Method of identifying membrane IgE specific antibodies and use thereof for targeting IgE producing precursor cells
The present invention relates to the discovery of antibodies that bind to novel epitopes present on membrane-anchored IgE and which bind to these novel epitopes on the surface of B cells and plasma cells. In addition, the antibodies of the present invention can mediate ADCC and can be useful to deplete those B cells and plasma cells expressing the novel epitopes of the invention. The antibodies of the present invention can be useful for the treatment of IgE-mediated diseases. Accordingly the present invention also provides compositions and methods for the prevention, management, treatment or amelioration of IgE-mediated diseases.
1. An isolated antibody or antibody fragment which specifically binds the peptide sequence of SEQ ID NO: 5, wherein said antibody or antibody fragment thereof does not bind membrane-anchored immunoglobulins other than membrane-anchored immunoglobulin E (mIgE) and wherein said antibody or antibody fragment thereof does not bind the polypeptide of SEQ ID NO:1, SEQ ID NO:6, SEQ ID NO:3 and/or SEQ ID NO:4.
2. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment does not bind the same epitope as antibodies or antibody fragments comprising the variable regions of A1c (encoded by SEQ ID NOS: 50 and 51) and B1 (encoded by SEQ ID NOS: 60 and 61).
3. The isolated antibody or antibody fragment of claim 1 , wherein the binding is not inhibited by antibodies or antibody fragments comprising the variable regions of A1c (encoded by SEQ ID NOS: 50 and 51) and B1 (encoded by SEQ ID NOS: 60 and 61).
4. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or fragment thereof depletes B cells or plasma cells expressing mIgE.
5. The isolated antibody or antibody fragment of claim 4 , wherein said antibody or antibody fragment depletes said B cells or plasma cells through ADCC.
6. The isolated antibody or antibody fragment of claim 1 , said antibody or antibody fragment comprising:
a. a light chain variable region having the 3 CDRs of the light chain of the antibody D5 encoded by SEQ ID NO: 7, and a heavy chain variable region having the 3 CDRs of the light chain of the antibody D5 encoded by SEQ ID NO: 8;
b. light chain variable region having the 3 CDRs of the light chain of the antibody F4 encoded by SEQ ID NO: 70, and a heavy chain variable region having the 3 CDRs of the light chain of the antibody F4 encoded by SEQ ID NO: 71;
c. a heavy chain variable region having the 3 CDRs of the heavy chain of the antibody D9 encoded by SEQ ID NO: 80; or
d. a heavy chain variable region having the 3 CDRs of the heavy chain of the antibody D9 encoded by SEQ ID NO: 80, and a light chain variable region.
7. The isolated antibody or antibody fragment of claim 1 , wherein the antibody or antibody fragment comprises a heavy chain variable region, and a variable light chain region, wherein the light chain comprises the amino acid sequence of SEQ ID NO:9, or SEQ ID NO: 72.
8. The isolated antibody or antibody fragment of claim 1 , wherein the antibody or antibody fragment comprises a light chain variable region, and a variable heavy chain region, wherein the heavy chain comprises the amino acid sequence of SEQ ID NO:10, SEQ ID NO: 73, or SEQ ID NO:81.
9. An isolated nucleic acid sequence coding for an amino acid sequence selected from the group consisting of SEQ ID NO: 9, 10, 72, 73 and 81.
10. An isolated cell comprising at least one nucleic acid sequence selected from the group consisting of SEQ ID NO: 7, 8, 70, 71 and 80.
11. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment is a humanized or human antibody or antibody fragment.
12. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment is selected from the group consisting of:
a. an scFv;
b. a Fab fragment;
c. an Fab′ fragment;
d. an F(ab)2;
e. an Fv;
f. a disulfide linked Fv; and
g. a bi-specific antibody.
13. A pharmaceutical composition comprising the isolated antibody or antibody fragment of claim 1 .
14. A method of ameliorating, or treating an IgE-mediated disease in a human comprising administering to an individual in need of such prevention, amelioration, or treatment an effective amount of the isolated antibody or antibody fragment of claim 1 .
15. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment comprises:
a light chain complementarity determining region 1 (V L CDR1) comprising the amino acid sequence of SEQ ID NO: 11;
a light chain complementarity determining region 2 (V L CDR2) comprising the amino acid sequence of SEQ ID NO: 12;
a light chain complementarity determining region 3 (V L CDR3) comprising the amino acid sequence of SEQ ID NO: 13;
a heavy chain complementarity determining region 1 (V H CDR1) comprising the amino acid sequence of SEQ ID NO: 14;
a heavy chain complementarity determining region 2 (V H CDR2) comprising the amino acid sequence of SEQ ID NO: 15; and
a heavy chain complementarity determining region 3 (V H CDR3) comprising the amino acid sequence of SEQ ID NO: 16.
16. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment comprises a light chain variable region comprising the amino acid sequence of SEQ ID NO: 9 and a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 10.
17. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment comprises a light chain variable region comprising the amino acid sequence of SEQ ID NO: 72 and a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 73.
18. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment comprises a heavy chain variable region comprising the amino acid sequence of SEQ ID NO: 81.
19. The isolated antibody or antibody fragment of claim 7 , wherein the heavy chain variable region comprises the amino acid sequence of SEQ ID NO: 10 or SEQ ID NO: 73.
20. The isolated antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment comprises:
a light chain complementarity determining region 1 (V L CDR1) comprising the amino acid sequence of SEQ ID NO: 74;
a light chain complementarity determining region 2 (V L CDR2) comprising the amino acid sequence of SEQ ID NO: 75;
a light chain complementarity determining region 3 (V L CDR3) comprising the amino acid sequence of SEQ ID NO: 76;
a heavy chain complementarity determining region 1 (V H CDR1) comprising the amino acid sequence of SEQ ID NO: 77;
a heavy chain complementarity determining region 2 (V H CDR2) comprising the amino acid sequence of SEQ ID NO: 78; and
a heavy chain complementarity determining region 3 (V H CDR3) comprising the amino acid sequence of SEQ ID NO: 79.