Analysis of MHC II (I-A/I-E) expression as a marker of APC activation
Expression of MHC Class II is an important regulator of APC function, being elevated upon activation and correlating with antigen presenting capacity, indicating immune cell maturation [28]. Analysis of the intensity of expression of the MHC class II marker I-A/I-E (referred to as MHC II) on lung APC subsets after RSV-RFP infection revealed significantly increased expression on cDC (Figure 4A), macrophages (Figure 4B) and B cells (Figure 4C) at 21 dpi, with macrophages also showing an earlier increase at 7 dpi (Figure 4B). Thus, the maturing impact of RSV infection on cDC and other APC subsets appeared long-lasting following resolution of clinical symptoms.