Humoral immunity, mediated by antibodies, plays a crucial role in neutralizing extracellular bacteria and their toxins, preventing infection.

Neutrophils, a type of phagocytic white blood cell, are the first responders to infection, engulfing and destroying pathogens through phagocytosis.

IgM antibodies are the first line of defense against viral infections, providing immediate, albeit short-lived, protection.

Memory cells retain information about past infections, enabling a rapid and robust immune response upon re-exposure to the same pathogen.

Tumor necrosis factor-alpha (TNF-alpha) is a key cytokine involved in initiating and regulating the inflammatory response.

Cytotoxic T cells, also known as killer T cells, are responsible for eliminating virus-infected cells and cancerous cells.

Cell-mediated immunity, involving the activation of T cells and macrophages, is responsible for delayed hypersensitivity reactions, such as those seen in tuberculin skin tests.

Natural killer (NK) cells are cytotoxic lymphocytes that play a crucial role in eliminating virus-infected cells and tumor cells.

Innate immunity, including physical barriers, chemical mediators, and phagocytic cells, provides the first line of defense against pathogens at mucosal surfaces.

Interferons are cytokines that play a crucial role in inhibiting viral replication and activating immune cells.

Adaptive immunity, involving the activation and differentiation of lymphocytes, is responsible for generating memory cells that provide long-term protection against pathogens.

Dendritic cells are specialized antigen-presenting cells that capture, process, and present antigens to T cells, initiating the adaptive immune response.

Cell-mediated immunity, involving the activation of T cells and macrophages, plays a crucial role in defending against intracellular pathogens.

Complement proteins are a group of proteins that work together to activate the inflammatory response, enhance phagocytosis, and directly kill pathogens.

Adaptive immunity, involving the activation and differentiation of lymphocytes, provides long-term protection against pathogens through the generation of memory cells.