Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russian Federation.
Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Sofia, Bulgaria.
Pharmacology. 2022;107(7-8):341-350. doi: 10.1159/000520343. Epub 2021 Dec 3.
As has been shown previously, various protein-modifying agents can change the antigen-binding properties of immunoglobulins. However, induced polyspecificity of human secretory immunoglobulin A (sIgA) has not been previously characterized in detail.
In the present study, human secretory immunoglobulin A (IgA) was exposed to buffers with acidic pH, to free heme, or to pro-oxidative ferrous ions, and the antigen-binding behavior of the native and modified IgA to viral and bacterial antigens was compared using Western blotting and enzyme-linked immunosorbent assay. The ability of these agents to modulate the antigen-binding properties of human sIgA toward a wide range of pathogen peptides was investigated using an epitope microarray.
We have shown that acidic pH, heme, and pro-oxidative ferrous ions influenced the binding of secretory IgA in opposite directions (either increasing or decreasing); however, the strongest effect was observed when using buffers with low pH. This fraction had the highest number of affected reactivities; most of them were increased and most of the new ones were toward common pathogens.
Thus, it was shown that all investigated treatments can alter to some degree the antigen-binding of secretory IgA, but acidic pH has the most potentially beneficial effect by increasing binding to a largest number of common pathogens' antigens.
如前所述，各种蛋白质修饰剂可以改变免疫球蛋白的抗原结合特性。然而，人类分泌型免疫球蛋白 A（sIgA）的诱导多特异性以前尚未详细描述。
在本研究中，将人分泌型免疫球蛋白 A（IgA）暴露于 pH 值较低的缓冲液、游离血红素或促氧化亚铁离子中，并使用 Western blot 和酶联免疫吸附试验比较天然和修饰的 IgA 对病毒和细菌抗原的抗原结合行为。使用表位微阵列研究这些试剂对人 sIgA 针对广泛的病原体肽的抗原结合特性的调节能力。
我们已经表明，酸性 pH 值、血红素和促氧化亚铁离子以相反的方向影响分泌型 IgA 的结合（要么增加要么减少）；然而，当使用 pH 值较低的缓冲液时，观察到的效果最强。该部分具有最高数量的受影响的反应性；大多数是增加的，大多数新的是针对常见病原体的。
因此，研究表明，所有研究的处理方法都可以在一定程度上改变分泌型 IgA 的抗原结合，但酸性 pH 值通过增加与大量常见病原体抗原的结合具有最潜在的有益效果。
