Table 2.

To generate antiserum for passive transfer, groups of 4 rabbits were immunized with 125 µg of Fla69, Fla32, Fla65, or Fla76 or placebo four times (on days 0, 21, 42 and 63) and sera was collected at 1 month post final vaccination and pooled for each group of rabbits. A. To determine the end-point protection titer (EPPT) by passive transfer, groups of 4 naïve rabbits were infused with the pooled immune serum in volumes corresponding to a dilution of 20, 100, 500, 2500 or 12,500 of the recipient’s blood volume for each vaccination cohort and compared to placebo. These animals were then challenged with HPV6, 16, 18, 31, 45 and 58 quazivirions (QV) and CRPV and papilloma size then scored 8 weeks later. The maximum dilution that showed complete protection is presented (EPPT). B. The in vitro neutralization titer of the pooled sera utilized was determined. (nd = not done).

Vaccine	Month	CRPV	HPV6	HPV16	HPV18	HPV31	HPV45	HPV58
A
Fla32	1	<20	20	500	20	20	<20	100
Fla65	1	<20	100	2500	500	500	100	500
Fla69	1	20	100	100	100	100	20	100
Fla76	1	20	2500	500	500	12,500	20	12,500
Placebo	1	<20	<20	<20	<20	<20	<20	<20
B
Fla32	1	nd	152	14,960	767	1113	219	nd
Fla65	1	nd	1781	16,494	3295	3470	7323	nd
Fla69	1	nd	12,361	15,846	20,106	2684	14,744	nd
Fla76	1	nd	9661	38,958	2286	7283	5390	nd