Department of Microbiology and Cell Science University of Florida
Ph.D (1962) Department of Microbiology,
Ohio State University
Training of undergraduate students, graduate students, and postdoctoral associates in basic research in immunology.
Description of Research
Our studies are focused on understanding the mechanism of action and modulation of cytokine function in the immune system. The knowledge gained from this is being used to develop anti-inflammatory, antiviral, and antitumor compounds. Some of our most recent work involves regulators of immune function, called Suppressors of Cytokine Signaling (SOCS). For example, we have developed a small peptide mimetic of an important SOCS, SOCS-1, that inhibits JAK2 tyrosine kinase activity and protects mice against experimental allergic encephalomyelitis (EAE), an animal model of multiple sclerosis in humans. This tyrosine kinase inhibitor peptide, Tkip, also inhibits activation of the oncogenic transcription factor STAT3 in prostate cancer cells. These studies thus have important implications for inflammatory diseases as well as cancer.
- American Men of Science
- Sigma XI
- Financial Scholarship, Senior Year of Undergraduate Studies
Johnson HM, Noon-Song EN, Dabelic R, and Ahmed CM. (2013). IFN signaling: How a non-canonical model led to the development of IFN mimetics. Frontiers in Immunology: In Press
Ahmed CM, Noon-Song EN, Kemppainen K, Pascalli MP, Johnson HM. (2012). Type I IFN receptor controls activated TYK2 in the nucleus: Implications for EAE therapy. J Neuroimmunology 254(1-2)101-109. pii: S0165-5728(12)00309-8.10.1016 Epub October 27.
Chang JH, Xiao Y, Hu H, Jin J, Yu J, Zhou X, Wu X, Johnson HM, Akira S, Pasparakis M, Cheng X, Sun SC. (2012). Ubc13 maintains the suppressive function of regulatory T cells and prevents their conversion into effector-like T cells. Nature Immunology 13(5):481-490.
Johnson HM, Noon-Song EN, Kemppainen K, Ahmed CM. (2012). Steroid-like signaling by interferons: Making sense of specific gene activation by cytokines. Biochem J 443(2):329-338
Johnson HM, Noon-Song EN, Ahmed CM. (2011). Controlling nuclear JAKs and STATs for specific gene activation by IFNγ and Other Cytokines: A Possible Steroid-like Connection. Journal of Clinical Cellular Immunology 2(4). pii: 1000112
Collins EL, Jager LD, Dabelic R, Benitez P, Holdstein K, Haider MI, Johnson HM, Larkin J 3rd. (2011). Inhibition of SOCS1-/-Lethal Autoinflammatory Disease Correlated to Enhanced Peripheral Foxp3+ Regulatory T Cell Homeostasis. J Immunol 187(5):2666-2676 Epub July 25.
Noon-Song EN, Ahmed CM, Dabelic R, Canton J, Johnson HM. (2011). Controlling nuclear JAKs and STATs for specific gene activation by IFNγ. Biochem Biophys Res Com 410(3):648-653 Epub June 13.
Jager LD, Dabelic R, Waiboli LW, Lau K, Haider MS, Ahmed CM, Larkin J 3rd, David S, Johnson HM. (2011). The kinase inhibitory region of SOCS-1 is sufficient to inhibit T-helper 17 and other immune functions in experimental allergic encephalomyelitis. J Neuroimmunol 232(1-2):108-118.
Bernard JL, Kerr BJ, Johnson HM, David S. (2011). Differential expression of SOCS1 in macrophages in relapsing-remitting and chronic EAE and its role in disease severity. Glia 58(15):1816-1826.
Ahmed CM, Dabelic R, Martin JP, Jager LD, Haider SM, Johnson HM. (2010). Enhancement of antiviral immunity by a small molecule antagonist of SOCS. J Immunol 185(2):1103-1113 Epub June 11.
Girolami EI, Bouhy D, Haber M, Johnson H, David S. (2010). Differential expression and potential role of SOCS1 and SOCS3 in Wallerian degeneration in injured peripheral nerve. Exp Neurol 223:173-182.
Frey K, Ahmed CM, Dabelic R, Jager LD, Noon-Song EN, Haider SM, Johnson HM, Bigley NJ. (2009). HSV-1 induced SOCS-1 expression in keratinocytes: Use of a SOCS-1 antagonist to block a novel mechanism of viral immune evasion. J Immunol 183:1253-1262.
Ahmed CM, Dabelic R, Waiboci LW, Jager LD, Heron LL, Johnson HM. (2009). SOCS-1 mimetics protect mice against lethal poxvirus infection: Identification of a novel endogenous antiviral system. J Virol 83:1402-1415.
