Key words: Acidification; Glycoprotein processing; Prodigiosin 25-C; Vacuolar type H÷-ATPase lar level has yet to be determined, although it is known to inhibit the mitogen response of murine splenocytes and growth of T cell lymphoma more strongly at a higher concentration of Con A [16,19]. Among a panel of inhibitors we tested, acidic monovalent ionophores (e.g. monensin and nigericin), V-ATPase inhibitors (e.g. bafilomycin B~ and concanamycin A), and Golgi mannosidase II inhibitor (swainsonine), were also more cytotoxic to those cells after addition of Con A [20]. These reagents, except for swainsonine, raise the pH in the acidic compartments and affect intracellular transport of glycoprotein [9,10,[21][22][23]. In this paper, we have studied the effect of prodigiosin 25-C on vacuolar acidification, intracellular transport of glycoprotein, and morphology of BHK cells, and we have found that prodigiosin 25-C uncouples V-ATPase and raises the pH of vacuolar organelles in intact cells.
To study the possible involvement of potential environmental pathogens in the pathogenesis of autoimmune diseases, it is essential to investigate antibody responses to a variety of environmental agents and autologous components. However, none of the conventional ELISA buffers can prevent the false positive and negative reactions attributed to its principal, which utilizes the high binding affinity of proteins to plastic surfaces. The aims of this study are to reveal all types of non-specific reactions associated with conventional buffer systems, and to re-investigate antibody responses to potential environmental pathogenic and autologous antigens in patients with autoimmune diseases using a newly developed buffer system "ChonBlock™" by ELISA. Compared to conventional buffers, the new buffer was highly effective in reducing the most intense false positive reaction caused by hydrophobic binding of immunoglobulin in sample specimens to plastic surfaces, "background (BG) noise reaction", and other non-specific reactions without interfering with antigen-antibody reactions. Applying this buffer, we found that IgG antibody responses to Escherichia coli O111:B4, E. coli lipopolysaccharide (LPS) and peptidoglycan polysaccharide (PG-PS) were significantly lower or tended to be lower in patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), whereas IgA antibody responses to these antigens were equal or tended to be higher compared to normal controls. As a consequence, the IgA/IgG antibody ratios against these agents were significantly higher in patients with RA and SLE, except for Crohn's disease, which showed significantly higher IgG responses to these antigens. To assay antibodies in human sera, it is indispensable to eliminate false positive and negative reactions by using an appropriate buffer system, and to include antigen non-coated blank wells to determine BG noise reactions of invidual samples. Finally, based on our preliminary analysis in this study, we propose that low IgG antibody responses to potential pathogenic environmental factors may be the fundamental disorder in autoimmune diseases.
The indirect ELISA is a widely utilized method to assay serum antibodies. However, a common and critical problem when analyzing serum antibodies is the disregard for the background noise reaction caused by the hydrophobic binding of immunoglobulin components in serum components to plastic. Unfortunately, current blocking agents cannot prevent this background noise reaction. To prevent further misuse of the ELISA technique, it is important to openly discuss the fundamental problems involved in the ELISA system.
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