Overcoming antigen masking of anti-amyloidbeta antibodies reveals breaking of B cell tolerance by virus-like particles in amyloidbeta immunized amyloid precursor protein transgenic mice
Overcoming antigen masking of anti-amyloidbeta antibodies reveals breaking of B cell tolerance by virus-like particles in amyloidbeta immunized amyloid precursor protein transgenic mice
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DOI：
10.1186/1471-2202-5-21
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发表时间：
2004-06-08
期刊：
影响因子：
2.4
通讯作者：
Morgan, D
中科院分区：
文献类型：
--
作者：
Li, QY;Cao, CH;Morgan, D
背景资料：在先前的工作中，我们检测到与非转基因同窝出生小鼠相比，表达人淀粉样前体蛋白（APP）的A β疫苗接种转基因小鼠的抗A β抗体滴度降低。我们进一步研究了这一观察结果，通过接种APP和非转基因小鼠与野生型人Abeta肽，Abeta肽含有“荷兰突变”，E22 Q，或野生型Abeta肽缀合到乳头瘤病毒病毒样颗粒（VLP）。结果：抗Abeta抗体滴度低于接种APP比非转基因小鼠，即使当接种高度免疫原性Abeta E22 Q。一个问题是，来自APP转基因的人Abeta可能会掩盖APP小鼠中的抗Abeta抗体。为了测试这种可能性，我们通过在低pH下孵育解离抗原-抗体复合物。低pH孵育使APP小鼠中的抗Abeta抗体滴度增加20-40倍，但对非转基因小鼠的血清没有影响。然而，即使在解离后，相对于非转基因小鼠，用野生型Abeta或E22 Q Abeta接种的转基因小鼠中的抗Abeta滴度仍然较低。重要的是，在基于VLP的疫苗接种后，非转基因小鼠和APP小鼠中解离的抗Abeta滴度相等。对照实验表明，酸解离后，增加的抗体滴度没有交叉反应与牛血清白蛋白，也没有α-突触核蛋白，并添加Abeta回解离血清阻断抗体titers.Conclusions的增加：循环人Abeta可以干扰ELISA测定抗Abeta滴度的测量。E22 Q Abeta肽疫苗比野生型肽更具免疫原性。与肽疫苗不同，针对Abeta的基于VLP的疫苗消除了Abeta自身耐受性的作用。
Background: In prior work we detected reduced anti-Abeta antibody titers in Abeta-vaccinated transgenic mice expressing the human amyloid precursor protein (APP) compared to nontransgenic littermates. We investigated this observation further by vaccinating APP and nontransgenic mice with either the wild-type human Abeta peptide, an Abeta peptide containing the "Dutch Mutation", E22Q, or a wild-type Abeta peptide conjugated to papillomavirus virus-like particles (VLPs).Results: Anti-Abeta antibody titers were lower in vaccinated APP than nontransgenic mice even when vaccinated with the highly immunogenic Abeta E22Q. One concern was that human Abeta derived from the APP transgene might mask anti-Abeta antibodies in APP mice. To test this possibility, we dissociated antigen-antibody complexes by incubation at low pH. The low pH incubation increased the anti-Abeta antibody titers 20-40 fold in APP mice but had no effect in sera from nontransgenic mice. However, even after dissociation, the anti-Abeta titers were still lower in transgenic mice vaccinated with wild-type Abeta or E22Q Abeta relative to non-transgenic mice. Importantly, the dissociated anti-Abeta titers were equivalent in nontransgenic and APP mice after VLP-based vaccination. Control experiments demonstrated that after acid-dissociation, the increased antibody titer did not cross react with bovine serum albumin nor alpha-synuclein, and addition of Abeta back to the dissociated serum blocked the increase in antibody titers.Conclusions: Circulating human Abeta can interfere with ELISA assay measurements of anti-Abeta titers. The E22Q Abeta peptide vaccine is more immunogenic than the wild-type peptide. Unlike peptide vaccines, VLP-based vaccines against Abeta abrogate the effects of Abeta self-tolerance.