CSF1R-based chimeric proteins

1. A method for treating cancer or an inflammatory disease comprising administering an effective amount of a pharmaceutical composition to a subject in need thereof, the pharmaceutical composition comprising a heterologous chimeric protein comprising:

(a) a first domain comprising a portion of colony stimulating factor 1 receptor (CSF1R) that is capable of binding a CSF1R ligand,

(b) a second domain comprising a portion of CD-40 ligand (CD40L) that is capable of binding an CD40L receptor, and

(c) a linker linking the first domain and the second domain and comprising a hinge-CH2-CH3 Fc domain.

2. The method of claim 1 , wherein the subject's T cells are activated when bound by the second domain of the heterologous chimeric protein and:

(a) one or more tumor cells are prevented from transmitting an immunosuppressive signal when bound by the first domain of the heterologous chimeric protein,

(b) a quantifiable cytokine response in the peripheral blood of the subject is achieved, and/or

(c) tumor growth is reduced in the subject in need thereof as compared to a subject treated with CD40 blocking antibodies and/or CSF1 or IL-34 blocking antibodies.

3. The method of claim 1 , wherein the first domain comprises substantially all of the extracellular domain of CSF1R and the second domain comprises substantially all of the extracellular domain of CD40L.

4. The method of claim 1 , wherein the chimeric protein is capable of:

(a) reducing or eliminating an immune inhibitory signal when the portion of CSF1R is bound to its ligand and/or

(b) increasing or activating an immune stimulatory signal when the portion of CD40L is bound to its receptor.

5. The method of claim 1 , wherein the chimeric protein is capable of contemporaneously binding the CSF1R ligand and the CD40L receptor, wherein the CSF1R ligand is CSF1 or IL-34 and the CD40L receptor is CD40.

6. The method of claim 1 , wherein the chimeric protein exhibits enhanced anti-tumor effects compared to CD40 agonist antibodies and/or CSF1R antagonistic antibodies.

7. The method of claim 1 , wherein the chimeric protein is capable of increasing or preventing a decrease in a sub-population of CD4+ and/or CD8+ T cells.

8. The method of claim 1 , wherein the chimeric protein is capable of enhancing tumor killing activity by T cells.

9. The method of claim 1 , wherein the chimeric protein is capable of providing a sustained immunomodulatory effect.

10. The method of claim 1 , wherein the chimeric protein is capable of causing activation of antigen presenting cells.

11. The method of claim 1 , wherein the hinge-CH2-CH3 Fc domain is derived from IgG4.

12. The method of claim 11 , wherein the hinge-CH2-CH3 Fc domain is derived from human IgG4.

13. The method of claim 1 , wherein the chimeric protein is expressed by a mammalian host cell as a secretable and functional single polypeptide chain.

14. The method of claim 1 , wherein the portion of CSF1R is at least 95% identical to the amino acid sequence of SEQ ID NO: 1 or SEQ ID NO: 2.

15. The method of claim 1 , wherein the portion of CD40L is at least 95% identical to the amino acid sequence of SEQ ID NO: 3 or SEQ ID NO: 4.

16. The method of claim 1 , wherein the linker comprises an amino acid sequence that is at least 95% identical to the amino acid sequence of SEQ ID NO: 25, SEQ ID NO: 26, or SEQ ID NO: 27.