Wielert Isabelle, Kraus-Römer Sebastian, Volkmann Thorsten E, Craig Lisa, Higgins Paul G, Maier Berenike
Institute for Biological Physics, University of Cologne, Cologne, Germany.
Center for Molecular Medicine Cologne, Cologne, Germany.
PLoS Biol. 2025 Jan 30;23(1):e3003022. doi: 10.1371/journal.pbio.3003022. eCollection 2025 Jan.
Type 4 pili (T4P) are multifunctional filaments involved in adhesion, surface motility, biofilm formation, and horizontal gene transfer. These extracellular polymers are surface-exposed and, therefore, act as antigens. The human pathogen Neisseria gonorrhoeae uses pilin antigenic variation to escape immune surveillance, yet it is unclear how antigenic variation impacts most other functions of T4P. Here, we addressed this question by replacing the major pilin of a laboratory strain with pilins from clinical isolates. We reveal that the resulting strains vary substantially in their attractive forces. Strongly interacting bacteria form microcolonies while weakly interacting bacteria retain a planktonic lifestyle. In mixed microcolonies, different variant strains segregate in agreement with the differential strength of adhesion hypothesis. By combining structural predictions and laser tweezers experiments, we show that the C-terminal region of the pilin is crucial for attraction. Lifestyle affects growth kinetics and antibiotic tolerance. In the presence of ceftriaxone or ciprofloxacin, the killing kinetics indicate strongly increased tolerance of aggregating strains. We propose that pilin antigenic variation produces a mixed population containing variants optimized for growth, colonization, or survivability under external stress. Different environments select different variants, ensuring the survival and reproduction of the population as a whole.
4型菌毛（T4P）是多功能细丝，参与粘附、表面运动、生物膜形成和水平基因转移。这些细胞外聚合物暴露于表面，因此可作为抗原。人类病原体淋病奈瑟菌利用菌毛抗原变异来逃避免疫监视，但尚不清楚抗原变异如何影响T4P的大多数其他功能。在这里，我们通过用临床分离株的菌毛替换实验室菌株的主要菌毛来解决这个问题。我们发现，所得菌株的吸引力差异很大。相互作用强烈的细菌形成微菌落，而相互作用较弱的细菌保持浮游生活方式。在混合微菌落中，不同的变异菌株会根据粘附差异强度假说进行分离。通过结合结构预测和激光镊子实验，我们表明菌毛的C末端区域对吸引力至关重要。生活方式影响生长动力学和抗生素耐受性。在头孢曲松或环丙沙星存在的情况下，杀灭动力学表明聚集菌株的耐受性大大增加。我们提出，菌毛抗原变异产生了一个混合群体，其中包含在外部压力下针对生长、定植或生存能力进行优化的变体。不同的环境选择不同的变体，确保整个群体的生存和繁殖。
