Immunology refresher Flashcards
Describe the anatomy of lymph nodes
Lymphoid follicles in cortex
Sinuses in medulla
what is the role of lymph nodes?
Filter lymph
Immune surveillance
Activation of immune response
Antigen presentation
Production of antibodies
Removal of cellular debris
Transport of immune cells
Describe the function of the spleen
Filters and stored blood
Stores WBCs and platelets
Antigen presentation
Haematopoiesis
What is the role of tonsils in immunology?
first-line defence against ingested or inhaled pathogens
Describe the anatomy of tonsils that aids its immunological role
Crypts increases SA for more interaction between immune cells and pathogens
Describe the role of the thymus
T-cell maturation
Education and differentiation
Immunological memory
Describe the immunological role of bone marrow
Site of blood cell production including lymphocytes
Describe the immunological role of Peyer’s patches
GALT
Immune response in the GIT
Lymphoid nodules in submucosa of the SI
What are the components of the innate immune response?
phagocytes
Natural killer (NK) cells
Complement system
Inflammatory response
Cytokines
Describe the role of phagocytes in the innate immune response
Neutrophils: Engulf and digest pathogens.
Macrophages: Engulf pathogens, present antigens, and activate other immune cells.
Dendritic Cells: Capture and present antigens to activate adaptive immune responses.
What is the role of natural killer (NK) cells in the innate immune response
detect and destroy virus-infected cells
Describe the role of the complement system in the innate immune response
Complement proteins enhance the ability of antibodies and phagocytic cells to clear pathogens.
Promote inflammation.
Describe the inflammatory response in innate immune response
Release of histamines and other chemicals to increase blood flow and attract immune cells.
Promotes phagocytosis and tissue repair
Describe the role of cytokines in the innate immune response
signalling molecules that regulate immune responses
What are the components of the adaptive immune response?
T lymphocytes
B lymphocytes
Antibodies (immunoglobulins)
Major histocompatability complex (MHC)
Regulatory T cells
Immunological memory
Cytokines
Describe the role of T cells in adaptive immunity
Helper T Cells (CD4+): Coordinate immune responses, activate B cells and cytotoxic T cells.
Cytotoxic T Cells (CD8+): Destroy infected or abnormal cells.
Describe the role of B cells in adaptive immunity
Plasma Cells: Produce antibodies that bind to and neutralize pathogens.
Memory B Cells: “Remember” pathogens for faster response upon re-exposure.
Describe the role of antibodies/immunoglobulins in adaptive immunity
Bind to pathogens, facilitating their destruction or neutralization.
Opsonization: Enhance phagocytosis by marking pathogens for engulfment.
Describe the role of major histocompatability complexes (MHCs) in adaptive immunity
MHC1: Presents intra-cellular antigens to cytotoxic T cells.
MHC2: Presents extra-cellular antigens to helper T cells.
Describe the role of regulatory T cells in adaptive immunity
Suppress immune responses to prevent excessive reactions or autoimmune responses.
Describe immunological memory
Enhanced response upon re-exposure to a previously encountered pathogen.
Describe the role of cytokines in adaptive immunity
Mediate communication between immune cells.
Regulate inflammation, immune cell activation, and differentiation.
What are the different complement pathways
Antibody-dependent pathway: links innate and adaptive immunity
Alternative and lectin pathways (antibody-independent): activated directly by interaction with pathogen surface
Explain the complement system pathway
Cascade activation of complement proteins => activation of C3 convertase (produced by liver)
C3 convertase => breaks into C3a and C3b
C3a => acts as a chemoattractant and anaphylotoxin (vasoldilation, activate smooth muscle cells, immune cells and increased fluids in tissue)
C3b => binds to microbial surfaces, tagging it for phagocytes with express complement receptors
Membrane attack complex (MAC) is end point => form pores in cell membranes => kills cell
What are the key functions of cytokines?
Cell activation and differentiation
Inflammation
Immune cell recruitment
What cells are APCs?
Dendritic Cells: capture, process and present antigens to activate T cells
Macrophages: engulf pathogens and present antigens
B cells: present antigens to T helper cells during activation of the adaptive immune response
Describe the role of major histocompatability complexes in antigen presentation
MHC molecules = cell surface molecules that bind to antigens and transport them to cell surface
T cells recognise antigen-MHC complex => activates T cells
Describe the process of T cell maturation
Describe the process of B cell maturation
How do naive T and b cells enter lymph nodes
Circulate in bloodstream
Enter lymph nodes via high endothelial venules
Initial interaction with endothelial cells through selectins
Chemokines induce expression of integrins on lymphocytes promoting adhesion to endothelial cells
What is diapedesis?
Naive lymphocytes squeeze through endothelial cells and basement membrane to enter lymph node
What is the role of chemokines in the lymph nodes and naive lymphocytes?
guide the migration of naive lymphocytes towards specific areas within the lymph node
Describe the activation of naive T cells in the lymph node
Naive T cells interact with dendritic cells that present antigens
Describe the activation of naive B cells in the lymph node
naive B cells interact with follicular dendritic cells and encounter antigens
