anaphy (2)

• Antigens are molecules that trigger an immune response, while antibodies bind to antigens on pathogens or abnormal cells.
• The immune system is the body's defense against foreign substances.
• Lymphocytes are white blood cells involved in immunity.
• The innate immune system is the first line of defense against infection and includes physical barriers such as skin and mucous membranes, phagocytes (macrophages), natural killer cells, complement proteins, and cytokines.
• Immunity refers to protection from infectious diseases.
• Active immunity involves exposure to a disease-causing agent (antigen) and subsequent production of protective antibodies by B lymphocytes.
• B lymphocytes produce antibodies specific to certain antigens.
• Innate immunity involves recognition of conserved structures called PAMPS by pattern recognition receptors (PRRs) expressed on various cell types.
• Passive immunity occurs when preformed antibodies enter the bloodstream through injection or placental transfer.
• T lymphocytes can kill infected cells directly (cytotoxic T cells) or activate other immune responses (helper T cells).
• Adaptive immunity provides specific protection against foreign substances through B-cell mediated humoral responses and T-cell mediated cellular responses.
• Natural killer cells attack cancerous cells without prior exposure.
• Adaptive immunity involves lymphocytes and provides specific protection against pathogens through memory B and T cells.
• Antibody molecules have two identical halves called Fab fragments that bind to antigens on pathogens or toxins.
• T cells recognize infected host cells and destroy them directly or indirectly via cytotoxic T cells.
• Passive immunity occurs when preformed antibodies enter the body through injection or placental transfer.
• Active immunization involves exposure to a weakened form of a disease-causing agent, while passive immunization involves receiving preformed antibodies.
• B cells produce antibodies that can neutralize viruses and bacteria by binding to their surface antigens.
• Vaccination is a type of active immunization where a small amount of dead or weakened microorganisms is injected into the body to stimulate an immune response without causing illness.
• Herd immunity occurs when enough people in a population have been vaccinated to prevent the spread of a contagious disease.
• Artificial active immunity is achieved through vaccinations with weakened or dead forms of pathogens, resulting in temporary immunity.
• Each half of the antibody has a variable region that can be different depending on the type of antigen it recognizes.
• Antibody-mediated immunity involves binding of antibodies to pathogens, leading to their destruction via opsonization, neutralization, agglutination, or activation of the complement cascade.
• The constant region of the antibody remains unchanged regardless of the antigen recognized.
• The complement system consists of proteins that work together to destroy foreign substances such as bacteria and viruses.
• Cytokines are signaling molecules produced by activated T cells that coordinate the immune response.
• T helper cells activate other immune system components such as B cells, macrophages, and cytotoxic T cells.
• C3b binds to the surface of the pathogen, marking it for destruction by phagocytes.
• Cell-mediated immunity (CMI) involves T lymphocytes recognizing foreign proteins on the surfaces of invading cells and destroying them directly.
• Cellular (or cell-mediated) immunity involves T cells attacking infected host cells directly.
• Complement components are activated by antibodies bound to pathogens, forming complexes called C3 convertases.
• Epitope refers to any part of an antigen recognized by an antibody.
• Cytokines are signaling molecules produced by various types of white blood cells that play important roles in regulating inflammation, tissue repair, and immune responses.
• Antibody-mediated immunity (ADCC) involves antibodies attaching to target cells and activating other components of the immune system to destroy them.
• Antibodies bind to specific epitopes (antigenic determinants) on the surface of foreign substances.
• Macrophages engulf and digest invading microorganisms through phagocytosis.
• T killer cells directly attack infected host cells.
• Activation of the classical pathway requires the presence of antibodies specific to the target molecule.
• T helper cells play a crucial role in activating B cells and other immune cells.
• Natural killer cells recognize abnormalities in cell surfaces and kill them without prior sensitization.