Rhesus V2 apex lineages bear tyrosine sulfation and O-linked glycosylation posttranslational modifications. (a) Summary of posttranslational modifications detected on F(ab’)2-digested rhesus and human antibodies by mass spectroscopy. Human antibodies are denoted with *. The number of sulfation groups detected per proteoform is written in red. All rhesus antibodies contained various types of O-linked glycosylation, while human antibody controls did not. Antibodies without structural data are denoted with n/a (not applicable). (b) Full list of individual detected experimental masses and corresponding deconvoluted posttranslational modifications that were summarized in panel (a). The number of sulfation groups detected per modification is written in red (#xSO3). (c) Representative deconvoluted mass spectra for rhesus lineage F(ab’)2 subunits with tyrosine sulfation peaks. Y axis: relative intensity. X axis: mass (Da). (d) Representative deconvoluted mass spectra for rhesus lineage F(ab’)2 subunits without tyrosine sulfation peaks. Y axis: relative intensity. X axis: mass (Da). (e) Deconvoluted mass spectra for human F(ab’)2-digested antibodies PGDM1400 and ACS202, which serve as positive and negative controls for tyrosine sulfation, respectively. Y axis: relative intensity. X axis: mass (Da).