OBJECTIVES: Heat shock protein 90 (hsp90) is targeted by the humoral response in invasive candidiasis. This paper tests for synergy between caspofungin and efungumab--a human antibody fragment against hsp90. METHODS: The MIC-0, MIC-2 values and FICI were determined for a range of yeasts against efungumab and caspofungin. These yeasts were injected intravenously into mice with: 100 microL of saline plus 100 microL of formulation buffer; 100 microL of caspofungin (1 or 4 mg/kg) plus 100 microL of formulation buffer; or 100 microL of caspofungin (1 or 4 mg/kg) plus 100 microL of efungumab 2 mg/kg. Yeast counts were determined for kidney, liver and spleen. Electron microscopy was performed on efungumab-stained Candida grown with and without caspofungin. RESULTS: The FICIs of efungumab and caspofungin at MIC-0 and MIC-2, respectively, were: fluconazole-susceptible Candida albicans: 0.5, 0.52; fluconazole-resistant C. albicans, Candida tropicalis and Candida krusei: 0.5, 0.5; Candida parapsilosis: 2, 0.5; Candida glabrata: 0.26, 0.28; and Candida guilliermondii: 2, 0.27. A statistically significant reduction in colony counts or increase in the number of negative biopsies (P < 0.05) was seen in mice on combination therapy at 1 mg/kg caspofungin for the renal biopsies of C. glabrata, liver biopsies of fluconazole-resistant C. albicans, C. krusei and C. guilliermondii and spleen biopsies of C. guilliermondii, and at 4 mg/kg for the renal biopsies of C. tropicalis, the liver biopsies of C. parapsilosis and the spleen biopsies of C. guilliermondii and C. glabrata. Electron microscopy confirmed extracellular hsp90 up-regulated by growth in caspofungin. CONCLUSIONS: Efungumab increased the susceptibility of Candida to caspofungin.
OBJECTIVES: Heat shock protein 90 (hsp90) is targeted by the humoral response in invasive candidiasis. This paper tests for synergy between caspofungin and efungumab--a human antibody fragment against hsp90. METHODS: The MIC-0, MIC-2 values and FICI were determined for a range of yeasts against efungumab and caspofungin. These yeasts were injected intravenously into mice with: 100 microL of saline plus 100 microL of formulation buffer; 100 microL of caspofungin (1 or 4 mg/kg) plus 100 microL of formulation buffer; or 100 microL of caspofungin (1 or 4 mg/kg) plus 100 microL of efungumab 2 mg/kg. Yeast counts were determined for kidney, liver and spleen. Electron microscopy was performed on efungumab-stained Candida grown with and without caspofungin. RESULTS: The FICIs of efungumab and caspofungin at MIC-0 and MIC-2, respectively, were: fluconazole-susceptible Candida albicans: 0.5, 0.52; fluconazole-resistant C. albicans, Candida tropicalis and Candida krusei: 0.5, 0.5; Candida parapsilosis: 2, 0.5; Candida glabrata: 0.26, 0.28; and Candida guilliermondii: 2, 0.27. A statistically significant reduction in colony counts or increase in the number of negative biopsies (P < 0.05) was seen in mice on combination therapy at 1 mg/kg caspofungin for the renal biopsies of C. glabrata, liver biopsies of fluconazole-resistant C. albicans, C. krusei and C. guilliermondii and spleen biopsies of C. guilliermondii, and at 4 mg/kg for the renal biopsies of C. tropicalis, the liver biopsies of C. parapsilosis and the spleen biopsies of C. guilliermondii and C. glabrata. Electron microscopy confirmed extracellular hsp90 up-regulated by growth in caspofungin. CONCLUSIONS:Efungumab increased the susceptibility of Candida to caspofungin.
Authors: Brad Moriyama; Lori A Gordon; Matthew McCarthy; Stacey A Henning; Thomas J Walsh; Scott R Penzak Journal: Mycoses Date: 2014-10-08 Impact factor: 4.377
Authors: Sheena D Singh; Nicole Robbins; Aimee K Zaas; Wiley A Schell; John R Perfect; Leah E Cowen Journal: PLoS Pathog Date: 2009-07-31 Impact factor: 6.823