Role of nitric oxide in the regulation of immune responses during rabies virus infection in mice

Abstract

Rabies virus (RABV) stimulates nitric oxide (NO) production, which either triggers T cell differentiation or suppresses T cell function depending on its concentration. Herein, we assessed the potential role of NO in regulation of immune responses during RABV infection in mice model. The experimental animals were divided into four groups and 100LD 50 of challenge virus standard (CVS) strain of RABV was inoculated intracerebrally on day 0 and subsequently aminoguanidine (AG; inducible nitric oxide synthase inhibitor) was injected intraperitoneally twice a day, up to 6 days. The samples were collected at 2, 4, 6, 8, 9, 10 and 12 days post infection (DPI). The immune cells including CD4? , CD8 ? T lymphocytes and natural killer (NK) cells were estimated from peripheral blood mononuclear cells (PBMCs) and splenocytes. Serum total NO concentration, histopathology, immunohistochemistry, direct fluorescent antibody technique and TUNEL assay was performed. Infection with CVS resulted in significant early increase in CD4? , CD8?and NK cells in blood and spleen until 2 DPI. From 4 DPI onwards significant reduction was noticed in these parameters which coincided with increased NO on 4 DPI, rising to maximum on 8 DPI, until their death on 10 DPI. Conversely, the CVS-AG treated group showed lower levels of NO and increased number of CD4 ? , CD8 ? and NK cells. Increased number of cells in blood and spleen coincided with increased survival time, delayed development of clinical signs, reduced viral load and less apoptotic cells. NO played important role in regulation of immune responses during RABV infection. The findings of present study confirmed the role of NO and/or iNOS using iNOS inhibitor (aminoguanidine) in immune response during RABV infection, which would further help in understanding the virus immunopathogenesis with adoption of newer antiviral strategies to counter the progression of disease.

Virological, immunological and pathological findings of transplacentally transmitted bluetongue virus serotype 1 in IFNAR1-blocked mice during early and mid gestation

“…Anti-coagulated blood was pooled according to the experimental groups for isolation of PBMCs as described previously 26 and diluted with 1x Dulbecco's phosphate buffered saline (D-PBS; pH 7.2; ratio 1:1) without calcium and magnesium. The blood was subjected to density gradient centrifugation method using Histopaque ® (Sigma Aldrich, St. Louis, Missouri, USA) with a density of 1.083 g/ml.…”

“…(2020) 10:2164 | https://doi.org/10.1038/s41598-020-58268-0 www.nature.com/scientificreports www.nature.com/scientificreports/ Separation of splenocytes. Splenocytes were separated from spleen by mincing into small pieces as described previously 26 . The splenocytes were squeezed from the splenic capsule in PBS (pH 7.4) through 70 μm nylon mesh cell strainer in a Petri dish to create a single cell suspension by gently mashing spleen pieces with rubber end of a plunger from 1 ml tuberculin syringe.…”

Melatonin is responsible for rice resistance to rice stripe virus infection through a nitric oxide-dependent pathway

“…For example, it was reported that nitric oxide (NO) induced by MT is responsible for disease resistance to Pst DC3000 infection in Arabidopsis [13]. Indeed, the vital role of NO in plant-pathogen interactions has been demonstrated by many studies [14][15][16][17][18]. NO can be produced through the nitrate/nitrite-dependent pathway that is known to be catalyzed by nitrate reductase (NR) [19] and through the L -arginine-dependent pathway that is known to be catalyzed by a mammalian NO synthase (NOS)-like enzyme [20,21].…”

Rabies, a Vaccine Preventable Disease: Current Status, Epidemiology, Pathogenesis, Prevention and Control With Special Reference to India

“…Further, role of inducible nitric oxide synthase (iNOS) and MEK-ERK1/2-MAP kinase signaling pathway inhibition in pathogenesis of rabies in mouse model has been studied (Madhu et al, 2016a;Madhu et al, 2016b;Manjunatha et al, 2017). Upon treatment with specific inhibitor of MEK1/2 in mouse model infected with rabies virus, disease development and clinical signs are delayed, survival time is increased and with reduced mortality than untreated mice .…”

“…2016 Nitric oxide played significant role in the regulation of immune responses during RABV infection in mice. Madhu et al (2016a) 6. 2015…”