The ability to mount multiple immune responses simultaneously varies across the range of the tree swallow

Abstract

Variation in immune responses is an important part of life history variation. When correlations between multiple immune measures are reported, studies report different patterns. I tested whether the correlation between levels of immune response was consistent across a species range. The ability of tree swallows Tachycineta bicolor to simultaneously produce immune responses to both a humoral immune response and T-cell mediated local inflammation to PHA was tested at three sites that span the breeding range. Females in Tennessee maintained stronger PHA responses than did females in either New York or Alaska. In New York and Alaska, individuals that produced strong PHA responses produced low levels of antibodies to a humoral challenge of sheep red blood cells (SRBC). However, in Tennessee, individuals that showed strong local PHA inflammation also mounted strong responses to SRBC. Increasing daily daytime temperatures led to increased PHA response, but there were no differences in the effect of temperature among sites. These results indicate spatial and/or temporal variation occurs in the ability to produce multiple immune responses simultaneously; this pattern suggests important geographic (or temporal) differences in factors driving investment in immune activity. In addition, these results suggest that studies extrapolating results across populations should be careful to consider geographic variation in immune activity.

Variation in Haematological Indices and Immune Function During the Annual Cycle in the Great TitParus major

“…This finding may indicate a trade-off between different immune branches suggesting that when one part of the immune system is challenged the other part is downregulated. Such a trade-off was found in Tree Swallows Tachycineta bicolor (Ardia 2007). Individuals that mounted a strong response against phytohaemagglutinin, which stimulates the cellular and innate component of the immune system, had reduced humoral antibody response against sheep red blood cells.…”

“…Immune responses are extremely complex, reflecting the need to protect the host against a plethora of pathogens (Nelson et al 2002). Moreover, trade-offs between different immune branches can arise (Ardia 2007), and an increase in one measure may evoke a reduction in another. Second, the sampling period may be too short or sampling is too infrequent to describe seasonal changes in the physiological condition and immune activity effectively (e.g.…”

Joint associations of blood plasma proteins with overwinter survival of a large mammal

“…The interpretation of relationships between immunological and ecological variables is complicated by the possibility that within‐year associations between immune markers can vary with year of observation (e.g. Ardia ; Hegemann et al . ; Pigeon et al .…”

Costs of Mounting an Immune Response during Pregnancy in a Lizard

“…This hypothesis remains largely untested in wild populations, particularly in reptiles. Few ecological studies have assessed the relations between humoral and cellular immune components (Blount et al 2003;Ardia 2007). An earlier study, involving the common lizard (Meylan et al 2010), found a negative correlation between humoral and cellular response.…”