biology

Marker vaccine

Marker vaccine is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Marker vaccine rather than just read about it. In short: A marker vaccine is a vaccine which allows for immunological differentiation of infected from vaccinated recipients. In veterinary medicine, it is also referred to a DIVA vaccine or a SIVA vaccine, referring to the differentiation (or segregation) of infected from vaccinated animals.

Key takeaways

Marker vaccine belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Marker vaccine to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Marker vaccine from memory before moving on to harder problems.

Reference excerpt

A marker vaccine is a vaccine which allows for immunological differentiation of infected from vaccinated recipients. In veterinary medicine, it is also referred to a DIVA vaccine or a SIVA vaccine, referring to the differentiation (or segregation) of infected from vaccinated animals. In practical terms, this is most often achieved by omitting an immunogenic antigen present in the pathogen being vaccinated against, thus creating a negative marker of vaccination. In contrast, vaccination with traditional vaccines containing the complete pathogen, either attenuated or inactivated, precludes the use of serology (e.g. analysis of specific antibodies in body fluids) in epidemiological surveys in vaccinated populations. Apart from the obvious advantage of allowing continued serological monitoring of vaccinated individuals, cohorts or populations; the serological difference between vaccinated individuals and individuals that were exposed to the pathogen, and were contagious, can be used to continuously monitor the efficacy and safety of the vaccine. The DIVA strategy has been applied in various countries to successfully eradicate pseudorabies virus from those countries. Swine populations were intensively vaccinated and monitored by the companion diagnostic test and, subsequently, the infected pigs were removed from the population. Bovine herpesvirus 1 DIVA vaccines are also widely used in practice.

Examples

Approved Pseudorabies: the earliest DIVA vaccine-test pairs were created when researchers discovered that some existing pseudorabies vaccine strains carry a deletion in the gE gene. As a result, vaccinated pigs do not develop an antibody against the intact gE while actually infected ones do. This is exploited to make a DIVA test. Novel genetically engineered gE-negative vaccines were constructed to transfer this feature onto more strains. Bovine herpesvirus 1: gE is likewise deleted in marker BoHV vaccines to allow for a similar detection scheme. There are also alternative deletion schemes, though in the case of tk it mainly serves to attenuate the virus.

In trial Mycobacterium bovis: the Danish strain of the BCG vaccine is a marker vaccine as it does not elicit immunity against a number of M. bovis antigens (while infections tend to do). This is exploited in the DST-F skin test for cattle, where a fusion protein of three such antigens are used.

Unknown Classical swine fever virus Avian influenza Actinobacillus pleuropneumonia Salmonella in pigs

References

Worked examples

Example 1 — a first encounter with Marker vaccine

Start with the simplest possible case. Write down what Marker vaccine claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Marker vaccine before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Marker vaccine ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Marker vaccine

In research: Marker vaccine appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Marker vaccine in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Marker vaccine is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animal disease control, Vaccination, so understanding it makes those chapters shorter.
In everyday life: Look for Marker vaccine outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Marker vaccine in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Marker vaccine means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Marker vaccine out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Marker vaccine in simple terms?

Why does Marker vaccine matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Marker vaccine?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Marker vaccine.