Feliform carnivores have a distinguished constitutive innate immune response

Abstract

Determining the immunological phenotype of endangered and threatened populations is important to identify those vulnerable to novel pathogens. Among mammals, members of the order Carnivora are particularly threatened by diseases. We therefore examined the constitutive innate immune system, the first line of protection against invading microbes, of six free-ranging carnivore species; the black-backed jackal (Canis mesomelas), the brown hyena (Hyena brunnea), the caracal (Caracal caracal), the cheetah (Acinonyx jubatus), the leopard (Panthera pardus) and the lion (Panthera leo) using a bacterial killing assay. The differences in immune responses amongst the six species were independent of their foraging behaviour, body mass or social organisation but reflected their phylogenetic relatedness. The bacterial killing capacity of black-backed jackals, a member of the suborder Caniformia, followed the pattern established for a wide variety of vertebrates. In contrast, the five representatives of the suborder Feliformia demonstrated a killing capacity at least an order of magnitude higher than any species reported previously, with a particularly high capacity in caracals and cheetahs. Our results suggest that the immunocompetence of threatened felids such as the cheetah has been underestimated and its assessment ought to consider both innate and adaptive components of the immune system.

Handling Stress and Sample Storage Are Associated with Weaker Complement-Mediated Bactericidal Ability in Birds but Not Bats

“…However, this result should encourage future comparative studies of the temperature dependence of complement between hibernating and nonhibernating species of bats and rodents to assess whether torpor is associated with the evolution of enzyme resiliency pertinent to antibacterial defenses. While we restricted our analysis to small-bodied endotherms to control for body mass and evolutionary history, broader comparative analyses could also assess whether this result represents a difference between bats and birds or between birds and mammals more generally, as a similar resilience of BKA to storage has been reported for some carnivores (Flies et al 2016;Heinrich et al 2016).…”

“…However, such measures of immune defense have not been examined across these orders, primarily as the assay must be optimized on a per-species basis to identify a sample dilution that yields average killing of approximately 50% (French and Neuman-Lee 2012). Direct comparison of the BKA between species therefore relies on using the same dilution factor across species (e.g., Matson et al 2006;Martin et al 2007) or serially diluting all samples in a study (Heinrich et al 2016). Alternatively, comparison of the dilution killing curve across species can also facilitate cross-species analyses when such data are available (Heinrich etal.2016).…”

Cheetahs have a stronger constitutive innate immunity than leopards

“…The method was previously described in detail in ref. 102. Briefly, serum samples were serially diluted with phosphate-buffered-saline (PBS), resulting in eight dilutions from 1:2 to 1:265.…”

Predictors and immunological correlates of sublethal mercury exposure in vampire bats

“…Test samples were run in 22 µl duplicates and challenged with 5 µl of a 10 4 bacteria ml −1 solution in PBS. We prepared tryptic soy broth (TSB; Bacto, BD) 2 days prior to each assay [ 57 ] and added 125 µl TSB to each well. Optical density (OD) was measured at 340 nm to determine background OD prior to bacterial growth and again after incubation for 12 h at 37°C.…”