Lysosomes in Lymphoid Tissue

Abstract

The density-distribution patterns of various enzymes and of labeled materials have been determined by isopycnic centrifugation in a sucrose-0.2 M KC1 gradient on homogenates of lymphoid tissues from rats injected with Triton WR-1339, 14C-labeled dextran, 51Cr-labeled erythrocytes, and cortisol. The results confirm and extend the conclusion, derived from previous investigations on normal animals, that the lysosomes of lymphoid tissues form two and possibly three, distinct populations. The evidence indicates that the L19 population belongs to macrophages and the Lx5 group to lymphocytes. The L30 population appears to be associated with a special type of phagocyte with a high capacity for dextran storage. All three populations seem to contribute to the activities found in soluble form in homogenates of normal lymphoid tissues.

Lysosomes in Rat Thoracic Duct Lymphocytes

“…And finally, in those experiments specifically designed to eliminate the few adherent cells remaining in our preparation (never exceeding more than 4 or 5 adherent cells/ million nonadherent cells), there was no indication that the 1.18 lysosomes had been removed, even in part. The occurrence of such lysosomes in lymphocytes explains our earlier finding that the L19 population is partly depleted after cortisol treatment (2).…”

“…There is at present no way of distinguishing between these three interpretations, but the third is the most likely one, because so far no evidence has been obtained for the occurrence of free cathepsin D in other cell types, and especially because cathepsin D happens to be most abundant in the special population of lysosomes identified in solid lymphoid tissues as belonging to the lymphocytes and distinguished in these tissues by their low equilibrium density (1.15) in sucrose gradients (1,2). If this view is correct, one may ask why the L15 lysosomes should rupture more easily upon homogenization of TDL than of solid tissues.…”

The subcellular distribution of antigen in macrophages

“…The synthetic polypeptides localized in a lysosomal fraction of a density 1.15. This adds a further example of functional heterogeneity of lysosomal particles of different density from those already described (17,36). The difference can hardly be attributed merely to size, since the polypeptides have a molecular weight about one-third that of BSA.…”

“…Antigen has been found within organelles which have been identified by electron microscopy as phagolysosomes (16). Lysosomal particles from lymphatic tissue appear to be functionally heterogeneous (17), and so the site of long-term retention may be distinct from those phagolysosomes and lysosomes in which the bulk of antigen is found shortly after uptake (18)(19)(20).…”

On Morphogenesis of the Acid Phosphatase Activity; Its Significance in Adrenal Pigments Formation of Lanolin-Treated Rabbits or Aged Rats and in Dextran Storage of Rat Lymph Node Macrophages

“…Thus, the ACPase activity should be cytochemically recognized as "reactive areas" rather than as "reactive particles" when observed biochemically (4,5), at least in the light of the present experimental results.…”