Immune potentiating compositions of cancer cells

1. A composition comprising:

a population of animal cancer cells that express a T cell co-stimulatory B-7 molecule selected from the group consisting of B7-1 and B7-2 on the surface of said cells at a level at least 10-fold above a wild-type population of said cells, said cells having been treated with a type II interferon (IFN) such that said cells have enhanced antigen presenting function relative to animal cancer cells that have not been treated with a type II interferon (IFN); and

a type I IFN in isolated form.

2. The composition of claim 1 , wherein the cells are cultured in the presence of a type II IFN from about 16 to about 96 hours and subsequently in the presence of at least one type I IFN from about 16 to about 72 hours.

3. The composition of claim 1 , wherein the type II IFN is present in the culture medium at a concentration of about 100 to about 2000 international units/mL.

4. The composition of claim 1 , wherein the type I IFN is present in the culture medium at a concentration of about 100 to about 2000 international units/mL.

5. The composition of claim 1 , wherein the animal cancer cells have been cultured in the presence of a type II interferon (IFN) in isolated form and both of a first type I IFN in isolated form and a second type I IFN in isolated form for a time and under conditions sufficient to enhance the antigen presenting function of said cells.

6. The composition of any one of claims 1 to 5 , wherein an individual type I IFN is selected from the group consisting of an IFN-alpha and an IFN-beta.

7. The composition of claim 1 , wherein the T cell co-stimulatory molecule is a B7-1 molecule.

8. The composition of claim 7 , wherein the B7-1 molecule comprises the sequence set forth in SEQ ID NO: 14.

9. The composition of claim 1 , wherein the T cell co-stimulatory molecule is a B7-2 molecule.

10. The composition of claim 9 , wherein the B7-2 molecule comprises the sequence set forth in SEQ ID NO: 16.

11. The composition of claim 1 , wherein the T cell co-stimulatory B7 molecule is a membrane molecule of the cells, wherein at least a portion of said molecule is exposed to the extracellular environment.

12. The composition of claim 1 , wherein the B7- 1 molecule comprises the sequence set forth in SEQ ID NO: 18 or 20.

13. The composition of claim 1 , wherein the cancer cells are derived from a tissue, organ or system selected from the group consisting of lung, breast, uterus, cervix, ovaries, colon, pancreas, prostate, testes, stomach, bladder, kidney, bone, liver, the reticuloendothelial system, esophagus, brain, skin, and soft tissue.

14. The composition of claim 1 , wherein the cancer cells are selected from the group consisting of melanoma cells and mammary carcinoma cells.

15. The composition of claim 1 , wherein said cells have been inactivated.

16. A composition, wherein said composition elicits an immune response against a target antigen, and wherein said composition comprises the composition of claim 1 and, wherein said cells have been washed to remove said IFNs and wherein an antigen corresponding to said target antigen has been loaded onto IFN-treated animal cells.

17. The composition of claim 1 , wherein said population of animal cancer cells has been isolated from a heterogeneous population of animal cells.

18. The composition of claim 1 , wherein said population of animal cancer cells has been modified to express the T cell co-stimulatory B7 molecule by introduction into the cells of a polynucleotide from which the T cell co-stimulatory B7 molecule is expressible.

19. The composition of claim 1 , wherein the T cell co-stimulatory B-7 molecule is B7- 1.