RESUMO
Analysis of the cDNA encoding murine interleukin (IL) 17 (cytotoxic T lymphocyte associated antigen 8) predicted a secreted protein sharing 57% amino acid identity with the protein predicted from ORF13, an open reading frame of Herpesvirus saimiri. Here we report on the cloning of human IL-17 (hIL-17), the human counterpart of murine IL-17. hIL-17 is a glycoprotein of 155 amino acids secreted as an homodimer by activated memory CD4+ T cells. Although devoid of direct effects on cells of hematopoietic origin, hIL-17 and the product of its viral counterpart, ORF13, stimulate epithelial, endothelial, and fibroblastic cells to secrete cytokines such as IL-6, IL-8, and granulocyte-colony-stimulating factor, as well as prostaglandin E2. Furthermore, when cultured in the presence of hIL-17, fibroblasts could sustain the proliferation of CD34+ hematopoietic progenitors and their preferential maturation into neutrophils. These observations suggest that hIL-17 may constitute (a) an early initiator of the T cell-dependent inflammmatory reaction; and (b) an element of the cytokine network that bridges the immune system to hematopoiesis.
Assuntos
Citocinas/biossíntese , Endotélio Vascular/imunologia , Células-Tronco Hematopoéticas/imunologia , Interleucinas/biossíntese , Linfócitos T/imunologia , Sequência de Aminoácidos , Animais , Artrite Reumatoide/imunologia , Sequência de Bases , Dinoprostona/biossíntese , Endotélio Vascular/efeitos dos fármacos , Fibroblastos/imunologia , Fator Estimulador de Colônias de Granulócitos/biossíntese , Hematopoese , Células-Tronco Hematopoéticas/efeitos dos fármacos , Herpesvirus Saimiriíneo 2/genética , Herpesvirus Saimiriíneo 2/metabolismo , Humanos , Inflamação , Interferon gama/farmacologia , Interleucina-17 , Interleucina-6/biossíntese , Interleucina-8/biossíntese , Interleucinas/química , Interleucinas/imunologia , Linfócitos/imunologia , Substâncias Macromoleculares , Camundongos , Dados de Sequência Molecular , Fases de Leitura Aberta , Proteínas Recombinantes/biossíntese , Valores de Referência , Homologia de Sequência de Aminoácidos , Pele/imunologia , Células Estromais/efeitos dos fármacos , Células Estromais/imunologia , Membrana Sinovial/imunologia , Transfecção , Fator de Necrose Tumoral alfa/farmacologia , Proteínas Virais/biossíntese , Proteínas Virais/químicaRESUMO
The human immunodeficiency virus type 1 (HIV-1) proteinase (PR) and its flanking sequences have been fused in frame between the DNA-binding domain and the transcription-activation domain of the yeast protein, GAL4. As has been shown before with the 3C proteinase of Coxsackie virus B3 (CVB3) [Das Mahapatra et al., Proc. Natl. Acad. Sci. USA 89 (1992) 4159-4162], the GAL4::PR fusion protein retains its GAL4 function, providing the PR is inactive. When PR is active, its autocatalytic activity in the hybrid protein is shown to inactivate the transactivation function of GAL4. This provides a simple assay to monitor PR activity. A dose-dependent effect of a potent PR-specific inhibitor is demonstrated in this system and illustrates the sensitivity of the assay. The assay is used for high throughput screening to identify novel inhibitors of the viral PR, and provides a method to generate and analyze mutants and revertants of the PR.