摘要
Antibodies are important in protection against some primary and most secondary viral infections. However, viruses have co-evolved with the immune system and might have adapted to the host's antibody response and in some cases might even subvert it. Here, Martin Bachmann and Rolf Zinkernagel summarize evidence that B cells use repetitiveness of viral surface antigens as a marker for foreignness, which plays an important role in the evolution of host-viral relationships.