UNIVERSITY OF NAIROBI

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1 UNIVERSITY OF NAIROBI COLLEGE OF BIOLOGICAL AND PHYSICAL SCIENCES FACULTY OF SCIENCE LECTURE NOTES ON SZL 204:BASIC IMMUNOLOGY PROF. HORACE OCHANDA DEPARTMENT OF ZOOLOGY UNIVERSITY OF NAIROBI REVIEWED BY: PROF. R.W. MWANGI DEPARTMENT OF ZOOLOGY UNIVERSITY OF NAIROBI EDITED BY: MR. P.M. KEIYORO DEPARTMENT OF EDUCATIONAL STUDIES UNIVERSITY OF NAIROBI 2004

2 2 COURSE OUTLINE Lecture 1.0 INNATE AND ADAPTIVE IMMUNE RESPONSE 1.1 Introduction to Immunology 1.2 Historical background and applications of Immunology 1.3 Innate immunity 1.4 Acquired immunity Lecture 2.0 CELLS OF THE IMMUNE SYSTEM 2.1 Introduction 2.2 Components of mammalian blood 2.3 Fluid components of mammalian blood 2.4 Cellular components of mammalian blood Lecture 3.0 LYMPHOCYTES 3.1 Introduction 3.2 B lymphocytes 3.3 T lymphocytes 3.4 Natural killer cells Lecture 4.0 THE MYELOID SYSTEM 4.1 Introduction 4.2 Cells of the myeloid system 4.3 Neutrophils 4.4 Eosinophils 4.5 Basophils 4.6 Mast cells Lecture 5.0 THE MONONUCLEAR PHAGOCYTIC SYSTEM 5.1 Introduction 5.2 Monocyte macrophage cells 5.3 Antigen - presenting cells 5.4 Platelets Lecture 6.0 THE LYMPHOID SYSTEM 6.1 Introduction 6.2 Sources of lymphoid cells 6.3 Primary lymphoid organs 6.4 Secondary lymphoid organs

3 3 6.5 Lymphocyte circulation Lecture 7.0 CYTOKINES, IMMUNOGENS, ANTIGENS AND VACCINES 7.1 Introduction 7.2 Cytokines 7.3 Immunogens and antigens 7.4 Haptens 7.5 Vaccines 7.6 Adjuvants 7.7 Antigen antibody binding 7.8 Cross reactivity Lecture 8.0 MOLECULES INVOLVED IN ANTIGEN RECOGNITION 8.1 Introduction 8.2 Immunoglobulins 8.3 Immunoglobulin structure 8.4 Enzymatic cleavage of immuniglobulins 8.5 Classification of immunoglobulins 8.6 Properties and functions of immunoglobulins 8.7 Immunoglobulin levels in children and adults 8.8 T cell antigen receptors Lecture 9.0 MAJOR HISTOCOMPATIBILITY COMPLEX 9.1 Introduction 9.2 Histocompatibility antigens 9.3 Major histocompatibility complex 9.4 Functions of the major histocompatibility complex Lecture 10.0 THE IMMUNE RESPONSE 10.1 Introduction 10.2 Antigen processing and presentation 10.3 Activation of helper T cells 10.4 Activation of helper B cells 10.5 Activation of cytotoxic T cells 10.6 A summary of events in an immune response Lecture 11.0 CELL MEDIATED AND ANTIBODY MEDIATED IMMUNE RESPONSES 11.1 Introduction 11.2 Primary and secondary immune responses

4 Cell mediated cytotoxicity 11.4 Chronic cell mediated responses Lecture 12.0 INFLAMMATION AND THE COMPLEMENT SYSTEM 12.1 Introduction 12.2 Inflammation 12.3 Classification of inflammation 12.4 Acute inflammation 12.5 Immunologicaly mediated inflammation 12.6 Chronic inflammation 12.7 The complement system Lecture 13.0 REGULATION OF THE IMMUNE SYSTEM AND IMMUNOLOGICAL TOLERANCE 13.1 Introduction 13.2 Mechanisms of immune response regulation 13.3 Immunological tolerance

