Immunology 1

• This subject aims to apply dental therapy and hygiene principles based on biomedical, behavioural, and materials sciences.
• The goal is to develop an understanding in the study of immunology.

Assessments

• Formative: Consolidation session to reinforce learning.
• Summative: E-assessment focused on Biomedical Sciences.

Intended Learning Outcomes

• Consolidate learning from "Introduction to Immunology" asynchronous session.
• Identify immune system organs and tissues.
• Discuss the origins and functions of immune system cells.
• Detail processes and functions of both non-specific and adaptive immune systems.

Consolidation of Learning

• Discussed are the characteristics and differences of innate and adaptive immunity
• Explored are immune cells' origins, types, and functions, along with non-specific barriers

Components of the Immune System

• Primary components: Tonsils, thymus, bowel, bone marrow and skin.
• Secondary components: Mucous membranes, lymph nodes and spleen.

Primary Components: Organs and Tissues

• Bone marrow: Forms all of the body's immune cells.
• B lymphocytes/cells: Mature in the bone marrow.
• T lymphocytes/cells: Travel to the thymus before circulating.

Cells of the Immune System

• Include: Monocytes, lymphocytes, neutrophils, eosinophil, basophil, macrophage, erythrocyte and platelets

Non-Specific Immune System (Innate) Barriers

• Skin-fatty acids: Affect pH, hindering some pathogen survival.
• Mucous membrane: Mucous and cilia lining tracts with lysozyme offer protection.
• Other factors: Temperature and pH act as barriers.
• Chemical mediators and immune responses contribute.
• Inflammation: Body's response to tissue damage or microbial invasion.

Humoral Factors of the Innate Immune System

• Complement system: A complex enzyme group in the bloodconsisting of factors 1-9.
• Classical pathway: Activated by immune complexes.
• Alternative and lectin pathways: Activated by bacterial cell wall structures.
• Activation of the complememt system releases histamine, increasing blood flow and vascular permeability.
• Complement proteins attract neutrophils. Microbes covered in complement proteins undergo phagocytosis.
• Cytokines: Glycoproteins that modulate the immune system.
• Main producers: Helper T cells (Th cells) and macrophages.

Inflammation: Role of Phagocytes

• Inflammation directs phagocytes to injured areas to isolate, destroy, and inactivate pathogens.
• It removes debris and prevents the spread of infection.
• It also prepares for healing and mobilizes effector cells with T and B lymphocytes.

Inflammation Process for Bacterial Invasion/Tissue Damage

• Bacterial invasion leads to histamine release by MAST cells.
• Increased delivery of blood leads to redness and increased temperature.
• Capillary permeability increases locally, leading to swelling and local fluid accumulation causing pain.
• Increase in phagocytes to the tissues along with secretion occurs.
• Defense against pathogens can result in systemic responses, such as fever, occurs.

Adaptive Immunity

• Adaptive immunity is activated when innate immunity cannot effectively eliminate infectious agents.
• Adaptive immunity is specific to the pathogen presented.
• Involves pathogen-specific immunologic effector pathways to eliminate specific pathogens/ infected cells.
• The development of immunologic memory eliminates the pathogen with subsequent infections.

T Cells and Antigen Presenting Cells (APCs) in Adaptive Immunity

• Attacks non-self pathogens but can mistakenly attack itself, causing autoimmune diseases like rheumatoid arthritis or lupus.
• Clonal expansion occurs with T and B lymphocytes.
• T cell activation involves antigen-presenting cells (APCs) like macrophages.

T-Cells

• T Cells only recognise antigen associated with MHC on APC cell surfaces.
• T helper cells produce B cells and antibodies.
• T helper cells also produce macrophages and killer T cells.

B Cells

• Plasma and Memory cell animation.