Konsep Dasar Imunitas (01) Blok6

Konsep Dasar Imunologi

SISTEM IMUN

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Contents

Gangguan Sistem Imun

Cara Kerja Sistem Imun

Tipe Sistem Imun & Respons Komponen Sistem Imun

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 :

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

Functions of Immunity

_{Immune defense}

_{Immune homeostasis} _{Immune surveillance}

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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

Functions and Manifestation of Immunity

Functions Normal Manifestation Abnormal Manifestation

Immune Anti-infection Hypersensitivity

Defense Immunodeficiency

Immune Eliminate injured and senile cells immune dismodulation

Homeostasis Tolerate to self components Autoimmune disease

Immune destroy transformed cells Tumor or

Surveillance (anti-tumor ) Persistent virus 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)}

Maturasi sel B di bone marrow

Maturasi sel T di thymus (edukasi sel T)

Blood stream Duktus

thoraksikus

Blood cells derived from bone marrow cells

Blood cells migrate through blood and lymph nodes or home to tissues

Tipe Sistem Imun

I. Imunitas Alami (Innate Immunity/

native immunity/ non-specific immunity /congenital immunity)

 II. Imunitas Didapat (Adaptive Immunity/ acquired immunity/specific immunity)

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

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Sistem Kekebalan

Non-spesifik

_{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)

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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,}

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Tahap inflamasi

1. Masuknya bakteri ke dalam jaringan

2. Vasodilatasi sistem mikrosirkulasi area yg terinfeksi

meningkatkan aliran darah (RUBOR/kemerahan & CALOR/panas)

3. Permeabilitas kapiler & venul yang terinfeksi

terhadap protein meningkat  difusi protein & filtrasi air ke interstisial (TUMOR/bengkak & DOLOR/nyeri)

4. Keluarnya neutrofil lalu monosit dari kapiler & venula ke interstisial

5. Penghancuran bakteri di jaringan  fagositosis (respons sistemik: demam)

Phagocytosis

The macrophage

expresses receptors for many bacterial constituents Mannos e recepto r LPS receptor (CD14) Scavenge r receptor Bacteria binding to macrophage receptors initiate the release of cytokines and small lipid mediators of inflammation Lipid mediators Cytokines Lysosome Phagolysosom e Phagosom e Macrophages engulf and digest bacteria to which they bind

Kemampuan mengenal benda asing/antigen  spesifik

menghancurkan antigen yg sdh dikenal sebelumnya

SISTEM IMUN DIDAPAT/SPESIFIK/ DIPEROLEH

Cara sistem ini didapat : 1. Aktif

2. Pasif

• 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,}

Immune system cells

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}

The process of immune

response

in adaptive immunity

_{Effector phase of immune response}

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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

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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,}

The Pathway of Specific Immune Response

Pathogens

Pathogens eaten by Macrophage

Displays portion of Pathogen on surface

Helper-T cell recognizes Pathogen

Step 1

Step 2

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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)