Anti-infectives Screening Core Services

Anti-infectives Screening Core Anti-infectives Screening Core Services
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Anti-infectives Screening Core Anti-infectives Screening Core Services

NYU School of Medicine’s Anti-infectives Screening Core offers in vivo and in vitro assays to evaluate the effectiveness of anti-infective drugs and other candidates in the treatment of several neglected parasitic tropical diseases. Our researchers follow strict protocols.

In Vivo Assays

Our researchers test compounds in vivo, using a method of parasite detection in mice based on infection with transgenic parasites expressing the bioluminescent enzyme luciferase. This allows for rapid automated determination.

Mice are first infected with a study parasite: Trypanosoma cruzi for Chagas disease, T. brucei spp. for human African trypanosomiasis, Leishmania spp. for leishmaniasis, and Plasmodium berghei for malaria, including liver and blood stages of the disease.

Several days after infection, when parasites are detectable, the mice are anesthetized. An IVIS® Lumina II, a device sensitive to luminescence that quantifies the level of infection, is then used to create images of the infection level in the mouse.

Typically, test compounds are then administered with intraperitoneal injection or oral gavage for 5 or 10 days. One day after the last treatment dose, researchers again conduct imaging of the mice to determine the level of infection.

Variations in the standard protocol—that is, in the duration of treatment, dose, and route of administration—are possible but should be discussed beforehand with our staff.

Murine Model for Acute Chagas Disease

To assess a murine model for acute Chagas disease, researchers infect female BALB/c mice with 105 trypomastigotes of T. cruzi Y strain expressing luciferase, following established protocol. Three days later, the infection is quantified with an IVIS® Lumina II imager. The luciferin signal is proportional to the parasite load.

Treatment begins on the fourth day of infection and continues daily. The researcher specifies the administration route, dose, and duration. Results are expressed as the ratio of infection at the end of treatment to the base infection in each animal.

The Anti-infectives Screening Core’s transgenic luciferase-expressing parasite was generously provided by Barbara Burleigh, PhD, of Harvard University T. H. Chan School of Public Health in Boston.

Murine Model for African Trypanosomiasis

To assess drugs and other candidates for treatment of African trypanosomiasis, BALB/c mice are infected with 105 T. b. brucei expressing Renilla luciferase. Our T. brucei protocol is followed. The infection is quantified three days later by an IVIS® Lumina II imager. Parasitemia is quantified five days after treatment.

Our transgenic luciferase-expressing parasite was generously provided by Nick Van Reet, PhD, of the Institute of Tropical Medicine in Antwerp, Belgium.

Murine Model for Liver-Stage Malaria

To study liver-stage malaria, Swiss Webster female mice are introduced to 20 to 50 Anopheles stephensi mosquitoes infected with a P. berghei ANKA strain expressing luciferase, according to protocol. After the mice are bitten and infected, parasitemia is quantified using an IVIS® Lumina II imager.

Mice are treated with test compounds for two days, while the parasite is in the liver. Researchers assess groups of five mice, including a negative control or vehicle group. A positive control group in which a well-known drug is used to manage the disease may also be included.

If the bioluminescent luciferin signal is too low in the liver for assessment, researchers allow the infection to progress into the blood and then calculate parasitemia. The blood-stage signal is proportional to the initial load of parasites in the liver.

Results are expressed as the luciferin signal for each animal.

Our core’s transgenic luciferase-expressing parasite was generously provided by Chris Janse, PhD, of Leiden University Medical Center in Leiden, the Netherlands.

Murine Model for Blood-Stage Malaria

Our murine model for blood-stage malaria requires infection of Swiss Webster females with 10³ red blood cells containing P. berghei ANKA strain expressing luciferase, adhering to our drug testing protocol. The parasitemia is quantified by luminescence detection, using the IVIS® Lumina II imager, with the signal being proportional to the load of parasites. The results are expressed as the luciferin signal at the end of treatment for each animal.

Our transgenic luciferase-expressing parasite was generously provided by Chris Janse, PhD, of Leiden University Medical Center in Leiden, the Netherlands.

In Vitro Testing

We conduct in vitro tests assessing the likelihood of whether potential anti-infectives result in host cell toxicity, as well as their potential in the management of four neglected tropical diseases: malaria, Chagas disease (also referred to as American trypanosomiasis), human African trypanosomiasis, and leishmaniasis.

Host Toxicity (TC50)

Researchers test for potential anti-infective toxicity against host cells (TC50).

L. amazonensis Axenic Amastigotes and Intramacrophage

Researchers test for potential anti-infective activity against L. amazonensis axenic amastigotes and intramacrophage. Our beta-lactamase-expressing parasite was generously provided by Frederick S. Buckner, MD, of the University of Washington in Seattle.

T. b. brucei Bloodstream Trypomastigotes

We test for potential anti-infective activity against T. b. brucei bloodstream trypomastigotes. This parasite was generously provided by Jayne Raper, PhD, of Hunter College in New York City.

T. cruzi Intracellular Trypomastigotes

Our scientists test for potential anti-infective activity against T. cruzi trypomastigotes in host cells. Our beta-galactosidase-expressing parasite was generously provided by Frederick S. Buckner, MD, of the University of Washington in Seattle.

P. falciparum Asexual Blood Stage

Testing for potential anti-infective activity against P. falciparum asexual blood stage is also available.

Protocols

The Anti-infectives Screening Core follows strict procedures to ensure high-quality results of in vitro and in vivo assays, as detailed in the following links to specific protocols: