'Laboratoire Colloïdes et Matériaux Divisés' (LCMD), ESPCI Paris, PSL Research University, CNRS UMR8231 Chimie Biologie Innovation, F-75005, Paris, France.
Unit of Antibodies in Therapy and Pathology, Institute Pasteur, UMR1222 INSERM, F-75015, Paris, France.
Commun Biol. 2020 Oct 26;3(1):614. doi: 10.1038/s42003-020-01296-3.
Antibodies with antibacterial activity need to bind to the bacterial surface with affinity, specificity, and sufficient density to induce efficient elimination. To characterize the anti-bacterial antibody repertoire, we developed an in-droplet bioassay with single-antibody resolution. The assay not only allowed us to identify whether the secreted antibodies recognized a bacterial surface antigen, but also to estimate the apparent dissociation constant (K) of the interaction and the density of the recognized epitope on the bacteria. Herein, we found substantial differences within the K/epitope density profiles in mice immunized with various species of heat-killed bacteria. The experiments further revealed a high cross-reactivity of the secreted IgG repertoires, binding to even unrelated bacteria with high affinity. This application confirmed the ability to quantify the anti-bacterial antibody repertoire and the utility of the developed bioassay to study the interplay between bacteria and the humoral response.
具有抗菌活性的抗体需要以亲和力、特异性和足够的密度与细菌表面结合，以诱导有效的清除。为了表征抗细菌抗体库，我们开发了一种具有单抗体分辨率的液滴内生物测定法。该测定法不仅允许我们确定分泌的抗体是否识别细菌表面抗原，还可以估计相互作用的表观解离常数 (K) 和细菌上识别表位的密度。在这里，我们发现用各种热灭活细菌免疫的小鼠中 K/表位密度谱存在显著差异。实验进一步揭示了分泌 IgG 库的高度交叉反应性，甚至可以高亲和力结合不相关的细菌。该应用程序证实了定量抗细菌抗体库的能力，以及开发的生物测定法在研究细菌与体液反应之间相互作用的实用性。
