abbas bab 1 imune response

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© 2005 Elsevier

SELAMAT BELAJARSELAMAT BELAJAR

Downloaded from: StudentConsult (on 8 October 2007 09:08 AM)

BAB 1PROPERTIES AND OVERVIEW OF IMMUNE

RESPONSES

BAB 1PROPERTIES AND OVERVIEW OF IMMUNE

RESPONSES

Innate and adaptive immunityType of adaptive immune responses.

Cellular components of adaptive immune system

Overview of immune responses to mocrobesSummary


Figure 1-1 Innate and adaptive immunity. The mechanisms of innate immunity provide the initial defense against infections. Adaptive immune responses develop later and consist of activation of lymphocytes. The kinetics of the innate and adaptive immune responses are approximations and may vary in different infections.

Innate and Adaptive Immunity


For structures shared byGroups of relatated microbes

For antigen of microbes andfor non microbial antigens

SPECIFICITY

Limited, germline-encodedVery large, receptors are Produced By somatic recombination of gene segments

None Yes

Yes Yes

Lymphocytes in epithelia,Antibodies secreted at Epithelial surfaces.

Skin, mucosal epithelia,Antimicrobial chemicals

AntibodiesComplement, others

LymphocytesPhagocytes (macrophage,neutrophils), NK cells

DIVERSITY

MEMORY

NONREACTIVITY TO SELF

CHARACTERISTICS

COMPONENTS

CELLULAR ANDCHEMICAL BARRIER

BLOOD PROTEINS

CELLS

INNATE IMMUNITY ADAPTIVE IMMUNITY


Types of adaptive immunity.

Figure 1-2 In humoral immunity, B lymphocytes secrete antibodies that prevent infections by and eliminate extracellular microbes. In cell-mediated immunity, helper T lymphocytes activate macrophages to kill phagocytosed microbes or cytotoxic T lymphocytes (CTLs) directly destroy infected cells


Active and passive immunity

Figure 1-3 Active and passive immunity. Active immunity is conferred by a host response to a microbe or microbial antigen, whereas passive immunity is conferred by adoptive transfer of antibodies or T lymphocytes specific for the microbe. Both forms of immunity provide resistance to infection and are specific for microbial antigens, but only active immune responses generate immunologic memory.


Cardinal Features of Adaptive Immune Responses

Figure 1-4 Specificity, memory, and contraction of adaptive immune responses. Antigens X and Y induce the production of different antibodies (specificity). The secondary response to antigen X is more rapid and larger than the primary response (memory). Antibody levels decline with time after each immunization (contraction, the process that maintains homeostasis). The same features are seen in cell-mediated immune responses.


Cellular Components of the Adaptive Immune System

Figure 1-5 Classes of lymphocytes. B lymphocytes recognize soluble antigens and develop into antibody-secreting cells. Helper T lymphocytes recognize antigens on the surfaces of APCs and secrete cytokines, which stimulate different mechanisms of immunity and inflammation. CTLs recognize antigens on infected cells and kill these cells. Regulatory T cells suppress and prevent immune response, e.g. to self antigens. NK cells use receptors with more limited diversity than T or B cell antigen receptors to recognize and kill their targets, such as infected cells.


SERANGAN BAKTERISERANGAN BAKTERI

Lapis I : Fisik Kimia Flora Normal

……………………………………….

Lapis II : PMN Comp Macroph Ig.

…………..NK cell……………....………

Lapis III: B cell T cell

Antibody (Ig)

Complement Cytotoxic T Cell

Neutralization Macrophage


Effector mechanism of Adaptive Immunity.

Effector mechanism of Adaptive Immunity.

Ag Neutralization

Complement Activation

Macrophage activation (Opsonization)

ADCC

Cell Lysis

Antibody

Eradicating Extracellular microbes

Eradicating Intracellular microbes

CTL


PENANGKAPAN ANTIGENPENANGKAPAN ANTIGEN• Penangkapan(fagositosis) antigen oleh sel

dendritik (APC) yang ada di epitel, diproses dan dibawa ke kelenjar limpe untuk dipresentasikan ke sel T.

• Mikroba intak atau antigen mikroba yang mengalir juga masuk kel limpe akan bertemu dengan sel B.


Pengenalan antigen oleh limpositPengenalan antigen oleh limpositClonal selection hypothesis:

• Antigen-specific clone telah ada sebelum antigen datang

• Tiap clone (B dan T) mempunyai reseptor yang identik dan berbeda dengen reseptor pada clone lain.

