U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home Research Publications at this Location





- ARS National Programs
- Search for a scientific manuscript
- Search for a research project
- ARS Software
- Programs and Projects
- Collaborations
- Subjects of Investigation
- Publications

Title:   Author  item
                                            DAI  WEI  - HIPPLE CANCER RES CTR, OHitem
                                            PAN  HUIQI  - HIPPLE CANCER RES CTR, OHitem
                                            Kwok, Oliveritem
                                            Dubey, Jitender
  Submitted to: Journal of Interferon Research
                                    Publication Type: Peer Reviewed Journal
                                    Publication Acceptance Date: 6/20/1994
                                    Publication  Date: N/A
                                    Citation: N/AInterpretive Summary: Infection by the protozoan (single celled) parasite Toxoplasma gondii is widespread in livestock and humans.  It causes mental retardation and loss of vision in children and abortion in livestock.  There is no effective vaccine for humans or animals. There are no drugs that eliminate the parasite from the body,  especially in AIDS patients.  It is estimated that 10% of all AIDS patients die of toxoplasmosis.  Interferon is a substance naturally liberated from host cells.  Interferon-gamma is known to inhibit the growth of Toxoplasma in cell culture as well as in patients infected with T. gondii.  Scientists at the Beltsville Agricultural Research Center and the Hipple Cancer Research Center have characterized the gene for the enzyme that mediates action of interferon-gamma on T. gondii.  These studies are  likely to be helpful in developing effective resistance against Toxoplasma parasites.
                                Technical Abstract: Interferon-gamma is known to inhibit the growth of Toxoplasma gondii both in vivo and in vitro.  The IFN-gamma-induced anti- toxoplasma activity in human cells is strongly correlated with the degradation of the essential amino acid L-tryptophan in vitro.  Destruction of L-tryptophan is due to an increased  activity of indoleamine 2,3-dioxygenase (INDO) which is transcriptionally activated by IFN-gamma.  To determine if indoleamine 2,3-dioxygenase alone is sufficient to block the T. gondii growth, we transfected human fibroblast cells with an INDO cDNA expression plasmid using metallothionein-inducible promoter. We showed that INDO mRNA and its enzymatic activity are inducible in fibroblast cells transfected with right-orientation INDO cDNA upon addition of CdCL2 to culture medium.  The elevated INDO  enzyme activity is strongly correlated with an inhibition of T. gondii growth.  No INDO mRNA nor enzyme activity is induced by CdCl2 in reverse orientation transfected cells, and no adverse effects were observed on T. gondii growth in cells transfected with the reverse INDO-construct or in control parent cells with or without supplementation of CdCl2.  These data all suggest that IFN-gamma-induced anti-toxoplasma activity is due at least in part to the activation of INDO gene.


Return to top


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov