Anatomy

Leishmaniasis

Attenuated vaccine

Biology

Microbiology

Gene

World Wide Web

Genome editing

Virology

Vaccination

Immunology

Cutaneous leishmaniasis

Strain (injury)

Leishmania

Recombinant DNA

Computer science

Leishmania major

Parasite hosting

Vector (molecular biology)

CRISPR

Genetics

Virulence

Immune system

Nature Communications

Leishmaniasis is a neglected tropical disease caused by Leishmania protozoa transmitted by infected sand flies. Vaccination through leishmanization with live Leishmania major has been used successfully but is no longer practiced because it resulted in occasional skin lesions. A second generation leishmanization is described here using a CRISPR genome edited L. major strain (LmCen-/-). Notably, LmCen-/- is a genetically engineered centrin gene knock-out mutant strain that is antibiotic resistant marker free and does not have detectable off-target mutations. Mice immunized with LmCen-/- have no visible lesions following challenge with L. major-infected sand flies, while non-immunized animals develop large and progressive lesions with a 2-log fold higher parasite burden. LmCen-/- immunization results in protection and an immune response comparable to leishmanization. LmCen-/- is safe since it is unable to cause disease in immunocompromised mice, induces robust host protection against vector sand fly challenge and because it is marker free, can be advanced to human vaccine trials.

A second generation leishmanization vaccine with a markerless attenuated Leishmania major strain using CRISPR gene editing