• Diperkirakan lebih sepuluh juta spesifitas yang berbeda pada B dan T.


Figure 1-7 The clonal selection hypothesis. Each antigen (X or Y) selects a preexisting clone of specific lymphocytes and stimulates the proliferation and differentiation of that clone. The diagram shows only B lymphocytes giving rise to antibody-secreting effector cells, but the same principle applies to T lymphocytes.

THE CLONAL SELECTION HYPOTHESIS


Figure 1-6 Phases of adaptive immune responses. Adaptive immune responses consist of distinct phases, the first three being the recognition of antigen, the activation of lymphocytes, and the elimination of antigen (the effector phase). The response contracts (declines) as antigen-stimulated lymphocytes die by apoptosis, restoring homeostasis, and the antigen-specific cells that survive are responsible for memory. The duration of each phase may vary in different immune responses. The y-axis represents an arbitrary measure of the magnitude of the response. These principles apply to humoral immunity (mediated by B lymphocytes) and cell-mediated immunity (mediated by T lymphocytes).

PHASE OF ADAPTIVE IMMUNE RESPONSES


Subclavicular vein

Lymph capillaries

Blood capillaries

Pulmonary circulationSystemic circulation

Lymph node

Lymphatic vessel

Valve


LYMPH NODES• 550 buah• 1-10 mm in diameter

Inguinal lymph node

EfferentL.n vessels

AfferentL.n. vessels

AfferentL.n. vessels

...….


Extravasasi O2,Nutrisi, sel-sel pertahanan

Cairan Extraseluler meningkat Masuk aliran limpe

Kelenjar limpe

Sirkulasi darahLimpa

Kuman atau antigen

Kuman atau antigenyg masuk darah

Respon Imun

RespoImun

Jaringan

Sirkulasi limpe


RINGKASANRINGKASAN• Respon imun dini terhadap mikroba, respon

imunitas innate dipicu oleh struktur pada mikroba.

• Respon imun adaptif adalah spesifik untuk mikroba yang berbeda dan nonmikrobial antigen yang meningkat jika ada paparan ulang (Immulogic memory).

• Imunitas humoral yang dimediasi oleh sel B dan antibodi yg dihasilkanya yang bekerja pada mikroba ekstraseluler.


• Imunitas seluler (CMI) dimediasi oleh sel T dengan produknya (sitokin) yang bekerja pada mikroba intraseluler.

• Imunitas bisa diperoleh melalui respon terhadap antigen (Imunitas aktif) atau melalui pemindahan antibodi atau sel T dari individu yang sudah imun (imunitas pasif).

RINGKASAN


RINGKASANRINGKASAN• Sistem imun memiliki kemampuan yang sangat

penting untuk berfungsi normal seperti

- spesifik terhadap antigen yang berbeda,

- kemampuan mengenal variasi antigen yg luas

-,kemampuan untuk proliferasi cepat dari

limposit yg spesifik untuk antigen akibat

paparan antigen bersangkutan,

- mempertahankan homeostasis,

- kemampuan membedakan antigen self dan

asing


RINGKASANRINGKASAN• Limposit satu2nya sel yang mampu secara

spesifik mengenal antigen sehingga merupakan sel utama pada imunitas adaptif.

• Subpopuasi limposit yaitu B dan T berbeda pada reseptor antigen dan fungsinya.

• Spesialis antigen-precenting cells (APC) memperkenalkan antigen kepada limposit (T).

• Eliminasi antigen sering perlu melibatkan berbagai sel efektor (Keroyokan)


RINGKASANRINGKASAN• Respon imun adaptif dimulai dengan

pengenalan antigen asing oleh limposit spesifik.

• Limposit berespon(proliferasi dan differensiasi menjadi sel effektor) untuk eliminasi antigen dan pembentukan sel memori yang akan lebih hebat responsnya jika antigen sama datang lagi.

• Aktifasi limposit membutuhkan bukan hanya antigen tetapi juga signal tambahan yang bisa berasal dari mikroba atau respon imun innate terhadap mikroba.


RINGKASANRINGKASAN• CD4 T cells (helper) menolong makrofag untuk

eliminasi mikroba yang difagositosisnya dan menolong sel B untuk produksi antibodi.

• CD8 T cells (CTL) membunuh sel yang mengandung mikroba jadi mengeliminasi reservoar infeksi.

• Antibodi menetralkan mikroba, membantu makrofag mengeliminasi mikroba dan mengaktifkan komplemen.

abbas bab 1 imune response

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