FIG 6.

Identification of rabbit B cells producing IR-specific antibodies. (Bar plot) Twenty VlsE-positive cell lines (x-axis) from rabbits immunized with recombinant VlsE were selected with the B cell sorting technique and tested against purified antigens with ELISA. Bovine serum albumin (BSA) was used as the negative control and the purified recombinant VlsE protein (of strain B31) as the positive control. An OD₄₅₀ value (y-axis) greater than 3 standard deviations above the mean BSA reactivity (dashed lines) was considered to show significant antibody-antigen reactivity. Five cell lines expressing anti-IR4 antibodies and one cell line expressing anti-IR6 antibodies were identified. (Inset) SDS-PAGE image of induction and purification of the recombinant B31 VlsE. Elution 1 and Elution 2 were combined into a single preparation with an estimated purity of ~65% and a concentration of ~5.0 mg/mL, which was subsequently used to immunize New Zealand rabbits. “Pre-ind,” pre-IPTG induction; “Post-ind,” postinduction; “Flo-through,” flowthrough sample; “Wash,” wash sample; “Elu1” and “Elu2,” elution samples.