Immunology Flashcards
Identify differences between innate and adaptive immunity
Innate Immunity: Present from birth, it is the first line of defense against pathogens. It includes physical barriers (e.g., skin), chemical barriers (e.g., antimicrobial peptides), and innate immune cells (e.g., neutrophils, macrophages, natural killer cells).
Adaptive Immunity: Develops after exposure to specific pathogens. It consists of specialized cells, including B cells and T cells, which produce antigen-specific responses to target and eliminate specific pathogens.
other differences include
Innate immunity is non-specific, while adaptive immunity is highly specific.
Innate immunity lacks memory, while adaptive immunity possesses immunological memory.
Innate immunity has a rapid response, while adaptive immunity has a slower response.
Innate immunity provides immediate but general protection, while adaptive immunity provides specific and long-lasting protection.
Describe the sequence of events that leads to acute inflammation
1.Vasodilation and increased vascular permeability cause redness, warmth, and swelling.
2.Immune cells are recruited and activated through adhesion and diapedesis.
3.Phagocytosis by neutrophils and macrophages destroys pathogens.
4.Tissue repair involves cell proliferation, angiogenesis, and extracellular matrix remodelling.
5.Inflammation resolves as anti-inflammatory signals are released.
What is the activation and function of macrophages
Activation: Macrophages can be activated by various stimuli, including microbial products, cytokines (such as interferon-gamma), and immune complexes. They can also be activated during tissue injury or inflammation.
Function: Macrophages play a critical role in innate immunity and are involved in phagocytosis, antigen presentation, and cytokine production. They engulf and destroy pathogens, present antigens to initiate an adaptive immune response, and secrete cytokines to regulate inflammation and immune responses.
What is the activation and function of Neutrophils
Activation: Neutrophils are primarily activated by microbial products and inflammatory mediators, such as bacterial toxins and cytokines like interleukin-8 (IL-8).
Function: Neutrophils are the most abundant type of white blood cells and act as the first line of defense against bacterial and fungal infections. They are highly efficient at phagocytosis and can release antimicrobial substances to kill pathogens. Neutrophils also play a role in initiating inflammation and recruiting other immune cells to the site of infection.
What is the activation and function of complement
Activation: The complement system can be activated through three main pathways: the classical pathway (triggered by antibodies binding to pathogens), the alternative pathway (activated spontaneously or by certain bacterial surfaces), and the lectin pathway (activated by pattern recognition molecules binding to pathogens).
Function: Complement proteins can opsonize pathogens, promoting their phagocytosis by immune cells. They can also directly kill pathogens by forming a membrane attack complex (MAC) that creates pores in the pathogen’s membrane. Additionally, complement activation can induce inflammation, attract immune cells, and regulate adaptive immune responses.
What is the functions of Interleukin 1 (IL-1), Interleukin 6 (IL-6), Tumor Necrosis Factor alpha (TNF-a)
IL-1: It promotes inflammation, activates endothelial cells, induces fever, and stimulates the production of acute-phase proteins.
IL-6: It plays a role in inflammation, stimulates the production of acute-phase proteins, and regulates immune cell differentiation and activation.
TNF-a: It is a potent pro-inflammatory cytokine that triggers inflammation, promotes cell death (apoptosis), and regulates immune cell activation and migration.
What is the activation and function of NK cells
Activation: Natural Killer (NK) cells can be activated by various signals, including the absence or downregulation of MHC class I molecules on target cells and the binding of activating receptors to ligands on infected or tumor cells.
Function: NK cells are a type of cytotoxic lymphocyte that plays a crucial role in innate immunity and early defense against viral infections and tumor cells. They can directly kill infected or transformed cells without prior sensitization and can also produce cytokines to regulate immune responses.
What is the activation and function of mast cells
Activation: Mast cells can be activated by various stimuli, such as allergens, immunoglobulin E (IgE) antibodies, complement proteins, and cytokines like IL-33.
Function: Mast cells are primarily involved in allergic reactions and immune responses against parasites. Upon activation, they release histamine, cytokines (such as IL-4 and IL-13), and other mediators that promote inflammation, vasodilation, and recruitment of other immune cells to the site of infection or allergy.
What is the function of Chemokines
Chemokines are small proteins that play a crucial role in immune cell migration and positioning. They act as chemoattractants, guiding immune cells to specific sites within tissues. Chemokines are involved in inflammation, immune surveillance, and the formation of lymphoid organs. They bind to specific chemokine receptors on immune cells, triggering cell movement and directing the immune response to the appropriate location.
What is the cell type difference between B cell receptors and T cell receptors
Cell Type: BCRs are found on the surface of B cells, whereas TCRs are found on the surface of T cells.
What is the difference in receptor structure of B cell receptors and T cell receptors
BCRs are composed of membrane-bound immunoglobulin molecules consisting of heavy and light chains. TCRs are composed of either alpha and beta chains or gamma and delta chains.
What are the difference in activation requirements for B cells and T cells
B cells can be activated by the direct binding of antigens to BCRs. T cells, on the other hand, require binding of TCRs to antigen-MHC complexes, along with co-stimulatory signals, for activation.
What is the difference in functions of B cell and t cells
Upon activation, B cells differentiate into plasma cells, which secrete soluble antibodies specific to the recognized antigen. Activated T cells can differentiate into cytotoxic CD8+ T cells or helper CD4+ T cells, which perform various effector functions in immune responses
What are 3 functions of MHC molecules
Antigen Presentation, Immune Surveillance, Self-Tolerance
Where do T cells develop
T cells develop in the thymus gland, which is a small organ located in the upper chest area behind the breastbone.
What are the main stages of T cell development
a) Commitment: Hematopoietic stem cells commit to becoming T cells.
b) Differentiation: Progenitor cells migrate to the thymus and differentiate into immature T cells.
c) Positive and Negative Selection: Immature T cells undergo a process called positive and negative selection in the thymus to ensure they have functional T cell receptors (TCRs) that can recognize foreign antigens but not self-antigens.
d) Maturation: Selected T cells mature and differentiate into distinct subsets, such as helper T cells (CD4+) and cytotoxic T cells (CD8+).
What is the significance of T cells in the immune system
T cells play a crucial role in adaptive immune responses. They are responsible for recognizing and eliminating infected or abnormal cells, activating other immune cells, and coordinating immune responses. T cells are essential for both cell-mediated immunity, carried out by cytotoxic T cells, and humoral immunity, supported by helper T cells.
What happens during positive selection of T cells?
Positive selection occurs when immature T cells with TCRs that can weakly recognize self-antigens presented by major histocompatibility complex (MHC) molecules receive survival signals. These T cells are allowed to mature and continue development.
What happens during negative selection of T cells?
Negative selection eliminates immature T cells that strongly recognize self-antigens presented by MHC molecules. This process helps to prevent the development of self-reactive T cells that could cause autoimmune reactions.
What are some subsets of T cells
Helper T cells (CD4+),Cytotoxic T cells (CD8+) , Regulatory T cells (Tregs), Memory T cells and Natural Killer T cells (NKT cells)