5 INTRODUCTION TO BASIC IMMUNOLOGY Welcome to the course unit SZL 204: Basic Immunology. This is an introductory course in Immunology. The unit provides you with a sound foundation of Immunology if you are intending to pursue Immunology and related subjects, such as Parasitology, at a higher level. It will also provide you with the necessary skills and knowledge to understand the basic concepts of Immunology. In this course unit, we will learn that Immunology is essentially the study of the immune system and its functions. These functions are basically defense against invading foreign organisms and removal from the body of unwanted cells. We will therefore learn about the constituent components of the immune system, how it is organized and how it functions. Under components, we will learn about the cells and organs that constitute the immune system. We will also learn about the molecules these cells produce in order to communicate with one another. The organization of the immune system is elaborate and we will therefore learn about it in a stepwise manner. We will start by defining the two main functional divisions that comprise the immune system. Thereafter, we will learn about the components of these two subdivisions. The functioning of the immune system, right from the time the immune response is activated or triggered off by the invading foreign organisms, up to the time these organisms are eliminated, will be studied in detail. Under this broad area of the functioning of the immune system, we will also learn about the various categories of immune systems. The course unit consists of a total of a series of topics which, for purposes of ease of time management, have been grouped into 13 lectures, each lasting about 45 minutes. The lectures are generally arranged in sequence such that the concepts you learn will enable you develop a platform to understand subsequent concepts. It is thus very important that you take the lectures sequentially as arranged. In Lecture 1, we will discuss how the mammalian immune system is organized. In Lectures 2, 3, 4 and 5, we will be looking at the cellular components of the immune system. In Lecture 6, we will be discussing

6 6 how cells of the immune system are organized into tissues and organs. In addition we will outline the classification of these tissues and organs. In Lecture 7, we will be looking at substances that elicit an immune response and how they are bound by cells or molecules of the immune system. In Lecture 8, we will discuss the characteristics of molecules involved in recognizing substances that elicit an immune response. By the time we are through with Lecture 8, we will have learnt about the basic features of the components of the immune system. In Lecture 9, we will look at the major histocompatibility complex, while in Lecture 10, we will outline the steps involved in an immune response. This will be from the time a foreign substance enters the body up to the time it is presented in a form that can be recognized by the immune system. Lecture 11 is a continuation of Lecture 10 since this is where we will look in detail at the final processes involved in destroying the foreign substances that enter the body. In Lecture 12, we will be discussing the other responses that the body employs in response to invasion by foreign substances or tissue damage. Finally, in Lecture 13, we will discuss the various mechanisms involved in the regulation of the immune response and immunological tolerance. Exercises and activities are given at various points throughout the unit. Please attempt these before proceeding on to subsequent sections. A summary of the content you have learned, followed by a series of self test questions, are given to you at the end of each lecture. These will help you assess yourself on how well you have comprehended the lecture content. If you find that you are unable to follow and comprehend the summarized key points of the lecture, or that you are unable to answer satisfactorily the self test questions, then it is advisable that you go over the lecture again. Also included is a list of abbreviations at the beginning and, at the end, a glossary of terms used in this unit in this booklet. These will help you in your study whenever you come across terms whose meanings you are unsure of. At the end of this course unit, you should be able to: i) Acquire the necessary skills and knowledge to enable you understand the concepts involved in the immune response. ii) Describe the processes by which the body defends itself against invading foreign organisms and removes unwanted cells. iii) Effectively apply this knowledge to your daily life.

7 Enjoy the course unit! 7

8 8 ABBREVIATIONS Ab antibody ABO system of human blood groups.. ADCC antibody - dependent cell mediated cytotoxicity. Ag antigen AIDS acquired immune deficiency syndrome. ATP adenosine triphosphate BCG Bacille Calmette-Guéerin BSA bovine serum albumin CAM cell adhesion molecule CD cluster of differentiation Con A concanavalin A CTLs cytotoxic T ltmphocytes DDT dichlorodipheniletrichloroethane DNA deoxyribonucleic acid EDTA ethylenediaminetetraacetate ELISA enzyme-linked immunosorbent assay FACS fluorescence-activated cell sorter GM-CSF granulocyte/macrophage colony stimulating factor