TABLE 2.

Immunization of rhesus monkeys with rB/HPIV3 expressing the G and/or F glycoproteins of RSV subgroup B or subgroup A induces neutralizing serum antibodies against RSV and hemagglutination-inhibiting antibodies against HPIV3

Immunizing virusa	Neutralizing serum antibody response to homologous RSVb (mean reciprocal log2 ± SE)		Serum hemagglutination-inhibiting antibody response to HPIV3c (mean reciprocal log2 ± SE)
	Pre	Day 27	Pre	Day 27
RSV A2d	≤3.3	8.8 ± 0.5	<2	<2
rB/HPIV3-GA	≤3.3	7.3 ± 1.4	<2	9.3 ± 0.3
rB/HPIV3-FA	≤3.3	7.3 ± 0.0	<2	8.8 ± 0.3
rB/HPIV3-GA + FAe	≤3.3	7.3 ± 0.8	<2	8.8 ± 0.3
rB/HPIV3-GAFA	≤3.3	8.8 ± 1.0	<2	9.5 ± 0.3
RSV B1d	≤3.3	7.8 ± 0.5	<2	<2
rB/HPIV3-GB	≤3.3	7.8 ± 1.0	<2	8.3 ± 0.8
rB/HPIV3-FB	≤3.3	6.8 ± 0.5	<2	7.5 ± 0.3
rB/HPIV3-GBFB	≤3.3	7.3 ± 0.8	<2	6.5 ± 0.3
rB/HPIV3	≤3.3	≤3.3	<2	10.0 ± 0.0

^aMonkeys (n = 4 for each immunization group) were inoculated intranasally and intratracheally with 10⁵ TCID₅₀ (PIV3) or 10⁵ PFU (RSV) in a 1-ml inoculum at each site.

^bSerum samples were taken on day 0 prior to immunization (Pre) and on day 27 postinoculation, and antibody titers were determined by 60% plaque reduction neutralization test using the homologous subgroup A (strain A2) or subgroup B (strain B1) virus.

^cSerum samples were taken on day 0 prior to immunization (Pre) and on day 27 postinoculation, and antibody titers were determined by HAI test.

^dThe B1 strain of RSV subgroup B virus replicated to a mean peak titer of 10^0.9 PFU/ml in NP swab fluid and to 10^1.0 PFU/ml in TL fluid. The A2 strain of RSV subgroup A virus replicated to a mean peak titer of 10^1.0 PFU/ml in NP swab fluid and to 10^2.8 PFU/ml in TL fluid.

^eEach animal received a mixture of 10⁵ TCID₅₀ of rB/HPIV3-G_A and rB/HPIV3-F_A.