A New Mouse Myeloma Cell Line that Has Lost Immunoglobulin Expression but Permits the Construction of Antibody-Secreting Hybrid Cell Lines

230

The HER2/c-erbB-2 gene encodes the epidermal growth factor receptorlike human homolog of the rat neu oncogene. Amplification of this gene in primary breast carcinomas has been show to correlate with poor clinical prognosis for certain cancer patients. We show here that a monoclonal antibody directed against the extracellular domain of p185HER2 specifically inhibits the growth of breast tumor-derived cell lines overexpressing the HER2/c-erbB-2 gene product and prevents HER2/c-erbB-2-transformed NIH 3T3 cells from forming colonies in soft agar. Furthermore, resistance to the cytotoxic effect of tumor necrosis factor alpha, which has been shown to be a consequence of HER2/c-erbB-2 overexpression, is significantly reduced in the presence of this antibody.

Section: Methodsmentioning

confidence: 99%

p185^HER2 Monoclonal Antibody Has Antiproliferative Effects In Vitro and Sensitizes Human Breast Tumor Cells to Tumor Necrosis Factor

Hudziak¹,

Lewis²,

Winget³

et al. 1989

230

“…The mice were boosted 1 and 2 months later with the same number of trypanosomes. Three days following the second boost, the spleens were removed aseptically, minced to make a single cell suspension, and fused with the X63-Ag8.653 nonsecreting myeloma cell line by using polyethylene glycol to generate hybridomas (16,18). The supernatants from the hybridoma cultures were screened by IFA as follows.…”

Section: Methodsmentioning

confidence: 99%

A Strand Bias Occurs in Point Mutations Associated with Variant Surface Glycoprotein Gene Conversion in Trypanosoma rhodesiense

Alarcon

Hall

et al. 1994

We previously described a bloodstream Trypansoma rhodesiense clone, MVAT5-Rx2, whose isolation was based on its cross-reactivity with a monoclonal antibody (MAb) directed against a metacyclic variant surface glycoprotein (VSG). When the duplicated, expressed VSG gene in MVAT5-Rx2 was compared with its donor (basic copy) gene, 11 nucleotide differences were found in the respective 1.5-kb coding regions (Y. Lu, T. Hall, L. S. Gay, and J. E. Donelson, Cell 72:397-406, 1993). Here we describe a characterization of two additional bloodstream trypanosome clones, MVAT5-Rx1 and MVAT5-Rx3, whose VSGs are expressed from duplicated copies of the same donor VSG gene. The three trypanosome clones each react with the MVAT5-specific MAb, but they have different cross-reactivities with a panel of other MAbs, suggesting that their surface epitopes are similar but nonidentical. Each of the three gene duplication events occurs at a different 5' crossover site within a 76-bp repeat and is associated with a different set of point mutations. The 35, 11, and 28 point mutations in the duplicated VSG coding regions of Rx1, Rx2, and Rx3, respectively, exhibit a strand bias. In the sense strand, of the 74 total mutations generated in the three duplications, 54% are A-to-G or G-to-A (A:G) transitions and 7% are C:T transitions, while 26% are C:A transversions and 13% are C:G transversions. No T:G or T:A transversions occurred. Possible models for the generation of these point mutations are discussed.

“…BALB/c mice were immunized with 50 ,ug of the fusion protein (first immunization and first booster injection) and with 150 ,ug of the fusion protein (second booster injection) by use of the ABM-2 Adjuvans system (Sebak, Aidenbach, Germany). Spleen cells from an immunized mouse were fused 3 days after the last booster injection with cells of murine myeloma cell line P3-X63-Ag8.653 (19) by use of polyethylene glycol as a fusion reagent. Cultures of hybrid cells were grown in selective hypoxanthine-aminopterinthymidine medium in 96-well tissue culture plates.…”

Section: Methodsmentioning

confidence: 99%

Developmental Regulation and Tissue Distribution of the Liver Transcription Factor LFB1 (HNF1) in Xenopus laevis

Bartkowski

Zapp

Weber

et al. 1993

The transcription factor LFB1 (HNF1) was initially identified as a regulator of liver-specific gene expression in mammals. It interacts with the promoter element HP1, which is functionally conserved between mammals and amphibians, suggesting that a homologous factor, XLFB1, also exists in Xenopus laevis. To study the role of LFB1 in early development, we isolated two groups of cDNAs coding for this factor from a Xenopus liver cDNA library by using a rat LFB1 cDNA probe. A comparison of the primary structures of the Xenopus and mammalian proteins shows that the myosin-like dimerization helix, the POU-A-related domain, the homeo-domain-related region, and the serine/threonine-rich activation domain are conserved between X. laevis and mammals, suggesting that all these features typical for LFB1 are essential for function. Using monoclonal antibodies, we demonstrate that XLFB1 is present not only in the liver but also in the stomach, intestine, colon, and kidney. In an analysis of the expression of XLFB1 in the developing Xenopus embryo, XLFB1 transcripts appear at the gastrula stage. The XLFB1 protein can be identified in regions of the embryo in which the liver diverticulum, stomach, gut, and pronephros are localized. The early appearance of XLFB1 expression during embryogenesis suggests that the tissue-specific transcription factor XLFB1 is involved in the determination and/or differentiation of specific cell types during organogenesis.