In this AADCRC program renewal, we will focus on three critical and understudied innate immune factors and how they impact viral infections in asthma: the anionic phospholipids of surfactant (palmitoyl- oleoyl-phosphatidylglycerol, POPG, and phosphatidylinositol, PI), Toll interacting protein (Tollip), and surfactant protein-A (SP-A). Because these mediators have complementary functions to modulate inflammation and immunity in asthma and infection, we propose three interrelated, synergistic, self-standing projects to investigate how these mediators orchestrate novel innate immune responses associated with viral infections in asthma. We will study three viruses with a spectrum of effects in airway disease, and determine how innate responses protect against them. Specifically, we will focus on rhinovirus C (RV-C), a known exacerbator of asthma that can cause severe disease; influenza A, a virus whose effect in asthma remains ambiguous and SARS-CoV-2, a virus that can cause severe lung disease, but for which asthma may not be a risk factor, and may in fact confer protection. We show innovative preliminary data indicating that 1) POPG, PI and SP-A attenuate RV-C infection; 2) Tollip exhibits protective effects as it is required for IL-13 to generate soluble ST2 that in turn attenuates the effects of IL-33 during influenza A infection; and 3) SP-A and type 2 cytokines confer protection in the effector and initiation phases of SARS-CoV-2 infection in asthma by inhibiting the expression and function of ACE2, the SARS-CoV-2 receptor, through effects upon transcription, receptor binding and downstream pro-inflammatory signaling. Thus, all these innate immune components appear to protect against viral infections in asthma. Our exciting preliminary data underpin our program’s overall hypothesis that POPG/PI, Tollip and SP-A function as unique immune modulators that attenuate the impact of specific viral infections (RV-C, Influenza A and SARS-CoV-2) in type-2 asthma. Therefore, supplementation of functional POPG/PI, SP-A and the IL-33 decoy receptor sST2 may be novel strategies against asthma exacerbations due to viral infections. Project 1 will critically test the activity of POPG/PI and SP- A supplementation as a novel molecular tool for disrupting infections due to RV-C, a virus known to exacerbate asthma. Project 2 will determine how Tollip protects against viral exacerbations caused by influenza A in asthma through inhibition of IL-33 signaling. Project 3 will determine how type-2 cytokines and SP-A synergize to protect against SARS-CoV-2 infection through inhibition of ACE2-mediated infection and IL-6 signaling pathways. We also include an Administrative Core and a Clinical Core, both which serve all projects equally. We build upon productive collaborations of over 20 years on innate molecular mechanisms underlying the interaction between type 2 inflammation and viral exacerbations of asthma. The strong synergy among our three projects will accelerate ...