6. immunology refresher Flashcards
explain the process of immunological memory
- primary immune response is when the immune system encounters a pathogen for the first time and initiates primary response (naive B cells activated and produce antibodies, primarily IgM followed by IgG –> IgG concentration gradually increases reaching peak after a few weeks and memory B cell specific to the pathogen are generated)
- memory B cells form and remain in the body for extended periods ready to respond quickly upon re-exposure. IgG levels decline after primary peake but does not return to baseline
- secondary immune response occurs upon re-exposure to the same pathgoen. memory B cells are rapidly activated and differentiate into plasma cells that produce large amounts of IgG, resulting in a rapid and significant increase in IgG levels much higher and faster than in primary response
what do neutrophils do
engulf and digest pathogens
what do macrophages do
engulf pathogens, present antigens, and activate other immune cells
what do dendritic cells do
capture and present antigens to activate adaptive immune responses
what is the function of natural killer cells
to detect and destroy virus infected cells
what is the function of the complement system
- complement proteins enhance the ability of antibodies and phagocytic cells to clear pathogens
- promotes inflammation
what is the function of the inflammatory response
- release histamine and other chemicals to increase blood flow and attract immune cells
- promotes phagocytosis and tissue repair
what are cytokines
signalling molecules that regulate immune responses
what do T helper cells do
coordinate immune responses, activate B cells and cytotoxic T cells
what do cytotoxic T cells do
destroy infected or abnormal cells
what do plasma cells do
produce antibodies that bond to and neutralize pathogens
what do memory B cells do
remember pathogens for faster response upon re-exposure
what do antibodies do
- bind to pathogens
- facilitate destruction or neutralization
what does opsonisation do
enhance phagocytosis by marking pathogens for engulfment
major histocompatability complex 1 does:
presents intra cellular antigens to cytotoxic T cells
major histocompatability complex 2 does:
presents extra cellular antigens to helper T cells
what do regulatory T cells do
suppress immune responses to prevent excessive reactions or autoimmune responses
what do cytokines do
- mediate communication between immune cells
- regulate inflammation, immune cell activation and differentiation
what are the roles of MHC in antigen presentation
MHC molecules bind to antigen fragments and transport them to the cell surface. T cells recognize these antigen-MHC complexes, leading to the activation of T cell responses. Antigen presentation is crucial for the coordination of adaptive immune responses. It allows the immune system to distinguish between self and non-self, facilitating targeted responses against specific pathogens.
what are the MHC molecules and what do they do
- MHC molecules are cell surface proteins that present antigens to T cells. There are two main classes:
- MHC I: Found on the surface of all nucleated cells. Presents antigens derived from intracellular pathogens (viruses, intracellular bacteria) to cytotoxic T cells.
- MHC II: Expressed on the surface of professional antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells. Presents antigens from extracellular sources to helper T cells.
