Final answer:
Cytokines are bioactive proteins released by immune cells to manage the body's response to infection, triggering inflammation, enhancing chemotaxis, and directly combating pathogens to protect the host from tissue damage.
Step-by-step explanation:
Cytokines are crucial for protecting the host against tissue damage during immune responses to infection. These chemical messengers assist in coordinating the body's defense mechanisms. Helper T cells release cytokines to activate both the adaptive and nonadaptive immune systems. Cytokines trigger inflammation, enhance chemotaxis, and directly inhibit pathogen growth.
When tissue injury or infection occurs, cytokines and other inflammatory molecules like histamines are produced by host cells. They cause dilation and increased permeability of capillaries, resulting in an influx of immune cells and blood constituents that help to fight infection and repair damaged tissue. The release of cytokines also initiates a positive feedback loop that amplifies the immune response.
Interferons, a specific class of cytokines, are released by infected cells to warn neighboring uninfected cells about a viral invasion, stimulating these cells to produce substances that hinder viral replication. Another class, interleukins, are largely produced by immune system cells and coordinate the body's defenses against pathogens. This array of cytokines serves not only to eliminate pathogens but also to regulate the immune response, mitigating potential tissue damage during infection.