Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997, Moscow, Russia.
Glycoconj J. 2012 Apr;29(2-3):87-91. doi: 10.1007/s10719-011-9368-8. Epub 2012 Jan 19.
Using printed glycan array (PGA) we compared the results of antibody profiling in undiluted, moderately (1:15) and highly (1:100) diluted human blood serum. Undiluted serum is suitable for studying blood as a tissue in its native state, whereas to study the serum of newborns or small animals one usually has to dilute the starting material in order to have sufficient volume for PGA experimentation. The PGA used in this study allows for the use of whole serum without modifications to the protocol, and the background is surprisingly low. Antibodies profiles observed in undiluted serum versus 1:15 dilution were similar, with only a limited number of new signals identified in the undiluted serum. However, unexpected irregularities were found when IgG and IgM are measured separately, namely, at a 1:15 dilution more intensive IgG signals for many glycans are observed. We believe that in conditions of moderate dilution IgG and IgM antibodies can compete with each other for antigen and as a result, the higher affinity anti-glycan IgGs give rise to more intense signals. Therefore depending on the purpose, different dilutions of serum will be optimal: in competitive 1:15 conditions the observed IgG/IgM ratio corresponds to their titer, whereas at 1:100 dilution the measured ratio corresponds to real molar concentration of IgG and IgM.
使用印刷糖基阵列（PGA），我们比较了未稀释、适度（1:15）和高度（1:100）稀释的人血清中抗体谱的结果。未稀释的血清适用于研究血液在其自然状态下作为组织的情况，而对于研究新生儿或小动物的血清，通常需要稀释起始材料，以便有足够的体积进行 PGA 实验。本研究中使用的 PGA 允许在不修改方案的情况下使用全血清，背景非常低。未稀释血清与 1:15 稀释血清中观察到的抗体谱相似，仅在未稀释血清中鉴定出有限数量的新信号。然而，当分别测量 IgG 和 IgM 时，发现了意想不到的不规则性，即在 1:15 的稀释度下，许多聚糖的 IgG 信号更强烈。我们认为，在适度稀释的条件下，IgG 和 IgM 抗体可以相互竞争抗原，因此，更高亲和力的抗糖 IgG 会产生更强烈的信号。因此，根据目的的不同，血清的不同稀释度将是最佳的：在竞争性的 1:15 条件下，观察到的 IgG/IgM 比值与其滴度相对应，而在 1:100 的稀释度下，测量的比值与 IgG 和 IgM 的真实摩尔浓度相对应。
