Konsep Dasar Imunologi SISTEM IMUN Riandini Aisyah
Contents Fungsi Sistem Imun Komponen Sistem Imun
Tipe Sistem Imun & Respons Cara Kerja Sistem Imun
Gangguan Sistem Imun
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Definisi Imunitas : resistensi tubuh thd masuknya substansi asing Respon imun : reaksi thd substansi asing yg terkoordinasi Sistem imun : sel & molekul yg bertanggung jawab dlm imunitas Imunologi : experimental science
Immunology Terms Antigen Any molecule that binds to immunoglobulin or T cell receptor
Pathogen Microorganism that can cause disease
Antibody (Ab) Secreted immunoglobulin
Immunoglobulin (Ig) Antigen binding molecules of B cells
Vaccination Deliberate induction of protective immunity to a pathogen
Immunization The ability to resist infection
Functions of Immunity Immune defense Immune homeostasis Immune surveillance
1. Melindungi tubuh dari invasi agen penyebab penyakit menghancurkan mikroorganisme atau substansi asing (bakteri, parasit, jamur, dan virus, serta tumor) yang masuk ke dalam tubuh 2. Mengenali dan menghilangkan sel yang abnormal
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Patogen bagi tubuh manusia 1. Bakteri 2. Virus 3. Parasit
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Functions and Manifestation of Immunity Functions Immune Defense
Normal Manifestation Anti-infection
Abnormal Manifestation Hypersensitivity Immunodeficiency
Immune Eliminate injured and senile cells Homeostasis Tolerate to self components
immune dismodulation Autoimmune disease
Immune Surveillance
Tumor or Persistent virus infection
destroy transformed cells (anti-tumor ) Prevent from persistent infection
Komponen Sistem Imun Leukosit (White Blood Cells) Limfosit T & Limfosit B
Organ Limfoid (Lymphoid Organ) Organ limfoid primer: • Sumsum tulang – origin of all immune cells – site for development and education of B cells
• Thymus: – site for development and education of T cells
Organ limfoid sekunder • Lymph nodes, limpa, lymphoid tissue – induction sites for immune responses
Jaringan tubuh (Body Tissues) • effector sites for immune responses
Maturasi sel B di bone marrow Maturasi sel T di thymus (edukasi sel T)
Blood stream Duktus thoraksikus Limfonodus
cells
Blood cells derived from bone marrow cells
cells
Blood cells migrate through blood and lymph nodes or home to tissues
Myeloid cells in immunity
Tipe Sistem Imun I. Imunitas Alami (Innate Immunity/ native immunity/ non-specific immunity /congenital immunity) II. Imunitas Didapat (Adaptive Immunity/ acquired immunity/specific immunity)
IMUNITAS ALAMIAH/INNATE IMMUNITY/ NON SPESIFIK
1. Respon langsung thd antigen 2. Tidak ditujukan terhadap mikroorganisme tertentu 3. Komponen : Barrier fisik / mekanik : kulit, selaput lendir, silia, batuk, bersin Biokimia & faktor terlarut : asam lambung, Humoral : komplemen, interferon (IFN), C-reactive prot (CRP) Seluler : sel fagosit (monosit, makrofag, neutrofil, eosinofil), sel NK
Sistem Kekebalan Nonspesifik
Dapat mendeteksi adanya benda asing & melindungi tubuh dari kerusakan yang diakibatkannya, namun tdk dpt mengenali benda asing yang masuk ke dalam tubuh. Yang termasuk dlm sistem ini: 1. Reaksi inflamasi/peradangan 2. Protein antivirus (interferon) 3. Sel natural killer (NK) 4. Sistem komplemen
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Inflamasi/ Peradangan Merupakan respons lokal tubuh thd infeksi atau perlukaan Tidak spesifik hanya untuk infeksi mikroba, tetapi respons yg sama juga terjadi pada perlukaan akibat suhu dingin, panas, atau trauma Pemeran utama: fagosit, a.l: neutrofil, monosit, & makrofag
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Tahap inflamasi 1. 2. 3. 4. 5. 6.
