Siedek E, Little S, Mayall S, Edington N, Hamblin A
Department of Pathology and Infectious Disease, Royal Veterinary College, London, UK.
Vet Immunol Immunopathol. 1997 Dec 12;60(1-2):15-31. doi: 10.1016/s0165-2427(97)00093-7.
Despite their important role in initiating T-cell responses in other species, dendritic cells have not been studied in the horse. A method for isolating blood dendritic cells by adherence and metrizamide gradients was adapted to equine cells. A number of monoclonal antibodies (mAbs), including some which label dendritic cells in other species, were tested for immunochemical reactivity with the isolated blood dendritic cells, and sections of lymph node and spleen. 62 +/- 6% of the isolated blood cells were MHC Class II positive and had typical dendritic cell morphology and only 4 +/- 2% contained non-specific esterase, a marker of mature macrophages. These dendritic cells also expressed MHC Class I, LFA-1, EqWC1 and EqWC2. Amongst the potentially cross-reactive antibodies a mAb against bovine CD1b was the most interesting by staining lymph node, but not blood, dendritic cells. Monoclonal antibodies against equine CD5 (T-cells), surface immunoglobulin (B-cells) and macrophages (CZ2.2) were used to enumerate the contaminating cells in preparations from blood by flow cytometry. 39 +/- 7% of the cells did not express T and B cell markers or CZ2.2 but were large and MHC Class II positive. Comparison of immuno-chemistry and flow data, together with examination of alveolar macrophages and adhered blood cells, all support the view that CZ2.2 detects a myeloid marker not seen on mature macrophages and possibly shared with dendritic cell precursors. The functional capacity of the isolates was assessed in terms of their stimulating ability in the mixed leukocyte reaction (MLR). Dendritic cell enriched isolates were more potent stimulators of MLRs than peripheral blood mononuclear cells or adherent cells. Thus equine dendritic cells isolated from blood express high levels of MHC Class I and II and LFA-1 and stimulate a vigorous MLR. They do not express markers characterising T and B cells but, by virtue of expression of the equine macrophage marker CZ2.2, appear closely related to mononuclear phagocytes.
尽管树突状细胞在其他物种的T细胞反应启动中发挥着重要作用，但尚未在马身上进行研究。一种通过贴壁和Metrizamide梯度分离血液树突状细胞的方法已应用于马细胞。测试了多种单克隆抗体（mAb），包括一些可标记其他物种树突状细胞的抗体，以检测其与分离的血液树突状细胞以及淋巴结和脾脏切片的免疫化学反应性。分离的血细胞中有62±6%为MHC II类阳性，具有典型的树突状细胞形态，只有4±2%含有非特异性酯酶，这是成熟巨噬细胞的标志物。这些树突状细胞还表达MHC I类、LFA-1、EqWC1和EqWC2。在可能交叉反应的抗体中，一种抗牛CD1b的单克隆抗体最有意思，它可对淋巴结树突状细胞染色，但不能对血液树突状细胞染色。抗马CD5（T细胞）、表面免疫球蛋白（B细胞）和巨噬细胞（CZ2.2）的单克隆抗体用于通过流式细胞术计数血液制备物中的污染细胞。39±7%的细胞不表达T和B细胞标志物或CZ2.2，但体积较大且为MHC II类阳性。免疫化学和流式数据的比较，以及对肺泡巨噬细胞和贴壁血细胞的检查，均支持以下观点：CZ2.2检测到一种在成熟巨噬细胞上未见的髓系标志物，可能与树突状细胞前体共有。根据分离物在混合淋巴细胞反应（MLR）中的刺激能力评估其功能能力。富含树突状细胞的分离物比外周血单个核细胞或贴壁细胞更有效地刺激MLR。因此，从血液中分离的马树突状细胞表达高水平的MHC I类和II类以及LFA-1，并刺激强烈的MLR。它们不表达表征T和B细胞的标志物，但由于表达马巨噬细胞标志物CZ2.2，似乎与单核吞噬细胞密切相关。
