Immunity

• The immune system is the body's defense against foreign substances.
• Antigens are molecules that stimulate an immune response, while antibodies are proteins produced by B cells to bind with antigens.
• T lymphocytes (T cells) play a role in cell-mediated immunity, which involves killing infected or cancerous cells directly.
• Antigens are molecules that stimulate an immune response, while antibodies bind to antigens on pathogens or abnormal cells.
• Immune responses can be innate (non-specific) or adaptive (specific).
• T lymphocytes (T cells) recognize antigen-presenting cells and can kill infected cells directly or indirectly through cytokines.
• Innate immunity includes physical barriers like skin and mucous membranes, as well as phagocytes, natural killer cells, complement proteins, interferons, and cytokines.
• Natural killer cells (NK cells) are T cells that can kill virus-infected cells without prior exposure to them.
• Natural killer cells destroy virus-infected cells without prior exposure.
• B lymphocytes produce antibodies specific to certain antigens.
• Phagocytosis involves engulfment and destruction of pathogens by phagocytes such as neutrophils and macrophages.
• Helper T cells activate other white blood cells such as cytotoxic T cells and B cells.
• Natural killer cells kill virus-infected cells and tumor cells without prior exposure.
• Cytotoxic T cells destroy abnormal cells through apoptosis.
• Macrophages engulf and destroy bacteria and other microorganisms.
• Adaptive immunity is specific to the type of invading organism and provides long-lasting protection against future infection.
• B lymphocytes (B cells) produce antibodies specific to certain antigens.
• Innate immunity includes physical barriers like skin and mucus membranes, as well as phagocytic cells like neutrophils and macrophages.
• The activated B cell undergoes differentiation into plasma cells that secrete large amounts of antibodies.
• Dendritic cells present foreign substances to helper T cells, activating the immune response.
• The immune system has two main types of responses: innate immunity and adaptive immunity.
• Antibody production is initiated when an antigen binds to the surface receptor on a B cell, leading to activation and clonal expansion.
• Cytokines are signaling molecules released by various types of white blood cells that regulate immune responses.
• Interferon is a protein produced by host cells in response to viral infection that inhibits the replication of viruses within the cell.
• Cytotoxic T cells directly attack infected host cells.
• Antibody production is initiated when an antigen binds to a B cell receptor on a B cell.
• The process of activating B cells involves the recognition of antigen by both B cell receptors and helper T cells.
• Complement system is a group of plasma proteins that work together with antibodies to enhance immune responses against foreign substances.
• Memory B cells are produced during this process and can quickly respond to subsequent exposures to the same antigen.
• Adaptive immune response involves the activation of B cells by helper T cells.
• Innate immunity provides immediate protection against foreign substances through physical barriers like skin and mucous membranes, chemical defenses like stomach acid and enzymes, and inflammation caused by histamine release from mast cells.
• Tumor necrosis factor (TNF) is a cytokine involved in inflammation and tumor destruction.
• T lymphocytes are involved in cell-mediated immunity, while B lymphocytes produce antibodies.
• Adaptive immunity involves specific recognition of pathogens through the interaction between antigens and lymphocytes (B and T cells).
• Adaptive immunity involves the recognition of pathogens by specialized white blood cells called lymphocytes.
• There are five classes of antibodies based on their structure and function.
• Antibody molecules have two identical heavy chains and two identical light chains held together by disulphide bonds.
• Each chain has variable regions at one end and constant regions at the other end.
• Antibody molecules have two identical heavy chains and two light chains held together by disulphide bonds.
• Memory B cells remain in circulation and can quickly respond to subsequent exposures to the same antigen.