1. Online Counseling Resource YCMOU ELearning Drive… School of Architecture, Science and Technology Yashwantrao Chavan Maharashtra Open University, Nashik – 422222, India

2. © 2008, YCMOU. All Rights Reserved.2 OC-SBT052-CP3-03 Introduction Programmes and Courses  SEP–SBT052–Unit-03

3. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.3 Credits  Academic Inputs by Arun Punaji More. M.Sc. (Microbiology) ‏ Experience: 11 Years arunmesh@hotmail.com

4. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.4 How to Use This Resource  Counselor at each study center should use this presentation to deliver lecture of 40-60 minutes during Face-To-Face counseling.  Discussion about students difficulties or tutorial with assignments should follow the lecture for about 40-60 minutes.  Handouts (with 6 slides on each A4 size page) of this presentation should be provided to each student.  Each student should discuss on the discussion forum all the terms which could not be understood. This will improve his writing skills and enhance knowledge level about topics, which shall be immensely useful for end exam.  Appear several times, for all the Self-Tests, available for this course.  Student can use handouts for last minutes preparation just before end exam.

5. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.5 Learning Objectives  After studying this module, you should be able to: Describe type III hypersensitive reaction Explain the mechanisms of type III hypersensitive reaction Describe different immunological diseases involving type III hypersensitive reaction

6. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.6 Introduction  The immune system mount the immunological responses with number of different mechanisms depending upon the nature of foreign antigens.  Sometimes the persistent presence of antigens in the body keep stimulating and amplifying the immune reaction causing the tissues damages.  Lodging of antigens and antibodies complexes in tissues elicit the immune reactions in that tissues causing their damages.  In this module you will learn this mechanism.

7. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.7 Type III Hypersensitive Reactions-1  The type III hypersensitive reaction is also called as immune complex-mediated hypersensitive reaction.  The reaction between soluble antigens and their corresponding antibodies generate antigen-antibody complexes which are also called as immune complexes.  Usually larger immune complexes are remove from the circulation immediately by different mechanisms.  However the smaller immune complexes are not remove so easily and get accumulated in different tissues.

8. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.8 Type III Hypersensitive Reactions-2  The accumulation of such immune complexes in tissues activate the complements factors in those tissues causing the tissues damage by activated complements.  The activated complements factors such as C3a, C4a and C5a are anaphylatoxin and further stimulate the tissue mast cells to degranulate.  The C3a, C5a and C5b67 are strong chemotactic for neutrophils which accumulate at these site and secrete lytic enzymes which cause tissue damages.

9. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.9 Type III Hypersensitive Reactions-3  Mechanism:- 1) Type III hypersensitive reaction involve the formation of Ag-Ab complexes in blood and tTissue fluid. 2) Accumulation of these immune complexes in certain anatomical sites result into the damages of tissues at that site by complement factors activated by these immune complexes.

10. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.10 Type III Hypersensitive Reactions-4  The activation of complement factors induce aggregation of platelets which release clotting factor which cause formation of microthrombi.  Usually the immune complexes in blood circulation accumulate in blood vessel wall, in synovial membrane of the joints, on glomerular basement of the kidney and choroid plexus of brain.  The type III hypersensitive reaction can be localized or generalized.

11. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.11 Type III Hypersensitive Reactions-5  Localized type III hypersensitive reaction:- This type reaction occur when the antigen remain localized which then react with the circulating antibody forming localized antigen- antibody complexes. These localized immune complexes cause intense local reaction characterized by edema, induration and hemorrhagic necrosis; this reaction is called as Arthus reaction. Inhaled antigens such as thermophilic actinomycetes,bacterial spores,fungi cause pulmonary Arthus reaction developing into Farmer's lung disease and pneumonitis.

12. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.12 Type III Hypersensitive Reactions-6  Arthus raction:-mechanism

13. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.13 Type III Hypersensitive Reactions-7 Generalized type III hypersensitive reaction:-  This type reaction occur when large quantity of foreign antigens enter into the blood stream leading to formation of immune complexes in the blood.  Such type reaction sometimes observed when antitoxin containing foreign serum such as horse anti-tetanus and anti-diphtheria serum is given to patients.  In such cases antibodies are produces in large amount against the foreign serum proteins.  Such patients develop serum sickness. characterized by fever, weakness,generalized vasculitis(rashes) with edema and erythema and lyphadenopathy and arthritis.

14. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.14 Type III Hypersensitive Reactions-8 Generalized type III hypersensitive reaction:-  The circulating immune complexes get deposited in arteries causing vasculitis, into kidney causing glomerulonephritis, into synovial joints causing arthritis.  The formation of circulating immune complexes also occur in some infectious diseases given below Meningitis Hepatitis Malaria Trypanosomiasis Post-streptococcal glomerulonephritis Mononucleosis

15. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.15 Type III Hypersensitive Reactions-9 Generalized type III hypersensitive reaction:-  The formation of circulating immune complexes also occur in autoimmune diseases given below Systemic lupus erythematosus Rheumatoid arthritis Goodpasture's syndrome  In systemic lupus erythematosus immune complexes of DNA and anti DNA antibodies are formed and accumulate in synovial joints causing arthritis, in kidney causing glomerulonephritis.

16. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.16 What We Learn…..  Mechanism of type III hypersensitive reactions.  Immunological disorders involving the type III hypersensitive reactions.

17. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.17 Critical Thinking Question  Why a patient with cirrhosis is more prone to infection and immunological disorder involving type 3 reaction?

18. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.18 Hints For Critical Thinking Question  Immune complexes are not clear efficiently.  Immunological rules of liver.

19. School of Science and Technology, Online Counseling Resource… © 2008, YCMOU. All Rights Reserved.19 Study Tips  Book Title: Immunology Title: Immunology Author: Author: Richard A. Goldsby, Thomas Kindt, Barbara A. Osborne. Publication: Publication: W.H. Freeman and Company, New York.  Book Title: Textbook of Microbiology Author: Author: R. Anathanarayan & C.K.J. Paniker Publication: Publication: Orient Longman publication, Chennai.

20. © 2008, YCMOU. All Rights Reserved.20 End of the Presentation Thank You !