Virology- advantages and disadvantages of using LD 50%

HI again

Could you please tell us what ended up finding? I'm curious about this one too.

Yes so all these test have advantages and disadvantages.
For the Hemaggluatinin assay one would add different dilutions of virus containing solution to different wells which contain a solution of RBC's. RBCs typicall roll to the bottom of the well creating a "plug", now when we add the virus it will agglutinate or clump the rbc's together causing them to be suspended in solution, hence preventing the formation of the plug at bottom of well. can be used to find the specific concentration that will cause symptoms to occur but the disadvantage is that not all viruses cause agglutination.

Plaque assay- one would add solution of virus to monolayer culture of cells and using specific staining and adhering techniques would apply compounds that immobilize virus particles to a given location. after sometime and a wash plaques will be observed reflecting the location of infection caused by the virus rupturing cells and can be used to experiment different drugs on viruses and show amount of live virus disadvantage is that not all viruses cause plaqueing to cell cultures.

Direct count- solution of virus mixed with known concentration of silicon beads mixed and viewed under electron microscope with known surface area and know concentration of beads, direct particle count of virus to bead ratio within given area , one can calculate concentration of virus particle disadvantage; cant differentiate between live and dead virus.

lethal dose 50%- using test animals and applying different dilutions of virus solution one can create a graph which shows the specific concentration required to kill 50% of the animals exposed to that specific concentration, and then that known concentration can be used in different ways ,e.g, Enders used it in polio research, to understand viral replication. disadvantage; cant be test on humans, cant kill humans obviously.

this is at best a crude summary of some virology techniques but if youre in the field it will suffice.

Thanks so much.