Further characterisation of cytokines in macropod marsupials: IL-10 and IL-10Δ3

- Macropod IL-10 maintains the five exon structure seen in eutherian mammals.
- IL-10 sequence and expression is confirmed in the tammar and rufous hare-wallabies.
- Tammar wallaby expresses an isoform of IL-10 in which the third exon is absent.
- The expression of IL-10 and its isoform occurs differentially in rufous hare-wallaby tissues.

Interleukin-10 is an immunomodulatory cytokine that has been implicated, along with IFN-γ, in the disease sequelae of mycobacterial infection. In order to investigate the role of IL-10 in marsupial disease models we sequenced and characterised the IL10 gene in the tammar wallaby (Macropus eugenii) and rufous hare-wallaby (Lagorchestes hirsutus). An isoform IL-10Δ3, in which an in-frame deletion of exon 3 occurs, was discovered in both macropod species. Analysis of wallaby and other reported marsupial IL-10 homologs suggests that while marsupial IL-10 is comparable to that of human IL-10, the predicted IL-10Δ3 protein may play a more complicated role in the modulation of IL-10-directed responses. Expression of the canonical gene and splicing variant was confirmed in both wallabies, and the rufous hare-wallaby showed differential expression across lymph node, spleen and liver, with isoform expression detected in the lymph node. This characterisation and expression of IL-10 in de novo tissues provides a basis for further study into the role of IL-10 in disease models in marsupials.