Table 1. Properties of new anti-RTB mAbs compared to 24B11 and SylH3.

mAb	EC50 c	Relative Kinetic Parameters a			IC50 d	Competition b
		ka (1/Ms)	kd (1/s)	KD (M)		SylH3	24B11
SylH3	2.5	2.20 x 105	8.06 x 10−6	3.67 x10-11	12	+	-
24B11	5	2.67 x 105	1.51 x 10−5	5.64 x 10−11	1.2	-	+
MH3	0.3	2.58 x 105	7.45 x 10−6	2.89 x10-11	1.6	-	+
8A1	2.5	3.67 x 105	2.75 x 10−5	7.49 x10-11	3.3	-	+
8B3	2.5	4.78 x 105	4.25 x 10−5	8.89 x10-11	27	+	+
LF1	2.5	1.02 x 105	6.92 x 10−6	6.79 x10-11	27	-	+
LC5	0.6	4.96 x 105	8.95 x 10−5	1.8 x10-10	-	-	-

^a, apparent binding association (k_a) and dissociation (k_d) rate constants, as well as apparent equilibrium dissociation constants (K_D), were determined by SPR using IgG molecules (not Fab fragments) and ricin toxin-coated GLC chips. The Langmuir model was used to analyze sensorgram results, as described in the Materials and Methods;

^b, competition ELISAs are described in the Materials and Methods. The minus (-) symbol indicates that binding inhibition values were <10% of controls;

^c As determined in the soluble ricin competition assay, described in Fig 3;

^d, nM.