Avian malaria and bird humoral immune response

• Published in: Malaria Journal
• Main Authors: Jessica Delhaye, Tania Jenkins, Olivier Glaizot, Philippe Christe
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2018
• Subjects: Keyhole limpet haemocyanin; Plasmodium relictum; Serinus canaria; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic; Keyhole
• Online Access: https://doi.org/10.1186/s12936-018-2219-3; https://doaj.org/article/894dc205d2d24aa3bf49c0b628ba4af0

Abstract Background Plasmodium parasites are known to impose fitness costs on their vertebrate hosts. Some of these costs are due to the activation of the immune response, which may divert resources away from self-maintenance. Plasmodium parasites may also immuno-deplete their hosts. Thus, infected individuals may be less able to mount an immune response to a new pathogen than uninfected ones. However, this has been poorly investigated. Methods The effect of Plasmodium infection on bird humoral immune response when encountering a novel antigen was tested. A laboratory experiment was conducted on canaries (Serinus canaria) experimentally infected with Plasmodium relictum (lineage SGS1) under controlled conditions. Birds were immune challenged with an intra-pectoral injection of a novel non-pathogenic antigen (keyhole limpet haemocyanin, KLH). One week later they were challenged again. The immune responses to the primary and to the secondary contacts were quantified as anti-KLH antibody production via enzyme-linked immunosorbent assay (ELISA). Results There was no significant difference in antibody production between uninfected and Plasmodium infected birds at both primary and secondary contact. However, Plasmodium parasite intensity in the blood increased after the primary contact with the antigen. Conclusions There was no effect of Plasmodium infection on the magnitude of the humoral immune response. However, there was a cost of mounting an immune response in infected individuals as parasitaemia increased after the immune challenge, suggesting a trade-off between current control of chronic Plasmodium infection and investment against a new immune challenge.