We established six murine monoclonal antibodies (MAbs) specific for b-pathway ganglio-series gangliosides by immunizing C3H/HeN mice with these purified gangliosides adsorbed to Salmonella minnesota mutant R595. The binding specificities of these MAbs were determined by an enzyme-linked immunosorbent assay and immunostaining on thin-layer chromatogram. These six MAbs, designated GGB19, GMR2, GMR7, GGR12, GMR5, and GGR13 reacted strongly with the gangliosides GD3, O-Ac-GD3, GD2, GD1b, GT1b, and GQ1b, respectively, that were used as immunogens. All these MAbs except GGB19 showed highly restricted binding specificities, reacting only with the immunizing ganglioside. None of other various authentic gangliosides or neutral glycolipids were recognized. On the other hand, MAb GGB19 exhibited a broader specificity, cross-reacting weakly with O-Ac-GD3, GQ1b, and GT1a, but not with other gangliosides or neutral glycolipids. Using these MAbs, we determined the expression of these gangliosides, especially GD1b, GT1b, and GQ1b on mouse, rat, and human leukemia cells. GD1b was expressed on rat leukemia cells, but not on mouse and human leukemia cells tested. Neither GT1b nor GQ1b was detected in these cell lines.