Anti-TEM1 antibodies and uses thereof

1. A method of diagnosing the presence of a tumor or a cancer growth in a subject, said method comprising sampling a tissue sample isolated from said subject with a composition comprising an antibody or antigen-binding fragment thereof, wherein said antibody or antigen-binding fragment is specific for both the mouse and human form of an endosialin tumor endothelial marker 1 (TEM1) and binds to an epitope sequence as set forth in SEQ ID NO: 40, wherein the antibody or antigen-binding fragment comprises a heavy chain variable region comprising a CDR1 sequence of residues 31 to 35 of SEQ ID NO: 43; a CDR2 sequence of residues 50 to 65 of SEQ ID NO: 43; and a CDR3 sequence of residues 98 to 102 of SEQ ID NO: 43, and wherein the antibody or antigen-binding fragment comprises a light chain variable region comprising a CDR1 sequence of residues 23 to 36 of SEQ ID NO: 48; a CDR2 sequence of residues 52 to 62 of SEQ ID NO: 48; and a CDR3 sequence of residues 97 to 104 of SEQ ID NO: 48, whereby specific binding of said antibody or antigen-binding fragment to said tissue sample is indicative of the presence of a tumor or cancer growth in said subject.

2. The method of claim 1 , further comprising a secondary reagent that specifically binds to said antibody or antigen-binding fragment but does not antagonize binding of said antibody or antigen-binding fragment to its target.

3. The method of claim 1 , whereby said secondary reagent is a photoactivatable agent, a fluorophore, a radioisotope, a bioluminescent protein, a bioluminescent peptide, a fluorescent tag, a fluorescent protein, or a fluorescent peptide.

4. The method of claim 1 , whereby said sampling comprises the step of analyzing said sample using a chromogenic immunological assay.

5. The method of claim 4 , whereby said sampling comprises the step of analyzing said sample using microscopic imaging.