| Response time | System | Mechanisms |
|---|---|---|
| Early ( | Innate, nonspecific (first line) | Barrier (skin and lining of organs) |
| Dryness, low pH | ||
| Mucus | ||
| Lysozyme, defensins | ||
| Middle (> | Innate, nonspecific (second line) | Inflammation |
| Phagocytosis | ||
| Natural killer cells | ||
| Complement system | ||
| Interferons | ||
| Late (> 96 hr) | Adaptive, specific | Humoral immunity (antibodies from B cells) |
| Cellular immunity (T cells) |