TRIM21 and infection: Determining the efficiency of pre-coating in the presence of both complement and TRIM21 neutralization mechanisms, we observed that a low concentration of antibody mutant or Fab was sufficient to recover about 10-fold of infection, likely reflecting the C1q-dependent neutralization, while higher concentrations were needed to dose-dependently restore infection to no antibody control levels, likely reflecting the TRIM21 component of neutralization (Figure 6G).