Layers of protection Intrinsic - Physical barriers ○ Skin mucous membranes - Secretions ○ Tears, sweat - Physical clearing ○ Mucous and cilia - pH ○ Stomach and vaginal - Microbiome ○ Compeditive inhibition ○ pvp Immune - Innate ○ Phagocytosis ○ Inflammation ○ Pattern recognition systems ○ Compliment ○ Cytokines, chemokines - Adaptive ○ Activated apc ○ Tcells ○ B cells ○ Complement ○ Cytokines