- 期刊
脂肪多醣體對免疫球蛋白A分泌的影響
Effect of Lipopolysaccharide on Immunoglobulin A Secretion
摘要
脂肪多醣體（lipopolysaccharide）為革蘭氏陰性細菌細胞壁之成份，在動物體外（in vitro）實驗中已知，LPS能有效地刺激B淋巴球成熟。當這些細菌侵入動物體內，最早接觸到的是黏膜免疫率統，而黏膜免疫率統中之主要抗體為IgA。本研究之目的即在探討LPS是否對B淋巴球之IgA分泌能力有影響。實驗所用之B淋巴球分別為正常脾臟細胞，純化之脾臟B細胞和漿細胞株（MOPC315）。結果發覺LPS對MOPC315漿細胞株之增生與IgA之分泌沒有影響；而LPS對脾臟細胞與純化之B細胞之增生與IgA分泌有促進作用。LPS可使脾臟細胞維持原有之細胞數目，到了第六天增加140%，若去除T細胞及巨噬細胞，則純化之B細胞數目到第四天增加到420%；以IgA分泌量而言，LPS使脾臟細胞維持分泌IgA到第四天，總累積量最高為1.16 μg/ml，若去除T細胞及巨噬細胞，則純化之B細胞IgA分泌可因LPS之刺激而不斷增加，到第七天，總累積量為1.33 μg/ml，而且無減緩跡象。本實驗之結果顯示，受LPS刺激之巨噬細胞及T細胞可能對B淋巴球之增生與IgA分泌有抑制作用。
並列摘要
Lipopolysaccharide (LPS), a major component in cell wall of gram-negative bacteria, has been shown to be an effective polyclonal activator of B lymphocytes under both in vivo and in vitro conditions. As the gram-negative bacteria invade into the human and animal body, the immune system which will be challenged first is the mucosal immune system. Mucosal immune system secrets antigen-specfic antibodies, most of them are immunoglobulin A (IgA), to act against bacteria. In this report, we investigate the regulatory effect of LPS on B lymphocyte growth and IgA secretion. LPS shows no effect on the growth and IgA secretion of an IgA-secreting plasma cell tumor, MOPC-315. However, normal spleen cells respond signifiantly to LPS stimulation with increasing both the cell number and IgA secretion. The cell number is increased to 140% as day 6 vs. day 0 and the IgA concentration is accumulated to 1.16 μg/ml at day 4 and then reached plateau. If both T lymphocytes and macrophages are depleted from spleen cells, the B cell-enriched population increases its cell number to 420% as day 4 vs. day 0 in response to LPS-stimulation. The cell number de lines after day 4 but IgA concentration persistently increases to 1.33 μg/ml at day 7 and no plaetau is found. The observation in this study indicates the potential suppressive effect of T-lymphocytes and macrophages on LPS-stimulated B lymphocyte activation.