LmjF.36.3850, a novel hypothetical Leishmania major protein, contributes to the infection.

Abstract

Leishmania is a protozoan parasite that resides in mammalian macrophages and inflicts the disease known as leishmaniasis. Although prevalent in 88 countries, an anti-leishmanial vaccine remains elusive. While comparing the virulent and avirulent L. major transcriptomes by microarray, PCR and functional analyses for identifying a novel virulence-associated gene, we identified LmjF.36.3850, a hypothetical protein significantly less expressed in the avirulent parasite and without any known function. Motif search revealed that LmjF.36.3850 protein shared phosphorylation sites and other structural features with sucrose non-fermenting protein (Snf7) that shuttles virulence factors. LmjF.36.3850 was predicted to bind diacylglycerol (DAG) with energy value similar to PKCα and PKCβ, to which DAG is a cofactor. Indeed, 1-oleoyl-2-acetyl-sn-glycerol (OAG), a DAG analogue, enhanced the phosphorylation of PKCα and PKCβI. We cloned LmjF.36.3850 gene in a mammalian expression vector and primed susceptible BALB/c mice followed by challenge infection. We observed a higher parasite load, comparable antibody response and higher anti-inflammatory cytokines such as IL-4 and IL-10, while expression of major anti-leishmanial cytokine, IFN-γ, remained unchanged in LmjF.36.3850-vaccinated mice. CSA restimulated LN cells from vaccinated mice after challenge infection secreted comparable IL-4 and IL-10 but reduced IFN-γ, as compared to controls. These observations suggest a skewed Th2 response, diminished IFN-γ secreting Th1-TEM cells and increased central and effector memory subtype of Th2, Th17 and Treg cells in the vaccinated mice. These data indicate that LmjF.36.3850 is a plausible virulence factor that enhances disease-promoting response, possibly by interfering with PKC activation and by eliciting disease-promoting T cells.

• Authors: Shubhranshu Zutshi, Aditya Yashwant Sarode, Soumya Kanti Ghosh, Mukesh Kumar Jha, Raki Sudan, Sunil Kumar, Late Parag Sadhale, Somenath Roy, Bhaskar Saha
• Journal: Immunology (Immunology) Vol. 163 Issue 4 Pg. 460-477 (08 2021) ISSN: 1365-2567 [Electronic] England
• PMID: 33764520 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2021 John Wiley & Sons Ltd.

Chemical References

• Antigens, Protozoan
• Cytokines
• Protozoan Vaccines

Topics

• Animals
• Antigens, Protozoan (genetics, metabolism)
• Cells, Cultured
• Cloning, Molecular
• Cytokines (metabolism)
• Gene Expression Profiling
• Humans
• Leishmania major (pathogenicity, physiology)
• Leishmaniasis, Cutaneous (immunology, parasitology)
• Macrophages (immunology)
• Mice
• Mice, Inbred BALB C
• Parasite Load
• Protozoan Vaccines (immunology)
• T-Lymphocytes, Regulatory (immunology)
• Th2 Cells (immunology)
• Vaccination
• Virulence (genetics)