TABLE 2.

Protective effect of passively transferred rabbit anti-tD15 antiserum against Hia in the infant rat model of bacteremia^a

Group	Rabbit serum	Anti-tD15 antibody titer	No. bacteremic/9 challenged	Mean CFU/25 μl of blood	Pb
1	Anti-Hia	6,400	0	0	0.00004
2	Anti-tD15	51,200	0	0	0.00004
3	Preimmune	<200	9	190

^aFive-day-old infant rats (nine per group) were passively immunized s.c. with 0.1 ml of indicated rabbit antiserum or preimmune serum. Twenty hours later, the animals were challenged i.p. with freshly grown Hia strain ATCC 9006 (10⁵ CFU, 0.1 ml) as described in Materials and Methods. 

^bStatistical significance of the difference in results obtained between antisera and preimmune sera, established by the Fisher exact test.