TABLE 1.

Characteristic of the DEN strains used in this study

DEN serotype	Strain	Genotypea	Place, yr of isolation
1	Jamaicab	V	Jamaica, 1977
	West Pacific	IV	Nauru, 1974
2	A15	Asian	Cuba, 1981
	Jamaicab	Asian	Jamaica, 1982
	I348600	American	Colombia, 1986

^aGenotypes were considered according to the classifications of Laille and Roche (17) and Rico-Hesse (23) for DEN 1 and 2, respectively.

^bDEN 1 and 2 strains used for PD10 and PD5 genetic constructions, respectively (26).