Sensitivity of heterotrimeric pseudoviruses to neutralization by VRC03. IC50s are plotted on the y axis versus the probability of any given trimer containing >0 (A), >1 (B), or 3 (C) mutant protomers. Probabilities were calculated according to the fraction of mutant plasmid transfected (0, 0.2, 0.4, 0.6, 0.8, or 1). Two independent sets of DNA preparations were generated and tested. AE, A204E.