Femke Buijs

Monoclonal Antibodies against Human Milkfat Globule Membranes Useful in Carcinoma Research

Abstract Murine monoclonal antibodies against antigens of purified membranes from human milkfat globules were generated. The various antigens detectable were partly characterized and studied for their usefulness in tumor classifications. Not only mammary cancers, but a variety of carcinomas from other than mammary gland epithelia showed positive reactions with selected series of these antibodies. Of these antibodies 115D8, against antigens of the Mam-6 group, seems to be the best one for targeting tumors in vivo.

Monoclonal antibodies against human acid α-glucosidase

Acid alpha-glucosidase purified from human placenta was used to immunize a mouse (strain Balb/cHeA) according to a procedure described earlier (Stähli, C., Staehlin, T., Miggiano, V., Schmidt, J. and Häring, P. (1980) J. Immunol. Methods 32, 297-304). After fusion of spleen cells with myeloma cells, about 10% of the hybrid clones obtained produced antibodies against acid alpha-glucosidase. Finally, eight stable clones producing antibodies against the enzyme were obtained. When purified acid alpha-glucosidase is analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate, two major protein bands (mol. wt. 76000 and 70000,) a minor band of mol. wt. 9600 and several minor bands with a mol. wt. of 67000 or lower are seen. Since all these components react with the monoclonal antibodies, they must have at least one antigenic determinant in common.

Monoclonal Antibodies Against Human Milkfat Globule Membranes Detecting Differentiation Antigens of the Mammary Gland

Abstract Monoclonal antibodies of mouse origin were raised against antigens of highly purified human milkfat globule membranes. Five groups of antigens, Mam-1 to Mam-5, could be distinguished based on immunoprecipitation followed by determination of the molecular weights, their presence or absence from milk proteins and their tissue distribution in normal and malignant mammary glands.

Simultaneous chemical induction of MTV and MLV in vitro.

Abstract Latent endogenous mammary tumour virus (MTV) and latent endogenous mouse leukemia virus (MLV) were simultaneously chemically induced with concomitant cell morphological alteration in tissue-cultured baby mouse kidney cells (BMKC) derived from the low mammary tumour mouse strains BALB c (substrains He.A and Crgl.A) and C57BL Li.A . 3-Methylcholanthrene (MCA) was used with BMKC prepared from BALB/c/He.A and BALB/c/Crgl.A mice and 5-bromodeoxyuridine (BrdU) with BMKC prepared from C57BL Li.A . Aggregates (pocks) of small rounded epithelioid cells appeared on the BMKC monolayers several weeks after chemical treatment. Cell lines produced from single pocks released MTV (B-particles) and MLV (C-particles) as found with electron microscopy and reverse transcriptase determinations. All isolated cell lines grew well when serum was omitted from the medium. In female syngeneic BALB/c/He.A mice MCA altered BMKC induced early (

Biological activities of murine mammary tumour virus in vitro: Increased macromolcular synetheses in mouse and hamster kidney cells; production of B- and C-particles in the mouse cells

Abstract Murine mammary tumour virus (MTV) induced an increased net synthesis of DNA, RNA and protein in short -term cultures of baby mouse kidney cells (BMKC) made from two different BALBc mouse substrains (He.A and Crgl.A). The dose-response ratio went through a maximum but growth inhibition was not observed. Similar effects were induced in baby hamster kidney cells (BHK 21C 13). In longer -term cultures of MTV-infected BMKC foci of piled-up small rounded epithelioid cells appeared on the monolayers. Cell lines derived from these foci grew well in media without serum and produced biologically active MTV (B-particles) and murine leukemia virus (MLV; C-particles). Higher in vitro passages of these cell lines induced less early ( 300 days) mammary tumours and more cases of leukemia than the lower passages after intraperitoneal injection. Cell-free extracts induced similar tumours. Not-infected control BMKC did not acquire the described properties. The nature of the induced MTV and MLV is discussed.

Monoclonal Antibodies Against Human Acid α-Glucosidase

Acid α-glucosidase purified from human placenta was used to hyperimmunize a mouse according to Stahli and coworkers (Stahli, C., T. Staehlin, V. Miggiano, J. Schmidt and P. Haring (1980) J. Immunol. Methods 32, 297-304). After fusion of spleen cells with myeloma cells, about 10% of the hybrid clones obtained produced antibodies against acid α-glucosidase. Finally, 9 stable clones producing antibodies against the enzyme were obtained. All of the clones reacted with denatured acid α-glucosidase, but none of those tested reacted with the native enzyme. When the purified enzyme is analysed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate, two major protein bands (mol wt 76 000 and 70 000), a minor band of mol wt 96 000 and several minor bands of mol wt ≤ 67 000 are seen. All these components react with the monoclonal antibodies, so that they must have at least one antigenic determinant in common.