The Immune System & HIV/AIDS – Vocabulary Flashcards

Vocabulary flashcards covering key Concepts in immunity, antibodies, hypersensitivity, autoimmunity, immune deficiencies, and HIV/AIDS, including treatments and safety.

Disease

A disorder of body function; major causes include inflammation, autoimmunity, allergy, infection, neoplasm, heredity, malnutrition, and stress.

Immunity

The body's ability to defend against infectious agents, foreign cells, and abnormal body cells; divided into non-specific (innate) and specific (acquired) immunity.

Non-Specific Immunity (Innate Immunity)

Immunity present at birth; provides immediate, general protection against any foreign agent; non-selective and includes barriers, phagocytosis, NK cells, fever, interferon, and inflammation.

Specific Immunity (Acquired Immunity)

Immunity developed in response to a specific foreign agent; targeted against that agent; includes Humoral (B cell) and Cell-Mediated (T cell) responses.

Antigen

A substance that triggers an immune response.

Humoral Immunity

Part of adaptive immunity mediated by B lymphocytes and antibodies produced by plasma cells.

B Lymphocytes (B Cells)

Lymphocytes that mature in the bone marrow and produce antibodies as part of humoral immunity.

Cell-Mediated Immunity

Adaptive immunity mediated by T lymphocytes; involves helper, cytotoxic, and suppressor T cells, plus memory T cells.

T Lymphocytes (T Cells)

Lymphocytes that mature in the thymus and coordinate cellular immune responses.

Thymus Gland

Organ where T cells mature.

Plasma Cells

Activated B cells that secrete antibodies.

Memory Cells

Long-lived lymphocytes that respond rapidly upon re-exposure to the same antigen.

Immunoglobulins (Ig)

Antibodies; proteins that bind antigens; major classes include IgG, IgA, IgM, IgE, and IgD.

IgG

The most abundant antibody; found in body fluids; protects against bacterial and viral infections.

IgA

Found in mucous membranes and secretions (saliva, tears); protects respiratory and gastrointestinal tracts.

IgM

The first antibody produced in response to an antigen; mainly in blood and lymph.

IgE

Associated with allergic reactions; binds to allergens and triggers histamine release from mast cells.

IgD

Existing in small amounts in the blood; least understood antibody.

Antigen-Antibody Complex

Binding of an antigen to an antibody; triggers neutralization, precipitation, agglutination, opsonization, and complement activation.

Neutralization

Antibody binding renders the antigen harmless.

Precipitation

Antigen-antibody complexes become insoluble and precipitate.

Agglutination

Antibodies bind multiple particles, causing clumping and easier removal.

Opsonization

Coating of pathogens with antibodies/complement to enhance phagocytosis.

Complement Fixation

Activation of complement proteins leading to lysis of cells or inflammatory responses.

Complement

A group of serum protein enzymes that mediate antigen-antibody reactions; can lyse cells, cause histamine release, and attract leukocytes.

Vaccine

A preparation that induces immunity; can be live attenuated, inactivated/killed, toxoid, or mRNA; triggers antibody production without causing disease.

Hypersensitivity

An exaggerated or harmful immune response causing tissue damage; includes allergies.

Allergy

An individual’s hypersensitive reaction to an allergen, causing symptoms and sometimes tissue damage.

Type I Hypersensitivity

IgE-mediated immediate allergic reaction; can cause asthma, dermatitis, angioedema, anaphylaxis; treated with epinephrine.

Mast Cell

Cells that release histamine and other inflammatory mediators during allergic reactions.

Anaphylaxis

A life-threatening systemic allergic reaction with hypotension and airway compromise; treated with epinephrine.

Type II Hypersensitivity

Cytotoxic hypersensitivity; IgG/IgM with complement destroy host cells; examples include transfusion reactions and Rh incompatibility.

Type III Hypersensitivity

Immune complex-mediated; antigen-antibody complexes deposit in tissues, causing inflammation and tissue destruction (e.g., glomerulonephritis, rheumatic fever).

Type IV Hypersensitivity

Cell-mediated delayed hypersensitivity; T-lymphocyte response; examples include contact dermatitis and transplant rejection.

Autoimmunity

An intolerance to self; the immune system produces antibodies against the body’s own tissues or antigens.

Autoimmune Diseases

Disorders caused by autoimmunity; examples include SLE, rheumatoid arthritis, multiple sclerosis, myasthenia gravis, scleroderma.

Systemic Lupus Erythematosus (SLE)

A chronic autoimmune disease affecting multiple organs; more common in women; difficult to diagnose.

Immune Deficiency

Disorders that prevent the body from fighting infections effectively; primary (congenital) or secondary (acquired).

X-Linked Agammaglobulinemia

Primary immunodeficiency with little or no antibodies; predominantly affects males;

Alymphocytosis

Very low lymphocyte counts leading to severe immune deficiency.

AIDS

Acquired Immunodeficiency Syndrome; advanced HIV infection with severe immune deficiency and opportunistic infections and cancers.

HIV

Human Immunodeficiency Virus; retrovirus that attacks CD4+ T cells, impairing immune function.

CD4 Receptor

Receptor on T-helper lymphocytes that HIV binds to for entry.

T-Helper Lymphocytes

CD4+ T cells; activate B cells and coordinate immune responses.

Opportunistic Infections

Infections that take advantage of a weakened immune system (common in AIDS).

Kaposi Sarcoma

A cancer associated with AIDS, presenting as lesions on skin and mucous membranes, among other sites.

HAART (Highly Active Antiretroviral Therapy)

Combination of at least three antiretroviral drugs from different classes to suppress HIV replication and prevent resistance.

ARV (Antiretroviral) Drugs

Medications used to treat HIV by interfering with viral replication.

NRTIs

Nucleoside Reverse Transcriptase Inhibitors; examples include zidovudine (AZT) and lamivudine (3TC).

NNRTIs

Non-nucleoside Reverse Transcriptase Inhibitors; inhibit reverse transcriptase at a different site than NRTIs.

Protease Inhibitors

Antiretroviral drugs that block HIV protease, preventing maturation of viral particles.

Integrase Inhibitors

Antiretroviral drugs that block HIV integrase, preventing integration of viral DNA into the host genome.

Entry/Fusion Inhibitors

Antiretroviral drugs that block HIV entry into host cells or fusion with the cell membrane.

Viral Suppression

Having fewer than 200 copies of HIV RNA per milliliter of blood; a goal of ART.

Undetectable Viral Load

Viral load not detectable by standard tests; indicates effective viral control.

Durably Undetectable

Viral load remains undetectable for at least six months after initial undetectable result.

Universal Precautions

Safety measures to prevent exposure to bloodborne pathogens; treat all blood and body fluids as potentially infectious; use PPE and proper sharps handling.

HIV Care Continuum

Series of steps from diagnosis to lifelong care, treatment, and achieving viral suppression.

AIDS-Related Complex (ARC)

Early HIV syndrome with swollen lymph nodes, fever, night sweats; may have asymptomatic periods.

Pneumocystis jirovecii

A common opportunistic fungal infection in AIDS.

Histoplasmosis

A fungal opportunistic infection seen in advanced HIV.

Cytomegalovirus (CMV)

Herpesvirus causing disease in people with weakened immunity (common in AIDS).

Toxoplasmosis

Protozoan opportunistic infection seen in AIDS.