Revision Test 2 Essential Immunology PDF

REVISON TEST 2 ESENTIAL IMMUNOLOGY: Immune system is composed of molecules, cells, tissues and organs that work collectively to provide protection against diseases. MOST ESSENTIAL FEATURE OF THE IMMUNE SYSTEM? Ability to distinguish between self and nonself TYPES OF IMMUNE SYSTEM: INNAT...

REVISON TEST 2 ESENTIAL IMMUNOLOGY: Immune system is composed of molecules, cells, tissues and organs that work collectively to provide protection against diseases. MOST ESSENTIAL FEATURE OF THE IMMUNE SYSTEM? Ability to distinguish between self and nonself TYPES OF IMMUNE SYSTEM: INNATE IMMUNE SYSTEM: 1ST line of defence, nonspecific. Protection against infections Examples of Innate Immunity: Epithelial barriers: Skin, mucous membranes, and cilia in the respiratory tract. Inflammatory response: Swelling, redness, heat, and pain at the site of infection. Fever: Elevated body temperature can inhibit the growth of pathogens. The complement system involved in opsonisation (process of marking pathogens for destruction). Cytokines signalling proteins that help regulate and coordinate innate immune response Natural killer cells Phagocytic cells engulf microbial pathogens ADAPTIVE IMMUNE SYSTEM: its more specific it develops overtime and tailors its response to the specific pathogen. developed by molecules such as antibodies and cells such as T lymphocytes and B lymphocytes B lymphocytes produce antibodies which are proteins that specifically target and neutralise pathogens. T lymphocytes play a central role in cell-mediated immunity, where the immune response involves the direct killing of infected cells or helping other immune cells carry out their function play a central role in cell-mediated immunity, where the immune response involves the direct killing of infected cells or helping other immune cells carry out their function  How does the innate immune system recognise microbial pathogens? Innate immune system express pattern recognition receptors (PRR), that recognise pathogen associated molecular pattern (PAMP), expressed by pathogen. Antibody Formation Antibodies are secreted in 2 forms 1- Soluble form Secreted in blood and tissue. 2- Membrane-bound antibody: Found on the surface of B-cell, also known as a B- cell receptor (BCR). Lymphoid organs: Primary lymphoid organs: A- bone marrow site of generation of blood cells Red blood cells White blood cells Platelets All different types of bloods cells are generated from a single haematopoietic stem cells. B- Thymus Thymus is the site of T-cell maturation the lobules are the structural and functional units of the thymus. Each lobule consists of two main regions: the outer cortex and the inner medulla. Cortex contains T-cells Medulla populated with lymphocytes, macrophages, and DCs  2-Secondary lymphoid organs Lymphatic system: Lymphatic system drains fluid from tissues and lymph nodes Spleen Main function to remove aging blood cells and particles. ESSENSTIAL IMMUNOLOGY 2 Development of monocytes and macrophages: Monocytes and macrophages are generated from precursors in the bone marrow give rise to circulating monocytes, which enter peripheral tissues, mature to form macrophages, and are activated locally Function of macrophages: They perform several function in the innate and adaptive immune system i.e.; phagocytosis process by which certain cells, called phagocytes, engulf and digest microbes, phagocytosis of necrotic host cells and apoptotic cells and Basophils derived from hematopoietic precursors which mature in the bone marrow and circulate in the blood, Natural killer cells which kill infected cells similar to cytotoxic T lymphocytes. Function of natural killer cells: Natural killer cells recognise ligands on infected cells or cells undergoing other types of stress and kill the host cells they respond to interleukin produced by macrophages and secrete Interferon-gamma (IFN-γ) which activates the macrophages to kill the phagocytosed microbes. Dendritic cells DCs are tissue residents and circulating cells that sense the presence of microbes and initiate immune defence reaction. Development and function of DCs DCs arise from a common precursor cell of the myeloid lineage in the bone marrow and further differentiate into subsets, expresses pattern recognition receptors (PRR), that recognise pattern associated molecular pattern (PAMP) expressed by pathogen Lymphocytes the only cells in the body that expresses distrbuted antigen receptors. Lymphocytes develop from bone marrow stem cells, mature in the generative lymphoid organs (bone marrow and thymus for B and T cells, respectively), and then circulate through the blood to secondary lymphoid organs. Fully mature T cells leave the thymus, but immature B cells leave the bone marrow and complete their maturation in secondary lymphoid organs Soluble Effector Molecules of Innate Immunity Complement proteins recognize microbes and promote innate responses, exist in soluble form in the blood and extracellular fluids ESSENTIAL MICROBIOLOGY 1 ESSENTIAL MICROBIOLOGY 2 MICROBES AND DISEASES HOST PATHOGEN INTERACTION: Pathogen is a micro-organism that has potential of causing a disease An infectious disease is any change from a state of health in which part or thw host body is not capable of carrying a normal function due to presence of microbial pathogen. Infection is the invasion and multiplication od pathogenic microbes in an individual or population. The ability of a pathogen to cause disease is called pathogenicity A primary (frank) pathogen is any organism that causes disease in a healthy host by direct interaction. Conversely, an opportunistic pathogen refers to an organism that is part of the host’s normal microbiota but can cause disease when the host is immunocompromised or when it has gained access to other tissue sites. Latent infection: is an infection where the pathogen (such as a virus or bacterium) remains dormant or inactive within the body for a prolonged period, often without causing symptoms. The pathogen is not actively replicating or causing tissue damage during the latent phase, but it can reactivate later. The site in which microbes enter from is called portal of entry, there are 4 sites in which it could enter. Respiratory tract Gastrointestinal tract Skin surface Urogenital tract To make you ill microbes must do Reach their target site Attach to target site they trying to infect Multiply rapidly Obtain nutrient host Avoid and survive immune response Toxin is a substance, such as a metabolic product of the organism, that alters the normal metabolism of host cells. Exotoxins are protein toxins released from viable bacteria. They form a class of poisons that is among the most potent, per unit weight, of all toxic substances. Endotoxins These are toxins inside bacterial cell that are released on cell breakdown. MICROBES IN THE ENVIRONMENT One Health is the idea that the health of people is connected to the health of animals, plants, and our shared environment. The One Health approach can apply to range of diseases: Antimicrobial resistance (AMR), which happens when germs like bacteria and parasites develop the ability to defeat the drugs designed to kill them and continue growing and spreading; Zoonotic diseases, which are infectious diseases that are caused by germs that spread between animals and people, such as Ebola, avian influenza, rabies, etc.; Vector-borne diseases, which affect people who get bitten by a vector (mosquitoes, ticks, lice and fleas) and include dengue fever, West Nile virus, Lyme disease and malaria; Food safety and foodborne diseases, caused by contamination of food and occur at any stage of the food production, delivery and consumption chain, such as norovirus, salmonella, listeria, etc.; and Environmental health, such as water pollution, air pollution and climate change. ESSENTIAL GENETICS: