Avian malaria and bird humoral immune response

Jessica Delhaye,Olivier Glaizot,Philippe Christe,Tania Jenkins

doi:10.1186/s12936-018-2219-3

Jessica Delhaye, Olivier Glaizot + Show 2 more

Open Access

https://doi.org/10.1186/s12936-018-2219-3

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Abstract

BackgroundPlasmodium 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.MethodsThe 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).ResultsThere 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.ConclusionsThere 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.

Highlights

Plasmodium parasites are known to impose fitness costs on their vertebrate hosts
Avian malarial parasites can impose fitness costs on their vertebrate hosts and several studies have shown that infection can lead to decreased reproductive success [1], decreased survival [2] or increased telomere degradation [3]
Parasitaemia of infected canaries increased after the first immune challenge (Table 1B, Fig. 2)

Summary

Introduction

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. Avian malarial parasites can impose fitness costs on their vertebrate hosts and several studies have shown that infection can lead to decreased reproductive success [1], decreased survival [2] or increased telomere degradation [3]. Part of these costs may be mediated by the activation of the host immune response which may be engaged in several life history trade-offs with for example self-maintenance, reproduction and survival [4, 5]. Malarial parasites may impose an additional cost to their vertebrate host due to the depletion of Delhaye et al Malar J (2018) 17:77 immune functions which may increase host susceptibility to other parasites and diseases

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