Figure 1
Source data is available upon request.
The impact of protein structure on antibody recognition and vaccine efficacy. (a) The Oo-ASP-1 amino acid sequence of the Pichia pastoris-expressed recombinant version (top), and native protein from European (middle) and North-American (bottom) isolates is partially presented. A total of nine positions in the ASP sequence were found to show sequence diversity. The corresponding residues are shown in black/green with the size of the letter reflecting its relative presence. Amino acid residue numbers prone to sequence diversity are indicated at the top. Dotted lines indicate residues with quasi identical polymorphism percentages. (b) Circular dichroism spectra of native Oo-ASP-1 (intact line) and P. pastoris recombinant (dashed line), normalized to allow comparison. (c) Competition ELISA showing binding preference of antibodies from calves immunised with native Oo-ASP-1 towards native Oo-ASP-1 (intact line), P. pastoris recombinant (dashed line) or a variant of the P. pastoris recombinant with included polymorphisms (dotted line). (d) Amino acid sequence of recombinant Oo-ASP-1 with the six intramolecular disulphide bonds numbered (1–6), and the cysteine involved in dimer formation (dimer). (e) Pichia pastoris recombinant Oo-ASP-1 structure17 showing the intramolecular disulphide bonds corresponding to panel A. (f) Immunisation-challenge study in cattle displaying O. ostertagi faecal egg output in calves immunised with size-exclusion purified native Oo-ASP-1 + QuilA (n = 7) versus QuilA-adjuvant controls (n = 7), presented as total cumulative eggs per gram faeces (EPG). Data are presented as mean values + / − standard error of the mean. P values were calculated using a one-tailed Mann–Whitney test. *P < 0.05, **P < 0.01 and ***P < 0.001 versus QuilA-adjuvant control. The experiments presented in (a), (b), (c) and (f) were conducted once. Data in (d) is based on two experiments.
