Peng H J, Chang Z N, Han S H, Won M H, Huang B T
Department of Medical Research, Veterans General Hospital-Taipei, Taiwan China.
Scand J Immunol. 1995 Sep;42(3):297-304. doi: 10.1111/j.1365-3083.1995.tb03659.x.
We have examined the effects of ingestion of chemically denatured ovalbumin (OVA) in mice. Both 8 M urea-denatured OVA (UD-OVA) and carboxymethylated UD-OVA (CM-OVA) were purified by gel filtration. Specific IgG antibody and systemic delayed-type hypersensitivity (DTH) responses to OVA were not suppressed by CM-OVA fed prior to or after immunization with OVA in complete Freund's adjuvant (CFA). When CM-OVA was used instead of OVA, for immunization, serum IgG and DTH responses to CM-OVA were orally tolerized by OVA, but not by UD-OVA or CM-OVA. Studies of antigen uptake in mice using sandwich ELISA tests showed that OVA, but not CM-OVA, was absorbed after antigen ingestion. In vitro studies further demonstrated that CM-OVA was digested much more rapidly than OVA. Moreover, studies using bovine serum albumin (BSA) demonstrated that both IgG and DTH responses to BSA were orally tolerant to BSA, but not to denatured BSA. Finally, studies using human gamma-globulin (HGG), a well-known tolerogen, also found that the IgG antibody response to HGG was not orally tolerized by denatured HGG. These results suggest that complete denaturation of globular proteins may affect their processing and absorption in the gut and thus abrogates oral tolerance induction.
我们研究了小鼠摄入化学变性卵清蛋白（OVA）的影响。8M尿素变性卵清蛋白（UD-OVA）和羧甲基化UD-OVA（CM-OVA）均通过凝胶过滤法纯化。在用完全弗氏佐剂（CFA）免疫OVA之前或之后喂食CM-OVA，对OVA的特异性IgG抗体和全身性迟发型超敏反应（DTH）并未受到抑制。当用CM-OVA代替OVA进行免疫时，血清IgG和对CM-OVA的DTH反应可被OVA口服耐受，但不能被UD-OVA或CM-OVA耐受。使用夹心ELISA试验对小鼠抗原摄取的研究表明，抗原摄入后OVA可被吸收，而CM-OVA则不能。体外研究进一步证明，CM-OVA比OVA消化得更快。此外，使用牛血清白蛋白（BSA）的研究表明，对BSA的IgG和DTH反应对BSA口服耐受，但对变性BSA不耐受。最后，使用众所周知的耐受原人γ球蛋白（HGG）的研究也发现，对HGG的IgG抗体反应不会被变性HGG口服耐受。这些结果表明，球状蛋白的完全变性可能会影响其在肠道中的加工和吸收，从而消除口服耐受的诱导。
