Carrier protein

A protein chemically linked to a small molecule that is too small to provoke a strong immune response alone. The protein supplies immune-recognition features that help make the linked molecule immunogenic.

Hapten: A small molecule that can bind antibodies but usually cannot provoke an immune response by itself. The hapten is the small molecule whose immune response the carrier enables.
Conjugate vaccine: A vaccine that links a poorly immunogenic antigen, often a bacterial polysaccharide, to a carrier protein. It applies carrier-protein immunology to generate stronger, T-cell-dependent responses.
Antigen: A substance specifically recognized by antibodies or immune-cell receptors. A carrier conjugate combines antigenic features from both the small molecule and protein.
T-independent antigen: An antigen that activates B cells without conventional helper T-cell recognition. Some repetitive antigens stimulate B cells directly, unlike typical hapten–carrier responses.
Hapten–carrier conjugate: A molecule formed by chemically linking a hapten to a larger carrier protein. This linked structure is the form that elicits responses to the hapten.
Haemophilus influenzae type b vaccine: A vaccine that protects against disease caused by the encapsulated bacterium Haemophilus influenzae type b. Its conjugate formulations link the bacterial capsule sugar to a carrier protein.
Immunogenicity: The capacity of a substance to provoke a measurable immune response. Carrier linkage increases the immunogenicity of many otherwise weak small molecules.
Unconjugated polysaccharide vaccine: A vaccine containing bacterial polysaccharides without linkage to a protein carrier. It generally produces weaker, less durable responses in young children than conjugate vaccines.
B cell: A lymphocyte that recognizes specific antigens and can differentiate into antibody-secreting cells. B cells bind the hapten portion of a conjugate and internalize the linked carrier.
Pneumococcal conjugate vaccine: A vaccine containing pneumococcal capsule sugars linked to carrier proteins. Carrier linkage makes capsule-specific responses effective in young children.

Linked from 9 pages