RB464, RB465, RB466 and RB467 antibodies recognize a Dictyostelium AlyA peptide by ELISA

Abstract

The recombinant antibodies RB464, RB465, RB466 and RB467 detect by ELISA a synthetic peptide from the Dictyostelium AlyA protein.

Introduction

AlyA (Amoeba LYsozyme, DDB_G0275123, UniProt #Q8T1G4) is a member of the amoeba lysozyme family in the amoeba D. discoideum (Muller et al., 2005). Here we describe the ability of four recombinant antibodies (RB464, RB465, RB466 and RB467) to detect by ELISA a synthetic biotinylated peptide from the AlyA protein.

Materials & Methods

Antibodies: ABCD_RB464, ABCD_RB465, ABCD_RB466 and ABCD_RB467 antibodies (ABCD nomenclature, http://web.expasy.org/abcd/) were produced by the Geneva Antibody Facility (http://unige.ch/medecine/antibodies/; Blanc et al., 2014) as mini-antibodies with the antigen-binding scFv portion fused to a rabbit IgG Fc (RRB464, RRB465, RRB466 and RRB467). HEK293 suspension cells (growing in FreeStyle™ 293 Expression Medium, Gibco #12338) were transiently transfected with the vector coding for the scFv-Fc of each antibody. Supernatants (~50 mg/L) were collected after 5 days.

Antigen: The antibodies were raised against a N-biotinylated synthetic peptide corresponding to 43 residues close to the AlyA C-terminus (LTDSRPLGPFNV TESEMAQLFIDHEIAMAQCEAEKTCNGFDLE).As a negative control, an irrelevant N-biotinylated peptide (EKNSRQRLLNPS) from mouse Pannexin-1 protein (UniProt #Q9JIP4) was used.

Protocol: The whole procedure was carried out at room temperature. Biotinylated peptides at saturating concentration (10 pmol/well) were immobilized on streptavidin-coated ELISA plates (Pierce #15124) for 30 min. Each well was rinsed three times with 100 μl of washing buffer (PBS + 0.5% (w/v) BSA + 0.05% (w/v) Tween20), then incubated for 1 hour with 50 µl of RRB antibody-containing supernatant diluted in washing buffer (Fig. 1). After rinsing 3 times (100 µl washing buffer), wells were incubated with horseradish peroxidase-coupled goat anti-rabbit IgG (Sigma #A8275, dilution 1:1000, 50 μl per well) for 30 min. After 3 rinses, Tetramethylbenzidine (TMB) substrate (Sigma #T5569) was added (50 μl per well). The reaction was stopped by the addition of 25 μl of 2 M H₂SO₄. The absorbance (OD) was measured at 450 nm, and the absorbance at 570 nm was subtracted.

Results

Antibodies RB464, RB465, RB466 and RB467 bound in a concentration-dependent manner to the AlyA peptide against which they were raised, but not to the negative control peptide (Fig. 1).

Figure 1. Specific binding of RRB antibodies to the target AlyA peptide, as detected by ELISA. ‘Control’ indicates the binding of RRB464 to the negative control peptide (all other control curves were superimposed).

Conflict of interest

The authors declare no conflict of interest.