Chapter 17 – Immunity: Vocabulary Flashcards

A set of vocabulary flashcards summarizing essential terms from Chapter 17 lecture notes on Immunity, covering innate and adaptive defenses, key immune cells, chemicals, clinical disorders, and immunization concepts.

Immunity

The body’s ability to resist infection or disease-causing agents.

Innate immunity

Inborn, nonspecific defenses such as barriers, phagocytes, NK cells, inflammation, and fever.

Adaptive immunity

Specific, acquired defenses mediated by T cells and B cells that develop after exposure to antigens.

Antigen

Any foreign substance that triggers an immune response.

Antibody (Immunoglobulin)

Protein produced by plasma cells that binds specifically to an antigen.

T cell

Lymphocyte responsible for cell-mediated adaptive immunity.

B cell

Lymphocyte that differentiates into plasma cells and memory cells for humoral immunity.

Plasma cell

Activated B cell that secretes large quantities of antibodies.

Memory B cell

Long-lived B cell that mounts rapid antibody production on re-exposure to an antigen.

Cytotoxic T cell (Tc)

T cell that directly kills virus-infected or abnormal cells.

Helper T cell (Th)

T cell that secretes cytokines to activate B cells, other T cells, and macrophages.

Regulatory T cell (Treg)

T cell that suppresses excessive immune responses to maintain tolerance.

Memory T cell

T cell that persists after an infection for faster future responses.

Antigen-presenting cell (APC)

Cell (e.g., macrophage, dendritic cell) that displays processed antigen with MHC to T cells.

Dendritic cell

Potent APC found in tissues; initiates primary T-cell responses.

Macrophage

Large phagocyte that engulfs pathogens and functions as an APC.

Neutrophil

Abundant granulocyte that performs rapid phagocytosis during acute infection.

Natural killer (NK) cell

Lymphocyte that kills virus-infected or tumor cells without prior sensitization.

Phagocytosis

Ingestion and destruction of microbes or debris by cells such as macrophages.

Toll-like receptor (TLR)

Innate receptor that recognizes common microbial patterns, distinguishing self from nonself.

Cytokine

Small signaling protein that regulates immunity, inflammation, and hematopoiesis.

Interleukin

Type of cytokine that communicates between leukocytes; e.g., IL-2 activates T cells.

Interferon

Antiviral cytokine produced by virus-infected cells that blocks viral replication and activates NK cells.

Histamine

Chemical released from mast cells that causes vasodilation and capillary leak in inflammation.

Prostaglandin

Lipid mediator that promotes inflammation, vasodilation, and pain.

Complement

Plasma protein cascade that enhances inflammation, opsonization, and pathogen lysis.

Membrane attack complex (MAC)

Pore formed by complement proteins that lyses target cell membranes.

Inflammation

Localized tissue response to injury marked by heat, redness, swelling, and pain.

Pyrogen

Substance that raises the hypothalamic temperature set point, producing fever.

Fever

Elevated body temperature that stimulates phagocytes, speeds metabolism, and inhibits microbial growth.

Barrier defenses

Physical and chemical surfaces (skin, mucous membranes, secretions, reflexes) that block pathogen entry.

Virulence

Ability of a microorganism to overcome host defenses and cause disease.

Portal of entry

Site at which a pathogen enters the host’s body.

Dose (of pathogen)

Number of microorganisms required to establish infection.

Allergy

Unfavorable immune response to a normally harmless substance.

Anaphylaxis

Rapid, life-threatening systemic allergic reaction.

Mast cell

Tissue cell loaded with histamine granules; central to allergic reactions.

IgE

Class of immunoglobulin that mediates immediate hypersensitivity reactions.

Autoimmunity

Immune attack against one’s own tissues.

Rheumatoid arthritis

Autoimmune disorder causing chronic joint inflammation and degeneration.

Immunodeficiency

Failure of one or more components of the immune system, congenital or acquired.

AIDS

Acquired immunodeficiency syndrome caused by HIV infection of helper T cells.

Multiple myeloma

Cancer of plasma cells in bone marrow leading to anemia, bone pain, and immune suppression.

Immune surveillance

Continuous monitoring by NK cells, cytotoxic T cells, and macrophages to destroy emerging cancer cells.

Immunotherapy

Medical stimulation or enhancement of a patient’s immune response to fight disease (e.g., cancer).

Transplant rejection

Immune attack on transplanted tissue due to antigenic differences between donor and recipient.

Tissue typing

Laboratory matching of donor and recipient antigens to reduce risk of rejection.

Immune suppression drugs

Medications that dampen immune responses to allow graft acceptance or treat autoimmunity.

Vaccine

Preparation of antigen that induces artificial active immunity without causing disease.

Live attenuated vaccine

Vaccine containing a weakened but viable pathogen that elicits strong immunity.

Toxoid

Inactivated toxin used as vaccine to stimulate antitoxin production.

Booster

Repeat inoculation to maintain or increase antibody levels over time.

Antiserum

Prepared serum containing ready-made antibodies for immediate passive protection.

Gamma globulin

Serum fraction rich in antibodies used for passive immunization.

Antitoxin

Antibody preparation that neutralizes a specific toxin.

Natural active immunity

Long-term immunity acquired after natural exposure to an antigen.

Natural passive immunity

Temporary immunity gained from maternal antibodies via placenta or breast milk.

Artificial active immunity

Long-term immunity produced by vaccination with antigen.

Artificial passive immunity

Short-term protection from injected antibodies (antisera or immune globulins).

Inflammatory exudate

Fluid rich in leukocytes and proteins that accumulates at an inflamed site, causing swelling and pain.

Pus

Thick exudate composed of dead cells, pathogens, and tissue debris.

Lymphadenopathy

Enlargement of lymph nodes, often near sites of infection or inflammation.

Bone marrow

Primary lymphoid organ where all blood cells, including lymphocytes, originate.

Thymus

Primary lymphoid organ where T cells mature and become immunocompetent.

Interleukin-2 (IL-2)

Cytokine that stimulates proliferation and activation of T cells; used in some cancer therapies.

Attenuated organism

Pathogen weakened so it can provoke immunity without causing serious disease.

Virulence factors

Traits (toxins, enzymes) that enhance a pathogen’s ability to cause disease.

Opsonization

Coating of a pathogen with antibody or complement to enhance phagocytosis.

Chemotaxis

Directed movement of leukocytes toward chemical signals released at infection sites.

Complement lysis

Destruction of pathogen cells by the membrane attack complex formed during complement activation.