Sadakazu Aiso

Interleukin 2 and interferon-gamma augment anticolon antibody dependent cellular cytotoxicity in ulcerative colitis.

In vitro effects of cytokines and therapeutic drugs on antibody dependent cellular cytotoxicity (ADCC) mediated by anticolon antibody were investigated in serum samples from patients with ulcerative colitis. A 51Cr release assay was used to examine ADCC activity with the colon cancer cell line, colo 205, as the target and peripheral blood mononuclear cells as the effector. High ADCC activity was shown in 13 of 32 (41%) patients with ulcerative colitis. This ADCC activity was inhibited by protein A treatment of the serum samples. Interleukin 2 (IL2) activated effector cells could enhance ADCC activity, but interferon-gamma (IFN-gamma) or tumour necrosis factor-alpha (TNF-alpha) had no effect on the cytotoxic activity of effector cells. Treatment of target cells with IFN-gamma increased the vulnerability of these cells to ADCC with a large increase of intercellular adhesion molecule-1 (ICAM-1) expression on their surface. Monoclonal antibodies to ICAM-1 inhibited this IFN-gamma enhanced ADCC activity. Interestingly, prednisolone (PSL) reduced ADCC activity, but sulphasalazine (SASP) or 5-aminosalicylic acid (5-ASA) did not. These results suggest that IL2 and IFN-gamma could enhance colonic epithelial cell injury mediated by the ADCC mechanism in ulcerative colitis and that ADCC enhanced by cytokines is restored by PSL treatment.

Monoclonal antibodies to the Golgi apparatus of serous exocrine cells

We demonstrated that a common antigen (Golgi-associated antigen, GAA 108) is present in the Golgi apparatus of serous exocrine cells, using an immunohistochemical method with monoclonal antibodies (MAb) 108 (IgG1) and 18 (IgM), raised to the microsomal fractions of rat parotid gland. The MAb reacted with polypeptides of molecular weights in the 58-170 KD range in parotid gland on Western blot analysis. The Golgi apparatus of the following cells was immunostained with these MAb: acinar cells of parotid gland, pancreas, and exorbital lacrimal gland, serous cells of sublingual gland, chief cells of stomach, and epithelial cells of rat prostate. However, positive reaction occurred throughout the entire cytoplasm of submandibular gland acinar cells. Immunoelectron microscopy (IM) revealed antigen (GAA 108) localization in the medial and trans-Golgi cisternae and trans-Golgi network (TGN), including condensing vacuoles, in parotid, exorbital lacrimal, and pancreatic acinar cells, and serous acinar cells of sublingual gland. Lysosomes and apical cell membranes also stained positively in some cells. In the submandibular gland reactions were observed in the medial and trans-Golgi cisternae, condensing vacuoles, secretory granule contents, cell membrane, and in some duct lumens. These results suggest that although GAA 108 is found in the Golgi apparatus of most serous exocrine cells, it is secreted by a regulated pathway in the acinar cells of submandibular gland.

Distribution of gamma-glutamyl transpeptidase in human salivary glands: immunohistochemical study using a monoclonal antibody.:

We studied in detail the distribution pattern of gamma-glutamyl transpeptidase (gamma-GT) in human salivary glands using a monoclonal antibody (MAb) to human kidney gamma-GT. In the sublingual gland, a strong reactivity of the enzyme was recognized along the luminal and lateral membranes of serous cells. Weak but positive reactivity was noted on the luminal membrane of mucous cells. The intercellular canaliculi in the demilune and luminal surfaces of excretory duct cells were also immunoreactive. In the submandibular gland, a weak reaction was observed on the luminal membrane of intercalated duct cells and striated duct cells. Faint reactivity was seen on the luminal membrane of striated duct cells of the parotid gland. No reaction was observed in serous cells of the parotid gland. The immunoreaction in the sublingual gland was stronger than that in submandibular or parotid glands.

The Effect of Copy Number on mRNA and Cell Surface Expression of an Aβk Transgene

Because allelic polymorphism of the class II antigens affects the immune response at several levels, we wanted to characterize the contribution of a particular chain or epitope in an in vivo system using transgenic mice. Initially, we introduced an Aβk genomic clone into [B10.S x SJL]F2 (H-2s/s) embryos and, from fourteen founders, have established twelve independent lines carrying from one to sixty-five copies of the transgene. The transgene was coexpressed with the endogenous allele in a tissue-specific manner, and Aβk mRNA expression correlated well with transgene copy number. Although the ratio of Aβk to Aβs expressed on the cell surface correlated well with the ratio of Aβk to Aβs mRNA, cell surface levels of the endogenous Aβs/Aαs complex and total la were reduced in H-2s/s mice overexpressing Aβk mRNA. However, extremely high levels of Aαk/Aβk cell surface expression were observed in Aβk x Aαk double transgenic mice, which implies that the excess mRNA is translated in the high copy number mice and that pairing of Aβk with Aαs is permissive but inefficient. Initial immune response experiments reflected the variation in cell surface levels of Aβk (and total Ia) and suggested that expression of the Aαs/Aβk heterodimer has some effect on the secondary antibody response to the I-Ak-restricted synthetic antigen (H,G)-A-L [(histidine, glutamic acid)-alanine-lysine; McDevitt and Chinitz 1969].