MLC1 and influenza: Our BLI experiment showed that VL D50Y abolished the binding activity of IGLV3-21 antibody 5J8 to influenza H1N1 A/California/07/2009 HA and weakened the binding affinity of another IGLV3-21 antibody, Fab234, to P. falciparum CSP by around 5-fold (Figure 3A; Figure S2).