Question

Pus is both a sign of infection and an indicator of immune defenses in action. Explain.

Short answer

Since pus comprises white blood cells, fluid, and cell debris, it is an indication of infection and immune response in motion. It signifies an active and partially effective inflammatory response against invading bacteria.

Step-by-step solution

Immune defense

A feature of the body's defense mechanism protects it against all invading microorganisms that might cause infection. Immunity is a type of immune protection that can be inherent (inborn) or acquired (learned). The immune system's strength determines the body's immunity.

Infection

Infection is a disorder that arises in the body and causes a change that makes a person feel uncomfortable and even pain. Pathogens such as viruses and other microorganisms cause infections by invading the host body cell.

Step 3: 

Pus is a fluid produced by the body when it is infected or inflamed. It is commonly referred to as purulent fluid. Extracellular fluid, inflammatory proteins, foreign pathogenic material (bacteria), and neutrophils make up the pus.

When a bacterial infection exists, pus (a complex mixture of bacteria), white blood cells (some dead, some living), and chemicals are released by both bacteria and WBCs, which may be poisonous or serve as messengers in the battle.