Immunology & Defense Flashcards
Distinguish between non-specific and specific defense.
(innate) non-specific= “first line of defense”
- born with it
- defense against anything foreign or abnormal
- includes physical barriers, NK cells, inflammation
(adaptive) specific= defenses take time to get started
- develops after birth, after exposure to antigen
- four properties( specificity, versatility, memory, tolerance)
- includes actions of cytotoxic T cells and B cells (+ antibodies)
For each of the following types of non-specific defense, describe what happens and how that helps to fight infection: phagocytes (includes neutrophils, eosinophils, and macrophages)
-cells that engulf big things like debris and other cells
example:
-neutrophils can engulf bacteria, macrophages can engulf cells and debris are created by the actions of NK cells)
For each of the following types of non-specific defense, describe what happens and how that helps to fight infection: natural killer cells (part of “immune surveillance”)
-a type of lymphocyte
-they will destroy anything that is foreign or abnormal, even if they don’t know what foreign or abnormal is.
-They destroy a cell that is infected by the chickenpox, or a cell infected by the influenza virus, or a cancerous cell… they are non-specific.
Immune surveillance= destruction of abnormal cells by NK cells in peripheral tissues
For each of the following types of non-specific defense, describe what happens and how that helps to fight infection: interferons
- they are chemical messengers that coordinate the defenses against viral infections
- “interfering” in viral replication
For each of the following types of non-specific defense, describe what happens and how that helps to fight infection: complement
- system of circulating proteins that assist antibodies in the destruction of pathogens. It also lyses cells and enhances phagocytosis and inflammation
- example: formation of membrane attack complex (MAC) that is used to kill many types of bacteria.
For each of the following types of non-specific defense, describe what happens and how that helps to fight infection: inflammation (“redness, heat, swelling, and pain”)
- localized, a tissue-level response that tends to limit the spread of an injury or infection
- an important part of a defense
For each of the following types of non-specific defense, describe what happens and how that helps to fight infection: fever
- an elevation of body temperature that speeds up tissue metabolism and the activity of defenses
- dangerous if fever is very high in young children, but important part of defense
- Pyrogens are the chemicals that “reset” our “thermostat”
For each of the following types of non-specific defense, describe what happens and how that helps to fight infection: physical barriers (our “first line of defense”)
- keep hazardous organisms and materials outside the body
- “first line of defense”
- secretions and layers of cells, tissues that help block invasion in the first place ex// skin and mucous membranes
Distinguish between innate immunity (=nonspecific defense) and adaptive immunity (=specific defense)
innate immunity:
-defense against a broad range of pathogens (non-specific)
-born with it (innate)
-the response is usually the same every time you’re exposed
Adaptive (specific) immunity:
-defense against a particular pathogen (specific)
-develops after birth, with exposure to antigen (adaptive)
-The response is greatly improved on your second(or subsequent) exposure to that particular pathogen (has memory)
Distinguish between cell-mediated and antibody-mediated immunity
cell-mediated:
-foreign/abnormal antigen presented on surface of infected or abnormal cell
-cytotoxic T cells get activated, destroy the infected/ abnormal cell
Antibody-mediated:
-B cells get activated, become plasma cells that produce and release antibodies
-Antibodies bind to a specific antigen, leading to many effects to ultimately destroy the foreign or infected cell
They both:
-reply on antigen-presenting cells
-both rely on helper T cells to become activated
-both exhibit “memory”
Describe the importance of helper T cells to cell-mediated immunity, antibody-mediated immunity, and non-specific defense.
Helper T cells:
-release cytokines to stimulate aspects of specific and non-specific defenses
Explain why HIV infection makes a person more susceptible to opportunistic infection
Because of MHC (Major histocompatibility complex) these membrane proteins help us be better to resist a wider variety of infections and other threats.
Describe the role of antigen-presenting cells in immunity. (This could include a description of examples of APCs, the class of MHC on their membranes, and the type of T cells that they interact with.)
-cells can pick up and display antigens on their surface without being infected themselves
-have class ll MHC proteins on their membranes
-can activate helper T cells (critical in initiating an adaptive immune response)
Examples of APCs:
-Dendrite cells(of the skin and some lymphoid tisues; pick up antigen, then travel to lymph nodes)
-Macrophages ( in connective tissues)
-Microglia (of CNS)
Differentiate between class I MHC and class II MHC.
I MHC class:
-recognized by cells with CD8 markers
-on all nucleated cells in our body
-if cell is showing foreign or abnormal antigen on class l MHC, this is generally a sign that cell is infected and must be destroyed
ll MHC class:
- recognized by cells with CD4 markers
-on specialized cells only (APCs, Bcells)
-If cell is showing foreign or abnormal antigen on class ll MHC, then it’s a sign that the APC has encountered the antigen and is signaling the need for an immune response, antigen cell is not infected so don’t destroy the APC
Differentiate between CD8 T cells and CD4 T cells.
- CD8 t cell is a T cell with a CD8 protein on it’s surface( cytotoxic T cells are one type of CD8 T cell)
- involved in killing specific cells
- CD4 t cells is a helper T cell
- involved in stimulating various aspects of our immune response
