Immunogenetics as a tool to assess Hantavirus risk in wild rodents

Immunogenetics, the analysis of genetic polymorphisms in specific recognition and immune regulation, is at the core of the study of host-parasite coevolution. We present here a synthesis of our recent works based on immune gene polymorphism to illustrate the power of this approach in improving our knowledge of rodent / hantavirus interactions.
Two candidate genes (encoding Mx2 protein and β3 integrin) were first investigated at the inter-specific level. Sequence and/or expression polymorphism were compared among twenty murid species, some of them being reservoirs and some others being non reservoirs of hantaviruses. Our results showed that SNPs as well as patterns of selection acting on these genes differed between these rodent species and could mediate their susceptibility to hantaviruses.
Four candidate genes (Mx2 gene and three genes from the Major Histocompatibility Complex) were next analyzed among populations of bank voles (Myodes glareolus), the reservoir of Puumala virus (PUUV). We revealed the existence of positive associations between Mhc alleles and PUUV infection in one hand and negative relationships between Tnf-α or Mx2 expression levels and PUUV prevalence in the other hand. These results suggested that tolerance to PUUV could have evolved in endemic areas. Such tolerance could be selected in response to the costs of immune responses that are activated against PUUV.
We will conclude on the advantages to combine this immune gene candidate approach with more recent analyses based on genome scan, to deepen our investigation of this intra- and inter-specific variability of rodent tolerance / susceptibility to hantaviruses.