Frey, KG; Ahmed, CMI; Dabelic, R; Jager, LD; Noon-Song, EN; Haider, SM; Johnson, HM; Bigley, NJ. 2009. HSV-1-Induced SOCS-1 Expression in Keratinocytes: Use of a SOCS-1 Antagonist to Block a Novel Mechanism of Viral Immune Evasion. JOURNAL OF IMMUNOLOGY 183 (2): 1253-1262
Ahmed, CM; Dabelic, R; Waiboci, LW; Jager, LD; Heron, LL; Johnson, HM. 2009. SOCS-1 Mimetics Protect Mice against Lethal Poxvirus Infection: Identification of a Novel Endogenous Antiviral System. JOURNAL OF VIROLOGY 83 (3): 1402-1415
Mujtaba, MG; Patel, CB; Patel, RA; Flowers, LO; Burkhart, MA; Waiboci, LW; Martin, J; Haider, MI; Ahmed, CM; Johnson, HM. 2006. The gamma interferon (IFN-gamma) mimetic peptide IFN-gamma(95-133) prevents encephalomyocarditis virus infection both in tissue culture and in mice. CLINICAL AND VACCINE IMMUNOLOGY 13 (8): 944-952
Johnson, HM; Ahmed, CMI. 2006. Gamma interferon signaling: Insights to development of interferon mimetics. CELLULAR AND MOLECULAR BIOLOGY 52 (1): 71-76
Ahmed, CMI; Johnson, HM. 2006. IFN-gamma and its receptor subunit IFNGR1 are recruited to the IFN-gamma-activated sequence element at the promoter-site of IFN-gamma-activated genes: Evidence of transactivational activity in IFNGR1. JOURNAL OF IMMUNOLOGY 177 (1): 315-321
Mujtaba, MG; Flowers, LO; Patel, CB; Patel, RA; Haider, MI; Johnson, HM. 2005. Treatment of mice with the suppressor of cytokine signaling-1 mimetic peptide, tyrosine kinase inhibitor peptide, prevents development of the acute form of experimental allergic encephalomyelitis and induces stable remission in the chronic relapsing/remitting form. JOURNAL OF IMMUNOLOGY 175 (8): 5077-5086
Ahmed, CM; Martin, JP; Johnson, HM. 2007. IFN mimetic as a therapeutic for lethal vaccinia virus infection: Possible effects on innate and adaptive immune responses. JOURNAL OF IMMUNOLOGY 178 (7): 4576-4583
Waiboci, LW; Ahmed, CM; Mujtaba, MG; Flowers, LO; Martin, JP; Haider, MI; Johnson, HM. 2007. Both the suppressor of cytokine signaling 1 (SOCS-1) kinase inhibitory region and SOCS-1 mimetic bind to JAK2 autophosphorylation site: Implications for the development of a SOCS-1 antagonist. JOURNAL OF IMMUNOLOGY 178 (8): 5058-5068
Fulcher, AJ; Ahmed, CMI; Noon-Song, EN; Kwan, RYQ; Subramaniam, PS; Johnson, HM; Jans, DA. 2008. Interferon gamma is recognised by importin alpha/beta: Enhanced nuclear localising and transactivation activities of an interferon gamma mimetic. FEBS LETTERS 582 (11): 1569-1574
Ahmed, CMI; Burkhart, MA; Subramaniam, PS; Mujtaba, MG; Johnson, HM. 2005. Peptide mimotics of gamma interferon possess antiviral properties against vaccinia virus and other viruses in the presence of poxvirus B8R protein. JOURNAL OF VIROLOGY 79 (9): 5632-5639
Subramaniam PS, Flowers LO, Haider SM, and Johnson HM (2004) Signal transduction mechanism of a peptide mimetic of INF-gamma. Biochemistry 43 :5445-5454. Flowers LO, Johnson HM, Mujtaba MG, Ellis MR, Haider SM, and Subramaniam PS. (2004) Characterization of a peptide inhibitor of JAK2 that mimics SOCS-1 function. J. Immunol 172 : 7510-7518. Ahmed CMI, M Burkhart, MG Mujtaba, PS Subramaniam, and HM Johnson. (2005) Peptide mimetics of gamma interferon possess antiviral activities against vaccinia and other viruses in the presence of poxvirus B8R protein. J. Virology 79:5632-5639. Flowers LO, Subramanaim PS, and Johnson HM. (2005). A SOCS-1 peptide mimetic inhibits both constitutive and IL-6 induced activation of STAT3 in prostate cancer cells. Oncogene 24:2114-2120. Mujtaba MG, Flowers LO, Patel CB, Patel RA, Haider MI, and Johnson HM. (2005). Treatment of mice with the suppressor of cytokine signaling mimetic peptide, tyrosine kinase inhibitor peptide, prevents development of the acute form of experimental allergic encephalomyelitis and induces stable remission in the chronic relapsing/remitting form. J. Immunol. 175: 5077-5086.