Microbiology RNB 10102 Topic 7.3 Immunity PDF

Microbiology RNB 10102 Topic : Body Defence and immunity Topic 7.3 Immunity Kogi Learning Outcomes At the end of the session, the student should be able to;  define immunity  describe the different types of immunity  identify ways of acquiring different types of immunity  identify different t...

Microbiology RNB 10102 Topic : Body Defence and immunity Topic 7.3 Immunity Kogi Learning Outcomes At the end of the session, the student should be able to;  define immunity  describe the different types of immunity  identify ways of acquiring different types of immunity  identify different types of vaccine IMMUNITY Definition  Immunity is the state of protection against infectious disease obtained either through an immune response generated by immunization or previous infection, or by other non-immunological factors.  IMMUNITY INNATE ACQUIRED/ (genetic, inborn ADAPTIVE NATURALLY ACQUIRED ARTIFICIALLY ACTIVE ACQUIRED Protection acquired by getting ACTIVE the disease Protection acquired by immunization with vaccine that stimulate PASSIVE PASSIVE the body to actively Protection Antibodies passively acquired by direct produce own antibody cross from mother to injection of baby via placenta or antibodies breast milk (immunoglobulin)) Acquired Immunity  Acquired immunity result from the active production or receipt of antibodies. Types of immunity Definition 1. Innate immunity ◦ The nonspecific first line of defence against foreign pathogens that is an integral facet of the immune response, which is mediated by dendritic cells (DCs), natural killer (NK) cells, macrophages, neutrophils, basophils, eosinophils and mast cells. Types of immunity Innate immunity (.. cont)  Sometimes referred to as genetic or inborn  Present from birth and are effective against potentially infective agent.  Do not depend on having previous experience with any particular microorganism Types of immunity 2. Adaptive immunity Definition  Protection from an infectious agent that is mediated by B and T Lymphocytes following exposure to specific antigen and characterized by immunological memory Types of immunity (Cont..) 2. ADAPTIVE IMMUNITY (…cont) ◦ Not present at birth ◦ Develop during our life ◦ Acquired immunity (immunity that result from active production or receipt of antibodies) can be achieved: a. naturally b. artificially Types of immunity (cont…) A. Naturally acquired  Can be gained passive or active i. Naturally Passive Acquired Immunity ◦ Immunity or resistance acquired as a result of a receipt of antibodies produce by another person or by animal (such protection usually temporary).  E.g. : IgG – transfer from mother to fetus across the placenta IgA - transfer from mother to baby in milk during feeding Types of immunity (cont…) A. Naturally acquired….cont.. ii. Naturally Active Acquired Immunity ◦ Result from the production of antibodies by the immune system in response to the presence of an antigen (produce within own body- usually long lasting). ◦ Occurs after exposure to an infectious organism (antigen). Types of immunity A. Naturally acquired … cont.. ii. Natural Acquired Active immunity …cont..  Antigen stimulate the immune system to produce specific antibodies and memory cells to ward off future encounters with same pathogen. ◦ E.g. after exposure to measles, mumps or chicken pox.  Usually long lasting Types of immunity (cont..) B. Artificially acquired ◦ Can be obtained by injection of vaccines ◦ Can be active and passive i. Artificially Acquired Active immunity  An antigen introduced during vaccination stimulate cell-mediated and antibody- mediated immune responses leading to production of memory cells ◦ E.g. of vaccines; Bacille Calmette-Guerin (BCG) – given against Tuberculosis.  