Lamont A G, Mowat A M, Parrott D M
Department of Bacteriology and Immunology, Western Infirmary, Glasgow, U.K.
Immunology. 1989 Apr;66(4):595-9.
We have examined the effects on both systemic and intestinal immunity of feeding different doses of ovalbumin (OVA) to mice. A single feed of doses of more than 1 mg OVA produced significant suppression of subsequent delayed-type hypersensitivity (DTH) and IgG antibody responses. Feeding 100 micrograms-1 mg OVA had no net effect on systemic immunity, but mice fed 10-50 micrograms OVA had consistently enhanced systemic DTH responses when immunized subsequently with OVA in adjuvant. Oral challenge of these mice with OVA produced alterations in mucosal architecture and in intra-epithelial lymphocyte counts, consistent with the presence of an intestinal DTH response. Similar changes were not found in mice fed tolerogenic doses of OVA. Although feeding low doses of OVA primed both systemic and intestinal DTH responses, this had no effect on serum IgG responses and very little systemic DTH could be revealed in OVA-fed mice without systemic challenge with OVA in adjuvant. We conclude that feeding certain low doses of protein antigens can induce priming of local and systemic DTH responses rather than the immune tolerance which is normally found. The development of clinical food hypersensitivities may be highly dependent on the dose of dietary antigen at the time of first encounter.
我们研究了给小鼠喂食不同剂量卵清蛋白（OVA）对全身和肠道免疫的影响。单次喂食超过1毫克OVA会显著抑制随后的迟发型超敏反应（DTH）和IgG抗体反应。喂食100微克 - 1毫克OVA对全身免疫没有净影响，但随后用佐剂中的OVA免疫时，喂食10 - 50微克OVA的小鼠全身DTH反应持续增强。用OVA对这些小鼠进行口服激发会导致黏膜结构和上皮内淋巴细胞计数发生改变，这与肠道DTH反应的存在一致。在喂食致耐受性剂量OVA的小鼠中未发现类似变化。尽管喂食低剂量OVA可引发全身和肠道DTH反应，但这对血清IgG反应没有影响，并且在未用佐剂中的OVA进行全身激发的情况下，喂食OVA的小鼠中几乎没有全身DTH反应。我们得出结论，喂食某些低剂量的蛋白质抗原可诱导局部和全身DTH反应的启动，而不是通常所见的免疫耐受。临床食物过敏的发生可能高度依赖于首次接触时饮食抗原的剂量。
