Kavisha K Patidar Assistant Professor Department of Microbiology Deogiri College Aurangabad Department of Microbiology Semester iii Unit 3 Title Immunity Teacher Kavisha K Patidar ID: 1032772
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1. Topic -ImmunityPresented byKavisha K Patidar Assistant ProfessorDepartment of MicrobiologyDeogiri College, Aurangabad
2. Department of MicrobiologySemester- iiiUnit -3Title:- ImmunityTeacher – Kavisha K Patidar
3. IntroductionThe term IMMUNITY, It is Latin word, “immunis” that means “free of burdens”The term immunity refers to the resistance exhibited by the host towards infection caused by micro organisms and their products(toxins). This is based on the property of self and non self recognition. That means immunity is carried out by the process of recognition and disposal of non self or materials that enter the body. Immune response is the reaction of the body against any foreign antigen.
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5. Innate immunityThese are also referred as “Non-specific immunity”. Resistance to infection which an individual possesses by virtue of his genetic and constitutional makeupNot affected by prior contact with microorganisms or immunization a. Non specific : Indicate a degree of resistance to infections in general b. Specific: Resistance to a particular pathogen is concerned.
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8. Mechanism of innate immunity: 1. Epithelial surface: a. Skin: • It acts as a machanical barrier to microorganisms and provide bactericidal secretions • Resident microflora of skin and mucous membrane surface help to prevent colonisation by pathogens .b. Respiratory tract: • Inhaled particales are arrested in the nasal passage on the moist mucous membrane surface. • Mucous membrane acts as a trapping mechanism hair like cilia propels the particles towards pharynx where its swallowed or coughed out. • Cough reflex acts as a defence mechanism
9. Chemical barriers 1. Oily and sweat secreted by integument make the skin acidic. 2. Saliva of buccal cavity contains LYSOZYME which kill the microorganism. 3. GUT secretions like HCl provides acidic medium which inhibits the growth of microbes. 4. Bile offers alkaline medium which check the growth of microorganism in intestine. 5. The lacrymal glands secrete tears containing lysozyme which prevent eye infections. 6. Cereminous glands of auditory canal secrete cerumen (ear wax) which traps the dust and bacteria. 7. Vaginal bacteria produce lactic acid from the glycogen thereby producing acidic environment to vagina as female’s best natural defense against pathogens.
10. 2. Antibacterial substance: • Nonspecific antibacterial substance present in the blood and tissue • Substance like properiden, complement, lysosyme, betalysin, basic polypeptide and interferon which have antiviral activity. • Complement system plays an important role in destruction of pathogenic microorganisms that invade blood and tissue.3. Cellular factor : • When infection cross the barrier of epithelial surface, tissue factor come into play for defence. • Exudates inflammatory reaction occurs by accumulation of phagocytes at the site of infection and deposition of fibrin which entangles the organisms to act as a barrier to spread of infection. Phagocytic cells ingest these organisms and destroy them.
11. 4. Inflammation: Inflammation occurs as a result of tissue injury or irritation, initiated by entry of pathogens or other irritants. It’s a nonspecific defence mechanism. Inflammtion leads to vasodilatation, increased vascular permeability and cellular infiltration. Microorganisms are phagocytosed and destroyed due to increased vascular permeability, which helps to dilute the toxic products present. Fibrin barrier is laid to wall off site of infection
12. 5. Fever: Rise of temperature fallowing infection is a natural defence mechanism. It destroyes the infecting organisms. Fever also stimulates the production of interferon which helps in recovery from viral infection.
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14. Acquired 0r ADAPTIVE immunityAcquired immunity is immunity you develop over your lifetime. It can come from: -a vaccine -exposure to an infection or disease -another person’s antibodies (infection-fighting immune cells)TYPES OF ADAPTIVE IMMUNITY Active immunity :- It is the production of immunity against particular organisms after exposure. a. Naturally acquired active immunity occurs when the person is exposed to a live pathogen, develops the disease, and becomes immune as a result of the primary immune response.
15. b. Artificially acquired active immunity can be induced by a vaccine, a substance that contains the antigen. A vaccine stimulates a primary response against the antigen without causing symptoms of the disease. Vaccine : -Live vaccine: BCG for tuberculosis, Sabin vaccine for poliomylitis -Killed vaccine: Hepatitis B vaccine, non-neural vaccine for rabies -Bacterial product: Tetanus toxoid vaccine, Deptheria toxoid for deptheria
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17. Passive immunity: a. Artificially acquired passive immunity is a short-term immunization by the injection of antibodies, such as gamma globulin, that are not produced by the recipient's cells. b. Naturally acquired passive immunity occurs during pregnancy, in which certain antibodies are passed from the maternal into the fetal bloodstream
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19. Herd immunity is a form of indirect protection from infectious disease that occurs when a sufficient percentage of a population has become immune to an infection, whether through vaccination or previous infections, thereby reducing the likelihood of infection for individuals who lack immunity.