primary and secondary immune response

Unit 3, 5 of 5

1. U-3, 5 OF 5 “DEFENSE MECHANISMS OF THE BODY” By: Aftab H. Abbasi RN, DCHN, BSN, MA, LL.B Lecturer Nursing Qadri College of Health Sciences Karachi QADRI COLLEGE OF HEALTH SCIENCES, KARACHI

2. “DEFENSE MECHANISM OF THE BODY” This unit focuses on the resistance of the body which microorganism’s encounter where they enter in the human body. - This unit highlights the importance of the resistance or defense of the body which will help learners in understanding that why infection occurs sometimes and not always.

3. “DEFENSE MECHANISM OF THE BODY” At the completion of this unit learners will be able to: 1- Explain the role of good health in protection against the microbial infection. 2- Define Resistance and Susceptibility. 3- Define Nonspecific Resistance. 4- Describe the role of the skin and mucous membrane in nonspecific Resistance. 5- Explain the process of Phagocytosis. 6- Define the Specific Resistance, Innate Resistance and Immunity. 7- Explain four types of acquired Immunity.

4. “DEFENSE MECHANISM OF THE BODY” At the completion of this unit learners will be able to : 8- Differentiate between humoral and cell mediated immunity. 9- Define Antigens, hapten and antibodies. 10- List the five classes of antibodies and their functions. 11- Explain the role of memory, tolerance and specificity in immunity. 12- Distinguish between primary and secondary immune response. 13- Define Hypersensitivity. 14- Differentiate between i.e. delayed and immediate Hypersensitivity.

5. 12- PRIMARY AND SECONDARY IMMUNE RESPONSE Differences between Primary and Secondary Immune Response: In a primary immune response, naive  B cells  are stimulated by antigen, become activated, and differentiate into antibody-secreting cells that produce antibodies specific for the eliciting antigen. A secondary immune response is elicited when the same antigen stimulates memory B cells, leading to the production of greater quantities of specific antibodies that are produced in the primary response. Some of the differences between Primary and Secondary Immune Response are as follows:

6. 12- PRIMARY AND SECONDARY IMMUNE RESPONSE S.N. Characteristics Primary Immune Response Secondary Immune Response 01. Definition Primary Immune Response is the reaction of the immune system when it contacts an antigen for the first time. Secondary Immune Response is the reaction of the immune system when it contacts an antigen for the second and subsequent times. 02. Appearance Appears mainly in the lymph nodes and spleen. Appears mainly in the bone marrow and then, in the spleen and lymph nodes. 03. Occurrence This occurs in response to the primary contact of the antigen. This occurs in response to the second and subsequent exposure to the same antigen. 04. Antibody Peak The antibody level reaches its peak in 7-10 days. The antibody level reaches its peak in 3-5 days.

7. 12- PRIMARY AND SECONDARY IMMUNE RESPONSE S.N. Characteristics Primary Immune Response Secondary Immune Response 05. Affinity of Antibody Low affinity to their antigens. High affinity to their antigens. 06. Responding Cells Naive B cells and T cells Memory B cells 07. Antibodies Both thymus-dependent and thymus-independent antibodies are involved in the primary immune response. Only thymus-dependent antibodies are involved in the secondary immune response. 08. Lag Phase Long (4-7 days) Short (1-4 days)

8. 12- PRIMARY AND SECONDARY IMMUNE RESPONSE S.N. Characteristics Primary Immune Response Secondary Immune Response 09. Types of Antibodies A large amount of IgM and a small amount of IgG are produced during the primary immune response. A large amount of IgG, a small amount of IgM, IgA, and IgE are produced during the secondary immune response. 10. Amount of Antibody Few antibodies are produced in the primary immune response. 100-1000 times more antibodies are produced in the secondary immune response. 11. Strength of the Response The primary immune response is usually weaker than secondary immune response. The secondary immune response is stronger.

9. 12- PRIMARY AND SECONDARY IMMUNE RESPONSE S.N. Characteristics Primary Immune Response Secondary Immune Response 12. Antibody level Antibody level declines to the point where it may be undetectable. The antibody level tends to remain high for longer. References: http://www.microbiologynotes.com/differences-between-primary-and-secondary-immune-response/

10. 13- Define Hypersensitivity Hypersensitivity (Immunological reaction) refers to : Undesirable immune reactions produced by the normal immune system. Hypersensitivity reactions : When an immune response result in exaggerated OR in appropriate reactions harmful to the host the term hypersensitivity OR allergy used.

