Antibodies & Vaccination – Core Vocabulary

A set of key vocabulary flashcards covering antibody structure & functions, monoclonal antibody production and applications, types of immunity, vaccination principles, and herd immunity for AS Biology revision.

Antibody

A Y-shaped globular glycoprotein (immunoglobulin) produced by B-lymphocytes that binds specifically to an antigen.

Immunoglobulin

The scientific name for an antibody; a class of glycoproteins involved in immune responses.

Heavy Polypeptide Chain

One of the two larger, identical protein chains that form the stem and inner arms of an antibody molecule.

Light Polypeptide Chain

One of the two smaller, identical protein chains that complete the outer arms of an antibody molecule.

Constant Region

The portion of an antibody whose amino-acid sequence is the same within a class and determines the mechanism of antigen destruction.

Variable Region

The antibody section with unique amino-acid sequences that forms the antigen-binding site and gives antigen specificity.

Antigen-Binding Site

The pocket at the tip of an antibody (110–130 amino acids long) that physically binds a specific epitope on an antigen.

Epitope

The precise part of an antigen molecule to which an antibody binds.

Hinge Region

Flexible portion of an antibody that allows the arms to adopt different angles when attaching to antigens.

Opsonisation

Process in which antibodies coat pathogens, making them more easily recognised and engulfed by phagocytes.

Agglutination

Clumping of pathogens caused by antibodies, reducing spread and aiding phagocytosis.

Lysis (antibody-mediated)

Destruction of a pathogen’s cell wall/membrane resulting in bursting when water enters by osmosis.

Monoclonal Antibody (mAb)

An identical antibody species produced from a single B-cell clone; binds one specific epitope.

Hybridoma Method

Technique that fuses antibody-producing plasma cells with immortal tumour cells to mass-produce monoclonal antibodies.

Plasma Cell

Activated B-cell that secretes large quantities of specific antibodies.

Myeloma Cell

A cancerous (tumour) B-cell able to divide indefinitely; used in hybridoma creation.

Fusogen

Chemical or electrical agent (e.g., polyethylene glycol) used to fuse plasma and tumour cells in hybridoma production.

Diagnostic Use (mAbs)

Application of monoclonal antibodies to detect molecules or pathogens, e.g., pregnancy tests, HIV tests, blood typing.

Therapeutic Use (mAbs)

Medical treatment using monoclonal antibodies, e.g., cancer therapy, rabies post-exposure, autoimmune disease control.

Rituximab

Monoclonal antibody that binds B-cell surface proteins to treat conditions like leukaemia and rheumatoid arthritis.

Herceptin (Trastuzumab)

Monoclonal antibody targeting HER2 receptors for the treatment of certain breast cancers.

Ipilimumab

Monoclonal antibody that blocks an inhibitory protein on T-cells, keeping the immune response active against melanoma.

Active Immunity

Long-term immunity gained when the body produces its own antibodies following antigen exposure or vaccination.

Passive Immunity

Short-term immunity provided by antibodies acquired from another source without activating the recipient’s immune system.

Natural Active Immunity

Immunity developed after infection with a pathogen in everyday life.

Artificial Active Immunity

Immunity produced after vaccination with antigenic material.

Natural Passive Immunity

Immunity a fetus or infant gains from maternal antibodies via placenta or colostrum.

Artificial Passive Immunity

Immunity provided by injection/infusion of pre-formed antibodies, e.g., tetanus antitoxin.

Memory Cell

Long-lived B or T lymphocyte formed during primary response that enables quicker secondary responses.

Primary Immune Response

Initial, slower response when the body first encounters an antigen; takes 1–2 weeks for antibodies to peak.

Secondary Immune Response

Faster, stronger antibody production upon subsequent exposure to the same antigen due to memory cells.

Vaccine

Suspension of antigens administered deliberately to induce artificial active immunity.

Live Attenuated Vaccine

Vaccine containing weakened but living pathogens that replicate slowly and elicit strong, lasting immunity.

Inactivated Vaccine

Vaccine containing killed pathogens or subunits/toxoids; safer but often requires boosters.

Booster Dose

Additional vaccine injection given after the primary course to raise or renew immunity.

Herd Immunity

Population-level protection arising when a high proportion of individuals are immune, hindering pathogen spread.

Antigenic Variation

Major changes in pathogen antigens that prevent prior vaccines or antibodies from recognising the pathogen.

Antigenic Concealment

Strategy where pathogens hide from immune detection by living inside cells or coating themselves in host proteins.

Adjuvant

Substance (e.g., aluminium salts) added to vaccines to enhance and prolong the immune response.

Toxoid

Inactivated bacterial toxin used as an antigen in subunit vaccines (e.g., diphtheria vaccine).

Subunit Vaccine

Vaccine composed of purified pathogen components, such as proteins or sugars, rather than whole organisms.

Whole Killed Vaccine

Inactivated vaccine containing entire pathogens that have been killed by heat, chemicals, or radiation.

Colostrum

Antibody-rich first milk produced after childbirth, supplying IgA for natural passive immunity to newborns.

IgA

Immunoglobulin class abundant in mucosal secretions and breast milk, providing localised immunity.

B-Lymphocyte

White blood cell that differentiates into plasma and memory cells, central to humoral immunity.

Fibrin

Insoluble protein forming blood clot mesh; targeted by radio-labelled antibodies to locate clots.