Characterization of a Murine Monoclonal Antibody against Human Esophageal Squamous Cell Carcinoma-Associated Antigen

A murine monoclonal antibody (MAb) 2G3 of the lgG1 type was raised using the human esophageal squamous cell carcinoma (SCC) cell line TE-2. Immunoblotting with 2G3 indicated that the antigen recognized by 2G3 has a molecular weight of 34 kD. Its activity was evaluated by immunoperoxidase and immunofluorescence on frozen and paraffin sections of various normal tissues, normal and benign tumors as well as various established cell lines. The pattern of reactivity revealed that the antigen recognized by 2G3 was expressed mainly by esophageal SCC. The only exception was represented by malignant breast tumors, where it reacted weakly. Scatchard analysis using 125I-labelled 2G3 showed that TE-2 has approximately 7.5 times more binding sites than the MCF-7 breast cancer cell line. The use of this new MAb is therefore proposed for the histopathological diagnosis of esophageal SCC.

An ICAM-1 like cell adhesion molecule is responsible for CD34 positive haemopoietic stem cells adhesion to bone-marrow stroma

The microenvironment in the haematopoietic organs plays an important role in regulating and sustaining differentiation and self-renewal of haematopoietic stem cells. Although crucial for stem cell maintenance and homing, the stromal cell-stem cell interactions are poorly understood. Here we show that an ICAM-like molecule is responsible for stem cell adhesion to stromal cells in vitro. The molecule was characterized by a monoclonal antibody 3E10. Immunoblotting results indicated that the molecule had an electrophoretic mobility equal to that of intercellular cell adhesion molecule-1 (ICAM-1). Binding inhibition assays, however, showed that inhibition of binding of enriched CD34 cells by 3E10 was more prominent in comparison with that of ICAM-1.

Tumor necrosis factor as marker for monocyte function in chronic myeloid leukemia

The intactness of monocyte function in chronic myeloid leukemia (CML) patients as assessed by their ability to secret tumor necrosis factor was evaluated. Monocytes from CML patients continued to respond to lipopolysaccharide (LPS) stimulation even during the refractory period, suggesting different pathways for stimulation by LPS and malignant processes.