Acuña Hidalgo Beatriz, Armitage Sophie A O
Institute of Biology, Freie Universität Berlin, Berlin, Germany.
Front Physiol. 2022 Mar 21;13:860875. doi: 10.3389/fphys.2022.860875. eCollection 2022.
Immune priming describes the phenomenon whereby after a primary pathogen exposure, a host more effectively fights a lethal secondary exposure (challenge) to the same pathogen. Conflicting evidence exists for immune priming in invertebrates, potentially due to heterogeneity across studies in the pathogen species tested, the antigen preparation for the primary exposure, and the phenotypic trait used to test for priming. To explore these factors, we injected with one of two bacterial species, or , which had either been heat-killed or inactivated with formaldehyde, or we injected a 1:1 mixture of the two inactivation methods. Survival and resistance (the inverse of bacterial load) were assessed after a live bacterial challenge. In contrast to our predictions, none of the primary exposure treatments provided a survival benefit after challenge compared to the controls. Resistance in the acute phase, i.e., 1 day post-challenge, separated into a lower- and higher-load group, however, neither group varied according to the primary exposure. In the chronic phase, i.e., 7 days post-challenge, resistance did not separate into two groups, and it was also unaffected by the primary exposure. Our multi-angled study supports the view that immune priming may require specific circumstances to occur, rather than it being a ubiquitous aspect of insect immunity.
宿主在初次接触病原体后，能更有效地应对同一病原体的致命二次接触（攻击）。关于无脊椎动物中的免疫预激发存在相互矛盾的证据，这可能是由于所测试的病原体种类、初次接触的抗原制剂以及用于测试预激发的表型特征在不同研究中存在异质性。为了探究这些因素，我们用两种细菌中的一种（或 ）进行注射，这些细菌要么经过热灭活，要么用甲醛灭活，或者我们注射两种灭活方法的1:1混合物。在活细菌攻击后评估存活率和抵抗力（细菌载量的倒数）。与我们的预测相反，与对照组相比，没有一种初次接触处理在攻击后提供生存优势。然而，在急性期，即攻击后1天，抵抗力分为低载量组和高载量组，但两组均不受初次接触的影响。在慢性期，即攻击后7天，抵抗力没有分为两组，也不受初次接触的影响。我们多角度的研究支持这样一种观点，即免疫预激发可能需要特定的情况才会发生，而不是昆虫免疫的一个普遍特征。
