Characterization of L2-specific monoclonal antibodies. (A) Schematic of the L2 protein with labeled key features. Numbers refer to amino acid positions of HPV16 L2: K4, MAb K4 epitope (aa 20 to 38); TM, N-terminal putative transmembrane region (aa 45 to 67); K1, MAb K1 epitope (aa 64 to 81); L2-1, MAb 33L2-1 epitope (aa 163 to 170); SNX17, sorting nexin 17 binding domain (aa 245 to 257); RBD, retromer binding domain (aa 446 to 455); MD, membrane-destabilizing domain (aa 454 to 473); DYN, dynein binding domain (aa 456 to 461); HA, C-terminal HA epitope. (B) Western blot using L2-specific antibodies (listed on the left side) to detect L2 protein from purified HPV16 and HPV18 pseudoviruses. To exclude cross-reactivity, HaCaT whole-cell extracts were run as controls.