Pendidikan:
1968 Lulus Dokter, Fakultas Kedokteran UI
1975 Internist Fakultas Kedokteran UI
1993 S3 Universitas Indonesia
1994 Guru Besar FK Universitas Brawijaya
Prof. DR. Dr. Handono Kalim, SpPD KR
Kegiatan Profesional:
Dewan Pengawas PB Indonesia Rheumatology Association (IRA) ,
Pembina Pusat Studi LAURA ( Lupus , Autoimun, Reumatik dan Alergi )
Staf Pengajar PsDIK dan Departemen Penyakit Dalam FK UB
Editor International Journal of Rheumatic Diseases ( IJRD)
Introduction to the Immune System
Tim MKK Imunologi FK Universitas Brawijaya 2023
Tujuan Pembelajaran/Learning Objectives
Mahasiswa mampu memahami dan menjelaskan mengenai : 1. Sel-sel dalam sistem imun
2. Imunitas alami/bawaan/innate dan imunitas adaptif 3. Tipe dan sifat imunitas adaptif
4. Jaringan sistem imun
5. Selayang pandang respons imun terhadap mikroba
Introduction
1. the nomenclature of immunology,
2. important general properties of all immune responses
3. the cells and tissues that are the principal components of the immune system.
In particular, the following questions are addressed:
• What types of immune responses protect individuals from infections?
• What are the important characteristics of immunity, and what mechanisms are responsible for these characteristics?
• How are the cells and tissues of the immune system organized to find and respond to microbes in ways that lead to their elimination?
Terminology
• Immunity : resistance to disease, specifically infectious disease.
• Immune system: the collection of cells, tissues, and molecules that mediate resistance to infections
• Immune response: the coordinated reaction of immune cells and molecules to infectious microbes.
• Immunology: is the study of the immune system, including its
responses to microbial pathogens and damaged tissues and its role in disease.
• Any substance that is specifically recognized by lymphocytes or antibodies is called an antigen
Physiologic function of the immune
system
Most important : To prevent or eradicate infections
Effectiveness of vaccination for some common
infectious diseases
CELLS OF THE IMMUNE SYSTEM
Hematopoiesis ( within bone marrow)
IMMUNE CELLS
Maturation of mononuclear phagocytes
11
Function of First Line
Immune cells
Lymphocytes and APC
Classes of
lymphocytes
Stages in the life history of lymphocytes
How can Immune Cells eliminate microbes?
First Innate immunity/response and then adaptive immunity/response
Immune Response Microbes
Innate Immunity
• The first line of defense is provided by epithelial barriers of the skin and mucosal tissues and by cells and natural
antibiotics present in epithelia, all of which function to block the entry of microbes.
• If microbes do breach epithelia and enter the tissues or circulation, they are attacked by phagocytes, specialized lymphocytes called innate lymphoid cells, which include
natural killer cells, and several plasma proteins, including the proteins of the complement system.
How can Innate Immunity attack microbes?
The two principal ways the innate immune system deals with microbes is by inducing inflammation and by antiviral mechanisms.
• Inflammation: is triggered by all classes of microbes, is the
recruitment of circulating blood leukocytes (e.g., phagocytes and lymphocytes) and various plasma proteins (e.g., complement,
antibodies, fibrinogen) to sites of infection, where they function to destroy the microbes and repair damaged tissue.
• The antiviral mechanisms render host cells inhospitable for viral infection and reproduction.
These innate responses are often sufficient to prevent infection within tissues or the blood.
From Innate to Adaptive immunity
Antigen presentation by APC to induce adaptive immunity
Innate and Adaptive Immunity
Innate immunity:
• immediate protection against microbial invasion
• always present in healthy individuals (hence the term innate),
• prepared to block the entry of microbes
• rapidly eliminate microbes that do succeed in entering host tissues.
Adaptive immunity:
• develops more slowly and provides more specialized defense against infections
• requires expansion and differentiation of lymphocytes in response to microbes before it can provide effective defense; that is, it adapts to the presence of microbial invaders
Two Types of Adaptive Immunity
Humoral immunity :
• is mediated by proteins called antibodies,
• which are produced by cells called B lymphocytes
• to defense against extracellular microbes
Cell-mediated immunity:
• is mediated by T lymphocytes
• to defense against intracellular microbes
Microbes
Cell-mediated immunity Humoral immunity
Responding lymphocytes
Effector mechanism
Functions
How can the adaptive immune system combat microbes?
