Ladics G S, Kawabata T T, Munson A E, White K L
Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298.
Toxicol Appl Pharmacol. 1992 Oct;116(2):248-57. doi: 10.1016/0041-008x(92)90304-b.
The objective of the present study was to determine which splenic cell type(s) of B6C3F1 mice was capable of metabolizing B(a)P. Separation of splenocytes based on density by centrifugation through discontinuous Percoll gradients along with immunomagnetic negative selection or antibody-mediated complement lysis was utilized to obtain highly enriched populations of splenocytes for B(a)P metabolism studies. Immunofluorescent cell staining in conjunction with flow cytometry and examination of Giemsa-stained cytospin cell preparations indicated that B- or T-cell populations of greater than 95% purity and an 80-90% pure population of splenic macrophages were routinely attained. Splenic cell populations were incubated with [3H]B(a)P for 24 hr. High-pressure liquid chromatography was used to separate and quantitate the B(a)P metabolites generated by the enriched splenic cell populations. The results of these studies demonstrate that the macrophage is the cell type responsible for the metabolism of B(a)P within the spleen. The major metabolites of B(a)P produced were as follows: an unidentified peak of polar metabolites containing polyhydroxylated metabolites, B(a)P-9,10-dihydroxy-9,10-dihydrodiol, and B(a)P-7,8-dihydroxy-7,8- dihydrodiol. Other splenic cell types examined, including B and T cells, polymorphonuclear cells, or the spleen capsule did not produce amounts of B(a)P metabolites significantly above background levels. Based on these findings, macrophages are the splenic cell types which metabolize B(a)P. As a result, macrophages may be the cell type targeted by B(a)P resulting in suppression of splenic humoral immune responses.
本研究的目的是确定B6C3F1小鼠的哪种脾细胞类型能够代谢苯并[a]芘。通过不连续的Percoll梯度离心法基于密度分离脾细胞，并结合免疫磁珠阴性选择或抗体介导的补体裂解，以获得高度富集的脾细胞群体用于苯并[a]芘代谢研究。免疫荧光细胞染色结合流式细胞术以及吉姆萨染色的细胞涂片制备检查表明，通常可获得纯度大于95%的B细胞或T细胞群体以及纯度为80%-90%的脾巨噬细胞群体。将脾细胞群体与[3H]苯并[a]芘孵育24小时。使用高压液相色谱法分离和定量富集的脾细胞群体产生的苯并[a]芘代谢物。这些研究结果表明，巨噬细胞是脾脏内负责苯并[a]芘代谢的细胞类型。产生的苯并[a]芘主要代谢物如下：一个含有多羟基化代谢物的极性代谢物未知峰、苯并[a]芘-9,10-二羟基-9,10-二氢二醇以及苯并[a]芘-7,8-二羟基-7,8-二氢二醇。所检测的其他脾细胞类型，包括B细胞、T细胞、多形核细胞或脾包膜，产生的苯并[a]芘代谢物量均未显著高于背景水平。基于这些发现，巨噬细胞是代谢苯并[a]芘的脾细胞类型。因此，巨噬细胞可能是苯并[a]芘靶向的细胞类型，从而导致脾脏体液免疫反应受到抑制。
