The subject invention concerns peptide mimetics of SOCS proteins and methods of use. In one embodiment, a peptide mimetic of the invention binds to a SOCS1 and a SOCS3 target protein. In a specific embodiment, a peptide mimetic of the invention comprises the amino acid sequence of SEQ ID NO:1 and/or SEQ ID NO:2 and/or SEQ ID NO:51, or a functional fragment or variant thereof. In a further embodiment, a peptide of the invention can comprise multiple copies of the mimetic sequence. In one embodiment, a peptide of the invention comprises two or more copies of SEQ ID NO:1 and/or SEQ ID NO:2 and/or SEQ ID NO:51. In a specific embodiment, a peptide mimetic of the invention comprises the amino acid sequence of SEQ ID NO:3 and/or SEQ ID NO:4 to and/or SEQ ID NO:52, or a functional fragment or variant thereof. The subject invention also pertains to methods of treating and/or preventing autoimmune conditions and/or disorders. In one embodiment, one or more peptide mimetics of the invention are used to treat an autoimmune condition or disorder in a person or animal. In a specific embodiment, a mimetic of the invention is used to treat SLE in a person or animal. The subject invention also concerns methods for diagnosing and/or monitoring progression of SLE in a person or animal.