Recognition specificities, development, and possible biological function of natural killer cells in the mouse. I. Spleen focus forming assay for natural killer activity and analysis of lectin-like recognition structures on the surface of murine natural killer cells.

A number of simple sugars have been tested and found to be effective in blocking lysis of YAC-1 tumor target cells by nonimmune murine natural killer (NK) effector cells. Using a spleen fragment culture system an assay has been developed which allows us to compare the inhibition of lysis observed in replicate culture wells prepared from cells contained in one spleen fragment (less than or equal to 1 X 10(6) cells). The inhibition pattern of any well was found to fall naturally into 1 of 25 (of the total 128 possible tested) patterns. Using this panel analysis of NK activity in individual mice of the same or different strain has been compared. Our data suggest that within any given strain the inhibition pattern of NK effector cells is quite uniform. Consistent differences are seen between strains which are interpreted in terms of a genetic control of the final expression of the NK recognition repertoire. In adult F1 hybrid individuals the pattern of recognition by NK cells is best considered a result of the codominant expression of genes contributed by each parent.