title: SOCS-1 mimetics protect mice against lethal poxvirus infection: identification of a novel endogenous antiviral system.
abstract: The suppressor of cytokine signaling 1 (SOCS-1) protein modulates cytokine signaling by binding to and inhibiting the function of Janus kinases (JAKs), ErbB, and other tyrosine kinases. We have developed a small tyrosine kinase inhibitor peptide (Tkip) that binds to the autophosphorylation site of tyrosine kinases and inhibits activation of STAT transcription factors. We have also shown that a peptide corresponding to the kinase-inhibitory region of SOCS-1, SOCS1-KIR, similarly interacts with the activation loop of JAK2 and blocks STAT activation. Poxviruses activate cellular tyrosine kinases, such as ErbB-1 and JAK2, in the infection of cells. We used the pathogenesis of vaccinia virus in C57BL/6 mice to determine the ability of the SOCS-1 mimetics to protect mice against lethal vaccinia virus infection. Injection of mice intraperitoneally with Tkip or SOCS1-KIR containing a palmitate for cell penetration, before and at the time of intranasal challenge with 2 x 10(6) PFU of vaccinia virus, resulted in complete protection at 100 microg. Initiation of treatment 1 day postinfection resulted in 80% survival. Administration of SOCS-1 mimetics by the oral route also protected mice against lethal effects of the virus. Both SOCS1-KIR and Tkip inhibited vaccinia virus transcription and replication at early and possibly later stages of infection. Vaccinia virus-induced phosphorylation of ErbB-1 and JAK2 was inhibited by the mimetics. Protected mice mounted a strong humoral and cellular response to vaccinia virus. The use of SOCS-1 mimetics in the treatment of poxvirus infections reveals an endogenous regulatory system that previously was not known to have an antiviral function.
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, P.O. Box 110700, Gainesville, FL 32611-0700, USA. ahmed1@ufl.edu
authors.forename: Chulbul M
authors.initials: CM
authors.lastname: Ahmed
authors.forename: Rea
authors.initials: R
authors.lastname: Dabelic
authors.forename: Lilian W
authors.initials: LW
authors.lastname: Waiboci
authors.forename: Lindsey D
authors.initials: LD
authors.lastname: Jager
authors.forename: Linda L
authors.initials: LL
authors.lastname: Heron
authors.forename: Howard M
authors.initials: HM
authors.lastname: Johnson
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000998:Antiviral Agents / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007111:Immunity, Cellular; D051379:Mice; D008810:Mice, Inbred C57BL; D018716:Molecular Mimicry; D012899:Smallpox / Q000276:immunology / Q000517:prevention & control*; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000737:chemistry*; D014616:Vaccinia virus / Q000187:drug effects / Q000235:genetics / Q000502:physiology
chemical_list: D000914:Antibodies, Viral; D000998:Antiviral Agents; C491590:Socs1 protein, mouse; D000071222:Suppressor of Cytokine Signaling 1 Protein; D050826:Suppressor of Cytokine Signaling Proteins