Several lines of evidence indicate that the inhibition of CypA-CA interactions in newly infected human target cells usually impairs viral infectivity, including studies evaluating the infection of target cells whose CypA expression has been reduced or eliminated, the effect of inhibiting CypA-CA interactions using cyclosporine A (CsA) or its analogs, and the impact on infectivity of CA mutations such as P90A and G89A that impair CypA binding [5,7-15]. Here, PPIA is linked to infection.