Effects of hyaluronidase and neuraminidase on immunoreactivity histidine-rich protein in newborn rat epidermis.
Frozen sections of newborn rat skin were treated with a variety of buffers, enzymes, and proteinase inhibitors in order to modify the reactivity of antigenic sites of histidine-rich protein and keratin. By indirect immunofluorescence, we found that antiserum to histidine-rich protein purified from granular cells reacted with keratohyalin granules but not cornified cells treated with hyaluronidase. The same antiserum reacted less distinctly with keratohyalin granules treated with neuraminidase; in contrast, it showed strong reactivity in cornified cells after the neuraminidase digestion. However, the enzyme digestions did not unmask the antigenic site(s) of keratohyalin granules to anti-keratin serum, as did saline in 0.1 M Tris-HCl buffer, pH 8.0. These results suggest that the antigenic site of histidine-rich protein is masked in keratohyalin granules by different mechanisms from the masking of keratin. Histindine-rich protein may be masked primarily with hyaluronic acid in keratohyalin granules, but the sugar moiety appears to be changed to sialic acid in cornified cells.
D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D006639:Histidine / Q000276:immunology*; D006651:Histocytochemistry; D006821:Hyaluronoglucosaminidase / Q000494:pharmacology*; D007106:Immune Sera / Q000276:immunology; D007633:Keratins / Q000276:immunology; D009439:Neuraminidase / Q000494:pharmacology*; D011506:Proteins / Q000276:immunology*; D051381:Rats; D012867:Skin / Q000276:immunology* / Q000648:ultrastructure
D007106:Immune Sera; D011506:Proteins; D006639:Histidine; D007633:Keratins; D009439:Neuraminidase; D006821:Hyaluronoglucosaminidase