Fig. 2.

Ig heavy-chain isotyping and sequencing. (A) Ig heavy-chain isotype of single-cell-sorted α-gal⁻ and α-gal⁺ CD3⁻ CD19⁺ lymphocytes from controls and patients with MMA. The number of cells with sufficient constant region coverage to reveal isotype are shown below each pie graph. (B) Frequency of amino acids at position 33 of Ig CDRH1 in α-gal⁻ or α-gal⁺ B cells. The four most common amino acids are depicted: tyrosine (Y), alanine (A), tryptophan (W), and glycine (G). Numbers below pie charts indicate the total number of B cells with sufficient CDRH1 coverage to identify amino acid position 33 from each group. (C) IGHV usage identified in B cells from MMA patients (open blue circles) and controls (black dots). Each data point represents the ratio of α-gal⁺/α-gal⁻ cells attributable to a particular germline for each patient or control. The dashed line represents equivalent numbers of α-gal⁺ and α-gal⁻ B cells (ratio = 1). Data points above the line indicate an IGHV bias for α-gal⁺ B cells. The bars represent the mean α-gal⁺/α-gal⁻ ratios for patients and controls combined. IGHVs containing W33 in CDRH1 are shaded yellow. Only germlines for which both α-gal⁺ and α-gal⁻ B cells were detected are displayed. Patient-specific germline counts from which these data were derived are shown in SI Appendix, Fig. S4.