Zepp F, Schulte-Wissermann H, Mannhardt W
Thymus. 1984;6(5):295-308.
The influence of H2-Ia-negative macrophages (Ia-M phi) on thymocyte viability and proliferation was investigated. Peritoneal as well as Ia-M phi of thymic origin were used in this study and yielded similar results. Cocultivation of thymocyte with 4.5% Ia- M phi diminished thymocyte viability by about 70% and mitogen-induced proliferation by about 90% in comparison to control cultures without addition of M phi. These suppressive effects were related to rosette formation between thymocytes and Ia- M phi: more than 80% of Ia- M phi formed rosettes with immature thymocytes. Mature thymocytes (i.e. PNA-negative, steroid-resistant cells) rosetted in only 5% and were consequently not affected by M phi-mediated suppression. Since Cytochalasin B, known to inhibit rosette formation, abolished the suppressive effects of M phi, and supernatants of M phi cultures exhibited no inhibition of thymocytes, close cell contact (rosette) is apparently necessary for the inhibitory phenomenon. Suppression, however, seems to depend further on the functional state of the M phi: ingestion of carbon particles significantly diminished the inhibitory effect on thymocytes despite further presence of rosettes. The results suggest that Ia- M phi have a regulatory function within thymus physiology. While Ia+ M phi promote thymocyte proliferation as described elsewhere, the Ia- M phi may control the number and kind of thymocytes released by the thymus gland.
研究了H2-Ia阴性巨噬细胞（Ia-M phi）对胸腺细胞活力和增殖的影响。本研究使用了腹腔来源以及胸腺来源的Ia-M phi，结果相似。与未添加M phi的对照培养相比，胸腺细胞与4.5%的Ia-M phi共培养使胸腺细胞活力降低约70%，丝裂原诱导的增殖降低约90%。这些抑制作用与胸腺细胞和Ia-M phi之间的玫瑰花结形成有关：超过80%的Ia-M phi与未成熟胸腺细胞形成玫瑰花结。成熟胸腺细胞（即PNA阴性、类固醇抗性细胞）仅5%形成玫瑰花结，因此不受M phi介导的抑制影响。由于已知抑制玫瑰花结形成的细胞松弛素B消除了M phi的抑制作用，且M phi培养上清液对胸腺细胞无抑制作用，因此紧密的细胞接触（玫瑰花结）显然是这种抑制现象所必需的。然而，抑制作用似乎进一步取决于M phi的功能状态：尽管仍存在玫瑰花结，但吞噬碳颗粒显著降低了对胸腺细胞的抑制作用。结果表明，Ia-M phi在胸腺生理学中具有调节功能。正如其他地方所描述的，Ia+ M phi促进胸腺细胞增殖，而Ia-M phi可能控制胸腺释放的胸腺细胞数量和种类。
