Unit 1-Lecture 1 Flashcards
How does a virus infect a cell?
1.Virus Attaches to cell receptor
2. Virus injects its genetic info into cell
What can be used as protection against viruses infecting cells?
Antibodies
What are antibodies and what do they do?
Proteins made by the host that can recognize and bind to specific viral proteins
-prevents virus attachment to cell–>NEUTRALIZES CELL
What does neutralized mean?
Virus can no longer infect cells
What can viruses do to evade antibodies?
They can EVOLVE
-change its surface proteins so old antibodies can no longer attach to virus
How do we use these ideas to track virus evolution?
We can track viruses OVER TIME and see how their antigenic properties change
What is antiserum
Contains antibodies produced by the host
Plaque Reduction Neutralization Test (PRNT)
A mixture of antiserum and virus w/ many dilutions is plated onto cells
-MORE PLAQUE = INFECTIOUS VIRUS
-LESS PLAQUE = EFFECTIVE ANTIBODY
Dilution
is always less than 1 because the concentration decreases
Dilution < 1
Dilution Factor
is greater than 1
Calculated: 1/dilution
Titer
log2(Dilution Factor)
PRNT Plot
-sigmoidal curve
-We use titer for the plot not dilution factor
How do we decide which antiserum neutralizes the virus best?
We can compare PRNT50 titer values of each curve
-The HIGHER the titer value the BETTER the neutralization
What does 0% neutralization mean?
-Total # of virus particles in the sample
-top of curve
What does 100% neutralization mean?
-No plaques only virus
-At the bottom left of curve
