Immunology

1. Immunology Is the science that deals with study of bodies defense factors and mechanisms acting to remove or eliminate harmful agents entering the body The term of immunity is derived from a Latin word (immunitus) which referred to the protection from legal persecution offered to the roman senators

2. Immunesystem Immuneresponse Is a system which involves in the prevention and control of disease Is the reaction that occur in the immune system when exposed to extrinsic or intrinsic structure having Antigen characteristics

3. Types of immuneresponse 1-Humoral immunity (Ab mediated immunity) 2-Cell mediated immunity Antibody (Ab) A type of glycoprotein molecule, also called immunoglobulin produced by a special cell called (B-lymphocyte) that binds to Ag

4. Antigen(Ag) • A substance (antigen) that is capable of reacting with the products of a specific immune response, e.g., antibody or specific T-lymphocytes • Antigen= Antibody generator Classes of immunology 1-Immunity: Protection against disease caused by non-self or altered body cells

5. 2-Serology: Study the reactions that occur between Ag and Ab outside the body 3-Immunochemistry: Study the nature of chemical structure of Ag and Ab 4-Immunobiology: Study the role of bodies organ and its relation to other organ in immunity

6. Factors that affects on immunity 1- Racial differences 2- Genetics 3- Age 4-Hormones: 5- Sex 6- Nutrition

7. Types of immunity 1- Non-specific (Innate) immunity 2- Specific (Adaptive) immunity Non- specific immunity • The immunity is not specific against one type of microorganism, but it act against large numbers of microorganisms and does not amplified • (It doesn't become stronger after many exposure to the microorganism because there is no memory cells)

8. Specific immunity • The immunity is specific against one type of microorganism • (It become stronger after many exposure to the microorganism because there is memory cells)

9. Types of specific immunity 1- Natural specific immunity This type naturally found inside the body A- Passive This type is naturally acquired from mother ex. Maternal Abprotect infant (via placentaand colostrum)

10. B- Active This type is naturally acquired from environment ex. Natural infection like measles Types of specific immunity 2- Artificial specific immunity A- Passive This type is artificially acquired (Abis acquired) ex. Tetanus antitoxin

11. B- Active This type is artificially injected with the source of infection, ex. Vaccinationlike tetanustoxoid Differences between specific and non specific immunity Non-specific (Innate) immunity Specific (Adaptive) immunity 1- There is immediate response 1- There is a lag time between exposure and response 2- It is not Ag specific 2- It is Ag specific

12. 3- There is no memory cells 3- There is memory cells 4- Cells like B- lymphocyte and T- lymphocyte 4- Cells like phagocyte cells and NK cell (Natural Killer cell) 5- Blood proteins like complement 5- Blood proteins like Ab

13. Innate immunity is the first line of defense against infections, the mechanism of innate immunity exist before encounter with microbes and are rapidly activated by microbes before the development of adaptive immune response Innate immunity

14. 1-Physical and mechanical barrier, like skin and mucous membrane 2-Secretions like tears, sweat, saliva and mucous The components of innate immunity • 3-Plasma proteins like complement and acute phase protein and interferon 4-Phagocytosis 5-Natural killer cell (NK cell)

15. The skin is a mechanical barrier in which it contains stratified squamous epithelial tissue, so it prevents the invasion of microorganism. Also skin contains sweat and acids, this gives acidic pH to skin so it prevent growth of microorganism, but not for all microorganism ex. Staphylococcus aureuswhich can invade the smooth non keratinized part of the skin.

16. Respiratory tract (RT) Eye Skin Urogenitaltract (UGT) Gastro intestinal tract (GIT) Diagram structure of human

17. GIT, RT and UGT all are enclosed by mucous membrane; it has been found that total space of mucous membrane that covered the internal surface of the body in the above-mentioned area is about 700 m2; therefore, these areas should have its own innate immunity represented by the following: • 1- Mucous secreted by respiratory cell has role in trapping the microorganisms and prevent its movement and spreading then they removed it by mechanical movement of cilia covering the cells in RT, or by coughing and sneezing. Also there is secretion of tears in eye and saliva in mouth , they contains enzymes (mostly lysozyme), peroxidase, and Ab which inactivates bacteria and make washing of such organs, therefore prevent colonization of microbes.

