Immunology Course Overview

Immunology Course Content

• The course covers the components of the immune system, immunogens, antigens, and antibodies.
• The development of B lymphocytes is part of the curriculum.
• The presentation of antigen by Major Histocompatibility Complex (MHC) is addressed.
• T lymphocytes and T-cells receptors are included.
• Mechanisms of the immune response, T and B lymphocyte interaction, and innate immunity are examined.
• Flow cytometry and blood typing are crucial components, presented across 2 lectures and labs.
• Cytokines are part of the material.
• A tetanus tutorial (small-group) is included.
• Complement systems, hypersensitivity reactions, autoimmunity, and autoimmune diseases are part of the curriculum.
• Case studies on hypersensitivity reactions (small-group tutorial) are featured.
• Immunity to infections and inflammation, HIV infection, and vaccine development are also part of the curriculum (phase 2).
• The course includes tumor immunology (phase 3).
• Pre-tests and post-tests are part of the small-group tutorials to guide students.
• Practice questions are used across the semesters.

Objectives

• Distinguishing innate from acquired immunity
• Identifying and describing immune system cells
• Describing lymphoid organs, structures, and associated cell functions
• Explaining lymphocyte recirculation's role in antigen trapping and immunity development

Importance of the Immune System

• Defense against infection (including pandemics)
• Vaccine/immunization
• Tumor defense
• Barriers to transplantation
• Immunotherapy against infections and cancers

Challenges to the Immune System

• Specificity, Diversity, Memory, Specialization, Resolution, Non-reactivity to self, and Mobility

Immune Defense

• Humans are constantly under attack from pathogens from conception.
• The immune system must defend against invaders from the air (e.g., viruses, bacteria, fungi, pollen), water (viruses, bacteria, parasites, foods), surfaces (viruses, bacteria, fungi, parasites), and internally (autoimmune diseases, cancers).

Immune System Recognition

• The core function of the immune system is recognizing "self" from "non-self."
• The immune system is trained to not react against the body.
• This recognition involves innate and acquired immune responses.

Two Types of Immunity

• Innate (non-specific): Basic immune elements present at birth, readily available, include body surfaces, mucous membranes, cough reflexes, and fever responses, and phagocytic cells (macrophages, granulocytes, NK cells).
• Acquired (specific): More specialized elements developing after birth, only present in vertebrates, activated by prior contact with a given agent (immunization), leading to lymphocyte activation, antibody production, and subsequent immunity to the same agent.

Hematopoiesis

• Hematopoiesis is the development of blood and blood-derived cells.
• It involves pluripotent hematopoietic stem cells in bone marrow that differentiate into various blood components.

Myeloid Lineage

• Includes granulocytes, immature/mature dendritic cells, mast cells, and macrophages.
• Plays a role in innate and adaptive immunity.
• Cells like macrophages and dendritic cells in the tissues act as phagocytes by engulfing bacteria.
• Other cells like neutrophils, eosinophils, basophils, and mast cells, play a role in killing bacteria and parasites.

Lymphoid Lineage

• B-cells mature in the bone marrow, producing antibodies.
• T-cells mature in the thymus, having antigen-specific receptors (TCRs), with CD4 helper cells and CD8 cytotoxic cells.
• Natural Killer (NK) cells mature in the bone marrow, lacking antigen-specific receptors, play a key role in innate immune responses.
• Small lymphocytes cannot be distinguished morphologically, but can be determined by antibody subtypes that recognize a marker feature (example, CD4 or CD8).
• Plasma cells reside in lymph nodes, are rarely found in the blood, and indicate pathologies such as cancer myeloma.

Antigen-Presenting Cells

• Antigen-presenting cells (APCs) (macrophages, dendritic cells, B lymphocytes) take up, digest, and display antigens on MHC class II molecules to activate CD4-positive T-cells.

Macrophages

• Macrophages are distributed throughout the reticuloendothelial system (e.g., in the liver, kidney, brain, lungs, spleen, lymph nodes.)
• All macrophages originate from blood monocytes.

Lymphocytes in Lymphoid Tissues

• Lymphocytes are found in specialized lymphoid tissues (e.g., lymph nodes, spleen, tonsils, adenoids).
• T-cells mature in the thymus but originate in the bone marrow.
• Lymphatic vessels drain extracellular fluid containing pathogens and debris to lymph nodes.

Lymphocyte Recirculation

• Lymphocytes recirculate through lymph nodes to encounter pathogens and antigens.
• This method helps ensure a proper immune response.

Lymph Node

• Lymph nodes are small (<1 cm) organs where afferent lymphatic vessels bringing lymph from tissues merge with efferent vessels.
• A critical part of pathogen and debris filtering.
• During infection, pathogens, debris, and antigen-presenting cells arrive in the lymph.

The Big Picture Immunological process

• This shows the different actions and cell interactions involved.

More of the Big Picture

• Th1 cells secrete IFN-γ, and Th2 cells produce TGF-β and IL-10 which impact each other in order to inhibit the proliferation of other cell types.

How Vaccines Work

• Diagram of the antigen-processing steps leading to antigen presentation.

The Immune Response

• Primary response is primarily IgM, in Secondary response is primarily IgG/IgA and is stronger.
• T-cells are important for both responses.

Tetanus Tutorial

• Review material on D2L, read the Tetanus Tutorial Plan, and do the pre-test.

This quiz covers key concepts in immunology, including components of the immune system, B and T lymphocyte development, antigen presentation, and mechanisms of the immune response. Additionally, it includes case studies on hypersensitivity reactions and explores topics such as tumor immunology and vaccine development. Perfect for students looking to test their understanding of this essential biological field.