Three-dimensional reconstruction of anomalous beige mouse macrophage lysosomes

Cells of the beige mouse, the murine counterpart of the Chediak-Higashi Syndrome, contain enlarged anomalous lysosomes. The three-dimensional structure of these lysosomes from peritoneal macrophage was ascertained by study of electron micrographs taken in a series of serial sections combined with computer-assisted analysis. The most common basic structural units identified were biconcave discs and hollow cup/ovoid-shaped structures. Other more bizarre forms were represented by the fusion of these basic lysosomal variants. Anomalous lysosomal forms were found in both beige resident and exudate peritoneal macrophage. A similar study of lysosomes in animals not carrying the beige mutation revealed the presence of smaller but structurally similar forms of the basic lysosomal variants. This latter finding indicates that the presence of lysosomal variants per se in the beige animal is not a finding unique to these animals but rather that their distinctiveness derives from their increased size and propensity to undergo fusion with each other. The usefulness of computer-assisted three-dimensional reconstruction is demonstrated.