-myc oncoproteins with a newly generated mouse IgM anti N-myc antibody

A new mouse monoclonal antibody specific for N-myc oncoprotein was generated and used in combination with an anti-c-myc antibody to develop two color immunofluorescence staining and ultrastructural immunolocalization of N-myc and c-myc in well established (SK-N-SH; CHP 126) and in newly established neuroblastoma (NB) cell lines. Analysis and quantitation of c-myc and N-myc in dually stained cells was done by flow cytometry. Immunolocalization was done by staining with immunogold secondary antibodies and transmission electron microscopy. The results obtained from analysis of 13 newly established NB cell lines revealed, great heterogeneity in the expression of N-myc oncoprotein with 10/13 cell lines over expressing the protein. C-myc oncoprotein was also expressed in all cell lines, however, the level of expression was 4-10-fold lower than the N-myc oncoprotein. Localization studies of c-myc and N-myc oncoproteins on the level of light microscopy and electron microscopy revealed exclusive nuclear localization of c-myc whereas N-myc was localized to the nucleus and to the cytoplasm.

Induction of plasmacytoid and hairy cell features by phorbol esters (TPA) in B-lymphoma cells: attempted correlation with disease activity

Mononuclear cells concentrated from the blood of 16 non-Hodgkin's lymphoma (NHL) patients in the leukemic phase, were exposed to 10 ng/ml of TPA in an attempt to induce differentiation. Immunoglobulin (Ig) secretion, surface markers (SmIg, GP-70), tartrate resistant acid phosphatase (TRAP) and surface features were followed for up to six days in vitro. TPA induced 'hairy cell' like features in NHL cells as defined by cell morphology, ultrastructure, cell surface markers and the presence of TRAP. Unlike the results obtained in patients with CLL, cells from different patients at the same stage of disease reacted in a similar way. Differences were evident between NHL mononuclear cells obtained from patients in partial remission and active disease when compared with those derived from patients in complete remission. In the former group, NHL cells were maximally induced by TPA to secrete Ig and higher proportions of TRAP positive cells. In addition hairy cell features as seen by light and scanning electron microscopy were also more pronounced. TPA also induced the maximal expression of SmIg and GP-70 in cells derived from patients in this group. Patients with NHL in leukemic phase in complete remission did not express surface membrane GP-70 before or after TPA treatment while SmIg was expressed to some degree before TPA treatment and further induced following treatment with TPA. GP-70 appears to be a more reliable marker for follow-up of NHL patients than any other marker studied here.