Novel cell junctions induced by activating Thy-1-specific antibodies

Abstract

KT16, like other anti-Thy-1 antibodies, induces T cell aggregation. Protein A-gold labelling shows the antibody to be concentrated along areas of intercellular contacts. Electron micrographs of KT16 treated T cells reveal a consistent type of junction between the cells. We demonstrate that this type of cell junction is Thy-1 specific, is predominantly the property of antibodies directed against a particular epitope, and is distinct from cellular aggregation caused by concanavalin A or anti-CD3 antibodies. The degree of adhesiveness induced by different anti-Thy-1 antibodies is related to their mitogenic capacity.

A novel anti-Thy-1 (CD90) monoclonal antibody induces apoptosis in mouse malignant T-lymphoma cells in spite of inducing bcl-2 expression

“…2b, right) and 5a-8 (data not shown)]. Therefore, MCS-34 recognized epitope A, like G7 and KT16 (Millrain et al, 1992). These results indicate that MCS-34 exhibits the same ability to recognize Thy-1 glycoprotein as G7 and KT16.…”

“…These special antiThy-1 MAbs may have a capacity to aggregate by themselves because the F(ab')z fragment of KT16 induces T-cell growth only in the presence of a second antibody (Millrain et al, 1992). These anti-Thy-1 MAbs are known to recognize both Thy-1.1 and Thy-1.2 (Millrain et aL, 1992), and the recognized epitope is designated Thy-1A (Pont et aL, 1985). We therefore examined 9 of our established anti-Thy-1 MAbs for their recognition capability.…”

“…6, and data not shown). A possible explanation for the different effects of MCS-34 and G7 on CS-21 cells might be their ability to activate the co-stimulatory signal (Millrain et al, 1992). This ability might be dependent on the isotypes of these MAbs (MCS-34, IgG2a; G7, IgG2c).…”

“…2a) and C57BL/6 mice ( Fig. 2a), indicating that MCS-34 recognized both the Thy-1.1 and Thy-1.2 allotypes, like G7 and KT16 (Millrain et al, 1992). We further determined the epitope recognized by MCS-34 on Thy-1 glycoprotein by cross-blocking analysis (Pont et al, 1985) using FACScan.…”

A novel anti‐Thy‐1 (CD90) monoclonal antibody induces apoptosis in mouse malignant T‐lymphoma cells in spite of inducing bcl‐2 expression

“…3). It has been reported that T-cell proliferation induced by G7 is correlated with the ability to induce cell-cell aggregation (Millrain et al, 1992). Although G7 alone could aggregate CS-21 cells, MCS-34 alone could not aggregate them.…”