Ia antigens in rat kidney, with special reference to their expression in tubular epithelium.

Abstract

The distribution of Ia antigens in rat kidneys has been investigated by an immunoperoxidase technique, using monoclonal antibodies directed at framework determinants on molecules equivalent to gene products of the I-A and I-E/C regions of the mouse major histocompatibility complex (MHC). Antigens mapping to both loci were detected in proximal convoluted tubule epithelium and on scattered dendritic cells in the interstitial connective tissues, glomeruli, and mucosa of the renal pelvis. All other structures were negative. Genetic studies indicate that the levels of expression of Ia molecules from both genetic loci are controlled by non-MHC genes in epithelium, but not on lymphocytes. The subcellular distribution of Ia molecules has been investigated in tubular epithelium and is discussed in relation to their possible functions in epithelia.

Subcellular distribution of class II major histocompatibility antigens in enterocytes of the human and rat small intestine

“…However, attempts to localize antigens to subcellular compartments by immunohistochemical means on frozen sections of unfixed tissue can be misleading, especially where cells have extensive intercellular interdigitations, as is the case in renal and intestinal epithelia (20). We have therefore extended these light microscopic observations to the ultrastructural level in order to identify which subcellular organelles contain class II MHC molecules in rat and human enterocytes.…”

“…Studies on renal tubule epithelium have indicated that frozen sections of unfixed tissue are unsuitable for localizing class II molecules to subcellular structures (20). Various fixatives were therefore tested on rat tissue to select a method which preserved tissue fine structure and also allowed detection of class II molecules with MRC 0X4 and MRC 0X6 MoAb.…”

“…The technique used to stain frozen sections for light microscopy has been described elsewhere (20). It involved sequential incubation first with MoAb and then with SHAM-HRP.…”

“…MI) and it was coupled to horseradish peroxidase (type VI. Sigma, St Louis, MI) essentially as described previously (20). Conjugates containing one or two molecules of peroxidase per F(ab')2 molecule were collected by gel filtration using a Sepharcryl S-3(X) (Pharmacia, Uppsala, Sweden) column.…”

“…Monospecific sheep anti-mouse IgG was prepared as described previously by passage through a rat IgG immunoabsorbent column, followed by adsorption to and elution from a mouse IgG-Sepharose 4B (Pharmacia, Uppsala, Sweden) immunoabsorbent column (20). F(ab')2 was prepared by digestion with pepsin (Product No.…”