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New approach to HIV testing

15th June 2017

Posted By Paul Boughton


The Flexi-Therm, coupled with one of the Vitl Heated Modules, provides accurate, repeatable heating for lab consumables including microplates, microtubes and larger tubes

Dan Goodman describes the relationship between testing and suppressing HIV

Numerous advancements in antiretroviral therapy (ART) have allowed HIV sufferers to sustain much longer and healthier lives.

However, this form of therapy is no cure; it works as a suppressant of the virus, leaving it ready to attack as soon as treatment is interrupted.

New research investigating the effects of combined treatments has noted remarkable results when two particular antibodies are administered immediately after infection.

In the USA, researchers from the Rockefeller University and the National Institutes of Health found two antibodies (3BNC117 and 10-1074) can, as professor Michel Nussenzweig at the university says, “induce potent immunity to HIV, allowing the host to control the infection” when received shortly after inoculation. 

The study focused on 13 macaque monkeys, each receiving three treatments over a two-week period following inoculation.

As expected, the virus was suppressed for six months until the antibodies were filtered out of the subjects’ systems.

However, it was noticed by investigators that five to 22 months later, the monkeys regained control of the virus, allowing them to suppress it for a further five to 13 months.

Following the success of the recent study researchers are replicating the experiment on those with longer exposure to the HIV virus in the hope of finding an effective treatment for those subject to late diagnosis.

Experiments such as this highlight the need for earlier diagnosis, therefore putting greater pressure on HIV testing.

From this research it may be assumed that the faster the test the better, though this is often far from the truth.

Rapid tests, also known as ‘point-of-  care’ tests, can be conducted away from specialised lab environments and can provide results in less than 30 minutes.

Despite these advantages, many laboratory professionals view the tests with scepticism, noting how their low specificity causes false positive results, often resulting in the need for a more specific retest for confirmation – cue the ELISA tests. 

Next-gen ELISA

First approved for HIV testing in 1985, enzyme-linked immunosorbent assay (ELISA) has played a key role throughout the years in identifying HIV positive samples. ELISA has advanced over time and the fourth-generation of the ELISA test is miles ahead of its predecessors thanks to its ability to detect not only HIV antibodies but also the P24 antigen. This allows for clearer results within a fraction of the time, accurately detecting HIV  from 11 days after being exposed to the virus. Recent generations of the ELISA tests have proven to be more sensitive and highly accurate, meaning fewer false positive/negative results when using the right equipment.

Temperature accuracy is a crucial element of the ELISA method. The use of enzymes in ELISA poses the risk of poor performance or worse, denaturation, so whether preparing samples for testing or carrying out ELISA itself, low temperature accuracy can have drastic effects on the end results. Therefore, it is necessary to use high-spec equipment during the heating process, to increase efficiency and in return gain more accurate results.

Dan Goodman is with Vitl





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