Bolton Jai S, Klim Hannah, Wellens Judith, Edmans Matthew, Obolski Uri, Thompson Craig P
Peter Medawar Building for Pathogen Research, Oxford OX1 3SY, UK.
Department of Zoology, University of Oxford, Oxford OX1 3SZ, UK.
Vaccines (Basel). 2021 Jun 16;9(6):657. doi: 10.3390/vaccines9060657.
The antigenic drift theory states that influenza evolves via the gradual accumulation of mutations, decreasing a host's immune protection against previous strains. Influenza vaccines are designed accordingly, under the premise of antigenic drift. However, a paradox exists at the centre of influenza research. If influenza evolved primarily through mutation in multiple epitopes, multiple influenza strains should co-circulate. Such a multitude of strains would render influenza vaccines quickly inefficacious. Instead, a single or limited number of strains dominate circulation each influenza season. Unless additional constraints are placed on the evolution of influenza, antigenic drift does not adequately explain these observations. Here, we explore the constraints placed on antigenic drift and a competing theory of influenza evolution - antigenic thrift. In contrast to antigenic drift, antigenic thrift states that immune selection targets epitopes of limited variability, which constrain the variability of the virus. We explain the implications of antigenic drift and antigenic thrift and explore their current and potential uses in the context of influenza vaccine design.
抗原漂移理论认为，流感病毒是通过突变的逐渐积累而进化的，这会降低宿主对先前毒株的免疫保护。流感疫苗就是在抗原漂移的前提下设计的。然而，流感研究的核心存在一个悖论。如果流感主要通过多个表位的突变进化，那么多种流感毒株应该会同时传播。如此众多的毒株会使流感疫苗很快失效。相反，每个流感季节主导传播的是单一或数量有限的毒株。除非对流感的进化施加额外的限制，否则抗原漂移无法充分解释这些现象。在这里，我们探讨对抗原漂移的限制以及一种与之竞争的流感进化理论——抗原节约。与抗原漂移相反，抗原节约理论认为免疫选择针对的是变异性有限的表位，这限制了病毒的变异性。我们解释了抗原漂移和抗原节约的含义，并探讨了它们在流感疫苗设计背景下的当前及潜在用途。
