Lyons P D, Blalock J E
Department of Physiology and Biophysics, University of Alabama, Birmingham 35294-0005, USA.
J Neuroimmunol. 1995 Dec 31;63(2):103-12. doi: 10.1016/0165-5728(95)00133-6.
The pro-opiomelanocortin (POMC) gene encodes a family of peptides originally identified in the pituitary gland. An important POMC-derived peptide hormone, corticotropin (ACTH), is also produced by leukocytes and modulates in vitro immune functions. The present investigation was undertaken to determine the kinetics and cellular distribution of ACTH immunoreactivity (ACTH-ir) in vitro in rat splenic leukocyte subpopulations. Cells were cultured with Concanavalin A (ConA), lipopolysaccharide (LPS), or media alone. ACTH-ir was identified with a specific antiserum raised against ACTH 1-24. Double indirect-immunofluorescence was done at 0, 21, and 48 h for B, t-helper (Th), and T-cytotoxic (CTL) cells. Initial kinetic studies demonstrated peak ACTH-ir in all cell types at 18-21 h for both ConA and LPS treatments. A few leukocytes (1-2%) expressed ACTH-ir at 0 h and these were found to be macrophages (MO). Lymphocyte ACTH-ir is 0% at 0 h and rises to 90 +/- 5% and 75 +/- 6% at 21 h with ConA and LPS, respectively. This sharply contrasts with 9 +/- 4% of each cell type positive in media alone at 21 h. The percent immunoreactivity among the three lymphocyte subpopulations did not significantly differ at any single treatment at a single time point. However, there were significant differences in the intensity levels among the subpopulations. At 48 h of ConA or LPS treatment only 10 +/- 4% of B, Th and Tc were positive, while none were positive in media alone. Stimulated peritoneal MO also increase positivity for ACTH-ir (85 +/- 5%). These results indicate that rat splenic B, CTL, and Th lymphocytes can be immunologically stimulated to express the peptide hormone ACTH and that basal ACTH expression in macrophages is distinct from that in lymphocytes. Thus, lymphocyte-derived ACTH may be a paracrine or autocrine regulator of immune function.
阿片促黑激素皮质素原（POMC）基因编码一类最初在垂体中发现的肽。一种重要的源自POMC的肽激素促肾上腺皮质激素（ACTH）也由白细胞产生，并调节体外免疫功能。本研究旨在确定大鼠脾白细胞亚群中ACTH免疫反应性（ACTH-ir）在体外的动力学和细胞分布。细胞用刀豆球蛋白A（ConA）、脂多糖（LPS）或单独的培养基培养。用针对ACTH 1-24产生的特异性抗血清鉴定ACTH-ir。在0、21和48小时对B细胞、辅助性T细胞（Th）和细胞毒性T细胞（CTL）进行双间接免疫荧光检测。初步动力学研究表明，对于ConA和LPS处理，所有细胞类型中的ACTH-ir在18-21小时达到峰值。少数白细胞（1-2%）在0小时表达ACTH-ir，这些细胞被发现是巨噬细胞（MO）。淋巴细胞ACTH-ir在0小时为0%，在21小时用ConA和LPS处理时分别升至90±5%和75±6%。这与单独培养基中21小时时每种细胞类型9±4%的阳性率形成鲜明对比。在任何单一处理的单一时间点，三个淋巴细胞亚群之间的免疫反应百分比没有显著差异。然而，亚群之间的强度水平存在显著差异。在ConA或LPS处理48小时时，只有10±4%的B细胞、Th细胞和Tc细胞呈阳性，而单独培养基中无阳性细胞。刺激的腹腔巨噬细胞ACTH-ir阳性率也增加（85±5%）。这些结果表明，大鼠脾B细胞、CTL细胞和Th淋巴细胞可被免疫刺激表达肽激素ACTH，巨噬细胞中的基础ACTH表达与淋巴细胞中的不同。因此，淋巴细胞衍生的ACTH可能是免疫功能的旁分泌或自分泌调节因子。
