Question

Suppose you were using a direct hemagglutination assay as a way to measure the amount of an antigen that causes red blood cell clumping. Describe how you would report the results as a titer, and also describe how you could go from this semi-quantitative measure to an absolute quantitation using a standard curve.

Answer 1

Here I am using the problem of hemagglutination by influenza virus to analyze test data. Hemagglutination is used to diagnose certain obstructive viruses, such as influenza virus. This method depends on a characteristic feature of some secreted viruses that can soak up red blood cells (RBCs). Specifically, hemagglutinin 5(H), an envelope glycoprotein of some enveloped viruses, provides this property. In the absence of virus cells, RBCs are precipitated by gravity down the well, leading to a cone-shaped red dot. In the presence of virus cells, RBC proteins are synthesized as a result of interactions between HA proteins. Virus cells and RBCs, forming a lattice. In this case, the RBC is not a red dot as it is spread over the clamp established. In a given sample, the red dot appears beyond the constant dilution. To perform a hematoma test,

Dual serial dilution of virus-containing samples to individual wells of a 96-well microtiter plate. Then, partitions of RBCs are added to each well. Too much damage to clapping samples is considered ha titer. The virus titer in the sample can be estimated by multiplying the dilution times. In theIn a standard situation, a unit of 1 H corresponds to 104 cells per ML. Hemagglutination is a scientific method for viral diagnosis but is still used today to diagnose influenza virus. The great advantage of this method is that it requires no equipment. In addition, it is strong and fast
The analysis tool, but the sensitivity is somewhat limited.
Now, we will discuss the experimental methods used in virus laboratories for research purposes, including virus cultivation, quantification, purification and genetic analysis.

Figure adapted from

Ryu, W. S. (2016). Molecular virology of human pathogenic viruses. Academic Press.