Forsdyke D R
Immunology. 1973 Oct;25(4):583-95.
Lymph node cells from immunized rabbits were cultured with varying concentrations of antigen in preheated (56°, 30 minutes) autologous serum which had been collected before immunization. [H]Thymidine was present for the last 6 hours of the 24-hour culture period and the radioactive labelling of acid-precipitable material was then determined. Changes in labelling due to variations of culture conditions were interpreted according to whether they were specific for control or antigen-treated cultures or non-specific. Cell concentration and serum concentration were predominantly non-specific variables influencing the labelling in control and antigen-treated cultures to a proportionate extent. However, at serum concentrations below 5 per cent labelling was disproportionately inhibited in antigen-treated cultures; there were further minor disproportionate inhibitions at higher serum concentrations. Labelling was inhibited by increasing the concentration of serum from 25 to 50 per cent, mainly due to a non-diffusible competitive inhibitory activity. Isotope-dilution analysis of the effects of serum on labelling over a wide range of serum concentrations indicated that the relationship was a complex one with at least three step-wise stimulations of the maximum labelling rate being produced by increasing the serum concentrations from 0 to 25 per cent. Labelling in antigen-treated cultures containing post-immunization serum was less than labelling in cultures containing an equal volume of preimmunization serum, but labelling in control cultures was enhanced by post-immunization serum. These results are shown to be compatible with the proposals (i) that labelling in control cultures reflects the response of cells to low concentrations of endogenous antigens, and (ii) that preimmunization serum and post-immunization serum contain natural' and acquired' antibodies respectively, which normally buffer cell-borne receptor sites against reaction with endogenous and exogenous antigens.
将免疫兔的淋巴结细胞与不同浓度的抗原在预热（56°，30分钟）的自体血清中培养，该血清在免疫前采集。在24小时培养期的最后6小时加入[H]胸腺嘧啶，然后测定酸沉淀物质的放射性标记。根据培养条件变化导致的标记变化是对照培养或抗原处理培养所特有的还是非特异性的来进行解释。细胞浓度和血清浓度主要是影响对照培养和抗原处理培养中标记的非特异性变量，且影响程度成比例。然而，在血清浓度低于5%时，抗原处理培养中的标记受到不成比例的抑制；在较高血清浓度下还有进一步轻微的不成比例抑制。将血清浓度从25%提高到50%会抑制标记，这主要是由于一种不可扩散的竞争性抑制活性。在广泛的血清浓度范围内对血清对标记影响的同位素稀释分析表明，这种关系很复杂，血清浓度从0提高到25%至少会产生三次逐步刺激最大标记率的情况。含有免疫后血清的抗原处理培养中的标记低于含有等体积免疫前血清的培养中的标记，但免疫后血清会增强对照培养中的标记。这些结果表明与以下观点一致：（i）对照培养中的标记反映细胞对低浓度内源性抗原的反应，（ii）免疫前血清和免疫后血清分别含有“天然”和“获得性”抗体，它们通常缓冲细胞携带的受体位点，使其不与内源性和外源性抗原发生反应。
