ANSC 40300 Lecture 2C PDF

Dr Kieran Meade Associate Professor of Immunobiology UCD College of Health and Agricultural Sciences ANSC40300 MSc in Animal Science...

Dr Kieran Meade Associate Professor of Immunobiology UCD College of Health and Agricultural Sciences ANSC40300 MSc in Animal Science L2C: Adaptive Immune www. immunobiology.ie System 1 Lecture content – lecture 2 Topic Title 2A Why is Evolution relevant? 2B What is the innate immune system? 2C What is the adaptive immune system? 2D Mans influence on the homeostasis of livestock 2 Evolution of adaptive immunity Adaptive immunity did not evolve until much later in evolutionary terms Although innate and adaptive cells are shown Sometimes the adaptive on different branches – immune response is referred remember they interact. to as the acquired immune response – as it ‘acquires’ a memory of what it has encountered previously. 3 Two types of lymphocytes There are two main arms of the adaptive immune response B cells which differentiate into plasma cells to produce Both of these cell types antibodies – this is referred to as the Antibody-Mediated are called Lymphocytes Immune Response (AMIR) and T cells which differentiate into many sub-types and are referred to as the Cell-Mediated Immune Response (CMIR) But all white blood cells are called leukocytes The antibodies we are most familiar with in human terms are against Covid-19 from infection or vaccination In livestock, the antibodies we are most familiar with are Immunoglobulins – and we already know there are different classes of these 4 What do we mean by adaptive immunity Adaptive immunity involves specialized immune cells that attack and destroy foreign invaders and prevent disease in the future by remembering what those substances look like and mounting a new faster and more efficient secondary immune response Each cell has a different job! Think about different pathogens and where they hide… 5 Making lymphocytes is lymphopoesis Bony fish have the ability to make lymphocytes in specialized lymphoid organs (Thymus, Spleen, Kidney and Hind gut). In humans, lymphocytes are made in a primary lymphoid organ – the red bone marrow. The other primary lymphoid organ is the Thymus – and it is here that T cells mature. They then travel to secondary lymphoid organs for to await activation. Secondary lymphoid organs include the Tonsils, Lymph nodes, Speen or Mucosa-Associated Lymphoid Tissue (MALT). Note: The kidney is no longer a major lymphoid organ in eutherians. 6 Lymphoid organs Lymphoid cells are found in lymphoid tissue and organs https://veteriankey.com/organs-of-the-immune-system/ 7 Starts in the bone marrow with a stem https://medium.com/@gl assfordelle/t-cell- cell formation-27ced43f8a2c There development starts with a HSC and develops into a myeloid cell (myelopoesis) for innate cells and lymphoid cell (lymphopoesis) for adaptive cells 8 B and T cells mature in different locations https://www.osmosis.org/learn/T-cell_development The type of B cell that makes Abs is called a plasma cell 9 B cells make antibodies (called Immunoglobulins - Ig) In humans, Abs can cross the placenta but they cannot in livestock due to a different structure of the placenta In agriculture, we are very concerned with Abs in colostrum for newborns! Comparative analyses of immunoglobulin genes: surprises and portents Flajnik 2002 10 Associated Lymphoid Tissue Lymphoid cells live in lymphatic tissue: Associated lymphoid tissue are bundles of lymphatic cells, called lymphatic nodules, located within the mucus membranes that line the gastrointestinal, respiratory, reproductive, and urinary tracts. These nodules contain lymphocytes and macrophages which defend against invading bacteria and other pathogens that enter these passages along with food, air, or urine. These nodules can be solitary or grouped together in clusters. Major clusters of lymphatic nodules include: Tonsils: Clusters of lymphatic tissue under the mucous membrane lining of the nose, mouth, and throat. Lymphocytes and macrophages in the tonsils provide protection against foreign substances and pathogens that enter the body through the nose or mouth. Adenoids: A cluster of lymphatic tissue that hangs from the upper part of the back of the nasal cavity. Adenoids get bigger after birth but usually stop growing by the age of 7. Peyer's patches: these are clusters of lymphatic nodules in the mucosa that lines the ileum of the small intestine. They play an important role in defending against the large number of pathogens that enter the gastrointestinal system. 11 https://wikieducator.org/Lymphatic_System_Answers  Lymphatic system Lymphoid cells also circulate within the lymphatic system 12 https://www.slideshare.net/vishalpatel118/lymphatic-system-77034364 Lymph node The lymphatic system has three functions: Lymph nodes are checked by vets at 1. The removal of excess fluids from slaughter for TB! body tissues. 2. Absorption of fatty acids and subsequent transport of fat, Lymph nodes differ chyle, to the circulatory system. from nodules in that the former has a well 3. Production of immune cells (such defined connective as lymphocytes, monocytes, and tissue capsule antibody producing cells called plasma cells). Cells and Organs of Immune System, Lokesh C Mishra 13 Lymph node – garda station The lymphatic system has three Frontline – like an functions: innate immune cell (survey, decide 1. The removal of excess fluids from whether to react) body tissues. 2. Absorption of fatty acids and subsequent transport of fat, chyle, to the circulatory system. 3. Production of immune cells (such Travels to station for as lymphocytes, monocytes, and handover to the local antibody producing cells called sergeant is like plasma cells). activating an adaptive cell with a specific piece of 14 information (antigen) Differences between innate and adaptive immunity 1. Innate immunity is immediate – always present; Adaptive immunity takes 5-7 days to develop 2. The innate immune system ‘directs’ the adaptive immune response 3. The innate immune response is non-specific but the adaptive immune response is 4. The adaptive immune system ‘remembers’ what it has previously encountered 5. The second (or memory) response is then much more rapid and specific 6. Q: So which part of the immune system do vaccines target? 15 Test yourself 1. Do you understand what cells constitute the adaptive immune system? 2. Where do these cells originate? 3. What is the process of lymphocyte development called? 4. Where do these cells mature and live? 5. Do you understand the difference between the AMIR and the CMIR? 6. What are the differences between innate and adaptive immune systems? 16