A new surface marker on mouse natural killer cells: receptors for Helix pomatia A hemagglutinin

Natural killer (NK) cells in normal mouse spleen have so far been found to lack conventional cell surface markers. Recently, neuraminidase treatment has been shown to uncover receptors for the A hemagglutinin of the snail Helix pomatia (HP) on populations (preferentially T cells) of human blood lymphocytes. We have used HP coupled to Sepharose in columns to fractionate mouse spleen cells. Fractions consisted of passed cells (fraction I) and cells eluted with the competitive hapten N-acetyl-D-galactosamine at either 0.1 mg/ml (fraction II) or 1.0 mg/ml (fraction III), NK activity and percentage of T and B cells in each fraction were determined. B cells were found enriched in fraction I. T lymphocytes, among them alloreactive cytotoxic T cells (CTL), were eluted in fraction III. However, NK activity of normal CBA spleens was highest in fraction II, fraction III was somewhat enriched, whereas fraction I was depleted of lytic activity. Thus, while NK cells possess HP receptors, their binding properties seem to differ from those of CTL. HP receptors represent the first simple and reliable marker detected on NK cells and might be useful for purification of this cell type.