Multiangle light scattering flow photometry of cultured human fibroblasts: comparison of normal cells with a mutant line containing cytoplasmic inclusions.

Multi-angle light scattering flow photometry was used to study the light scattering properties of normal cultured fibroblasts and a mutant fibroblast line containing cytoplasmic lysosomal inclusions. The effect of glutaraldehyde fixation on the light scattering properties of the cells was also examined and correlated with their ultrastructure. Normal fibroblasts showed uniform organelle distribution with few vacuoles or dense bodies in the cytoplasm while the mutant line showed abnormal cytoplasmic inclusions of varying morphology, density and lucency. As predicted by light scattering theory, the mutant cells containing the cytoplasmic inclusions scattered more light at large angles (greater than theta = 1.85 degrees) than did the normal cells. Glutaraldehyde fixation decreased light scattering at small angles (less than theta = 1.85 degrees), increased light scattering at larger angles (greater than theta = 1.85 degrees) in both normal and mutant cells and enhanced resolution of the light scattering signatures. The mutant line scattered 2-3 times more light at a wide angle (greater than theta = 12.74 degrees) than did the normal cells. These data suggest that abnormal lysosomal storage inclusion bodies in the cytoplasm of the cells can be detected by differential light scattering methods.