Modification and application of a simple, surface hydrophobicity detection method to immune cells.

A simple method to assess fungal cell surface hydrophobicity involves enumeration of cell-attached, polystyrene latex microspheres. Modifications and conditions of this method for application to immune cell populations were investigated. The media used for suspending cells and microspheres appeared to influence microsphere attachment. Several tissue culture media supported high levels of microsphere attachment, but serum inhibited attachment. The concentration of microspheres also influenced the apparent level of detectable cell surface hydrophobicity. Under conditions which allow different levels of apparent cell surface hydrophobicity to be discriminated, the assay revealed that surface hydrophobicity of YAC-1 cells, which are used as standard targets in murine natural killer cell assays, varied depending on the time of harvest during growth and that phagocytic populations differed in cell surface hydrophobicity. Trypsinization experiments indicated that one hydrophobic constituent of the cell surface includes protein. These results indicate that the microsphere assay is a useful method for assessing cell surface hydrophobicity. The possibility that the assay could be used to determine quantitatively the surface free energies of immune cells and cell targets is discussed.