Table 1.

Direct and competitive ELISA results for polyclonal antibodies A (PAO pilin specific), B1, B2, C1, C2, D1, E1, and E2 (PAO pilin and PAK pilin cross-reactive antibodies).

			Pilin Competitor
Aba	Plated Pilin	Direct ELISA	PAK	IC50a,b (nM)	PAO	IC50a,b (nM)	PAK (ADN)c	IC50 (nM)	PAO (KSK)d	IC50 (nM)
A	PAK	nbe	ncf	nag	nc	na	nc	na	nc	na
	PAO	+	nc	na	+	2.3	nc	na	nc	na
B1	PAK	+	+	10	nc	na	+	15	nc	na
	PAO	+	nc	na	+	5.8	+	20	nc	na
B2	PAK	+	+	92	nc	na	+	64	nc	na
	PAO	+	nc	na	+	7.8	+	565	nc	na
C1	PAK	+	+	34	nc	na	+	32	nc	na
	PAO	+	nc	na	+	1.3	+	9.6	nc	na
C2	PAK	+	+	3.3	nc	na	+	37	nc	na
	PAO	+	nc	na	+	25	+	61	nc	na
D1	PAK	+	+	110	nc	na	+	57	nc	na
	PAO	+	nc	na	+	9.0	+	8.8	nc	na
E1	PAK	+	+	100	nc	na	+	71	nc	na
	PAO	+	nc	na	+	7.1	+	42	nc	na
E2	PAK	+	+	31	nc	na	+	11	nc	na
	PAO	+	nc	na	+	7.6	+	160	nc	na

^aIC₅₀, The pilin competitor concentration at which 50% of the antibodies (Ab) are competed off the plated pilin. Antibodies designated A, B, C, D, and E are obtained from immunogens shown in Fig. 3. The number following the letter denotes antibodies from different rabbits. Antibodies from different rabbits that were similar to the reported antibodies are not shown. For example, all antibodies to immunogen A from three different rabbits were similar and PAO specific.

^bGeometric mean of IC_5D values for cross reactive antibodies B1, B2, C1, C2, D1 , E1, and E2 for PAK (32 nM) and PAO (7.7 nM).

^cPAK (ADN) is a PAK pilin mutant where ADN denotes residue substitutions, K128A/S143D/K144N, frorn PAO pilin

^dPAO (KSK) is a PAO pilin mutant where KSK denotes residue substitutions, A128K/D143S/N144K, from PAK pilin.

^enb, no binding of the antibody to the pilin by direct ELISA

^fnc, no competition from the pilin competitor for the antibodies binding to the plated pilin.

^gna, not applicable.