Acquired Immunity Overview

Acquired or Adaptive Immunity

• Resistance based on specific responses to eliminate a foreign substance
• It can be cellular (CMI) or humoral (HMI)
• Includes T cells, B cells, antibodies, and cytokines
• T cells mature in the thymus and provide help to B cells and other phagocytic cells
• B cells mature in the bone marrow and differentiate into plasma cells that produce antibodies
• Antibodies are responsible for killing virally infected target cells

Characteristics of Adaptive Immunity

• Specificity for each individual pathogen or microbial agent
• Ability to remember a prior exposure
• Increased response to a pathogen upon repeated exposure

Types of T Cells

• Helper T cells coordinate immune responses by communicating with other cells
• Killer T cells are cytotoxic killer cells and natural killer cells

Killer Cells

• Two types: cytotoxic T cells and natural killer cells
• Cytotoxic T cells recognize a specific antigen on a foreign invader
• Natural killer cells do not need to recognize a specific antigen
• Both types contain granules filled with potent chemicals and kill on contact
• Killer cells bind to the target, aim weapons, and deliver lethal chemicals

Cytotoxic T Cells

• Help rid the body of cells infected by viruses and cells transformed by cancer
• Recognize a specific antigen on the foreign cell
• Responsible for rejection of tissue and organ grafts

Natural Killer NK Cells

• Armed with granules containing lethal doses of chemical
• Attack cells lacking the self MHC molecule

Cytotoxins

• Polypeptides that cause cell injury, inflammation, intestinal secretion through inhibition of protein synthesis

Modes of Acquiring Immunity

• Immunity is acquired through Natural and Artificial mechanisms - passive or active

Passive Immunity

• Natural passive immunity is provided through placental transfer of IgG and colostral transfer of IgA
• Artificial passive immunity is provided through antibodies or immunoglobulins and immune cells

Antibodies

• Immunoglobulins
• Glycoproteins found in serum containing 82% to 96% polypeptide and 2% to 14% carbohydrate
• Five major classes: IgG, IgM, IgA, IgD, IgE
• The key element of the humoral immune response
• Appear primarily in the gamma (γ) globulin band with serum electrophoresis at pH 8.6

Tetrapeptide Structure of Immunoglobulins

• Contains four-chain polypeptide
• Two large polypeptide chains are heavy (H) chains
• Two small polypeptide chains are light (L) chains

Explore the intricacies of acquired or adaptive immunity in this quiz. Learn about the roles of T cells, B cells, antibodies, and the various responses of the immune system. Test your knowledge on the characteristics and types of adaptive immunity.