Positive selection involves targeting the desired cell population with an antibody specific to a cell surface marker (CD4, CD8, etc.). … Negative selection is when several cell types are removed, leaving the cell type of interest untouched.

What is the difference between negative and positive thymocyte selection?

Positive selection selects cells which are able to bind MHC class I or II molecules with at least a weak affinity. … Negative selection destroys thymocytes with a high affinity for self peptides or MHC. This eliminates cells which would direct immune responses towards self-proteins in the periphery.

What does negative selection differential mean?

Positive selection differentials would cause the mean phenotype to increase, whereas negative selection differentials would cause it to decrease. The phenotype at which such directional selection ceases (and only stabilizing selection remains) is the ESS.