Tumor vaccine composed of C-class CpG oligodeoxynucleotides and irradiated tumor cells induces long-term antitumor immunity

Table 1 The antitumor preventive effect of the tumor vaccine composed of irradiated tumor cells and CpG ODNs.

Group	Number of mice^a	Number of survivors^b	Proportion of survivors (%)	Average survival AM ± SE (days)	p-value^c	p-value^d
Control	22	0	0.0	16.09 ± 1.14
1 × 90d*	21	8	38.1	60.38 ± 8.21	<0.0001
2 × 90d*	20	14	75.0	85.30 ± 5.97	<0.0001	0.012
3 × 90d*	21	19	90.5	94.38 ± 3.93	<0.0001	0.003
1 × 60d**	21	6	28.6	51.00 ± 7.86	<0.0001
2 × 60d**	22	16	72.7	82.82 ± 6.69	<0.0001	0.002
3 × 60d**	18	16	88.9	89.10 ± 5.12	<0.0001	<0.001
1 × 30d***	22	7	31.8	62.14 ± 7.60	<0.0001
2 × 30d***	22	15	68.2	81.00 ± 6.66	<0.0001	0.022
3 × 30d***	20	20	100.0	100.00 ± 0.00	<0.0001	0.003

The vaccine was composed of 1 × 10⁶ irradiated B16F1 tumor cells and 30 μg of CpG ODNs; each vaccine administration was followed by two additional injections of CpG ODNs (2 and 4 days after vaccine administration).
^a number of animals included in the experimental group
^b surviving animals - are animals which survived at least 100 days after tumor challenge
^c p-value: group compared to control group
^d p-value: group compared to group vaccinated once starting the same day prior to tumor challenge
* vaccination started 90 days before the injection of viable tumor cells; the vaccine was applied once (1×), twice (2×) or three times (3×) in 15 days interval
** vaccination started 60 days before the injection of viable tumor cells; the vaccine was applied once (1×), twice (2×) or three times (3×) in 15 days interval
*** vaccination started 30 days before the injection of viable tumor cells; the vaccine was applied once (1×), twice (2×) in 15 days interval or three times (3×) in 15 days interval, except for the last vaccination, which was performed 7 days after second vaccination
The experiment was repeated three times.

ISSN: 1471-2172