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Immune response varies with rate of dispersal in invasive cane toads (Rhinella marina).

Brown GP, Shine R - PLoS ONE (2014)

Bottom Line: Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin.Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another.The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia.

ABSTRACT
What level of immunocompetence should an animal maintain while undertaking long-distance dispersal? Immune function (surveillance and response) might be down-regulated during prolonged physical exertion due to energy depletion, and/or to avoid autoimmune reactions arising from damaged tissue. On the other hand, heightened immune vigilance might be favored if the organism encounters novel pathogens as it enters novel environments. We assessed the links between immune defense and long-distance movement in a population of invasive cane toads (Rhinella marina) in Australia. Toads were radio-tracked for seven days to measure their activity levels and were then captured and subjected to a suite of immune assays. Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin. Baseline and post-stress corticosterone levels were unrelated to distance moved. Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another. This pattern suggests that sustained activity is accompanied by trade-offs among immune components rather than an overall down or up-regulation. The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

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Related in: MedlinePlus

Relationship between a conglomerate immune measure and distance moved.Immune PC1 values of individual cane toads regressed on the total distances moved by those animals during seven days of prior radio-tracking. Positive values of PC1 indicate toads with poor bacteria-killing and phagocytosis scores, low neutrophil levels, and a large skin-swelling response to phytohemagglutinin.
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pone-0099734-g006: Relationship between a conglomerate immune measure and distance moved.Immune PC1 values of individual cane toads regressed on the total distances moved by those animals during seven days of prior radio-tracking. Positive values of PC1 indicate toads with poor bacteria-killing and phagocytosis scores, low neutrophil levels, and a large skin-swelling response to phytohemagglutinin.

Mentions: The first three PCs from the analysis explained 70% of the variation among our 14 measures of immune function (Table 5). PC1 showed heavy loadings on all variables except for the BKA index for O. anthropi, and levels of corticosterone and lymphocytes. Positive values of PC1 described toads with strong PHA responses, poor bacteria-killing and phagocytic abilities and low neutrophil concentrations. Using the three PC’s as independent variables in multiple regression revealed that PC1 was positively related to distance moved (Table 6, Fig. 6) but not to a toad’s sex or body size (Table 6). PC2 and PC3 were not significantly related to any of the explanatory variables (Table 6).


Immune response varies with rate of dispersal in invasive cane toads (Rhinella marina).

Brown GP, Shine R - PLoS ONE (2014)

Relationship between a conglomerate immune measure and distance moved.Immune PC1 values of individual cane toads regressed on the total distances moved by those animals during seven days of prior radio-tracking. Positive values of PC1 indicate toads with poor bacteria-killing and phagocytosis scores, low neutrophil levels, and a large skin-swelling response to phytohemagglutinin.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061023&req=5

pone-0099734-g006: Relationship between a conglomerate immune measure and distance moved.Immune PC1 values of individual cane toads regressed on the total distances moved by those animals during seven days of prior radio-tracking. Positive values of PC1 indicate toads with poor bacteria-killing and phagocytosis scores, low neutrophil levels, and a large skin-swelling response to phytohemagglutinin.
Mentions: The first three PCs from the analysis explained 70% of the variation among our 14 measures of immune function (Table 5). PC1 showed heavy loadings on all variables except for the BKA index for O. anthropi, and levels of corticosterone and lymphocytes. Positive values of PC1 described toads with strong PHA responses, poor bacteria-killing and phagocytic abilities and low neutrophil concentrations. Using the three PC’s as independent variables in multiple regression revealed that PC1 was positively related to distance moved (Table 6, Fig. 6) but not to a toad’s sex or body size (Table 6). PC2 and PC3 were not significantly related to any of the explanatory variables (Table 6).

Bottom Line: Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin.Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another.The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, University of Sydney, Sydney, New South Wales, Australia.

ABSTRACT
What level of immunocompetence should an animal maintain while undertaking long-distance dispersal? Immune function (surveillance and response) might be down-regulated during prolonged physical exertion due to energy depletion, and/or to avoid autoimmune reactions arising from damaged tissue. On the other hand, heightened immune vigilance might be favored if the organism encounters novel pathogens as it enters novel environments. We assessed the links between immune defense and long-distance movement in a population of invasive cane toads (Rhinella marina) in Australia. Toads were radio-tracked for seven days to measure their activity levels and were then captured and subjected to a suite of immune assays. Toads that moved further showed decreased bacteria-killing ability in their plasma and decreased phagocytic activity in their whole blood, but a heightened skin-swelling response to phytohemagglutinin. Baseline and post-stress corticosterone levels were unrelated to distance moved. Thus, long-distance movement in cane toads is associated with a dampened response in some systems and enhanced response in another. This pattern suggests that sustained activity is accompanied by trade-offs among immune components rather than an overall down or up-regulation. The finding that high mobility is accompanied by modification of the immune system has important implications for animal invasions.

Show MeSH
Related in: MedlinePlus