September, 2003- While many members of the MBC faculty use animals for research, these tend to be the usual lab rats, mice, and rabbits. Dr. Les Baillie , a microbiologist who specializes in anthrax, has begun to use something decidedly un-usual-sharks! In collaboration with Drs. Helen Dooley and Martin Flajnik of the Department of Microbiology and Immunology, University of Maryland Baltimore, Dr. Baillie is exploring the possibility of using nurse sharks to produce antiserum against anthrax.

Antibody-based assays, used to detect biological substances, are both specific and rapid. However, they are temperature sensitive and easily rendered useless under extreme conditions. However, unlike antibodies produced in mammalian species, shark antibodies, which are structurally quite different from human antibodies, are extremely temperature stable. Shark antibodies retain activity even after boiling and can be stored for long periods of time. This makes them ideal for developing environmental tests for the presence of anthrax, where field conditions can make traditional antibody assays impossible.

One of the continuing problems, on which Dr. Baillie is focusing his research, is the lack of a real time, specific test for the presence of anthrax. Culture techniques are time consuming and, while molecular techniques such as PCR are available, they are complicated by the cross reactivity of Bacillus anthracis (anthrax) with its evolutionary kin. PCR, while it can be very specific, is not easily done in the field, is subject to contamination, and requires expensive hardware.

Dr. Baillie and his colleagues showed that immunization with recombinant protective antigen from B. anthracis could produce a highly specific and thermal stable antiserum. Their work is just preliminary, having started with two sharks. Early indications suggest that this approach should work. Anthrax is just one of many microorganisms and biological substances for which there are no good environmental assays.

Dr. Baillie envisions developing a test similar to the familiar pregnancy home test (an antibody based test for hCG, a pregnancy induced hormone). The new anthrax detection test should be easily and unequivocally done by untrained individuals, although a more complicated test requiring some training would still be a great leap forward. A quantitative version of the "quick" field test would also be of great value.

The first step is still finding a good source of antibodies and it looks like Dr. Baillie has reeled in a keeper!

Written by Pamela Wright