May last long, or long life. Types of immunity (cont…) B. Artificially acquired …cont.. ii. Artificial Acquired Passive Immunity  Intravenous injection of immunoglobulins (antibodies) from human or animal  Does not produced antibodies and memory cells; e. g. Antiserum, Antitoxin, Gamma globulin  Immunity is short lived and offers only immediate, short term protection  Types of Acquired Immunity ACTIVE PASSIVE Natural Artificial Natural Artificial Clinical or Vaccines Congenital Antiserum subclinical Inactivated (across Antitoxin clinical (Killed) placenta) Gamma pathogen Colostrum globulin Attenuated (weakened) pathogens Extracts (parts of pathogen) summary  Ways of acquiring artificially active and passive immunity Immunizing Agents Divided into:  Vaccines ✓ Live attenuated ✓ Inactivated or killed vaccines  Toxoids  Immunoglobulin Immunizing Agents Vaccines  Immunological substances designed to provide protection against a disease  It stimulates the production of protective antibodies and other immune mechanisms.  May be prepared from live attenuated, inactivated or killed organisms. Example of Immunizing Agents Vaccines;  Live attenuated vaccines – BCG (stands for Bacille Calmette-Guerin)  Oral polio (sabin)  Killed or inactivated vaccines – typhoid, cholera, rabies, polio (Salk) Toxoids:  diphtheria,  tetanus Example of Immunizing Agents Immunoglobulin a. Non-humanimmunoglobulin (antisera) - diphtheria, tetanus, gas gangrene, botulism, rabies b. Human immunoglobulins;  Human normal Ig, hepatitis A, measles, mumps  Human specific, Ig, hepatitis B, varicella, diphtheria Vaccines- artificially active  Vaccines is an antigenic materials when introduced into the body it stimulate the specific antibodies against a specific microorganism. Vaccines can be: 1. Attenuated microbes. ◦ These are living, non-virulent strains of a microbe Examples of vaccines that contain attenuated microbes include:  the MMR vaccine containing attenuated measles, mumps and rubella viruses;  oral polio vaccine containing attenuated poliomyelitis viruses  Bacille Calmette-Guerin (BCG) – given against Tuberculosis. Vaccines - artificially active 2. killed organisms, fragmented microorganisms, or antigens produced by recombinant DNA technology a. Examples of vaccines containing killed or inactivated microbes include: ◦ the rabies vaccines containing whole, killed rabies viruses; ◦ the influenza vaccines consist of inactivated influenza viruses, either whole or broken down Active artificial acquired - Vaccines b. Fragments of microorganisms e.g. immunizations against:  Hemophilus influenzae type b. Vaccine C. Recombinant DNA technology include:  Hepatitis B vaccine (HepB),  Diphtheria, tetanus, acellular pertussis (or whooping cough) vaccine (DTAP);  Hepatitis A vaccine (HepA);  Cervarix, the vaccine against human papilloma virus (HPV) types 16 and 18 ❖ Recombinant DNA is a DNA that has been created artificially. DNA from two or more sources is incorporated into a single recombinant molecule. Vaccine 3. Toxoid  An exotoxin that has been treated to be nonpoisonous but still capable of stimulating an immune response against the natural exotoxin  The body responds by making antibodies capable of neutralizing the exotoxin. Examples of vaccines containing toxoids include: ◦ diphtheria and tetanus Passive artificially acquired immunity I. Immune globulin (IG) an antibody- containing serum obtained from another person: E.g. include:  Human hepatitis B immunoglobulin (HBIG) to prevent hepatitis B in those not actively immunized with the help of vaccine; ◦ For e.g. A nurse who has accidentally exposure to hepatitis B virus via a needlestick injury and does not have immunity, may receive hepatitis B immunoglobulin in an attempt to provide instant protection from virus. Passive artificially acquired immunity Antiserum: Serum containing antibodies to a specific antigen(s). ◦ Obtained from injecting an animal (horse, rabbit, goat) with antigen (snake venom, botulism or diphtheria toxin).  Passive immunity provides immediate but temporary protection.  Types Of Vaccine Types of Vaccine Examples Live (attenuated) Adenovirus, measles, (rubeola), mumps, virus German measles (rubella), polio (oral), small pox (varicella), yellow fever. Dead (incativated) Hepatitis B, influenza, Japanese viruses or viral encephalitis, polio, rabies antigens Live (attenuated) BCG, typhoid fever bacteria Bacterial capsular Hib (for protection against antigens Heamophilus influenzae type b), meningococcal, pneumococcal Bacterial Toxoids Diphtheria, tetanus