11. 13- Define Hypersensitivity Hypersensitivity reactions : F our types; based on the mechanisms involved and time taken for the reaction, a particular clinical condition (disease) may involve more than one type of reaction . Classification of Hypersensitivit y: Type I Type I, II and III Antibody Mediated Type II Type III Type IV Type IV Cell Mediated

12. Type I (Immediate) Hypersensitivity Commonly called allergy. Mediated by IgE antibodies produced by plasma cells in response to stimulation of Th2 cells by an antigens. The antigens that stimulate it are called allergens ( i.e. House dust, Pollens, Cosmetics, Insects, Clothing and Drug ). Exposure may be ingested, inhalation, injection or direct contact. Type I hypersensitivity reactions can be systemic (e.g ., systemic anaphylaxis) or localized to a specific target tissue or organ (e.g., allergic rhinitis, asthma).

13. Type II (Cytotoxic) Hypersensitivity Cytotoxic Type II hypersensitivity involves IgG or IgM antibody-mediated. IgM or IgG immunoglobulin react with cell-surface antigens to activate the complements system and produce direct damage of the sell surface. Transfusion reactions and hemolytic disease of the newborn are examples of type II hypersensitivity.

14. Type III (ICM) Hypersensitivity Type III (Immune Complex–Mediated) Hypersensitivit y: Type III hypersensitivity is also known as immune complex hypersensitivity. The reaction may take 3 - 10 hours after exposure to the antigen (as in Arhus reaction ). The reaction may be general (e.g., serum sickness) or may involve individual organs including or other organs. Antigens causing immune complex mediated injury are:  Exogenous  Endogenous

15. Type IV (Cell Mediated) Hypersensitivity Type IV (Delayed or Cell-Mediated) Hypersensitivit y: - Delayed hypersensitivity is a function of T Lymphocytes, not antibody. It starts hours (or Days) after contact with the antigen and often lasts for days. It can be transferred by immunologically committed (Sensitized ) T cells, not by serum. Principal pattern of immunologic response to variety of intra cellular microbiologic agents i.e.: Mycobacterium Tuberculosis Viruses Fungi Parasites

16. Hypersensitivity Reactions Conclusion :

17. 14- Delayed VERSUS immediate Hypersensitivity Immediate hypersensitivit y: Immediate hypersensitivity (type I) is also known as immediate contact urticaria or contact urticaria syndrome, and the reaction occurs very rapidly. Common causes include insect bites and ingested peanuts. It is mediated by IgE antibodies, which bind to the surface of mast cells. Within minutes of skin contact by an antigen, the mast cells release histamine and other factors, causing an inflammatory reaction.

18. Immediate Hypersensitivity Anaphylaxis is an extreme form of immediate hypersensitivity. It is a life-threatening reaction involving massive histamine release, which can lead to breathing difficulties and low blood pressure. Instance of anaphylaxis due to skin contact from an essential oil or constituent. There is also recorded cases of anaphylactic shock from fragrance inhalation.

19. Delayed VERSUS immediate Hypersensitivity Delayed H ypersensitivit y: Type IV hypersensitivity reaction also known as cell mediated hypersensitivity or delayed type of hypersensitivity is the T lymphocytes mediated destruction of cells along with dendritic cells, macrophages and cytokines playing major roles. The reaction is mediated by specific subsets of CD4+ helper T cells (Th-1 and Th-17 cells) or by CD8+ cytotoxic T cells . Type IV hypersensitivity occurs 24 hours after contact with an antigen, usually starting at 2 or 3 days and often last for many days. For this reason, type IV hypersensitivity reaction is termed as “delayed hypersensitivity ”. Type IV hypersensitivity is unique in that, unlike the first three types of hypersensitivity which are antibody mediated, type IV hypersensitivity is cell mediated and also a delayed reaction.

20. Delayed VERSUS immediate Hypersensitivity Here is the comparison table: 1- Alternative Name: Type I Type II Type III Type IV Allergic hypersensitivity Cytotoxic hypersensitivity Immune complex hypersensitivity Cell-mediated hypersensitivity/ Delayed type of hypersensitivity 2- Principle: Type I Type II Type III Type IV Antibody-mediated degranulation of granulocytes leading to the destruction of cells. Antibody-mediated destruction of healthy cells. Antigen-antibody complex-mediated destruction of cells. T lymphocytes mediated the destruction of cells.

