Means and methods to increase adenovirus production

1. A method for increasing the yield of replication-incompetent adenoviruses having at least a partial deletion in the E1-region, wherein said adenoviruses are generated in a production cell, the method comprising the steps of:

(a) expressing in said production cell an adenoviral pIX polypeptide from a nucleic acid sequence encoding said adenoviral pIX polypeptide under the control of at least a minimal endogenous pIX promoter and at least one heterologous promoter, wherein said minimal endogenous pIX promoter is located downstream of said heterologous promoter; and

(b) expressing in said production cell the elements necessary for the production and assembly of said adenoviruses from corresponding coding sequences,

thereby increasing the yield of said adenoviruses generated in said production cell in comparison to the yield of replication-incompetent adenoviruses having at least a partial deletion in the E1-region generated in said production cell in the absence of said nucleic acid sequence encoding said adenoviral pIX polypeptide, wherein the adenovirus is a human adenovirus of subgroup D.

2. A method for the construction of a replication-incompetent adenovirus library, wherein the adenoviruses have at least a partial deletion in the E1-region, comprising the steps of:

(a) providing one or more nucleic acid sequences in expressible form comprising at least two partial adenoviral genomes, wherein each nucleic acid sequence of said one or more nucleic acid sequences comprises at least one partial adenoviral genome, each partial adenoviral genome further comprising at least one transgene, wherein the at least two partial adenovirus genomes and/or the two transgenes differ from each other;

(b) introducing the one or more nucleic acid sequences of step (a) into production cells comprising one or more nucleic acid sequences in expressible form comprising a partial adenoviral genome which complements each partial adenoviral genome comprised by the one or more nucleic acid sequences of step (a) by transfection, wherein each complemented adenoviral genome encodes the elements necessary for the production and assembly of said different adenoviruses and comprises the coding sequence for an adenoviral pIX polypeptide under the control of at least a minimal endogenous pIX promoter and a heterologous promoter, wherein said minimal endogenous pIX promoter is located downstream of said heterologous promoter; and

(c) culturing the production cells under conditions suitable for the assembly and production of said differing adenoviruses,

thereby constructing said replication-incompetent adenovirus library.

3. The method of claim 1 , wherein one or more of said coding sequences of step (b) are introduced into the production cell for expression

(a) by transduction using the replication-incompetent adenoviruses having at least a partial deletion in the E1-region that are to be produced in the cell; or

(b) by transfection.

4. The method of claim 1 , wherein the subgroup D adenovirus is of serotype 19a.

5. The method of claim 1 , further comprising the step of assessing the expression level of said pIX protein in the production cell and/or the increase in yield of said adenoviruses.

6. The method of claim 1 , wherein the subgroup D adenovirus is selected from the group consisting of serotypes 8, 9, 13, 15, 17, 19, 20, 22 to 25, 27 to 30, 32, 33, 36 to 39, 42 to 49 and 51.

7. The method of claim 1 , wherein the production cell is selected from the group consisting of a HEK293 production cell, a Per.C6 production cell, a CAP cell, a GH329 production cell and a pTG6559 production cell.

8. The method of claim 1 , wherein the heterologous promoter is

(a) a heterologous minimal pIX promoter; or

(b) selected from the group consisting of a viral promoter, a cellular promoter, synthetic promoter and a hybrid promoter.

9. The method of claim 8 , wherein the heterologous minimal pIX promoter of (a) originates from a human adenovirus serotype 5.

10. The method of claim 8 , wherein the heterologous promoter of (b) is selected from the group consisting of CAG, CMV, PKG, SV40, EF1 alpha and RSV.

11. The method of claim 1 , wherein the coding sequence for said adenoviral pIX polypeptide is under the control of an additional heterologous promoter.

12. The method of claim 4 , wherein the heterologous promoter is

(a) a heterologous minimal pIX promoter that originates from a human adenovirus serotype 5; or

(b) an SV40 viral promoter.