Lappin M B, Dearman R J, Norval M, Kimber I
Department of Medical Microbiology, University of Edinburgh Medical School, Edinburgh EH8 9AG, UK.
Am J Contact Dermat. 1998 Mar;9(1):34-9.
Previous investigations in BALB/c strain mice have revealed that, after skin sensitization, draining lymph node cells (LNC) produce high levels of interleukin 6 (IL-6) and that the secretion of this cytokine correlates closely with the proliferative activity of LNC. The main source of IL-6 within draining lymph nodes was found to be dendritic cells (DC), most of which derive from epidermal Langerhans cells.
To explore further the relationship between DC-derived IL-6 production in lymph nodes, LNC proliferative activity, and the development of contact sensitization, comparisons between BALB/c and C3H/HeN strains of mice have been conducted.
Contact sensitizing potential was measured in both strains of mice as a function of lymphocyte proliferative responses (assessed by the incorporation of radiolabelled thymidine) and challenge-induced increases in ear thickness. The concentration of IL-6 in skin homogenates and the production of IL-6 by allergen-activated LNC were measured by enzyme-linked immunosorbent assay (ELISA).
In both strains of mouse, topical exposure to oxazolone, a potent contact allergen, induced a vigorous proliferative response by draining LNC and the development of skin sensitization. However, under these conditions of exposure, activated LNC prepared from mice of C3H/HeN strain failed to secrete substantial amounts of IL-6, the levels of this cytokine being on average some 20- to 40-fold less than those measured in BALB/c mice. The failure of LNC from C3H/HeN mice to secrete comparable levels of IL-6 was not attributable to a reduced ability of DC to accumulate in draining lymph nodes after skin sensitization. Nor did reduced IL-6 secretion by C3H/HeN LNC reflect a systemic inability to elaborate this cytokine. Epicutaneous exposure of C3H/HeN mice to oxazolone resulted in the induction of cutaneous IL-6 at levels similar to, or greater than, those observed after identical treatment of BALB/c strain mice.
The conclusion drawn is that there does not exist a universal association between IL-6 production in draining lymph nodes and the vigor of proliferative responses by LNC. Further, cutaneous immune responses and skin sensitization may proceed apparently normally in the absence of high levels of IL-6 production by lymph node cells.
先前对BALB/c品系小鼠的研究表明，皮肤致敏后，引流淋巴结细胞（LNC）会产生高水平的白细胞介素6（IL-6），且这种细胞因子的分泌与LNC的增殖活性密切相关。发现引流淋巴结内IL-6的主要来源是树突状细胞（DC），其中大多数源自表皮朗格汉斯细胞。
为了进一步探究淋巴结中DC产生IL-6、LNC增殖活性与接触性致敏反应发生之间的关系，对BALB/c和C3H/HeN品系小鼠进行了比较。
通过淋巴细胞增殖反应（通过放射性标记胸腺嘧啶核苷掺入法评估）和激发诱导的耳部厚度增加来衡量两种品系小鼠的接触致敏潜力。采用酶联免疫吸附测定（ELISA）法检测皮肤匀浆中IL-6的浓度以及变应原激活的LNC产生IL-6的情况。
在两种品系小鼠中，局部接触强效接触性变应原恶唑酮均会诱导引流LNC产生强烈的增殖反应以及皮肤致敏反应。然而，在这些接触条件下，从C3H/HeN品系小鼠制备的活化LNC未能分泌大量IL-6，该细胞因子的水平平均比在BALB/c小鼠中测得的水平低约20至40倍。C3H/HeN小鼠的LNC未能分泌相当水平IL-6的原因并非是皮肤致敏后DC在引流淋巴结中聚集的能力降低。C3H/HeN LNC分泌IL-6减少也并非反映出全身无法产生这种细胞因子。C3H/HeN小鼠经皮暴露于恶唑酮后，诱导产生的皮肤IL-6水平与对BALB/c品系小鼠进行相同处理后观察到的水平相似或更高。
得出的结论是，引流淋巴结中IL-6的产生与LNC增殖反应的强度之间不存在普遍关联。此外，在淋巴结细胞不产生高水平IL-6的情况下，皮肤免疫反应和皮肤致敏反应可能仍能明显正常进行。
