Anti-Ricin [A9]

Absolute Antibody

Anti-Ricin [A9]

9

The VHH antibody was specific for RTA as confirmed by competition ELISA. The crystal structure of ricin catalytic subunit in complex with the VHH antibody was determined. The antibody had relatively weak toxin-neutralizing activity (IC50 ~750 nM), as shown by Vero cell cytotoxicity assays. The antibody binding affinity (KD) for ricin holotoxin (0.08 nM). The binding affinity, and, toxin-neutralizing activity of the antibody was mediated by CDR2 containing five consecutive Gly residues that interact with alpha-helix B. In order to prove this, a variant of the antibody lacking Gly AC151residue 59 (A9delta59) was generated. Binding studies and toxinneutralizing assays confirmed that the removal of a single glycine residue from A9s CDR2 significantly reduced binding affinity for RTA (~10-fold weaker; 1.76 nM versus 0.102 nM) and eliminated toxin-neutralizing activity (Rudolph et al., 2018; PMID: 30265352).

ELISA, Neutralisation/Blocking, Other Application

Research Use Only

Monoclonal

A9

LOC8261245

ricin

RCOM_2159810, rRNA N-glycosylase, ricin, proricin A chain, ricin E beta chain, ricin homolog, truncated

Mouse

IgG1

Ricin

Plant

-20°C,2°C to 8°C

41116161