Innate and Adaptive Immune Responses

Understanding Adaptive Immunity

The human immune system consists of two key branches: innate immunity and adaptive immunity. While innate immunity provides immediate but non-specific defense, adaptive immunity ensures targeted responses, memory formation, and long-term protection.

Key Characteristics of Adaptive Immunity

• Specificity: Adaptive immunity targets specific pathogens through antigen recognition.
• Memory: The immune system remembers past infections, allowing for faster response upon re-exposure.
• Diversity: It can generate numerous antigen receptors to recognize various pathogens.
• Self-tolerance: Prevents immune cells from attacking the body’s own tissues.

Major Components of Adaptive Immunity

Adaptive immunity is primarily mediated by:

• B lymphocytes (B cells): Responsible for humoral immunity by producing antibodies.
• T lymphocytes (T cells): Central to cellular immunity, including helper and cytotoxic T cells.
• Antigen-presenting cells (APCs): Such as dendritic cells, which present antigens to T cells.

How Adaptive Immunity Functions

When a pathogen enters the body, antigen-presenting cells process and present its antigens to T cells. This activation triggers:

• Humoral response: B cells differentiate into plasma cells, producing pathogen-specific antibodies.
• Cell-mediated response: Cytotoxic T cells attack infected cells, while helper T cells support immune functions.

Clinical Relevance

Adaptive immunity is crucial for vaccine development, autoimmune disease management, and immunotherapy in cancer treatment. Understanding its mechanisms aids in improving medical strategies against infectious diseases.