Project Lead(s): Keertan Dheda
The most common opportunistic infection in HIV-infected individuals is tuberculosis (TB).
Severely immunocompromised individuals have higher mortality risk than the average TB patient and have the most to gain from rapid diagnosis of TB and immediate treatment.
Currently, rapid detection of TB in such patients can be achieved at the point-of-care within just 30 minutes using the Determine TB-LAM, a commercially available, lateral-flow urine ‘strip test’ assay.
A previous study, however, has shown that the LAM test had a specificity of >95% but sub-optimal sensitivity of ~50%.
The project team initially proposed to address this sub-optimal sensitivity by developing an ultra-sensitive aptamer detection lateral flow assay.
However, technical difficulties in generating LAM aptamer made them focus instead on the use of antibodies against LAM and monoclonal antibodies raised against a biomarker for extra-pulmonary TB (EPTB), interferon gamma (IFNγ).
While the team did not develop a working prototype as intended, they did manage to optimize several components that together will eventually form an ultrasensitive prototype TB diagnostic device to detect TB in HIV patients.
Achievements of the project include:
· Raising anti-IFNγ monoclonal antibodies
· Creating a working ELISA assay to use as a reference standard, which has been validated in clinical samples
· Creating polyclonal and monoclonal anti-LAM antibodies
· Developing a working anti-IFNγ lateral flow assay
· Creating working anti-IFNγ aptamers
· Developing a proof-of-concept working electrochemical circuit on a printed electrode, using the monoclonal antibodies to IFNγ and LAM.
The most important outputs from the project have been production of an immunoassay for IFNγ and LAM detection, and the improvement of detection in biomarker-spiked non-TB clinical samples when applied to an electrochemical platform.
When applied to an in-house lateral flow assay, the combination will increase the sensitivity and decrease the inter-reader variability of the current LAM lateral flow strip test, resulting in an entirely new point-of-care assay for TB.
The project garnered the attention of the Medical Research Council (MRC) and Strategic Health Innovation Partnerships (SHIP), which have provided additional funding of $3,210,084 for an additional two years.
The project has also enabled a strong ethos of collaboration, which is pivotal in seeing the point-of-care device through to large-scale manufacturing.
The current consortium will tap into Antrum Biotech’s expertise in leveraging further funding from the government and NGOs, once the initial prototype is validated.