Invasive species have dramatically expanded their range because of increasing globalization,and their adaptation to new environments and is hypothesized to result in phenotypic differences (e.g.immunity) between the original and invasive populations.The western house mouse (Mus musculus domesticus) ,which successfully spread across the world from Persia in the past centuries,is a suitable candidate for evolutionary studies.In the present study,we tested the hypothesis with laboratory outbred offspring of the wild-caught house mouse from Europe (France and Germany) and Persia (Iran) .We found that 1) the European mice had lower total leukocyte counts but higher immunoglobulin E concentration compared to their Persian counterparts; 2) the relative and absolute eosinophil counts of European mice were slightly higher than that of the Persian mice but monocytes behaved inversely,and 3) there were no significant differences in measured immunological parameters between European populations.We suggest that founder effects and environmental differences (e.g.helminth species richness) underlie our findings,but validation will be required.