TABLE 1.

Virus-neutralizing antibody titers in sera of immunized mice^a

Immunization	Virus used for immunization (titer)
	Noneb	cAdc	rAdd	iDEN-2e
First	NDf	ND	ND	ND
Second	ND	ND	17	15
Third	ND	ND	73	106

^aAliquots of DEN-2 virus (250 TCID₅₀) were preincubated with serial dilutions of heat-inactivated, pooled antisera and then used to infect BHK cells in 96-well plates (5 wells were assayed for each dilution of antiserum). The antiserum dilution corresponding to the 50% end points of virus infectivity was determined by cumulative averaging using the method of Reed and Muench as described by Burleson et al. (3); the reciprocal of this dilution is expressed as the neutralizing titer.

^bMock immunization with PBS.

^ccAd lacking E1 (does not encode any dengue virus antigen).

^drAdD2E (rAd lacking E1 and expressing DEN-2E virus protein).

^eFormalin-inactivated DEN-2 virus (from Biodesign International).

^fND, No detectable virus-neutralizing antibody titer.