IS

• Immunity is the condition of being resistant to infection.
• Immunity is divided into two branches: the natural immunity and the acquired immunity.
• Both the natural immunity and the acquired immunity are essential to maintain good health.
• The immune response involves interaction between B and T cells with the involvement of macrophages.
• B cells can act as antigen presenting cells, once activated by helper T cells, they can differentiate into plasma cells and memory cells.
• The plasma cells will produce antibodies that will attach to the current type of invader present.
• These invaders may be bacteria, viruses or fungi.
• Phagocytes prefer the pathogens that have been marked with antibodies.
• Memory cells are responsible for recognizing past infections.
• Immunity is the sum total of the defense mechanism of the human body to resist infectious diseases.
• The mechanisms of protection against infection and disease are primarily divided into two major categories: Natural/Innate/Non-specific Immunity and Acquired/Adaptive/Specific Immunity.
• Cell-mediated immunity involves the production of specifically reactive T-lymphocytes.
• Common routes of vaccine administration include intramuscular and subcutaneous, intradermal or intranasal, and oral.
• Natural active immunity develops during convalescence from an infection or recovery from a disease like chickenpox.
• Artificial passive immunity is obtained after injection of gamma globulin for the induction of an immune state, which is acquired by injection of immune sera or anti-toxin originally manufactured by a human or an animal.
• Artificial active immunity is obtained after vaccination, which is acquired by injection of synthetic or biological preparations such as vaccine, toxin, and toxoid.
• For the vaccines that kill microbes, they only induce humoral immunity.
• Natural passive immunity develops after the placental passage of antibody from mother to fetus.
• Humoral immunity involves antibody production.
• Passive immunization involves the administration of serum preparations, which are antitoxin, immune globulin or gamma globulin, and specific immune globulin.
• Active immunization involves the administration of vaccines to recipients, which involves the administration of killed or attenuated microorganisms or their products to the recipients.
• Natural/Innate/Non-specific Immunity is the ability of an individual to resist infection by means of normally present body functions.
• Acquired/Adaptive/Specific Immunity is a type of resistance that is characterized by specificity for each individual pathogen.
• Humoral (fluid) or biochemical factors include cytokines and complement systems.
• Granulocytic cells include neutrophils, which are the principal leukocyte associated with phagocytosis and localized inflammatory responses, and eosinophils, which are capable of killing parasites and produce major basic protein and Eosinophil cationic protein.
• Physical factors include intact skin, which is impervious to almost all organisms, and viscous mucus, which protects epithelial cells and traps invading pathogens.
• Monocytes are mononuclear cells.
• Immune processes under the second line of defense include phagocytosis, which is the associated cells are neutrophils, monocytes, and eosinophils, and inflammation, which is associated with basophils and mast cells.
• Biochemical factors include secretions or body fluids that flush microbes, very low pH of vagina and stomach that are not conducive for the growth of microorganisms, and miscellaneous defenses or physiologic factors such as pH, body temperature, oxygen tension, hormonal balance, and age.
• Basophils have granules that contain histamine and heparin and play a role in hypersensitivity reactions.
• Cellular components include phagocytic cells, which are capable of phagocytosis, and natural killer cells, which are cytotoxic lymphocytes that can kill tumors, virally infected cells, parasitic, fungal, and bacterial organisms.
• Natural immunity consists of pre-formed or rapidly formed components and is present at birth, provides non-specific responses, has an immediate response, and is not antigen specific.
• Acquired immunity is characterized by specificity for each individual pathogen, remembers prior exposure which results in a faster response, and is not antigen specific.
• The external defense system, also known as the first line of defense, consists of structural barriers that prevent most infectious agents from entering the body.
• The internal defense system, also known as the second line of defense, consists of internal components that promote inflammation and phagocytosis.
• B cells transform into plasma cells in the immune response, which make antibodies that bind to viral antigens.
• Advantages of active immunity include long term resistance, cell-mediated immunity, and prompt availability of large amounts of antibodies.
• Three stages of immune response are recognition, activation, and differentiation.
• Specific immunity is acquired through natural active infection, natural passive infection, artificial active vaccination, and artificial passive RhoGAM.
• Common examples of active immunity include convalescence, vaccination, exposure to microbial products, placental passage of antibody, and injection of antiserum or gamma globulin.