Cutaneous Immune Activity, but Not Innate Immune Responsiveness, Covaries with Mass and Environment in Nestling House Wrens (Troglodytes aedon)

Abstract

Immunological measures are increasingly being applied to ecological and evolutionary studies of wild vertebrates, yet frequently it is not clear how condition and environmental factors correlate with various immune parameters. We used mixed-model ANOVA to examine the effects of several measures of condition (both morphological and physiological) and environmental factors on two measures of immune responsiveness in nestling house wrens (Troglodytes aedon L.) to test the hypothesis that nestlings in good condition mount stronger immune responses than those in poor condition. Based on previous studies, we predicted that the innate bactericidal response would be less likely to be affected by condition-related factors than the cutaneous response, which includes both innate and the more costly adaptive components. Both cutaneous immune activity (i.e., phytohaemagglutinin [PHA] response) and innate immune responsiveness (i.e., plasma bactericidal activity) varied significantly among broods. Nestling PHA response was significantly influenced by year, mass, and the time of day that the challenge was administered. However, besides nest of origin, no other variable examined had a significant effect on bactericidal activity. Morphological condition, assessed as body mass adjusted for structural size, differed significantly among nests and years and was positively correlated with hematocrit but not plasma albumin/gamma-globulin proteins, indicating that these are measures of different aspects of health state.

Field Investigation of Innate Immunity in Passerine Birds in Suburban Chicago, Illinois, Usa

“…Additionally, Whiteman et al (2006) found that ectoparasite abundance on the Galapagos Hawk (Buteo galapagoensis) was negatively correlated with natural antibody titers, as measured by the hemolysis-hemagglutination assay. The lack of correlation between constitutive innate immunity and condition indices observed in this study is consistent with previous studies in birds (Palacios et al, 2009;Forsman et al, 2010), which suggest that the innate branch of the immune system is less sensitive to body condition than adaptive immunity. Additionally, anthropogenic food availability to urban birds is well known (Chamberlain et al, 2009), which might suggest that the birds measured here were not energetically limited, resulting in a minimal trade-off with immune function.…”

“…In particular, the assay measures different humoral and cellular components of constitutive innate immunity, which represents an organism's first defense against invading pathogens (Matson et al, 2005). Microbicidal assays have been used to study differences in constitutive innate immunity among vertebrate species (Matson et al, 2006a, b) and under different environmental conditions (Allen et al, 2009;Zimmerman et al, 2010), physiologic conditions (Forsman et al, 2010), and infection profiles (Wilcoxen et al, 2010b;Beechler, pers. comm.…”

Sex-Specific Effects of High Yolk Androgen Levels on Constitutive and Cell-Mediated Immune Responses in Nestlings of an Altricial Passerine

“…These common results in males could be interpreted on the light of common components in the innate and adaptive axes of the immune system (Forsman et al 2010;Vinkler et al 2010). In fact, some studies have shown that the PHA swelling response is an integration of both specific and induced immunity and also of constitutive and nonspecific immunity (Martin et al 2006a;Salaberria et al 2013).…”

Impacts of Short-Term Food Restriction on Immune Development in Altricial House Sparrow Nestlings

“…A food-restriction study in nestling sand martins showed that trade-offs between growth and phytohemagglutinin (PHA) skin-swelling response (which involves both induced innate and adaptive cell-mediated immune components; Martin et al 2006) occurred when resources were experimentally limited (Brzęk and Konarzewski 2007). Several correlational studies of young birds showed a positive relationship between body mass or condition and magnitude of PHA skin-swelling response (Saino et al 1997;Soler et al 1999;Alonso-Alvarez and Tella 2001;Hoi-Leitner et al 2001;Chin et al 2005;Snoeijs et al 2005;Martin et al 2006;Martín-Vivaldi et al 2006;Forsman et al 2010). However, in some studies, a positive correlation was not observed when young birds were well fed, indicating a threshold for the resource dependence of the PHA response (AlonsoAlvarez and Tella 2001; Chin et al 2005;Snoeijs et al 2005;Martín-Vivaldi et al 2006).…”