• Secreted antibodies bind to extracellular microbes, block their ability to infect host cells, and promote their ingestion and
subsequent destruction by phagocytes.
• Phagocytes ingest microbes and kill them, and helper T cells enhance the microbicidal abilities of the phagocytes.
• Helper T cells recruit leukocytes to destroy microbes and enhance epithelial barrier function to prevent the entry of microbes.
• Cytotoxic T lymphocytes (CTL) kill cells infected by microbes.
Properties of Adaptive Immune Responses
Clonal
selection
Phases of
adaptive immune response
Active immunity and Passive immunity
• Immunity may be induced in an individual by infection or vaccination (active immunity)
• or conferred on an individual by transfer of antibodies
or lymphocytes from an actively immunized individual
(passive immunity).
Change in proportions of naive and memory T cells with age
The tissues of the immune system
The tissues of the immune system
Generative lymphoid organs,
• in which T and B lymphocytes mature and become competent to respond to antigens
• Bone marrow and thymus
Peripheral lymphoid organs
,• in which adaptive immune responses to microbes are initiated
• Lymphnodes, spleen, mucosal associated lymphoid tissues
Circulation of lymphocytes
Lymphnode
Lymph node
Spleen
The lymphatic system
Mucosal immune system.
Summary
Summary (1)
• The physiologic function of the immune system is to protect individuals against infections.
• Innate immunity is the early line of defense, mediated by cells and molecules that are always present and ready to eliminate infectious microbes.
• The two principal ways the innate immune system deals with microbes is by inducing inflammation and by antiviral
mechanisms
Summary (2)
• Adaptive immunity is mediated by lymphocytes stimulated by microbial antigens, requires clonal expansion and
differentiation of the lymphocytes before it is effective, and responds more effectively against each successive exposure to a microbe.
• Lymphocytes are the cells of adaptive immunity and are the only cells with clonally distributed receptors with fine
specificities for different antigens.
Summary (3)
• Adaptive immunity consists of
a. humoral immunity, in which antibodies neutralize and eradicate extracellular microbes and toxins,
b. cell-mediated immunity, in which T lymphocytes eradicate intracellular microbes.
• Adaptive immune responses consist of sequential phases:
antigen recognition by lymphocytes, activation of the
lymphocytes to proliferate and to differentiate into effector and memory cells, elimination of the microbes, decline of the
immune response, and long-lived memory.
Summary (4)
• Antigen recognition : Antigen-presenting cells (APCs) capture antigens of microbes that enter through epithelia,
concentrate these antigens in lymphoid organs, and display the antigens for recognition by T cells.
• Lymphocytes and APCs are organized in peripheral lymphoid organs, where immune responses are initiated and develop.
• Naive lymphocytes circulate through peripheral lymphoid organs, searching for foreign antigens.
Summary (5)
• Different populations of lymphocytes serve distinct functions and may be distinguished by the surface expression of
particular membrane molecules.
• B lymphocytes are the only cells that produce antibodies.
• B lymphocytes express membrane antibodies that recognize antigens, and the progeny of activated B cells, called plasma cells, secrete the antibodies that neutralize and eliminate the antigen.
Summary (6)
• T lymphocytes recognize peptide fragments of protein antigens displayed on other cells.
• Helper T lymphocytes produce cytokines that activate
phagocytes to destroy ingested microbes, recruit leukocytes, and activate B lymphocytes to produce antibodies.
• Cytotoxic T lymphocytes (CTLs) kill infected cells harboring microbes in the cytoplasm.
.
Referensi utama
• Imunologi Dasar Abbas (fungsi dan kelainan sistem imun), 2021; edisi bahasa Indonesia ke enam. Editor: Prof Handono Kalim. Editor edisi asli: Abul K. Abbas, Andrew H. Lichtman, Shiv Pillai. Elsevier Singapore
