science

Virosome

Virosome is a science 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 Virosome rather than just read about it. In short: A virosome is a drug or vaccine delivery mechanism consisting of unilamellar phospholipid membrane (either a mono- or bi-layer) vesicle incorporating virus-derived proteins to allow the virosomes to fuse with target cells. Viruses are infectious agents that can replicate in their host organism, however virosomes do not replicate.

Key takeaways

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

Reference excerpt

A virosome is a drug or vaccine delivery mechanism consisting of unilamellar phospholipid membrane (either a mono- or bi-layer) vesicle incorporating virus-derived proteins to allow the virosomes to fuse with target cells. Viruses are infectious agents that can replicate in their host organism, however virosomes do not replicate. The properties that virosomes share with viruses are based on their structure; virosomes are essentially safely modified viral envelopes that contain the phospholipid membrane and surface glycoproteins. As a drug or vaccine delivery mechanism they are biologically compatible with many host organisms and are also biodegradable. The use of reconstituted virally derived proteins in the formation of the virosome allows for the utilization of what would otherwise be the immunogenic properties of a live-attenuated virus, but is instead a safely killed virus. A safely killed virus can serve as a promising vector because it won't cause infection and the viral structure allows the virosome to recognize specific components of its target cells.

Virosomes structure Virosomes are vehicles that have a spherical shape with a phospholipid mono/bilayer membrane. Inside of the virosome, there is a central cavity that holds the therapeutic molecules such as nucleic acids, proteins, and drugs. On the surface of the virosome, there can be different types of glycoproteins. Glycoproteins are a type of protein that have an oligosaccharide chain bonded to amino acid chains. The different types of glycoproteins on the surface of the virosome increases the specificity of the target cells because the surface glycoproteins help with recognition as well as the attachments of the virosomes to their target cells. In the case of the influenza virosome, the glycoproteins are antigen, haemagglutinin, and neuraminidase. Antigens are molecules that triggers an immune response when targeted by a specific antibody that corresponds to the shape of the antigen. Haemagglutinin is a viral glycoprotein that causes red blood cell agglutination. Neuraminidase are enzymes that break glycosidic linkages. The size and surface molecules presented on of the virosome can be modified so that it can target different types of cells.

Virosome applications Virosomes deliver antigens and therapeutic agents to their targeted cells. Virosomes can act as immunopotentiating agents and as agents of targeted drug delivery. Virosomes as immunopotentiating agents activate cell mediated and humoral immune responses. Virosomes are suspended in saline buffers and are administered through respiratory, parenteral, intravenous, oral, intramuscular, and topical routes.

Influenza virosomes

In contrast to liposomes, virosomes contain functional viral envelope glycoproteins: influenza virus hemagglutinin (HA) and neuraminidase (NA) intercalated in the phospholipid bilayer membrane. They have a typical mean diameter of 150 nm. Essentially, virosomes represent reconstituted empty influenza virus envelopes, devoid of the nucleocapsid including the genetic material of the source virus.

Non-influenza virosomes They are also being considered for HIV-1 vaccine research. They were used as a drug carrier mechanism for experimental cancer therapies.

Benefits and challenges The benefits of virosomes are that the specific structure and small size help with the precision of target cells. The phospholipid membrane protects the virosome from adverse reactions in the body and the membrane allows the virosome to be biocompatible and biodegradable in the body. The challenges of virosomes are the rapid detection and activation of the immune response against the viral glycoproteins, which can result in a decrease of the virosomes. However, glycoproteins can still induce a prophylactic response against the virus, which helps with establishing virosomes as vaccine delivery systems. If the virosome is administered into the bloodstream, the virosome can disintegrate. However, if the virosome can reach the target quickly enough, the drug delivery will still happen. There are some challenges with virosomes, but there are ways in which the virosome can still help activate the immune response.

References

External links "What are virosomes?" "Virosome based vaccine"

Illustrations

Worked examples

Example 1 — a first encounter with Virosome

Start with the simplest possible case. Write down what Virosome claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Virosome 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 Virosome 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 Virosome

In research: Virosome appears in science 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 Virosome 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: Virosome is common in secondary-school and first-year university syllabi. It links to neighbouring topics Vaccination, so understanding it makes those chapters shorter.
In everyday life: Look for Virosome 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Virosome in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Virosome 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 Virosome out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Virosome in simple terms?

Why does Virosome matter?

Because it connects several science 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 Virosome?

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 Virosome.