Essential role of neutrophils in the protective immune response induced by a live attenuated leishmania vaccine.
No licensed vaccine exists against visceral leishmaniasis (VL), a disease caused by the Leishmania donovani parasite. We have previously reported both macrophages and dendritic cells play important role in the protection induced by a live attenuated centrin gene-deleted L. donovani (LdCen(-/-) ) parasite vaccine. The role of neutrophils in orchestrating the initial innate response to pathogens is widely recognized. To investigate the early interaction of LdCen(-/-) with neutrophils, we immunized mice intradermally in the ear pinna with LdCen(-/-) Compared with LdWT infection, LdCen(-/-) parasites induced higher recruitment of neutrophils to the ear dermis and ear draining lymph nodes (dLN) as early as 6-18 h after immunization, which were predominantly proinflammatory in nature. Neutrophils from ear dLN of LdCen(-/-) -immunized mice exhibited heightened expression of costimulatory molecules and attenuated expression of coinhibitory molecules necessary for higher T cell activation. Further phenotypic characterization revealed heterogeneous neutrophil populations containing Nα and Nβ subtypes in the ear dLN. Of the two, the parasitized Nα subset from LdCen(-/-) -immunized mice exhibited much stronger Ag-specific CD4(+) T cell proliferation ex vivo. Adoptive transfer of neutrophils bearing LdCen(-/-) parasites induced an increased Th1 response in naive mice. Importantly, neutrophil depletion significantly abrogated Ag-specific CD4(+) T cell proliferation in LdCen(-/-) -immunized mice and impaired protection against virulent challenge. Conversely, replenishing of neutrophils significantly restored the LdCen(-/-) -induced host-protective response. These results suggest that neutrophils are indispensable for protective immunity induced by LdCen(-/-) parasite vaccine.
Bhattacharya P;Dey R;Saxena A;Karmakar S;Ismail N;Gannavaram S;Dagur PK;Satoskar M;Satoskar S;De Paoli S;Takeda K;McCoy JP Jr;Nakhasi HL
Journal of Immunology
2020
2020-11-11
journalArticle
<a href="http://doi.org/10.4049/jimmunol.2000829" target="_blank" rel="noreferrer noopener">10.4049/jimmunol.2000829</a>
A second generation leishmanization vaccine with a markerless attenuated leishmania major strain using CRISPR gene editing
expression; cells; growth; immunity; immunization; protection; immunogenicity; balb/c mice; centrin deleted parasites; cutaneous leishmaniasis
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. Here, the authors engineer an attenuated knock-out Leishmania (LmCen(-/-)) vaccine that is safe in immunocompromised mice and induces an immune response and protection similar to leishmanization with wild-type Leishmania. Since LmCen(-/-) is antibiotic resistant marker free, it is a candidate for clinical development.
Zhang W; Karmakar S; Gannavaram S; Dey R; Lypaczewski P; Ismail N; Siddiqui A; Simonyan V; Oliveira F; Coutinho-Abreu I; DeSouza-Vieira T; Meneses C; Oristian J; Serafim TD; Musa Abu; Nakamura R; Saljoughian N; Volpedo G; Satoskar M; Satoskar S; Dagur PK; McCoy JP; Kamhawi S; Valenzuela JG; Hamano S; Satoskar AR; Matlashewski G; Nakhasi HL
Nature Communications
2020
2020-07-10
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journalArticle
<a href="http://doi.org/10.1038/s41467-020-17154-z" target="_blank" rel="noreferrer noopener">10.1038/s41467-020-17154-z</a>