This document summarizes a seminar presentation on the complement system and hypersensitivity of the immune response. It provides an overview of the complement system, including that it is comprised of 20 plasma proteins that form an essential part of innate immunity. It describes the three pathways of complement system activation - the classical, alternative, and lectin pathways. It also outlines the four types of hypersensitivity reactions classified by Gell and Coombs.

1. GM INSTITUTE OF TECHNOLOGY
P.B.ROAD, DAVANGERE
SEMINAR ON :
COMPLEMENT AND
HYPERSENSITIVITY OF
IMMUNE RESPONSE TO
INFECTION
BY:
MEGHANA.L
5TH SEMESTER
BIOTECHNOLOG
Y

2. COMPLEMENT SYSTEM
CONTENTS:
 OVERVIEW
 ACTIVATION PATHWAYS
 IMMUNE EFFECTS

3. WHAT IS A COMPLEMENT SYSTEM?
It is a group of 20 plasma proteins that forms essential
part in the innate immunity.
The word “complement” is used because our
complement system enhances or complements our
immunity.

4. •Complement system proteins are mainly synthesized in the liver and
widely distributed among body fluids and tissues.
•Comes into effect only when activated.
•11 proteins are mostly involved namely B, C1-C9 and D.
•These are enzyme precursors and they catalyse the enzymatic
reactions to form final product.

5. HOW IT IS ACTIVATED?
1. ANTIGEN- ANTIBODY REACTION
CLASSICAL PATHWAY
2. BACTERIAL ENDOTOXIN
ALTERNATIVE PATHWAY
3. LECTIN PATHWAY
MANNOSE BINDING LECTIN

6. CLASSICAL PATHWAY

7. ALTERNATIVE PATHWAY

8. LECTIN MANNOSE PATHWAY

9. IMMUNE EFFECTS OF THE VARIOUS
COMPLEMENT PRODUCTS
1.OPSONISATION
2.CELL LYSIS

10. 3.CHEMOTAXIS
4.ACTIVATION OF MAST CELL

11. HYPERSENSITIVITY
CONTENTS:
 INTRODUCTION
 CAUSES
 TYPES

12. What is hypersensitivity?
Hypersensitivity is increased reactivity or increased
sensitivity by the animal body to an antigen to which it has
been previously exposed.
They are usually referred to as the overreaction of the
immune system. These reaction may be damaging,
uncomfortable, and occasionally fatal.

13. CAUSES
Immune responses that are the cause of hypersensitivity
diseases
may be specific for antigens from different sources:
 Autoimmunity: reactions against self antigens.
 Reactions against microbes.
 Reactions against non-microbial environmental antigens.

14. Types of Hypersensitivity Reactions
 The Gell’s and Coombs’ classification of hypersensitivity
reactions considers four types of reactions.
 Type I, II, and III reactions are basically mediated by
antibodies with or without participation of the complement
system
 Type IV reactions are cell-mediated.

15. Type I: Immediate reaction

16. Type 2: Antibody-mediated
cytotoxic reaction

17. Type 3: Immune complex
mediated reaction

18. Type 4: Delayed type
hypersensitivity reaction