The term "naturally-occurring" as used herein as applied to an object refers to the fact that an object can be found in nature. For example, a polypeptide or polynucleotide sequence that is present in an organism (including viruses) that can be isolated from a source in nature and which has not been intentionally modified by man in the laboratory is naturally-occurring. A "native sequence Fc region" or "native sequence Fc" comprises an amino acid sequence that is identical to the amino acid sequence of an Fc region found in nature. A "polypeptide" refers to a chain comprising at least two consecutively linked amino acid residues, with no upper limit on the length of the chain. The term "expression" as used herein refers to a process by which a polynucleotide produces a gene product, for example, an RNA or a polypeptide. The term "substantially equal" means a compared rate or level has a difference of no more than 0.01%, 0.5% or 1% from the reference rate or level.



The term "similar" as used herein means a compared rate or level has a difference of no more than 10% or no more than 15% from the reference rate or level. The term "comparable" as used herein means a compared rate or level resulted from using, e.g., the fusion protein is equal to, substantially equal to, or similar to the reference rate or level. The term "fragment" or "variant" when referring to polypeptide binding domains or binding molecules of the present disclosure include any polypeptides which retain at least some of the properties (e.g., IL2 binding activity for IL2R.alpha.) of the reference polypeptide. Different regions within a single polynucleotide or polypeptide target sequence that aligns with a polynucleotide or polypeptide reference sequence can each have their own percent sequence identity. As used herein the terms refer to the characteristics of the recombinant polypeptide disclosed herein, and do not indicate, imply or infer any methods or process by which the fusion polypeptide was made.



As stated above, polypeptide variants include, e.g., modified polypeptides. As used herein, the terms "inhibits" or "blocks" (e.g., referring to inhibition/blocking of binding of IL2 to IL2R.alpha. In one embodiment, the immunoglobulin constant region or a portion thereof comprises CH2 domain, CH3 domain, and a hinge region, i.e., Free Cam Websites an Fc region or an FcRn binding partner. These include, but are not limited to ribosome binding sites, translation initiation and termination codons, and elements derived from picornaviruses (particularly an internal ribosome entry site, or IRES, also referred to as a CITE sequence). A polynucleotide, which encodes a gene product, e.g., a polypeptide, can include a promoter and/or other transcription or translation control elements operably associated with one or more coding regions. Similarly, a variety of translation control elements are known to those of ordinary skill in the art. A variety of transcription control regions are known to those skilled in the art.



Families of amino acid residues having similar side chains have been defined in the art. As used herein the term "associated with" refers to a covalent or non-covalent bond formed between a first amino acid chain and a second amino acid chain. The first amino acid or nucleotide sequence can be directly joined or juxtaposed to the second amino acid or nucleotide sequence or alternatively an intervening sequence can covalently join the first sequence to the second sequence. 25 at first but quickly growing to 400 strong. Native sequence human Fc regions include a native sequence human IgG1 Fc region; native sequence human IgG2 Fc region; native sequence human IgG3 Fc region; and native sequence human IgG4 Fc region as well as naturally-occurring variants thereof. Native sequence Fc include the various allotypes of Fcs (see, e.g., Jefferis et al. IL2 to IL2R.alpha. by no more than 50%, for example, by about 40%, men-live-cam 30%, 20%, 10%, 5% or 1%, determined, e.g., as further described herein. IL2 to IL2R.alpha. by at least about 50%, for example, about 60%, 70%, 80%, 90%, 95%, 99%, or 100%, determined, e.g., as further described herein.