Cells and functions

Characteristics of the Innate Immune System

• Cells express PRR or Fc Receptors

• Effects are seen within hours of infection

• Response to antigen is non-specific

• Response is stable upon subsequent exposures

Characteristics of the Adaptive Immune System

• Cells express lymphocyte receptors or release antibody molecules

• Effects are seen within one week of infection

• Response to antigen is specific

• Response is bigger, faster, and stronger upon subsequent exposures

Cells that belong in the innate immune system

• Macrophages

• Neutrophils

• Basophils

• Dendritic Cells

• Mast Cells

• Eosinophils

• Natural Killer Cells

• Innate Lymphoid Cells

• Natural Killer Cells

Cells that belong in the Adaptive immune system

• B lymphocytes

• Plasma Cells

• T lymphocytes

First Stage of inflammation

Surface wound introduces bacteria into underlying tissue

Second Stage in inflammation

Local phagocytes recognize bacteria via pattern recognition receptors

Third Stage in inflammation

Activated macrophages release pro-inflammatory cytokines and chemokines

Fourth Stage in inflammation

Cytokines cause vasodilation and vascular permeability of blood vessels

Fifth Stage in inflammation

Chemokines cause infiltration of monocytes

Sixth Stage in Inflammtion

Infected tissue becomes inflamed, causing redness, heat, swelling, and pain

Helps Activate Macrophage

Th1 Cells

Helps activate mast cells, eosinophils, and basophils

Th2 Cells

Helps activate neutrophils

Th17 Cells

Inhibits other T lymphocytes

Regulatory T Cells (Treg)

Initiates B cell activation, proliferation, and differentiation

Follicular helper T cells (Tfh)

Performs antigen presentation to T lymphocytes

Macrophages, Mature Dendritic Cells, and B lymphocytes

Performs recepter-mediated phagocytosis

Macrophages, neutrophils, and immature dendritic cells

Primary producer of pro-inflammatory cytokines

Machrophages

Produces Antibodies

Plasma cell

Releases granules upon activation

Mast Cells, eosinophils, and basophils

Extracellular bacteria and fungi

Neutrophils and Group 3 ILC’s

Extracellular parasites

Basophils, Eosinophils, Group 2 ILC’s, Mast Cells

Intracellular pathogens

Cytotoxic T Cells, Group 1 ILC’s, Natural Killer Cells

Primary Lymphoid Tissue

Bone Marrow

Primary Lymphoid Tissue

Thymus

Secondary Lymphoid Tissue

Adenoids

Secondary Lymphoid Tissue

Appendix

Secondary Lymphoid Tissue

Lymph Nodes

Secondary Lymphoid Tissue

Tonsils

Secondary Lymphoid Tissue

Spleen

Secondary Lymphoid Tissue

Peyer’s Patch

Where do foreign antigens enter the lymph node? Where are they coming from?

Afferent lymphatic vessel; site of infection within the tissue

Where do naive B and T lymphocytes enter the lymph node? Where is their first destination within the lymph node?

Afferent lymphatics or high endothelial venules (HEV); paracortical area

Where do activated B lymphocytes proliferate and differentiate within the lymph node?

Germinal Center

Where do activated T lymphocytes proliferate and differentiate within in the lymph node?

Paracortical Area

Where do activated T lymphocytes and antibodies exit the lymph node?

Efferent lymphatic vessel; site of infection within the tissue

Where do foreign antigens enter the spleen? Where are they coming from?

Central Arterioles; general circulation (blood)

Where do naive B and T lymphocutes enter the spleen? Where is their first destination in the spleen?

Central Arterioles; periarteriolar lymphoid sheath (PALS)

Where do activated B lymphocytes proliferate and differentiate within the spleen?

Germinal Center

Where do activated T lymphocytes proliferate and differentiate within the spleen?

Periarteriolar Lymphoid Sheath (PALS)

Where do activated T lymphocytes and antibodies exit the spleen?

General Circulation (Blood)

Where do antigens enter the Peyer’s patch? Where are they coming from?

M cells; site of infection within mucosal tissues

Where do naive B and T lymphocytes enter the Peyer’s patch? Where is their first destination within the Peyer’s patch?

High endothelial venules (HEV); T cell dependent area (TDA)

Where do activated B lymphocytes proliferate and differentiate within the Peyer’s Patch?

Germinal Center

Where do activated T lymphocytes proliferate and differentiate within the Peyer’s Patch

T cell dependent area (TDA)

Where do activated T lymphocytes and antibodies exit the Peyer’s Patch? Where is their final destination?

Afferent Lymphatic Vessel: site of infection within mucosal tissues