Dr. Anant Biotech explains the phenomenon of 2 faint lines in ATK.
December 5th Dr. Anant Chongkaewwattana, Researcher in Virology, Biotech Post a message via Facebook Anan Jongkaewwattana with a picture stating that
This picture is beautiful and clearly explained. According to an article in the latest issue of the journal Nature reviews microbiology, it can be seen that samples collected from nose, throat swabs or saliva contain either viable viruses that are infectious or viable particles that cannot continue to infect. with fragments of protein that have escaped from such particles, or fragments of RNA genetic material attached to the sample Genetic testing by qRT-PCR or RT-PCR is the process of breaking the virus to release its genetic material for measurement. This is the use of the detection signal as a representative of the virus present in the specimen.
But because the sample collected had RNA fragments in the first place Therefore, RT-PCR assays can detect viral RNA that is isolated from the actual virus or from the originally contaminated RNA that does not come directly from the viral particle. which is exactly what many people call “Infection” there
In the case of ATK assays, which detect viral nucleocapsid proteins, they come from two sources: virus particles directly or The protein fragments are attached along with the broken particles. But since proteins cannot be amplified like RNA amplification by RT-PCR, their measurements are less sensitive. A very positive ATK signal requires a certain amount of protein. The denatured viral protein alone would not be enough to produce such a strong signal.
Makes the ATK check that gets a clear tick It means that the intact virus particles are still present in the sample. In other words, the ATK is clearly positive, that is, the infectious virus is still present….On the other hand, the ATK that is faint after being sick for a while may mean that Protein fragments that are released from the virus as well.
Detection of complete infectious particles continues This can be done by incubating the sample with the cells in the laboratory. Then measure changes in those cells, such as the expression of viral proteins, cell death, or increased viral load. This is to confirm that the subject actually contains a viral infectious virus. The researchers were able to compare the viral loads in such samples. By continuously diluting the sample to find the last point where the cell changes, for example, if diluted 1000 times, still able to find cells expressing viral proteins at 5 points, it can be roughly said that The sample contained infectious viral particles at 5000 per volume of sample tested.
PS: The attached picture is an example of SARS-CoV-2 infected cells stained with 1 antibody, i.e. infected cells.