Histologi of Histologi of The Immune System The Immune System

E. A. JALAL

The Lymphoid Organs

Central/Primary lymphoid organs

Bone marrowThymus

Peripheral/Secondary lymphoid organs

Lymph nodesSpleen Mucosa-associated lymphoid

tissue (MALT)

Gut-associated lymphoid tissue (GALT)

Nasal-associated lymphoid tissue (NALT)

Bronchus-associated lymphoid tissue (BALT)

Urogenital tract and other mucosa

Bone Marrow

Thymus

Hassal corpuscle

Cortex

Medulla

Thymus

T cells development in thymus

Thymus derived lymphocytes

( T Lymphocytes)

• CD8+, CD3+ αβ TCR Naïve Cytotoxic T Cells

• CD4+, CD3+ αβ TCR Naïve Helper T Cells

• CD4+, CD25+, FOXP3+ Regulatory T Cells

• CD4+, αβ TCR NK T / Natural Killer T Cells

• CD3+, γδ TCRγδ T Cells

Lymphocytes mature in the bone marrow or the thymus,

then congregate in lymphoid tissue throughout the body

• The lymph nodes filter out antigens draining from the peripheral bodily tissues.

A lymph node

Capsula fibrosa

Cortex

Para cortex

MedullaHylus

Figure 1-8 part 1 of 2

Lymphonodules Germinal center

Afferen lymph vessel

Sinus sub capsularis

Sinus trabecularis

High Epithelial Venule

Medullary cords and sinuses

Spleen

Spleen

Spleen. Trabecula, central artery, splenic corpuscle

White pulp

Red pulp

Red pulp

Reticular fiber, spleen

The Mucosal Immune System

Mucosa-associated lymphoid tissues

MALTs

GALTs

Peyer’s patch

M cells

Lymphocytes in Lamina Propria

Waldeyer’sring

Tonsila palatina

Tonsila lingualis

Tonsila pharingea

Bronchus-associated LT

Solitary lymph node, upper resp tract

Mucosal Immune System

• IELs – Intra Epithelial

Lymphocytes• LP

– Lamina Propria Lymphocytes

• ILF– Isolated Lymphoid

Follicles• PP

– Peyer’s Patches• MLN

– Mesenteric Lymph Nodes

Mucosal Immune System