21. Delayed VERSUS immediate Hypersensitivity 3- Primary Mediator: Type I Type II Type III Type IV IgE IgG / IgM IgG / IgM Specific subsets of CD4+ helper T cells or CD8+ cytotoxic T cells. 4- Other components as mediators: Type I Type II Type III Type IV Immediate or within a few hours 5-8 hours 2-8 hours After 24 hours only, mostly 48-72 hours after contact Type I Type II Type III Type IV Mast cells, Basophils , histamine & other pharmacological agents Complement, Neutrophils Complement, phagocytes and K cells Dendritic cells, macrophages, and cytokines 5- Reaction time:

22. Delayed VERSUS immediate Hypersensitivity 6- Antigen: Type I Type II Type III Type IV Free in circulation (Soluble) Fixed on cells Free in circulation ( Soluble) Soluble or cell-bound 7- Antigen origin: Type I Type II Type III Type IV Exogenous Endogenous or exogenous Exogenous or endogenous Exogenous or endogenous 8- Antibody: Type I Type II Type III Type IV Fixed on mast cells and basophils Free in circulation Free in circulation Not applicable

23. Delayed VERSUS immediate Hypersensitivity 9- Mechanism: Type I Type II Type III Type IV Allergen-specific IgE antibodies bind to mast cells via their Fc receptor. When the specific allergen binds to the IgE, cross-linking of IgE induces degranulation of mast cells. IgG or IgM antibody binds to a cellular antigen, leading to complement activation and cell lysis . IgG can also mediate ADCC with cytotoxic T cells, natural killer cells, macrophages, and neutrophils . Antigen-antibody complexes are deposited in tissues. Complement activation provides inflammatory mediators and recruits neutrophils . Enzymes released from neutrophils damage tissue. Th2 cells secrete cytokines, which activate macrophages and cytotoxic T cells.

24. Delayed VERSUS immediate Hypersensitivity 10- Complement activation: Type I Type II Type III Type IV No Yes Yes No 11- Appearance: Type I Type II Type III Type IV Weal & flare Lysis & necrosis Erythema & edema Erythema & induration 12- Transfer with serum: Type I Type II Type III Type IV Passive transfer possible with serum Passive transfer Passive transfer Cannot be transferred with serum; but possible with T cells transfer

25. Delayed VERSUS immediate Hypersensitivity 13- Desensitization: Type I Type II Type III Type IV Easy but short-lived Easy but short-lived Easy but short-lived Difficult but long-lived. 14- Examples: Type I Type II Type III Type IV Asthma, Rhinitis, Atopic eczema, Bee sting reaction Rhesus incompatibility ( Rh hemolytic disease), Transfusion Reactions, Cell Destruction due to autoantigens , Drug-Induced Hemolytic Anemia Glomerulonephritis , Systemic Lupus Erythematosus , Farmer’s lung arthritis, Vasculitis The tuberculin reaction, Granuloma formation, Allergic contact dermatitis, Type-1 diabetes

26. Delayed VERSUS immediate Hypersensitivity References: https://courses.lumenlearning.com/microbiology/chapter/hypersensitivities/ http://www.biologydiscussion.com/immunology/4-main-types-of-hypersensitivity-immunology/61851 https://www.slideshare.net/drsomeshwaranamsana/hypersensitivity-reactions-dr-somesh-microbiology http://www.yourarticlelibrary.com/immunology/type-iii-hypersensitivity-and-its-mechanism-human-immunology/28081 Lydyard, P.M., Whelan,A.,& Fanger,M.W. (2005).Immunology (2 ed.).London: BIOS Scientific Publishers. Owen, J. A., Punt, J., & Stranford, S. A. (2013). Kuby Immunology (7 ed.). New York: W.H. Freeman and Company .

27. 11- Role of memory, tolerance and specificity in immunity Specificity, Memor y and Tolerance : Specificity refers to the adaptive immune system's ability to target specific pathogens. Memory refers to its ability to quickly respond to pathogens to which it has previously been exposed. Tolerance , also referred to as immunological tolerance or immunotolerance, is an active state of unresponsiveness to specific antigens in an effort to prevent destructive over-reactivity of the immune system.

28. DEFENSE MECHANISMS OF THE BODY

29. QADRI COLLEGE OF HEALTH SCIENCES, KARACHI By: Aftab H. Abbasi RN, DCHN, BSN, MA, LL.B Lecturer Nursing Qadri College of Health Sciences Karachi