how to test for immunity

[chipsta1101]

For my science fair project I want to test how much acai berries can improve a person's immune system, but I am not sure how I would go about testing that. If anyone has any suggestions, please respond.

[Walker]

Hi there,

Determining the efficacy of supplements in improving health is certainly an important arena of scientific research. With so many (often expensive) supplements out there, how are we to know how to choose what to spend our limited medical dollars on?

The broad question you are interested in is whether acai berries have benefits to the immune system. As you select a more refined question to ask from inside this general concept, you will be able to determine what sort of experimental set-up can let you answer your question. Different experimental systems are better suited for different specific questions. For example, if you are interested in the human response to acai berries, you are constrained by the logistics and ethics of working with humans as research subjects! Studying humans, you could do things like interview people about their frequency of acai berry intake and see if there's a correlation with their self-reported health or number of days of sickness, or provide acai berries to half your classmates for a month during cold season to see if that group comes down with fewer colds. (Keep in mind that when doing this kind of research with humans, it is vitally important to do so only with their full understanding and consent and to protect the privacy of their medical information! You'll need to be careful about receiving the appropriate guidance and approvals along the way!) Using vertebrate animals, you have the advantage of being able to do more extensive manipulations (of diet, etc), but you must frame your questions in a way that does not cause suffering to your subjects. Alternatively, you can get away from the ethical and practical concerns of working with humans or vertebrates by studying mammalian immune cells in culture (if you happen to have access to the rather specialized cell culture equipment required for this kind of work). Of course, using non-vertebrate animals, it is possible to use much more sophisticated manipulations to ask more refined questions. For example, you could put acai berries in the diet of mealworms and determine whether it made them more resistant to bacterial infection. A downside of this is that invertebrates have a much less sophisticated immune system than we vertebrates do, so there are many aspects of our immune systems that can not be studied in invertebrates. Finally, there are chemical investigations that can be done with the berries themselves, for example, you could study their antioxidant activity or some other variable that you know could be related to immune system function.

I hope these thoughts are helpful as you imagine your options. There are many different questions you could ask. You just have to decide where your own interests lie and then plan a strategy to approach those interests experimentally!

Best wishes,

Will

[chipsta1101]

If I were to test the mealworms, what bacteria would you recomend for me to introduce to them? Also, how would I measure the antioxidant content of an acai berry?

[Steve Binder]

Hi,

I thought I would add some information that addresses your original question.

When we discuss immunity in "people" there are a variety of laboratory tests
that can be performed. For example, levels of immunoglobulins (IgG, IgM and IgA)
can be measured. Also, measuring complement levels (C3, C4, C50) might be
considered.

It is not really practical to do this kind of work in a science project because of
the legal/ethical requirements surrounding blood samples in people. So this
is why doing the study in a formal way in humans would be challenging, at least
for a science project.

Another concern tho is the definition of "immunity". Not everyone will agree
on what it means to improve immunity. The protein markers above may or
may not be responsive to a supplement. So I would advise you to make sure
you are clear on how you will measure immunity if you take on this kind of study.
Exposing an organism to an invasive bacteria may or may not be a good
definition of immunity, since immunity is unlike to improve from 0% to
100% as a result of any treatment.

Regards,

Steve

[chipsta1101]

Out of all of these, what do you think the most reasonable and accurate way to test it without the hassle of ethics and safety rules would be. Also, if I was to extract the antioxidants, which does sound interesting to me, how exactly would I do that?

[Walker]

Hi there,

To get an idea of what could be a good pathogen to use for a study with mealworms, you'll want to do a little background reading in the area. The NIH database, Pubmed is a great place to go to find out what professional scientists are using as practical systems for study. You can go to PubMed at

http://www.ncbi.nlm.nih.gov/pubmed

and search for something like "mealworms infection" or "tenebrio immunity" (Tenebrio is the genus of the common mealworm) to pull up a list of abstracts that contain these keywords. Scanning the list, I see that E. coli has been used by at least one group, and might be an easy choice.

The previous expert made an important point about choosing the best readout for immunity. If you choose a "coarse" readout (say, the mealworm lives or dies after immune challenge), then your experiment may not have enough sensitivity to detect an effect of your treatment (maybe all the insects become overwhelmed by bacteria, but the treatment makes them get "even more" overwhelmed, for example. The two cases could be indistinguishable if all you do is come back in a week and count dead bugs!) So you can consider what the best way is to get information from your system. Maybe you could homogenize the animals at a certain time point and measure their bacterial load, for example, by plating out known dilutions of homogenate on a petri dish and figuring out how many bacteria the worms contained by counting the colonies that grow on the dish.

-Will