Analysis of Monocyte Cell Fate by Adoptive Transfer in a Murine Model of TLR7-induced Systemic Inflammation

Myeloid plasticity is a hallmark of the innate immune response to Toll-like receptor (TLR) activation. Here, we provide a protocol for monocyte cell fate tracking by adoptive transfer in the context of systemic inflammation induced by TLR7 activation, the principal innate immune receptor sensing viral RNA in mice. Defined monocyte subsets are isolated from the bone marrow of donor mice by cell sorting and adoptively transferred into the systemic circulation of congenic hosts, with or without concurrent activation of TLR7 via the topical application of the small molecule agonist, imiquimod, in a cream formulation that induces a systemic inflammatory response. Advantages are the precise definition of donor cell populations and resulting cell fate without the need for host conditioning in a model that recapitulates key aspects of the systemic inflammatory response to TLR7 stimulation.