Surprising Findings in Single Domain Antibody

Surprising Findings in Single Domain Antibody
Sleeping sickness caused by trypanosoma brucei can be transmitted to other people or animals
through by tsetse flies.
According to a new research paper published on the open-access journal Microbial Cell Factories
by BioMed Central on February 15, 2012, researchers use a kind of single-domain antibody
released by tsetse flies under natural environment to defense against these trypanosomata, which
means that this kind of single domain antibody plays a similar role as Trojan horses. They are the
first step in making specific single domain antibodies that can kill or stunt the growth of
trypanosomata.
As wiki explained, single domain antibody (camel antibody) is an antibody fragment consisting of
a single monomeric variable antibody domain. Like a whole antibody, it is able to bind selectively
to a specific antigen. With a molecular weight of only 12–15 kDa, single-domain antibodies are
much smaller than common antibodies (150–160 kDa) which are composed of two heavy protein
chains and two light chains, and even smaller than Fab fragments (~50 kDa, one light chain and
half a heavy chain) and single-chain variable fragments (~25 kDa, two variable domains, one from
a light and one from a heavy chain).
Sleeping sickness threatens millions of lives living in sub-Saharan Africa. In the first stage
(hemolymph stage) of trypanosoma brucei infection, its symptoms are fever, headache, joint pain
and itching. After this parasite infection across the BBB and enters the second stage (nerves stage),
it leads to thoughts confusion, poor coordination and sleep disorders. This disease is fatal without
timely treatment. The diagnosis and treatment of this disease, however, are not easy. Only those
who have received special training can handle. After infected by trypanosome, bovines can be
anemic and may even die from anemia. The comprehensive conclusion is that trypanosomata have
brought serious negative effect to public health and agricultural development throughout the
African continent.
Sodalis glossinidius are internal symbiotic bacteria that are similar to beneficial bacteria settled in
our intestine. Theycan be found in the midgut, muscle, fat and salivary glands of tsetse flies. As
female tsetse will pass these bacteria to their offsprings, the genetically modified bacteria should
be able to pass down from one generation to another once these female flies are released in the
wild.

Professor Van Den Abbeele, an expert from Antwerp Institute of Tropical Diseases, explained,
“When we study live trypanosomes inside the simulated intestine of tsetse, we found that these
genetically modified bacterium expressed single domain antibodies have biological activity and
can bind to the entire surface of the parasite. Since we know that this technology is effective, we
are now studying these single domain antibodies that can damage or block the development of this
type of parasites in tsetse intestine. “
Epidemic Sleeping sickness of these years first appeared in the 1970s. Although we have been
trying to decline the number of new cases in the past 10 years, this disease has not yet been
eradicated. This new technology gives people hope to fight against this devastating disease.
About author
Candy Swift is a reporter focusing on bio-pharmaceutical industry. She is also a service consultant
of Creative Biolabs.
https://medium.com/@candyjkswift/surprising-findings-in-single-domain-antibody-dacada16fce
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