Gill H K, Liew F Y
Eur J Immunol. 1978 Mar;8(3):172-6. doi: 10.1002/eji.1830080306.
A previous study (Eur. J. Immunol. 1977. 7: 714) has shown that mice injected intravenously (i.v.) with 4 x10(9) sheep red blood cells (SRBC) produce cells which suppress delayed-type hypersensitivity (DTH). These suppressor cells are theta-positive, antigen-specific and act via a soluble factor which does not bear immunoglobulin determinants (Eur. J. Immunol. 1978. 8: 168). The present paper demonstrates that these suppressor cells are inhibitable by cyclophosphamide (CY). Mice injected with graded amounts of CY two days prior to SRBC injection, showed maximum augmentation of DTH at 200 mg/kg body weight, a dose which completely suppressed the appearance of splenic plaque-forming cells (PFC) to SRBC. In contrast, lower doses of CY enhanced both DTH and PFC responses. Time course studies showed that CY inhibited the precursors of suppressor cells and had little or no effect on suppressor cells which have already encountered antigens. This was further confirmed by passive transfer studies which showed tha- suppressor cells were inhibited if CY was administered at the same time or 2 days before SRBC injection, but were not affected if CY was given after antigen stimulation. Direct evidence for the effect of CY on suppressor cells was obtained by cell fractination with a Ficoll density gradient. The denser suppressor cell population was absent from the spleens of mice treated with 200 mg/kg of CY 2 days before i.v. injection with 1 x 10(9) SRBC.
先前的一项研究（《欧洲免疫学杂志》1977年。第7卷：714页）表明，静脉注射（i.v.）4×10⁹个绵羊红细胞（SRBC）的小鼠会产生抑制迟发型超敏反应（DTH）的细胞。这些抑制细胞是θ阳性、抗原特异性的，并且通过一种不带有免疫球蛋白决定簇的可溶性因子起作用（《欧洲免疫学杂志》1978年。第8卷：168页）。本文证明这些抑制细胞可被环磷酰胺（CY）抑制。在注射SRBC前两天注射不同剂量CY的小鼠，在体重200mg/kg时DTH增强到最大程度，该剂量完全抑制了脾脏中针对SRBC的斑块形成细胞（PFC）的出现。相反，较低剂量的CY增强了DTH和PFC反应。时间进程研究表明，CY抑制抑制细胞的前体，对已经接触过抗原的抑制细胞几乎没有影响。被动转移研究进一步证实了这一点，该研究表明，如果在注射SRBC的同时或前两天给予CY，抑制细胞会被抑制，但如果在抗原刺激后给予CY则不受影响。通过用Ficoll密度梯度进行细胞分级分离获得了CY对抑制细胞作用的直接证据。在用200mg/kg的CY处理2天的小鼠脾脏中，在静脉注射1×10⁹个SRBC前，较密集的抑制细胞群体缺失。
