LEC 2

• Immunology is derived from the Latin word “Immunis” which means: "Free from Taxes or Burden or Changes".
• Immunology involves processes by which the body defends and maintains the constancy of its internal review against invasion by foreign organisms or the mutation or development of unwanted cells or cell products within itself.
• The capacity (ability) of an animal to recognize what is Self or Non-self involves Cell Surface Molecules that are proteins in nature that can recognize and bind specifically to a particular shaped-structure on another molecule.
• Resistance of a host organism to an invasive pathogen or their toxic products is referred to as Resistance to Infection.
• Immunity was introduced in medicine to refer to those people who did not get further attacks of Smallpox or Plague once they had the disease.
• Immunity refers to all mechanisms used by the body as a protection against environmental agents which can include: Microorganisms and their Products, Food, Chemicals, Drugs, Pollen, Animal hair or dander.
• Tests to determine the degree of histologic compatibility for D and R of transplants include mixed lymphocyte culture and histocompatibility antigen (HLA) typing by lymphotoxicity.
• Haplo-identical siblings share one haplotype and are the 2nd choice for donor.
• Nonidentical siblings don’t share haplotypes and are not an ideal donor.
• Grafts of HLA-identical siblings persist for several weeks, and rejection occurs due to a minor H difference.
• Skin grafts of nonidentical siblings are rapidly rejected and this is rarely performed.
• Possible outcomes/combinations of siblings include HLA-identical siblings, haplo-identical siblings, and nonidentical siblings.
• Grafts of haplo-identical siblings show a wide variation in the rejection time, even with matched HLA, there will still be rejection.
• HLA-identical siblings share identical haplotypes and are the ideal donor if you are to undergo transplant.
• If you are not immune, then you are susceptible.
• Natural immunity, also known as innate, nonspecific, or nonadaptive immunity, is inherent, innate and genetically determined.
• Natural immunity is conferred by all elements by which an individual is born with and is always present and available at very short notice to protect the individual from challenges by foreign invaders.
• Natural immunity does not involve specific recognition of a foreign agent and operates through various factors: Body surfaces, Internal Components, Cells, Phagocytes.
• Species immunity is a type of natural immunity where a given organism is capable of producing disease in one animal species and not in the other.
• Active immunity involves both humoral and cellular components of the immune system.
• Passive immunity can be both humoral and cellular, with antibodies coming from another source.
• For passive immunity, there is no process involved, so no memory cells are produced.
• Post-exposure immunization can provide protection against development of disease by administering rabies vaccine and immune globulin against the rabies virus, toxoid and antitoxin against diphtheria and tetanus toxins, and immune system globulins against HIV.
• Humoral immunity is achieved through antibody production.
• The advantage of using attenuated organisms is that they multiply, providing a constant supply of antigen for the immune system.
• The disadvantage of using attenuated organisms is the risk of reversion to greater virulence during multiplication in the vaccines.
• Attenuated organisms have lost their pathogenicity but still retained their antigenicity, so they can still stimulate antibody production.
• Protection through passive immunization is the objective achieved by injections of immune globulin to protect a traveler against Hepatitis A Virus (HAV) in countries where that disease is common.
• Edward Jenner demonstrated that deliberate administration to humans of lymph from a cow with Vaccinia led to protection against smallpox.
• Active immunization is one way of acquiring immunity.
• Cellular immunity involves cells like T lymphocytes, macrophages, and other cells.
• Active immunization involves the administration of vaccines containing antigens in the form of live or dead organisms or attenuated organisms.
• Uses of immunization include protection against infectious diseases and protection generated prior to possible exposure to an infectious agent.
• Racial immunity is immunity that is possessed by a Race and among one animal species, there may be a difference in susceptibility.
• The histocompatibility (transplantation) Ag are expressed starting 12 weeks of fetal life.
• Complement components are detected in the human fetal intestinal tissues by the 19th week of gestation and reaches adult complement level within 3 - 5 months after birth.
• The appearance of Immunoglobulin classes in the fetus and neonate is determined by the development of their lymphoid organs, with the thymus being the largest in size relative to the body size at any age.
• The genetic loci involved in the rejection of foreign or nonself tissues form a region known as the major histocompatibility complex (MHC).
• Passive immunization is a major function of the immune system.
• The human immune system in the embryo arises from the gut-associated tissues.