18. 3- Secretion of stomach makes the environment of stomach acid pH thus preventing and kills microbes 4-Another mechanism which prevent pathogenic microbes are the normal flora which are present in the intestine, these normal flora produce inhibitors which prevents pathogenic microbes from growing, because of that antibiotic uptake may kill those normal flora and gives chance for opportunistic microbes for growing. 2-Urine also makes mechanical washing for UGT

19. Table 1: Examples of innate immunity mechanisms

20. Table 2: Biological activities of secretory products in innate immunity

21. Inflammation A complex of series of events that finish in the accumulation of proteins, fluid, and phagocytic cells in an area of tissue that has been injured or invaded by microorganisms.

22. Signs of inflammation The classical symptoms of inflammation were first described by the Roman physician Aulus Cornelius, who named them calor (heat), rubor (redness), tumor (swelling), and dolor (pain). These symptoms result from structural and functional changes occurring in the vasculature of affected tissues in response to invasion by an infectious agent.

23. Redness is caused by the dilation of the blood vessels. Heat is due to the increasing of blood in the inflamed area. Swelling is due to enlargement of the blood vessels and movement of fluid into the tissues (edema), and the pain is caused by pressure on the nerve ending by the swollen tissues and also by the action of kinins on the nerve endings.

24. The inflammatory response is an important mechanism in the maintenance of our health, it is a two-edged sword. In many allergic reactions, this inflammatory process is activated inappropriately and may produce widespread tissue destruction, which may result in severe weakness and on occasion may result in death.

25. For example rheumatoid arthritis is caused by inappropriate inflammation of the joints, and glomerulonephritis results from inappropriate inflammation and destruction of many kidney glomeruli which causes thousands of death each year.

26. Stages of inflammation • Acute inflammation • Subacute inflammation • Chronic inflammation All inflammations start with an acute phase from which they normally progress into a subacute stage. However relatively few acute inflammations will progress into a chronic stage.

27. Acute inflammation Most acute inflammations result from infections caused by mechanical injury like cut, wood fragment, burn, or damaged stomach wall. For example, when a person steps on a rusty nail, the nail will have millions of bacteria on its surface, which remains behind when the nail is removed. Within hours the area surrounding the spot of infection may become inflamed. Microscopic tissue analysis of the infected area should reveal the infected area is swarming with neutrophils. During acute inflammatory phase, few lymphocytes or macrophages are encountered at the site of inflammation.

28. Possibly the first chemotactic factors that activate neutrophils may not be able to activate other WBCs to the same degrees, or may be respond at a slower rate. Another reason may be that neutrophils are much more numerous than other WBCs. This acute phase is usually associated with tissue destruction, pain, and swelling.

29. Subacuteinflammation A few days after initial acute inflammatory response, the infected area proceeds to a subacute phase. Swelling becomes less marked and pain becomes less throbbing. Microscopic analysis of the infected tissue will reveal that the neutrophils have been largely replaced by macrophages and lymphocytes. This subacute phase is associated with the formation of new tiny blood vessels and connective tissue. Many fibroblasts appear in the area and begin to produce new collagen fibers to repair the damaged tissues. The acute phase is associated with tissue destruction, and the subacute phase is associated with reconstruction. Within about a week, the subacute phase disappears and the infection appears to be over.

30. Chronic inflammation In a few situations macrophages and lymphocytes may be unable to eradicate the infection because the pathogens multiply faster the WBCs can destroy them. In that case additional macrophages migrate to the infected area. Macrophages undergo a change that transforms them into giant cells. Such extra large cells are produced by the process of endomitosis that is, the nucleus keeps dividing within a common cytoplasm. Each time the nucleus divides, the cell becomes larger until it reaches giant proportions. These giant cells warp themselves around the pockets of infection. They are aided by newly arrived fibroblasts, which will continue to produce vast amounts of dense connective tissue fibers.

31. Chronic inflammation These pockets of multiplying microorganisms become completely surrounded by giant cells and fibrous connective tissue. As a result they are separated from nutrients supplied by the blood and hence die inside these clumps of connective tissue called granulomas. If many granulomas are produced in vital tissues such as heart muscle, liver, lungs, or kidneys, they may interfere with the normal functioning of the host, which may lead to other complications. However such chronic inflammations are relatively rare and may occur in such infectious diseases as tuberculosis and leprosy.