Spleen mass as a measure of immune strength in mammals

Abstract

1. In studies of birds and their pathogens, spleen size has frequently been used to make inferences about immune system strength. However, the use of spleen size in mammals is more complicated because, in addition to having an immune function, the mammalian spleen is also a reservoir for red blood cells. 2.To assess the reliability of mammalian spleen mass as an indicator of immune activity, we quantified the white and red pulp mass by histology of spleens from shot red deer Cervus elaphus. We then analysed the relationships among spleen mass, the amounts of white and red pulp, and the deer's body condition relative to faecal counts of the nematode parasite Elaphostrongylus cervi. 3. White and red pulp mass were positively correlated so that an increase in spleen mass was a positive function of both components of the spleen. In male deer, which had significantly lower body condition and higher parasite loads than females, parasite counts were negatively correlated with spleen mass, white pulp mass, and red pulp mass. 4. Our findings suggest that (i) spleen mass in shot red deer is a reliable measure of white and red pulp content; and (ii) when looking at the red deer life history, which is greatly influenced by sex of the deer, splenic mass and white pulp mass could be used as reflections of immune system strength. 5. Future studies of mammalian spleens can contribute to the understanding of evolved strategies of immune response investment in mammals. However, determination of the white and red pulp spleen components using various sampling methods must be made prior to their application.

Immune response to aTrichinella spiralisinfection in house mice from lines selectively bred for high voluntary wheel running

“…Generally, increased spleen and liver masses are associated with a classic inflammatory response (Hart, 1988). Many studies have demonstrated that spleen mass is commonly negatively associated with overall body condition and positively correlated with parasite infection (Corbin et al, 2008;Cowan et al, 2009;Schulte-Hostedde and Elsasser, 2011). As seen previously (Swallow et al, 2005;Meek et al, 2009;Downs et al, 2012), spleen and liver masses were not significantly different between HR and C mice, and mini-muscle mice had heavier livers.…”

“…However, the spleen is often enlarged in organisms with parasitic infections, perhaps indicating heightened immune response caused by increased production/storage of lymphocytes and immunoglobulins. As the spleen is considered to be an immunologically important organ (Corbin et al, 2008;Cowan et al, 2009;Schulte-Hostedde and Elsasser, 2011), spleen mass is expected to increase with infection. Additionally, hematocrit is expected to be positively correlated with both infection (Meagher, 1998;Downs et al, 2012) and V · O2max performance.…”

Parasite diversity of disease-bearing rodents of Southeast Asia: habitat determinants and effects on sexual size dimorphism and life-traits

“…This was explained as an investment in the production and stockage of lymphocytes in the spleen in order to counteract potential infections (Møller et al, 1998). However, other studies have suggested that spleen mass reflects the host condition and therefore should be negatively related to parasite infection (Corbin et al, 2008;Lutermann and Bennett, 2008;Navarro-Gonzalez et al, 2011). However, these hypotheses are not mutually exclusive.…”

What does testosterone do for red deer males?

“…(ii) Evaluation of immunocompetence We used spleen mass as our measure of immunocompetence as (i) spleen tissue is involved both in humoral and cellular immune responses, (ii) it has previously been shown to correlate negatively with nematode parasite burden in the red deer ( Vicente et al 2007;Corbin et al 2008).…”