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Masuknya bakteri ke dalam jaringan Vasodilatasi sistem mikrosirkulasi area yg terinfeksi meningkatkan aliran darah (RUBOR/kemerahan & CALOR/panas) Permeabilitas kapiler & venul yang terinfeksi terhadap protein meningkat difusi protein & filtrasi air ke interstisial (TUMOR/bengkak & DOLOR/nyeri) Keluarnya neutrofil lalu monosit dari kapiler & venula ke interstisial Penghancuran bakteri di jaringan fagositosis (respons sistemik: demam) Perbaikan jaringan
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Phagocytosis
Scavenge r receptor
Lipid mediators
Mannos e recepto r
Lysosome Phagosom e
LPS receptor (CD14)
The macrophage expresses receptors for many bacterial constituents
Cytokines
Bacteria binding to macrophage receptors initiate the release of cytokines and small lipid mediators of inflammation
Phagolysosom e
Macrophages engulf and digest bacteria to which they bind
Macrophages
SISTEM IMUN DIDAPAT/SPESIFIK/ DIPEROLEH
Kemampuan mengenal benda asing/antigen spesifik menghancurkan antigen yg sdh dikenal Cara sistem ini didapat : sebelumnya 1. Aktif 2. Pasif Dasar kerja INGATAN/MEMORI !!
• Innate imm response makes a crucial contribution to the activation of adaptive imm • Immature dendritic cells (DCs) catch pathogens (antigens) and carry pathogenic material to a lymph node where the antigens are presented to lymphocytes.
Innate vs adaptive immunity Innate immunity First line of defense (present in all individuals at all times) Immediate (0 – 4 hours) Non-specific Does not generate lasting protective immunity Adaptive immune response (late: > 96 hours) Is initiated if innate immune response is not adequate (> 4 days) Antigen-specific immunity Generates lasting protective immunity (e.g. Antibodies, memory T-cells)
Immune system cells Adaptive immunity Selluler :
Lymphocyte • B cells • T cells – Cytotoxic T cells (CTLs) – Helper T cells (Th)
• Memory cells Humoral :
Antibodi
Types of Immunity Humoral immunity Immunity that is mediated by antibodies Can be transferred by to a non-immune recipient by serum
Cell Mediated Immunity Immune response in which antigen specific T cells dominate
The process of immune response in adaptive immunity Recognition of antigens Activation,proliferation and differenciation of T or B lymphocytes Effector phase of immune response ----Elimination of antigens
Sistem Kekebalan Humoral Antigen (Ag) merangsang sel B berubah menjadi sel plasma yg memproduksi antibodi (Ab). Ab disekresi ke darah atau limf lokasi sel plasma yg teraktivasi; semua Ab akan mencapai darah gamma globulin = imunoglobulin (Ig)
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Imunoglobulin (Ig) Ada 5 kelas: 1. Ig M berperan sbg reseptor permukaan sel B & disekresi pd tahap awal respons sel plasma 2. Ig G Ig terbanyak di darah, diproduksi jika tubuh berespons thd antigen yg sama Ig M & IgG berperan jika tjd invasi bakteri & virus serta aktivasi komplemen 3. Ig E melindungi tubuh dr infeksi parasit & mrp mediator pd reaksi alergi; melepaskan histamin dari basofil & sel mast 4. Ig A ditemukan pd sekresi sistem perncernaan, pernapasan, & perkemihan (cth: pd airmata & ASI) 5. Ig D terdapat pada banyak permukaan sel B; mengenali antigen pd sel B 33
Fungsi Antibodi
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Sistem Kekebalan Seluler Limfosit T spesifik untuk kekebalan terhadap infeksi virus & pengaturan pd mekanisme kekebalan. Sel-sel T harus kontak langsung dg sasaran Ada 3 subpopulasi sel T: sel T sitotoksik, sel T helper, & sel T supressor Major histocompatibility complex (MHC): kode human leucocyte-associated antigen (HLA) yg terikat pd permukaan membran sel; khas pd setiap individu Surveilens imun: kerjasama sel T sitotoksik, sel NK, makrofag, & interferon
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The Pathway of Specific Immune Response Step 1 Pathogens eaten by Macrophage
Step 2 Displays portion of Pathogen on surface
Step 3 Pathogens
Helper-T cell recognizes Pathogen
Cara Kerja Sistem Imun
Aktivasi Sel T
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Pembentukan Kekebalan Jangka Panjang (long-term immunity) Pada kontak pertama dg antigen mikroba, respons antibodi terjadi lambat dlm bbrp hari sampai terbentuk sel plasma & akan mencapai puncak dlm bbrp minggu (Respons primer); & akan membentuk sel memori Jika terjadi kontak dg antigen yg sama, krn adanya sel memori, respons yg terjadi mjd lebih cepat (Respons sekunder) 41
Gangguan Sistem Imun
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