TISSUE-CULTURE LOADING TEST WITH STORAGE GRANULES FROM ANIMAL-MODELS OF NEURONAL CEROID-LIPOFUSCINOSIS (BATTEN-DISEASE) - TESTING THEIR LYSOSOMAL DEGRADABILITY BY NORMAL AND BATTEN CELLS

Storage granules (SGs) from ovine and canine models of Batten disease were found to be easily phagocytosed by four cell types studied, The c ell types tested were human fibroblasts and peripheral monocytes (cont rol and from a late infantile Batten disease patient), rat C6 cell lin e, and neonatal cardiomyocytes. The phagocytosed SGs elicited an incre ase in acid phosphatase activity which was localized in the phagolysos ome. After phagocytosis SGs were followed for various times ranging fr om 7 to 21 days and were found to be of unchanged density (phase contr ast), autofluorescence, and ultrastructural appearance, These findings point to their undegradability, or very low degree of degradability, in phagolysosomes in both normal or Batten cultured cells, The Batten disease SGs are not toxic and did not cause any adverse affect on the host cells. Either the normal clearance rate from lysosomes is too slo w to be measured by this technique or subunit c accumulation in lysoso mes need not result from a primary lysosomal protease defect, Subunit c may aggregate, because of the lack of some normally preventive facto r, resulting in a physical barrier to the degradation of this highly a polar molecule. (C) 1995 Wiley-Liss, Inc.