维生素A促进人淋巴细胞抗体生成能力的机理探讨

AUGMENTATIVE EFFECT OF VITAMIN A ONIMMUNOGLOBULIN SYNTHESIS OF HUMANLYMPHOCYTES

对７名足月新生儿脐血和６名健康成人静脉血中的单个核细胞与不同浓度的视黄醇和视黄酸进行了体外培养试验，通过对培养液中免疫球蛋白含量的测定，观察淋巴细胞产生抗体的能力。结果表明，自脐血中分离的淋巴细胞，当维生素Ａ的最佳效应浓度为１×１０￣（－６）ｍｏｌ／Ｌ时，淋巴细胞产生的ＩｇＭ水平明显高于无维生素Ａ培养对照组。自成人血中分离的淋巴细胞在维生素Ａ浓度为１×１０￣（－１４）ｍｏｌ／Ｌ时表现出ＩｇＧ的产量增加。提示正常血清水平的维生素Ａ对维持和促进新生儿淋巴细胞对外来性抗原的反应有非常明显的影响。使用自脐血中分离纯化的Ｔ和Ｂ淋巴细胞及经Ｅｐｓｔｅｉｎ一Ｂａｒｒ病毒诱导克隆化的人Ｂ淋巴细胞株，研究视黄酸在体外条件下对Ｔ和Ｂ细胞的免疫调节机制。结果表明，视黄酸能调节Ｔ细胞产生白细胞介素６和某种淋巴因子，从而辅助Ｂ细胞产生抗体；在视黄酸作用下，当Ｂ淋巴细胞产生大量抗体和白细胞介素６的同时，其细胞内ＤＮＡ的合成反而减少。提示视黄酸调节人淋巴细胞抗体合成作用环节可能在于促进了细胞核内ｍＲＮＡ的转运和复制，而不是促进ＤＮＡ的合成。

AbstractMononuclear cells from cord blood (CBMC) oradult peripheral blood(APBMC) were incubated withretinol (RO) and retinoic acid (RA), immunoglobulinconcentrations in the culture were assayed to deterniine the effect of RO and RA on antibody producingfunction of lymphocytes. The results showed that pro-duction of IgM in the culture with RO and RA wassigmficantiy higher than that in the control, theoptinial concentration of RO and RA was 1×10￣(-6)mol/ L, sinular to physiological level of humanseruni. In contrast, the augmentative effect of RO onMBMC demonstrated a lower response. Our studysuggesteil that vitamin A nutritional status is moreimportant to maintain lymphocytes function ofnewbom infants. To explore the mechanism ofregulatory effects of vitamin A on humanlymphocytes, T cells purified from cord blood andEBV transfornied human B cell lines were incubatedwith RA. The results showed that RA induced T cellsto produce factors which exhibited an effect of promoting B cells immunoglobulin synthesis. The coneen-tration of IL-6 in supematants of B cell lines incubated with RA increased significantly in parallel withaugmentation of immunoglobulin production.