A functioning immune system is essential for survival, but even the sophisticated cellular and molecular…

The innate and adaptive immune responses compose the systemic immune system (affecting the whole body),…

Lymph is the watery fluid that bathes tissues and organs and contains protective white blood…

The adaptive immune system has a memory component that allows for a rapid and large…

Unlike B cells, T lymphocytes are unable to recognize pathogens without assistance. Instead, dendritic cells…

The adaptive, or acquired, immune response takes days or even weeks to become established—much longer…

The vertebrate, including human, immune system is a complex multilayered system for defending against external…

Viruses cause a variety of diseases in animals, including humans, ranging from the common cold…

A virus must “take over” a cell to replicate. The viral replication cycle can produce…

Figure 12.1 (a) This smallpox (variola) vaccine is derived from calves exposed to cowpox virus.…