SBIR-STTR Award

It is important to be able to screen blood samples for the presence of pathogenic viruses such as htlv-iii, the causitive agent in acquired immune deficiency syndrome (aids). This proposal details a novel approach for the identification and quantitation of specific mucleic acid sequences. It uses fluorescent, rather than radioactive or enzyme-linked oligodeoxynucleotide probes. It is a homogeneous assay and does not require any separation steps, such as filtration or electrophoresis. It is designed to be accurate, specific, sensitive, inexpensive, rapid and easy to perform. These attributes would allow this assay to be applied to the screening of blood samples for known pathogenic viruses. This phase i study will demonstrate the feasibility of the described approach using a synthetic oligodeoxynucleotide target as a model of the viral genome.

Phase I efforts showed the feasibility of a dual probe fluorescent assay for aids dna fragments. Reagents, instruments and procedures will be developed for the routine screening of blood samples for hiv, the causative virus for aids. The assay will directly detect the virus, in contrast to the currently utilized assays in which the individual's antibody response to the virus is measured. The new approach is designated a "dual probe contact assay." in this assay, a positive response will be elicited only when a pair of different dna probes come in contact. This contact will occur only on the designated target (HIV) dna. The response elicited on contact will be a fluorescent signal. Two convenient methods of detecting this fluorescence will be explored - an immunoassay time decay fluorometer (available commercially) and a polaroid camera with appropriate light source. A 3-dimensional molecular design study will be undertaken in order to facilitate the choice of chemically synthesized probes to be prepared. The resulting probes will be tested with the target dna for efficacy. The probes will be altered as needed to produce a response only with the desired target. In the second year of the project implementation into a practical assay will be accomplished. The assay will be optimized using target, synthetic nucleic acid added to normal blood. One or both of the above mentioned detection systems will be used along with reagent and protocols in a clinical laboratory for evaluation of blood samples for hiv. Commercialization will be undertaken in phase III.