Biology-In-Human-Welfare-Human-Health-And-Disease-2

Immunity:

Defense against pathogens (bacteria, viruses, fungi).

Innate and acquired components.

Crucial for preventing infections and fighting diseases.

Interferons:

Signaling proteins during viral infections.

Alert neighboring cells.

Activate antiviral defenses.

Limit viral spread.

Cells of Acquired Immunity:

B cells produce antibodies.

T cells have various immune functions.

Specific and targeted defense.

Antibodies:

Produced by B cells.

Bind to antigens (foreign substances).

Neutralize and mark pathogens for destruction.

Essential in clearing infections.

Cell-Mediated Immunity:

Mediated by T cells.

Recognize and attack infected cells.

Produce cytokines.

Coordinate immune response.

Active vs. Passive Immunity:

Active: Immune response to antigen, long-lasting.

Passive: Transfer of pre-formed antibodies or cells, immediate but temporary.

Vaccination:

Preventive measure.

Introduce harmless antigens.

Stimulate immune system.

Forms memory for future protection.

Crucial for disease control and prevention.