TABLE 2.

Competition experiments between MAbs 12C9 and 18E2^a

Concn of unlabeled MAb	% Relative binding of biotinylated MAb
	12C9		18E2
	0.5 μg/ml	1 μg/ml	2 μg/ml	4 μg/ml
0	100	100	100	100
Equal concentrations	94	100	99	91
2-fold excess	94	100	97	87
10-fold excess	91	95	99	86
100-fold excess	90	93	78	84

^aCompetition experiments were performed on wells coated with crude extract of P. halstedii race 1 using a mixture of biotinylated MAb (at a concentration which gives about 50% binding) and an equal concentration or a 2- to 100-fold excess of the other unlabeled MAb. The results are the means of triplicate determinations and are expressed as the binding of the biotinylated MAb relative to that of the control performed in the absence of the unlabeled MAb. None of the values was significantly different from the others.