Granulocyte/Macrophage Colony-Stimulating Factor-Derived Macrophages Exhibit Distinctive Early Immune Response to Lymphocytic Choriomeningitis Virus Infection

Granulocyte/macrophage colony-stimulating factor (GM-CSF) and macrophage CSF (M-CSF) modulate differentiation and immune functions of macrophages (M phi). Our aim was to evaluate how different M phi differentiation conditions influence the M phi response to virus infection. To address this, we differentiated bone marrow-derived M phi in either GM-CSF or M-CSF and measured the cytokine responses to two different strains of lymphocytic choriomeningitis virus (LCMV) (clone 13; Cl13 or Armstrong; ARM). GM-CSF M phi infected with either LCMV-ARM or -Cl13 produced more IL-6 than M-CSF M phi, whereas M-CSF M phi generated more IL-10 than GM-CSF M phi. Interestingly, in M-CSF M phi, LCMV-ARM induced more IL-10 production than Cl13. However, we could not detect any IL-12p70 or IL-23 after infection from either cell types. We also observed that GM-CSF M phi was more efficient than M-CSF M phi in supporting antigen-specific CD8(+) T cell proliferation. Taken together, our data demonstrate that GM-CSF and M-CSF M phi differ in how they respond to viral infection by their production of different cytokines, and their support for CD8(+) T cell proliferation.