Innovative research in the development of leishmaniasis prevention through leishmaniasis vaccine: modulation of GAPDH-mediated immune response

Innovative research in the development of leishmaniasis prevention through leishmaniasis vaccine: modulation of GAPDH-mediated immune response
Fatemeh Balangi,¹ Hamid Daneshvar,^2,*
1. Department of Medical Immunology, Afzalipour Faculty of Medicine, Kerman University of Medical Sciences
2. Department of Medical Immunology, Afzalipour Faculty of Medicine, Kerman University of Medical Sciences
Introduction: Leishmaniasis represents one of the most neglected tropical diseases, causing severe morbidity and mortality across endemic regions which affecting 12 million people worldwide. The causative agent, Leishmania major, employs sophisticated molecular machinery to evade host immune responses, making vaccine development extraordinarily challenging. GAPDH emerges as a dual-function protein - beyond its classical role in cellular energy metabolism, this enzyme orchestrates complex immunomodulatory processes. Within Leishmania parasites, GAPDH concentrates in specialized secretory vesicles that directly interface with host immune cells, particularly macrophages. These extracellular vesicles (EVs) function as molecular messengers, delivering GAPDH to host cells where it manipulates Tumor Necrosis Factor-α (TNF-α) expression. TNF-α activation triggers robust cellular immunity through CD4+ and CD8+ T-cell responses, representing the body's primary defense against intracellular pathogens like Leishmania. In this research, we investigate the effect of GAPDH and the level of expression of IFN-γ and IL4 in mice infected with wild type and mice vaccinated with reduced Leishmania.
Methods: Our investigation employed cutting-edge analytical techniques to quantify GAPDH levels using high-precision liquid chromatography. This advanced instrumentation enables detection of minute protein concentrations, providing unprecedented accuracy in measuring therapeutic targets. The experimental design incorporated three distinct mouse cohorts: • Control group: Baseline immune response parameters • Wild-type infection group: Natural disease progression monitoring • Attenuated vaccine group: Protective immunity assessment Following a three-month observation period, we utilized enzyme-linked immunosorbent assay (ELISA) technology to measure critical cytokine levels - interferon-gamma (IFN-γ) and interleukin-4 (IL-4) - from splenic tissue samples.
Results: Our findings reveal dramatic differences in immune response patterns between wild-type infection and vaccination scenarios: GAPDH Reduction The attenuated vaccine demonstrated significantly reduced GAPDH concentrations compared to wild-type parasites, suggesting successful targeting of this critical virulence factor. Protective Immune Polarization Vaccinated animals exhibited: • Elevated IFN-γ levels: Indicating robust Th1-mediated cellular immunity • Decreased IL-4 expression: Reduced Th2 response associated with disease susceptibility Conversely, wild-type infected animals showed: • Suppressed IFN-γ production: Compromised cellular immune defenses • Increased IL-4 levels: Immune deviation favoring parasite survival
Conclusion: Previous research demonstrates that Leishmania major suppresses TNF-α expression through GAPDH-mediated mechanisms. The present investigation reveals significant immunological advantages of an attenuated Leishmania vaccine characterized by reduced GAPDH expression compared to wild-type strains. Comparative Immune Response Analysis Mice immunized with the attenuated vaccine exhibited a pronounced shift toward TH1-mediated cellular immunity, characterized by: • Elevated IFN-γ production - indicating robust cell-mediated immune activation • Decreased IL-4 levels - demonstrating reduced TH2 response bias • Enhanced TNF-α expression - resulting from diminished GAPDH interference In contrast, wild-type Leishmania infection promoted a TH2-skewed immune profile with increased IL-4 production and reduced IFN-γ levels, creating conditions favorable for parasite persistence. Mechanistic Insights and Vaccine Efficacy The attenuated vaccine's reduced GAPDH expression disrupts the parasite's ability to suppress TNF-α, thereby facilitating: 1. Restoration of pro-inflammatory signaling cascades 2. Amplification of TH1 immune responses 3. Enhanced protective immunity against leishmaniasis These findings establish that GAPDH attenuation in Leishmania major vaccines significantly improves immunogenicity by promoting favorable cytokine profiles and cellular immune responses essential for effective parasite clearance and long-term protection. This research, which explores the role of GAPDH, advances our understanding of leishmaniasis pathogenesis and rational vaccine design strategies targeting specific parasite virulence factors to enhance protective immunity.
Keywords: Leishmania, vaccine, GAPDH, IFN-γ