naa a22 4500 528784536 20180924065517.0 cr unu---uuuuu 180924e20131022xx s 000 0 eng 10.3929/ethz-b-000074464 doi 10.1371/journal.pone.0078427 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/74464 Genotype-Specific vs. Cross-Reactive Host Immunity against a Macroparasite [Elektronische Daten] [Christian Rellstab, Anssi Karvonen, Katja-Riikka Louhi, Jukka; id_orcid 0000-0002-1731-727X Jokela] PLoS ONE Open access ethresearch Vertebrate hosts often defend themselves against several co-infecting parasite genotypes simultaneously. This has important implications for the ecological dynamics and the evolution of host defence systems and parasite strategies. For example, it can drive the specificity of the adaptive immune system towards high genotype-specificity or cross-reactivity against several parasite genotypes depending on the sequence and probability of re-infections. However, to date, there is very little evidence on these interactions outside mammalian disease literature. In this study we asked whether genotype-specific or cross-reactive responses dominate in the adaptive immune system of a fish host towards a common macroparasite. In other words, we investigated if the infection success of a parasite genotype is influenced by the immunization genotype. We reciprocally immunized and re-exposed rainbow trout (Oncorhynchus mykiss) to a range of genotypes of the trematode eye fluke Diplostomum pseudospathaceum, and measured infection success of the parasite. We found that the infection success of the parasite genotypes in the re-exposure did not depend on the immunization genotype. While immunization reduced average infection success by 31%, the reduction was not larger against the initial immunization genotype. Our results suggest significant cross-reactivity, which may be advantageous for the host in genetically diverse re-exposures and have significant evolutionary implications for parasite strategies. Overall, our study is among the first to demonstrate cross-reactivity of adaptive immunity against genetically diverse macroparasites with complex life cycles. Creative Commons Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0 ethresearch Rellstab Christian joint author Karvonen Anssi joint author Louhi Katja-Riikka joint author Jokela Jukka; id_orcid 0000-0002-1731-727X joint author PLoS ONE S.l. : Public Library of Science 8 (10), p. e78427 1932-6203 http://hdl.handle.net/20.500.11850/74464 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/74464 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Rellstab Christian joint author ETHRESEARCH 700 1- Karvonen Anssi joint author ETHRESEARCH 700 1- Louhi Katja-Riikka joint author ETHRESEARCH 700 1- Jokela Jukka; id_orcid 0000-0002-1731-727X joint author ETHRESEARCH 773 0- PLoS ONE S.l. : Public Library of Science 8 (10), p. e78427 1932-6203 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access