Immune System Vocabulary

Note – This page is work in progress. As we add more blog posts and reference journal article reviews we will update this page and have links to posts with better definitions and references.  As immunology vocabulary is very complex it is often very difficult to read journal articles.


Asymptomatic – Used to denote infections that never make people feel sick. #asymptomatic


Bivalent Vaccine – A bivalent vaccine elicits an immune response against two different antigens. This can means two different viruses, or two variations of one virus. or two bacteria.

Breakthroughs – The term breakthrough has an established history in vaccinology—counting up these events is necessary to know how well inoculations are working in and out of trials.


Covalent Vaccine – The same as Bivalent except the two target antigens are in equal parts.


Evidence-based medicine – Medical practice or care that emphasizes the practical application of the findings of the best available current research.  


Fully vaccinated – To reduce the risk of getting infected or seriously sick  with a disease, and decrese the chances that the virus will be passed on to others.  Often vaccine effective rates are given as a percentage such as 95% effective.  This mean you have a 5% chance of getting the disease.  This term is often misunderstood.   It takes your body several weeks to become disease resistant after vaccination.  


IgE – Immunoglobulin E (IgE) is an antibody.  It is a protein produced by the immune system in response to a possible invader. It is primarily involved in the allergic response but also fights infections from bacteria, viruses and parasites.


Multivalent Vaccine – Vaccines have been designed to protect against even more than two types of viruses


Natural immunity – Used it to describe the protection left behind after an infection by a bonafide pathogen.


Orthologue A homologous gene that is related to those in different organisms by descent from the DNA of a common ancestor.


Polyclonal response – Polyclonal B cell response is a natural mode of immune response exhibited by the adaptive immune system of mammals. It ensures that a single antigen is recognized and attacked through its overlapping parts, called epitopes, by multiple clones of B cell.


Quarantine – from Italian meaning 40 days – current meaning – describes the period of time when people who think they’ve been exposed to to an infectious disease are supposed to cloister themselves—a precaution in case an infection manifests.  If you have a positive test or symptoms you go into isolation.


Subvariant – One of two or more distinctive forms or types of the same variant.


T cell receptor (TCR) – The T-cell receptor (TCR) is a protein complex found on the surface of T cells, or T lymphocytes, that is responsible for recognizing fragments of antigen as peptides bound to major histocompatibility complex (MHC) molecules. The binding between TCR and antigen peptides is of relatively low affinity and is degenerate: that is, many TCRs recognize the same antigen peptide and many antigen peptides are recognized by the same TCR

The TCR is composed of two different protein chains (that is, it is a heterodimer). In humans, in 95% of T cells the TCR consists of an alpha (α) chain and a beta (β) chain (encoded by TRA and TRB, respectively), whereas in 5% of T cells the TCR consists of gamma and delta (γ/δ) chains (encoded by TRG and TRD, respectively). This ratio changes during ontogeny and in diseased states (such as leukemia). It also differs between species. Orthologues of the 4 loci have been mapped in various species. Each locus can produce a variety of polypeptides with constant and variable regions.



Vaccine effectiveness – A measure of vaccine effectiveness often given as a percentage based on clinical trials.  

Vaccine-acquired immunity – Immunity via a vaccine such as Polio vaccine.  this takes place in the days and weeks following a vaccination where the bodies immune system developed antigens to inactivate a pathogen.

Vaccinology – A field recently that has come into existence.  An expertise related to the creation and deployment of vaccines. The field ‘borrows’ from epidemiology, immunology, infectious disease, pediatrics, preventive medicine, public health and virology.

Variant one of two or more viruses or bacteria of the same kind that differ in some way from one another.