School of Architecture, Science and Technology, Yashwantrao Chavan Maharashtra Open University, Nashik , India.

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

2 OC-SBT052-CP02-U02-04 Introduction Programmes and Courses SEP SBT052 Unit 02 2

3 Credits Academic Inputs by Name: Qualification: Experiences: Mr.Arun Punaji More M.Sc. in Microbiology. 11 years in the field of Academic teaching. 3

4 How to Use This Resource-1 Counselor at each study center should use this presentation to deliver lecture of minutes during Face-To-Face counseling. Discussion about students difficulties or tutorial with assignments should follow the lecture for about 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. 4

5 How to Use This Resource-2 Appear several times, for all the Self-Tests, available for this course. Student can use handouts for last minutes preparation just before end exam. The students can also automate the slide show of this presentation by setting the key: advance every to 5sec or 10 sec in the preference setting of the acrobat reader. After this setting the slide of this presentation will automatically change every set second value that you have set in the advance every key of preference setting of your acrobat reader running in full screen mode. 5

6 Learning Objectives After studding this modules you should be able to Describe the complement system. Describe classical pathway of complement system. Describe the role of complement system in immune system. 6

7 Introduction-1 In the body many chemical play important roles of destroying the pathogens by reacting with them and initiating other processes of immune responses. For example lysozyme enzyme react with cell wall of bacteria breaking the peptidoglycan layer in the cells wall causing the death of pathogenic bacteria controlling the infection until the antibody mediated or cell mediated immune response is mounted. The other chemical which can attach the pathogens and their toxins include C-reactive proteins synthesized by liver and complement factors which are special types of glycoproteins attacking pathogens and helping the phagocyte in phagocytosis. 7

8 Introduction-2 The complement proteins play very crucial role in controlling the infection at the early stage, preventing the spread of infection to other tissues. In this presentations we will learn about the complement system. 8

9 Complement System-1 Complements are group of serum glycoproteins circulating in blood in inactive state. These protein are collectively called as complement system. Complement proteins are produced mainly by livers. Significant amount of complement proteins are also produced by monocytes, tissue macrophages and epithelial cells of genitourinary and gastrointestinal tract. Wherever there is Ag and Ab reaction, complements get activated. When activated the complement proteins get reacted with each other in a sequence of chemical reaction in which product thus formed act as enzyme which catalyze the next reaction of the sequence in cascade way. In short the Ag+Ab complex activate complement proteins. 9

10 10. Complement System-2 Complement proteins play an important role in killing of microorganism coated with antibodies. Complement proteins also help in clearing the micro as well macro Ag+Ab complexes from tissue and blood. R.B.C. and macrophages possess receptors for complement protein, C3b. R.B.C. bind to C3b+Ag+Ab complex and deliver this complex to liver and spleen where it is removed by macrophages without killing R.B.C.. Binding of C3b to macrophages activate them to phagocytose Ag+Ab complex.

11 Complement System-3 Complements also facilitate opsonization to enhance phagocytosis. Complements can also amplify inflammatory reactions having detrimental effects on the host tissues. Complements can initiate anaphylaxis. The complement proteins are reffered to as C1(qrs), C2, C3, C4, C5. C6, C7, C8 and C9. The other proteins which also help in the activation of these complement factors are as follow: Factors B, D, H, I and Properdin (P). 11

12 12. Classical Pathway-1 There are number of way by which the complement system get activated. The major mechanisms by which the complement system get activated are Classical Pathway Alternate Pathway and Lectin Pathway

13 Classical Pathway-2 The sequence of events in the activation of various complement factors. 13

14 Classical Pathway-3 When antibody react with antigen, the stable complex of antigen-antibody molecules activate the first component of complement factors, C1. The activated C1 becomes enzyme. The activated C1 factor split the C2 into C2a and C2b and C4 into C4a and C4b. The C2b and C4a are released free into tissue fluid whereas the C4b and C2a combine to formed a new enzyme(c4bc2a) called as C3 convertase. The enzyme C4bC2a or C3 convertase split the complement C3 into C3a and C3b fragments; from which the C3a is set free into the tissue fluid and C3b combine with C4bC2a ie C3 convertase forming new complex, C4bC2aC3b which is also called as C5 convertase. The C5 convertase split the C5 complement into C5a and C5b. 14

15 Classical Pathway-4 The C5a fragmant is set free into tissue fluid whereas the C5b combine with C6,C7,C8 and numerous molecules forming the membrane atack complex (MAC). The membrane attack complexes make holes into cytoplasmic membrane of the pathogens leading to hypotonic lysis of the pathogens. 15

16 What We Learn... Characteristic features of complement factors. The functions of major complement factor-enzymes in immune system. Classical pathway: The mechanism of activation of complement system. 16

17 Critical Thinking Questions... To which type of infections the patient with defective complement system becomes susceptible? 17

18 Hints for Critical Thinking Questions... Complement system enhance phagocytosis by the process of opsonization. 18

19 Study Tips... Title: Roitt s Essential Immunology,10th ed. Author: Roitt I.M. Publisher: Blackwell Science Title: Microbiology Author: Robert W. Bauman Publisher: Benjamin Cummings, San Francisco. Title: Microbiology Author: Pelzar Chan and Krige. Publisher:. 19

20 Study Tips... Title: Microbiology An Introduction. Author: Tortora and et al. Publisher: Pearson Education, Singapore. Title: An Overview of the Immune System. Author: Parkin J, Cohen B. Journal: Lancet 2001; 357:

21 Thank You! 21

Chapter 16: Innate Immunity

Chapter 16: Innate Immunity 1. Overview of Innate Immunity 2. Inflammation & Phagocytosis 3. Antimicrobial Substances 1. Overview of Innate Immunity The Body s Defenses The body has 2 types of defense