www.immunology.unideb.hu
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Esther Bokhobza estherbokhobza@gmail.
com
Basic Immunology
BSc in Physiotherapy
Weeks 1-15Wednesdays 10-12
F.402
Immunitas = freedom from (Latin)
What is the function of the immune system?How does it recognize, eliminate and remember pathogenic
microorganisms?
How does it differentiate between harmful and harmless? How does it differentiate between self and non-self?
What about its specificity? What about flexibility? (Influenza)Speed? Is there room for failure? (Immunodeficiency)
Keep in mind!Harmful self- tumorsHarmless non-self- normal flora
Immunitas = freedom from (Latin)
We live in a potentially hostile world filled with infectious agents of diverse shape, size and composition which would
very happily use us as rich sanctuaries…
…had we not developed a series of defense mechanisms.
WHY IS THE IMMUNE SYSTEM SO IMPORTANT?
Viruses
Multicellular parazites (helminths)
Monocellular parazites
Virus
3 hours
3 hours
Bacteria
PATHOGENS
Cells of human body: 90% microbes, 10% human
Gut bacteria: 1014
Human cell population: 1013
DEFENCE MECHANISMS
Microbiological barriers
The normal floraA microbial community that inhabits the skin and mucosal membranes of mouth, gut and vagina. Symbiotic, non-pathogenic microbes, living in „peaceful” commensalisms.
In this ecosystem, the fittest survive and there is a competition over nutrients with pathogenic organisms. (Bacteria, Fungi, Protozoa, Viruses and Helminthes).
Physical and chemical barriers
pH of 3-4 Pepsin
Stomach
Skin
Tight junctions Keratin layer Antibacterial peptides; Defensins pH of 5.5 Fatty acids
Burns and susceptibility to infections!
pH of 3.8-4.5 Lactobacillus Lactic acid
Vagina
Eye Tear film (Oils, lactoferin, mucin and lyzosyme)
Respiratory tract
Impaired cilia movement (CF)!
Cilliary movement Coughing, sneezing
Primary lymphoid organs:
- Bone marrow- Thymus
Secondary lymphoid organs:
- Spleen- Lymphatic vessels- Lymph nodes- Adenoids and tonsils- MALT (Mucosal Associated Lymphoid Tissue) GALT (Gut Associated Lymphoid Tissue) BALT (Bronchus Associated Lymphoid Tissue) SALT (Skin Associated Lymphoid Tissue)
NALT (Nasal Associated Lymphoid Tissue)
LYMPHOID ORGANS!!
Bone marrow
Hematopoietic cells leave the central cavity and drain to a central vein
The bone marrow of a 65kg person weights 2.6kg and produces around 500 billion cells per day
Red bone marrow The site of hematopoiesis
Thymocytes
Epithelial cells
Dendritic cells
Macrophages
Thymus
Thymocytes from the bone marrow arrive at the thymus and mature into T cells
Spleen
Weights 150g, in the upper left abdomen. The
spleen filters the blood and serves as a secondary lymphoid organ
Spleen
Lymphocyte aggregations similar to the lymph node only that cells and pathogens enter from the blood
Red pulp- filters the blood; from antigens, microorganisms and worn-out RBCs
Lymphatic vessels
Lymphatic nodes
Lymph node
Secondary lymphatic tissues
Lymphatic tissues that are more diffused are generally known as MALT (Mucosa associated lymphatic tissue). Similar microanatomy as the lymph nodes and spleen
• Most of the pathogens get into human body through mucosa • A thin, huge surface, dinamic structure• Intense and active immune surveillance mechanisms ensure the
protection
• Mucus contains glycoproteins, proteoglycans, special enzymes• Anti microbial peptides provide biological defence mecanism
against intection• Most of the lymphocyte reside arround the mucosal surface
Secondary lymphatic tissues
MALT
Kripta
GALT
• The small intestine contains lymphoid nodules; the
Peyer’s patches and isolated lymphoid follicles.
• Pathogens are delivered across the mucosa to APCs by specialized mucosal epithelial cells are called the M cells (microfold cells).
• The Lamina propria contains lymphatic tissue underlying the gastrointestinal tract connective tissue
GALT
Intra-epithelial lymphocytes
GALT
• Antigens arising from Peyer’s patches and Lamina Propria travel to T cell areas in the GALT or Mesenteric lymph nodes.
• The large intestine contains isolated lymphoid follicles and the appendix
Guarding the gastrointestinal entrance
Waldeyer’s ring: Pharyngeal, Tubal, Palatine and Lingual Tonsils
Tonsilitis
NALT
Supplementary material
Edward Jenner 1796
The induction of immunity/protection from smallpox (cowpox)
FIRST VACCINATION
Louis Pasteur 1880
Immunization with attenuated pathogens against rabies
Ilya Mechnikov1883
Probiotics
Paul Ehrlich1900Phagocytosis
Pathogen recognition by special receptor, clonal proliferation to multiply cells that are able to
recognize the pathogen
Koch Laboratory, Germany 1890
Diphteria and Tetanus toxin
Emil Behring Shimbasaru Kitasato
1. Many diseases occur only once (natural protection)
2. Some diseases can be prevented by vaccination
3. The blood contains anti-bacterial activity (anti-toxins, serum therapy)
Protective humoral factors
Antibodies in serumbound to relevant pathogens
