American Association for Cancer Research

Table 1

Cellular immune responses to multiple tumor antigens after therapy with vaccine and radiation

Treatment^d	Antigen^a
		ConA	HSA	CEA (μg/ml)^b					p53 (μg/ml)					Peptide^c
		ConA	HSA			25	12.5	6.25	1.25	0.625	0.3125	CEA	p53	gp70
Vaccine + Radiation	930	0.8	3.9	2.9	1.7	3.8	3.6	2.6	2,000	320	28,940
Control	887	1.3	1.1	0.8	1.0	1.2	0.7	0.7	<2.5^e	<2.5	<2.5

Treatment^d	Antigen^a
		ConA	HSA	CEA (μg/ml)^b					p53 (μg/ml)					Peptide^c
		ConA	HSA			25	12.5	6.25	1.25	0.625	0.3125	CEA	p53	gp70
Vaccine + Radiation	930	0.8	3.9	2.9	1.7	3.8	3.6	2.6	2,000	320	28,940
Control	887	1.3	1.1	0.8	1.0	1.2	0.7	0.7	<2.5^e	<2.5	<2.5

For proliferation, antigen concentrations were ConA (2.5 μg/ml), human serum albumin (25 μg/ml), CEA (25–6.25 μg/ml), or p53 (1.25–0.3125 μg/ml). Each value represents the stimulation index of the mean CPM of triplicate samples versus media. SD never exceeded 10%.

CEA, carcinoembryonic antigen; ConA, concanavalin A; rV, recombinant vaccinia; TRICOM, triad of costimulatory molecules; rF, recombinant fowlpox; GM-CSF, granulocyte macrophage colony-stimulated factor.

For peptide-specific IFN-γ production, concentrations of peptides CEA, p53, and gp70 were 10, 2, and 1 μg/ml, respectively. Each value represents IFN-γ (pg/ml/10⁶ cells/24 h).

Three CEA-Tg mice/group were given MC38-CEA⁺ tumors s.c. Eight days later mice were vaccinated with rV-CEA/TRICOM admixed with rF-GM-CSF. On day 14, tumors were irradiated (8 Gy). On days 15, 22, and 29, mice were boosted with rF-CEA/TRICOM admixed with rF-GM-CSF. Responses from pooled splenic T cells from cured mice were analyzed 6 months following the tumor transplant for CEA protein and p53 MHC-II-peptide-specific proliferation and CEA, p53, and gp70 peptide-specific IFN-γ production. Control mice, normal age-matched CEA-Tg mice.

Detection limit was 2.5 pg/ml.

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