Does baseline innate immunity change with age? A multi-year study in great tits

Abstract

Throughout their life animals progressively accumulate mostly detrimental changes in cells, tissues and their functions, causing a decrease in individual performance and ultimately an increased risk of death. The latter may be amplified if it also leads to a deterioration of the immune system which forms the most important protection against the permanent threat of pathogens and infectious diseases. Here, we investigated how four baseline innate immune parameters (natural antibodies, complement activity, concentrations of haptoglobin and concentrations of nitric oxide) changed with age in free-living great tits (Parus major). We applied both cross-sectional and longitudinal approaches as birds were sampled for up to three years of their lives. Three out of the four selected innate immune parameters were affected by age. However, the shape of the response curves differed strongly among the innate immune parameters. Natural antibody levels increased during early life until mid-age to decrease thereafter when birds aged. Complement activity was highest in young birds, while levels slightly decreased with increasing age. Haptoglobin levels on the other hand, showed a linear, but highly variable increase with age, while nitric oxide concentrations were unaffected by age. The observed differences among the four studied innate immune traits not only indicate the importance of considering several immune traits at the same time, but also highlight the complexity of innate immunity. Unraveling the functional significance of the observed changes in innate immunity is thus a challenging next step.

Immunosenescence in wild animals: meta‐analysis and outlook

“…Depicted are phylogenetic relatedness on the left, scientific names for all species included (blue = data collected in wild population, red = data collected in captive population), and for each species the number of effects in each main component of the immune system and the relevant references. References: 1: (Lindsay et al ); 2: (Beirne et al ); 3: (Mazzaro et al ); 4: (Mellish et al ); 5: (Schneeberger et al ); 6: (Cheynel et al ); 7: (Graham et al ); 8: (Nussey et al ); 9: (Watson et al ); 10: (Grandoni et al ); 11: (Ezenwa & Jolles ); 12: (Ahmad et al ); 13: (Abolins et al ); 14: (Nehete et al ); 15: (Nehete et al ); 16: {Castro:2015hz}; 17: (Cicin‐Sain et al ); 18: (Čičin‐Šain et al ); 19: (Coe & Ershler ); 20: (Coe et al ); 21: (Ershler et al ): 22: (Higashino et al ): 23: (Eichberg et al ); 24: (Jayashankar et al ); 25: (Setchell et al ); 26: (Chakrabarti et al ); 27: (Sharma et al ); 28: (Massot et al ); 29: (Richard et al ); 30: (Madsen et al ); 31: (Ujvari & Madsen ); 32: (Ujvari & Madsen ); 33: (Sparkman & Palacios ); 34: (Zimmerman et al ); 35: (Zimmerman et al ); 36: (Zimmerman et al ); 37: (Groffen et al ); 38: (Lavoie et al ); 39: (Alonso‐Alvarez et al ); 40: (Hill et al ); 41: (Counihan & Hollmén ); 42: (Neggazi et al ); 43: (Terrón et al ); 44: (Apanius & Nisbet ); 45: (Lozano & Lank ); 46: (Lozano & Lank ); 47: (Nebel et al ); 48: (Torres & Velando ); 49: (Haussmann et al ); 50: (Lecomte et al ); 51: (Catry et al ); 52: (Wilcoxen et al ); 53: (Vermeulen et al ); 54: (Møller & Haussy ); 55: (Saino et al ); 56: (Palacios ...…”

Coupling lifespan and aging? The age at onset of body mass decline associates positively with sex-specific lifespan but negatively with environment-specific lifespan

“…For example, physiological traits such as metabolic rate, the immune system and resistance to oxidative stress decline with age within individuals in free-living great tits Parus major (e.g. Bouwhuis et al, 2011;Bize et al, 2014;Vermeulen et al, 2017). Great tits also show declines in residual reproductive value and hence body mass declines may have evolutionary potential (Bouwhuis et al, 2012).…”

Immune parameters in two different laying hen strains during five production periods

“…Changes in number and function of immune cells within blood, lymphatic, and other tissues throughout life are described for many vertebrate species including birds ( Haussmann et al, 2005 ; Lavoie, 2005 ; Lavoie et al, 2007 ; Koutsos and Klasing, 2014 ; Simon et al, 2015 ; Vermeulen et al, 2017 ; Alkie et al, 2019 ). The most conspicuous changes are represented by the ontogeny of the immune system during fetal development and childhood, resulting in a fully competent immune system ( Dowling and Levy, 2014 ; Simon et al, 2015 ), as well as by the so-called immunosenescence leading to higher disease susceptibility in aging individuals ( Torroba and Zapata, 2003 ; Lavoie, 2005 ; Dowling and Levy, 2014 ; Simon et al, 2015 ).…”