Which mediators may be increased within 72 hours after an initial infection?

The correct option highlights mediators that show increased levels within 72 hours following an initial infection. During the early phase of an immune response, particularly in the innate immunity stage, neutrophils and macrophages are crucial as they migrate to the site of infection to engulf pathogens and debris. This rapid recruitment is part of the body's immediate response to infection.

Additionally, complement proteins are activated quickly to tag pathogens for destruction and facilitate opsonization, enhancing phagocytosis. Fibrinogen is another acute-phase reactant that increases during infection; it plays a role in forming clots and also acts as a substrate for the formation of fibrin at the site of inflammation. C-reactive protein (CRP) is also an acute-phase protein synthesized by the liver and elevated in response to inflammatory cytokines; it serves as a marker of inflammation and enhances opsonization, making pathogens more recognizable to immune cells.

The combination of these mediators effectively represents the body's response in the early stages of an infection, highlighting both innate immune components and acute-phase reactants that facilitate the propagation of the immune response.