Exogenous interferon prolongs survival of rabies infected mice

Abstract

Rabies is an acute viral infection that causes encephalomyelitis in almost all warm blooded animals and is invariably fatal once the clinical signs appear. The present study was carried out to assess the effect of recombinant human interferon alpha (rhIFN α-2A) treatment on the survival of rabies infected mice and its correlation with cytokines expression. The gene expression of TNF-α and IL-6 was measured by SYBR Green Real Time PCR for two groups-"Pre-exposure" (mice were inoculated with rhIFN α-2A prior to rabies infection) and "Post-exposure" (mice were inoculated with rhIFN α-2A post rabies virus infection). Delayed mortality was observed in interferon treated infected groups. In addition, statistically significant decrease (P < 0.0001) in the expression of TNF-α and IL-6 was observed, both in the pre-exposure and post-exposure groups. These findings indicate that modulation of cytokine secretion using exogenous biologicals such as rhIFN may offer novel therapeutic approaches to treat diseases such as rabies.

Keywords: Cytokines; Interferon; Rabies; Therapeutic.

Fig. 1

Clinical manifestations recorded over the duration of experimentation in the animals a Ruffled fur, b Toe walking, c Hunched back, d Hind limb paralysis and e Complete immobilization; f shows survival chart of animals under study. Graphs depict number of animals v/s days post infection in experimental groups

Fig. 2

Detection of rabies nucleoprotein antigen by FAT using FITC tagged antibody. The presence of well-distributed, punctiform nucleoproteins showing apple green fluorescence was considered as a positive. a Normal mouse brain, b rabies infected mouse brain, c detection of rabies N gene using nested RT-PCR—Lane 1 Ladder, Lane 2 1477 bp product of the first round (outer), Lane 3 762 bp product of the second round (inner) of PCR

Fig. 3

Results of fold change in expression for a TNF-α and b IL-6 are expressed as the mean ± SEM for each group. Evaluation of the significance of differences between the means of parameters was performed using the One way ANOVA and Tukey test. In all cases P < 0.05 was considered significant. (*P < 0.05; **P < 0.01; ***P < 0.0001)