Field of Science

Could we do the serum-survival experiment here?

As I wrote a few days ago, our attempts to send pools of transformed Haemophilus influenzae cells to London (to be tested by our collaborators there) were thwarted by FedEx, and we're now considering doing the experiment ourselves.

The experimental plan is to incubate pools of transformed bacteria in human blood and look for survivors.  The bacterial cells are of the standard lab strain, which is rapidly killed by factors in blood.  The pools consisted of cells that had been transformed with fragments of chromosomal DNA from a strain that survives just fine in blood, and we're hoping that any survivors from our transformed pools will have acquired the gene or genes responsible for survival.

The RA did her PhD in the London lab, and she has done such assays when she was there.  BUT big logistic and administrative problems are created by research using blood.  The London lab uses heparin-treated blood freshly drawn from a lab volunteer.  I'd be happy to volunteer - needles don't bother me, and although I don't have the survival-assay protocol I don't think very much blood is needed.  But getting permission to take blood from any of us would require obtaining permission from the university's 'Ethics of Human Experimentation' committee.  And none of us knows how to draw blood... 

UBC has a Centre for Blood Research, located just upstairs in our building - they study, among other things, ways to improve collection and use of blood and blood products.  I wonder if we might be able to get blood from them? 

Experiments using human blood almost certainly also have lab-safety issues, and we'd probably need to get a new permit especially for this work.  The post-doc thinks the regulations aren't very onerous - we'd just have to work in a biosafety hood, and the group next door has one they don't use very often.  But I'd need to check this too.

Another possibility is using commercial human serum rather than blood.  When I wrote a post about this phenomenon last month, I showed a graph from an experiment that used human serum, not blood.  I just went back and checked their Methods section; that serum had been obtained by the researchers from volunteer blood that was allowed to clot normally, and stored frozen at -70 °C.  But normal human serum can be purchased from various suppliers.  Hmm, so can normal human blood...  I'll have to ask our London collaborators whether they use fresh blood because frozen blood and serum don't work well.

Of course, if we don't send our cells to our London collaborators, they'll have to send their blood-resistant strain to us so we have the right positive control for the experiments.  They'd have to deal with the shipping problem, but we'd have to first obtain an importation permit.  Luckily we know how to do that, and it normally only takes a few days (once the Christmas disruption is over).  I just checked the catalog of the American Type Culture Collection, and we can't get the strain we need from them. 

4 comments:

  1. Also reminder that UBC HSE doesn't let labs research on blood from anyone in or near that lab. (If I recall correctly)

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  2. Hi Rosie,

    I work with Campylobacter and for our serum resistance assays we use commercial serum from Innovative Research (http://www.innov-research.com/innovative/Human-Biologicals/Serum/Complement-Preserved-Serum/Pooled-Complement/Pooled-Complement-Preserved-Human-Serum/prod_54.html).

    As for a protocol, we use a version modified from Blaser et al. outlined here:
    http://iai.asm.org/cgi/content/full/68/12/6656?view=long&pmid=11083778#B8

    Hope this helps!

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  3. You're transforming an H. influenza strain that dies off in blood with a strain that survives just fine in blood - meaning you hope to create an infectious strain from a non-infectious strain?

    Is this correct, for example: "Hib disease is spread through contact with discharges or droplets from the nose or throat of an infected person. Hib disease can spread from person to person through sneezing, coughing, or speaking closely with an infected person. A person does not have to have symptoms to spread the bacterium."?

    Why are you surprised that FedEx would not want to ship such a strain, in this post-anthrax attack world? You might also want to make sure everyone in your lab (and the people they come into contact with) has been given the Hib vaccine, I'd guess.

    Why not see if you can get some broad-spectrum antibiotic-resistance plasmids in there too, while you're at it?

    It all seems a bit reckless - or am I missing something? You might end up doing the serum-survival experiment in the serum of a living lab worker, is the point... pesky human experimentation rules, what?

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  4. Check with labs doing human genetic work--sufficient DNA quantities usually require 3-10mL of blood from patients and controls, so they'll be well-versed in safety and ethics requirements.

    Not familiar with UBC, but it is generally true that you can't use blood from lab members to prevent situations of coercion.

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