The document summarizes key components of the innate immune system. It describes how white blood cells like neutrophils, macrophages, and natural killer cells provide nonspecific defenses against pathogens. It also explains how mechanisms like inflammation, fever, complement activation, and toll-like receptors help the innate immune system recognize and respond to foreign threats. The innate system acts as the body's early warning system to initiate a protective response before the adaptive immune system mounts an antigen-specific response.

1. Resistance and the Immune System: Innate Immunity Chapter 19

2. Overview of Host Immune Defenses

12. Inflammation