Among S trimer-specific antibodies produced during natural infection, the IGHV3-30, IGKV3-20, and IGHJ6 genes were enriched, while the frequencies of IGHV3-53, IGKV1-39, and IGLV3-21 were not significantly increased61, suggesting that the latter might be genetic features of RBD-specific antibodies. Here, IGHJ6 is linked to infection.