Immunology Phase 1 and 2 Quiz

Immunology Content (Phase 1)

• Components of the immune system are covered.
• Immunogens, antigens, and antibodies are discussed.
• The development of B lymphocytes is detailed.
• The role of the Major Histocompatibility Complex (MHC) in antigen presentation is explained.
• T lymphocytes and T-cell receptors are examined.
• Control mechanisms of the immune response are explored.
• The activation, function, and interaction of T and B lymphocytes are detailed.
• Innate immunity is described, including immune cell markers, flow cytometry, and blood typing.
• Cytokines.
• Tetanus tutorials are part of small-group activities.
• The complement system is included.
• Overview of hypersensitivity reactions is covered.
• Autoimmunity and autoimmune diseases are detailed.
• Case study of hypersensitivity reactions are used in small group tutorials.

Immunology Content (Phases 2/3)

• Phase 2 covers immunity to infections and inflammation.
• The immunology of HIV infection is detailed.
• Vaccine development is discussed.
• Phase 3 covers tumor immunology.
• Small-group tutorials are part of study activities.
• A pre-test is used to save class time, and students present a case to their group.
• A post-test is used; students better understand answers and perform better on the exam by doing it together.

The Big Picture (Immune Response)

• This diagram shows the primary response of the immune system.
• It illustrates the interactions of various cells like NK cells, APCs, B cells, CD4+ T cells and CD8+ T cells.
• The roles and types of memory cells are presented.

Objectives

• Distinguish innate from acquired immunity.
• Identify and describe the cellular components of the immune system.
• Describe lymphoid organs, structures, and associated cells & functions
• Explain the importance of lymphocyte recirculation for antigen trapping and immunity development.

Importance of the Immune System

• The immune system defends against infections, including pandemics.
• It provides protection through vaccinations and immunizations.
• It also protects against tumors, barriers to transplantation, and assists in immunotherapies against infection and cancer.

Challenges to the Immune System

• Specificity is a crucial aspect of the system.
• System diversity supports functionality.
• An effective memory component is essential.
• The system needs proper specialization.
• Resolution of infections.
• Non-reactivity to self helps avoid autoimmune diseases.
• Mobility supports the wide range of the system.

Immune Defense

• Human beings face constant pathogen attacks from conception
• Immune systems defend against enemies from the air, water, surfaces, and from inside the body.
• Examples of the different types of enemies include viruses, bacteria, fungi, pollens, danders, parasites, and foods.
• Autoimmune disease and cancer are examples of internal enemies.

How does the immune system recognize potential invaders?

• Recognizing 'self' versus 'non-self' is a fundamental function of the immune system.
• The immune system is trained not to react against our own bodies.
• It achieves this by having innate and acquired immune responses.
• In this respect, innate immune responses are nonspecific, while acquired responses are specific.

Two Types of Immunity

• Innate immunity comprises basic, inherent elements, always available for immediate action.
• It includes body surfaces (e.g., skin, mucous membranes), the cough reflex, temperature regulation (fever) and phagocytic cells (e.g., macrophages). Components include natural killer (NK) cells.
• Acquired immunity involves specialized elements developed after birth.
• Acquired immunity is present only in vertebrates and only acts if the body has prior contact with a pathogen/agent. The initial contact produces immunity against further exposure.

How does our body generate such an effective, elaborate system?

• This question asks how our complex immune system is formed.

Hematopoiesis: Development of Blood and Blood-Derived Cells

• Hematopoiesis is the development of blood and blood-derived cells from pluripotent hematopoietic stem cells in the bone marrow.
• The process involves the development of various blood cell types such as granulocytes, megakaryocytes, erythrocytes, and mast cells.
• Different types of blood cells arise from common lymphoid and myeloid progenitors.
• These cells develop and mature in the bone marrow before being released into the bloodstream then to tissues throughout the body.

The Myeloid Lineage

• Cells of the myeloid lineage mainly play innate immunity roles but some play parts in adaptive immunity.
• These cells can be found in both blood and tissues.
• Different types of cells are at different levels of maturity (immature, mature, activated).
• Granulocytes are a part of this lineage.
• Macrophages and dendritic cells also fall under this lineage, these play roles in antigen presentation and phagocytosis.

The Lymphoid Lineage

• B cells mature in bone marrow and produce antibodies specifically targeting antigens. Once activated, B-cells multiply, differentiating into plasma cells to produce antibodies.
• T cells mature in the thymus, and possess antigen-specific receptors (TCRs). They have important roles relating to immunity.
• Main types of T cells include helper T-cells and cytotoxic T cells.
• Natural Killer cells (NK) mature in the bone marrow, do not have antigen specific receptors, and form a critical part of the innate immune response.
• Small lymphocytes include various types of immune cells (e.g., B and T).
• Plasma cells are formed by the activation of B cells and are important for antibody production.

Antigen-Presenting Cells

• Antigen-presenting cells can ingest and digest pathogens.
• Intracellular components are broken into peptides, which are displayed on MHC molecules.
• CD4+ T-cells can then identify presented peptides.

Macrophages are Distributed Throughout the Reticuloendothelial System

• Macrophages are distributed throughout the body, originating from blood monocytes.
• They are found in various tissues, organs, parts of the brain and tissues throughout the body.

Lymphocytes are Distributed in Specialized Lymphoid Tissues

• Lymphoid cells mature in bone marrow except for T cells which mature in the thymus.
• These cells circulate and are present in lymphoid tissue throughout the body. Lymph nodes help support the lymphatic system, draining fluids from tissues.

Q: How do immune cells find pathogens in order to respond to them? A: Lymphocyte Recirculation

• Lymphocytes circulate continuously throughout the body.
• Lymphatic vessels, nodes, and the circulatory system are all parts of this return pathway.
• Pathogens, along with debris are found in lymph as well as macrophages and dendritic cells.
• The pathogens are brought to the nearest lymph node (draining lymph node) and there a response is facilitated.

The Lymph Node

• Lymph nodes are small organs in the lymphatic system.
• Afferent lymphatic vessels of the lymphatic system lead to larger efferent vessels that bring lymph from tissues into lymph nodes.
• During an infection, pathogens, debris and Antigen-Presenting cells (APCs) arrive in lymph.

The Immune Response

• Primary response: dominated by IgM antibodies, less effective.
• Secondary response: better and faster response, higher levels of IgG/IgA antibodies with stronger binding.
• T cells are also important for antibody response.

How Vaccines Work

• Vaccines introduce antigens to stimulate an immune response, leading to immunity.
• Exogenous antigens (e.g., viral proteins in a vaccine) trigger the processing and presentation of peptides to CD4+ T cells.
• Endogenous antigen processing and presentation is also triggered.
• Immune cells eventually recognize pathogens and mount an appropriate response (primary or secondary immune response).

Please review material on D2L for the Tetanus Immunity Tutorial. Read the Tetanus Tutorial Plan and do the Pre-Test!

• These instructions provide task for students to prepare for class.

Test your knowledge on the components of the immune system, including immunogens, antigens, and antibodies. This quiz covers the development of B and T lymphocytes, innate immunity, cytokines, and hypersensitivity reactions. Explore the role of the Major Histocompatibility Complex (MHC) as well as case studies related to autoimmune diseases.