CSF2 and viral infectious disease: Continuous sister-brother breeding of AKR/J mice led to the generation of several strains prone (SAMP) or resistant (SAMR) to develop an accelerated senescence.26 Among them, SAMP8 mice have been widely used as a model for geriatric and neurological disorders,27, 28, 29 and display several immune alterations: deficient CD4+ T-cell function, low IgG1 in sera, presence of auto-antibodies and impaired responses to viral infection and to granulocyte macrophage colony-stimulating factor (GM-CSF).2, 7, 30, 31, 32