Innate v. Adaptive
This defense system has no persistent memory and mounts a non-specific response within seconds to hours
What is innate immunity?
These are the most highly adherent, motile, phagocytic leukocytes and are the very first cells recruited to acute bacterial inflammatory sites
What are neutrophils?
These large Y-shaped blood proteins are produced by the immune system to recognize and combine with specific antigens
What are antibodies (or immunoglobulins)?
The Gell-Coombs classification system for hypersensitivity reactions utilizes this four-letter mnemonic standing for Anaphylactic, Cytotoxic, Immune Complex, and Delayed
What is ACID?
This pathophysiological condition is characterized by an abnormally low white blood cell count, usually caused by decreased production in the bone marrow due to toxins or radiation
What is leukopenia?
This primary physical barrier contains insoluble keratins that create a hurdle against infection
What is the skin?
These specialized tissue macrophages are found in the liver, where they monitor and digest particles in the portal circulation
What are Kupffer cells?
Representing 75-80% of all immunoglobulins in the blood, this is the only class that can cross the placenta to provide passive immunity to a fetus
What is IgG?
Mismatched blood transfusions are a classic example of this specific type of hypersensitivity, which is mediated by IgG or IgM antibodies mistakenly binding to antigens on the surface of your cells
What is Type II (Cytotoxic) hypersensitivity?
This disease results from a genetic mutation causing the uncontrolled production of abnormal white blood cells that invade tissues like the bone marrow and spleen
What is leukemia?
This type of immunity relies on B lymphocytes, T lymphocytes, and antibodies to provide highly specific persistent memory
What is adaptive (or acquired) immunity?
Along with basophils and mast cells, these weak phagocytes accumulate in tissues to defend against parasites and participate in Type I allergic reactions
What are eosinophils?
With 10 binding arms that act like a net, these are the earliest produced antibodies and their presence indicates an active, acute infection
What is IgM?
In this type of hypersensitivity, antibodies bind to free-floating antigens in the bloodstream, creating clumps that wedge into narrow blood vessels and joints to cause diseases like Lupus
What is Type III (Immune Complex) hypersensitivity?
This autoimmune disorder is characterized by the immune system improperly creating antibodies directed against acetylcholine receptors
What is Myasthenia gravis?
These sensors, which include Toll-like receptors, detect molecular signatures like PAMPs and DAMPs to distinguish "self" from "non-self"
What are Pattern Recognition Receptors?
This unique capability allows neutrophils and macrophages to pass directly through intact capillary walls to reach sites of infection
What is diapedesis?
This immunoglobulin guards the body's entry portals because it is the most abundant antibody in secretions like saliva, tears, sweat, and breast milk
What is IgA?
Characterized by rapid, life-threatening symptoms like bronchospasm and profound hypotension, this severe Type I systemic allergic reaction requires epinephrine for treatment
What is anaphylaxis?
Smallpox, polio, and yellow fever are prevented using this specific class of vaccine, which utilizes a weakened organism to induce immunity
What are live (attenuated) vaccines?
Secreted in conjunctival tears and other mucosal surfaces, this enzyme specifically digests peptidoglycan found in bacterial cell walls
What is lysozyme?
These cells are of lymphoid origin but act within the innate immune system to kill virus-infected or tumor cells without needing MHC (major histocompatibility complex) restriction
What are Natural Killer (NK) cells?
While evolved to defend against large parasites, this antibody can mistakenly bind to harmless environmental proteins like pollen or peanuts and signal mast cells to trigger severe allergic reactions
What is IgE?
This is the only class of hypersensitivity that is exclusively cell-mediated, relying entirely on T cells to produce a reaction 24-72 hours after exposure, such as a poison ivy rash
What is Type IV (Delayed-Type) hypersensitivity?
This type of temporary immunity, lasting only 2 to 3 weeks, is achieved by infusing antibodies or activated T-cells from an immune individual directly into a nonimmune individual
What is passive immunity?