Helminth protein

Key takeaways

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

Reference excerpt

A helminth protein, or helminthic antigen, is a protein derived from a parasitic worm that causes an immune reaction. When secreted, these proteins may modify the host's immune response in order to promote longevity of the parasite. Helminth proteins can result in a deregulated response to infection, and are implicated in reduced reactivity to other antigens. Other helminth proteins promote parasite survival in other ways, particularly since parasites must depend on hosts for the supply of essential nutrients. Despite their pathogenic properties, helminth proteins have potential to be co-opted to treat a number of other human diseases.

Immunoregulation Helminth proteins modulate the immune response of their hosts, but do not suppress it entirely. A number of proteins are able to induce production of IL-10, an anti-inflammatory cytokine. IL-10 is partially responsible for reducing expression of co-stimulatory molecules such as CD86 on macrophages. CD86 is one of the proteins which interact with CD28 to activate T helper cells; without it, T helper cell response is mitigated. Schistosome proteins also contain abundant proteases which and cleave IgE antibodies. Alpha-1, a protein released by schistosome eggs, can also be a chemokine binding protein, preventing the recruitment of other immune cells like neutrophils. T. canis C-type lectins are additionally able to bind to mammalian carbohydrates, suggesting that they may promote evasion of the host's immune system by preventing the migration of host immune cells. A number of helminth species also secrete high levels of antioxidants to avoid phagocytosis; those antioxidants are needed because phagocytes like macrophages frequently produce reactive oxygen species like oxygen radicals, superoxide, and hydrogen peroxide to attack parasites. Additionally, many nematodes residing in the gut may secrete acetylcholinesterase, which is responsible for the degradation of acetylcholine to terminate neuronal signals. Acetylcholinesterase may prevent parasite clearance from the gut by preventing acetylcholine-mediated signaling from stimulating the production of intestinal chloride and mucus.

Lipid Acquisition Parasites like helminths do not synthesize their own fatty acids or sterols, and are consequently dependent on their hosts for essential nutrients. A number of different classes of lipid-binding proteins have been investigated and characterized. Of these, NPA (nematode polyprotein antigen/allergen) FAR, and Sj-FABPc demonstrate different binding affinities for fatty acids and/or retinoids. Ov-FAR-1, which is produced by the riverblindness parasite Onchocerca volvulus binds retinol with great affinity, and this activity may result in the pathology it causes. Ov-FAR-1, however, binds fatty acids with less affinity. On the other hand, Sj-FABPc, found in Schistosoma japonicum, binds fatty acids with high affinity, but does not bind to retinol. All three of these proteins are able to deliver lipids to acceptor membranes, but this transfer process in Ov-FAR-1 and ABA-1A1 (a type of NPA) requires an aqueous diffusion step. Sj-FABPc uses a collision mechanism, and transfer is not affected by changing salt concentrations, suggesting that it may be important to intracellular targeted transport and metabolism of fatty acids. Ov-FAR-1 and ABA-1A1 may instead behave similarly to extracellular lipid-binding proteins.

Genomic Prediction The Helminth Secretome Database (HSD) is a repository for helminth proteins predicted using expressed sequence tags (ESTs). Previously identified ESTs, which correspond to known helminth proteins, are used to predict the location and function of newly discovered helminth proteins based on genomic sequencing. Additionally, the database can also be used to develop protein targets for new drugs to treat helminth infections.

Potential Therapeutics Given the modulatory properties of helminth proteins, it has been suggested that they may be co-opted to successfully treat other human diseases, particularly those associated with auto-immunity disorders. In particular, immunization with P28GST, a schistosome glutathione S-transferase enzyme in rats has been shown to reduce colitis lesions and expression of pro-inflammatory cytokines by eosinophil responses to inflammation. P28GST is thus a promising potential therapeutic for treating inflammatory bowel diseases like Crohn's disease and ulcerative colitis. Additionally, injection of proteins secreted by Fasciola hepatica in nonobese diabetic mice prevented the onset of type I diabetes, with 84% of the mice showing normal glucose levels 26 weeks after injection. This phenomenon is attributed to the suppression of interferon-gamma secretion from autoreactive T cells following the activation of regulatory M2 macrophages. This result supports the possibility of eventually using helminth products to treat type I diabetes in humans as well.

References

Worked examples

Example 1 — a first encounter with Helminth protein

Start with the simplest possible case. Write down what Helminth protein 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 Helminth protein 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 Helminth protein 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 Helminth protein

In research: Helminth protein 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 Helminth protein 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: Helminth protein is common in secondary-school and first-year university syllabi. It links to neighbouring topics Animal proteins, Flatworm biology, so understanding it makes those chapters shorter.
In everyday life: Look for Helminth protein 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.

How to study Helminth protein in 20 minutes

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

Frequently asked questions

What is Helminth protein in simple terms?

A helminth protein, or helminthic antigen, is a protein derived from a parasitic worm that causes an immune reaction. When secreted, these proteins may modify the host's immune response in order to promote longevity of the parasite.

Why does Helminth protein 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 Helminth protein?

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 Helminth protein.