Figure 3.

Simplified Overview of Emerging Approaches for Discernment of Roles of Fc in Ab-mediated Immunity to Viruses. (A) In classical models, experimental animals (often mice) are challenged on day 0 with infectious virus, preceded (or sometimes followed) by intervention with active or passive immunization. (B) To disambiguate the collection of phenomena that only affect virions and their spread, and examine more closely the requirements for effective Fc-mediated effects against viral Ag-expressing cells, one can challenge mice instead with cells engineered to express viral Ags, somewhat mimicking prior models of tumor immunotherapy. See text and references for many of the potential complexities and opportunities in each step, including modified Abs, and highly modified mice.