Molecular characterization and immunostimulant-induced expression analysis of type I interferon gene in Labeo bata (Ham.)

Abstract

Immunostimulants stimulate the immune system by involving many cytokines. Interferons, a crucial cytokine, shares both antiviral and antibacterial properties. Hence, the present study aimed to evaluate the effect of immunostimulant on type I interferon (I-IFNs) gene expression in Labeo bata. For the first time, genes coding for I-IFN has been cloned, amplified, and sequenced from L. bata (bata). The sequence analysis revealed that bata I-IFN consists of 1,800 bp genomic sequence with five exons and four introns and an ORF of 537 bp encoding for a putative protein of 178 amino acids. The molecular weight of the mature protein was 19.17 kDa, which consists of 160 amino acids and a signal peptide of 18 amino acids at the N terminus. The sequence showed the highest similarity to that of L. rohita (91.25 %). To study the effect of dietary administration of chitosan, vitamin C and β glucan on expression of I-IFN gene in L. bata (pre and post challenged with bacterial pathogen Edwardsiella tarda), fishes were fed in three different doses (low, medium and high doses) of immunostimulants for 30 days in three separate experiments. Differential expression pattern of I-IFN gene in L. bata was demonstrated in the experiments with significantly higher expression in medium doses of immunostimulants i.e. 5 gm chitosan, 200 mg vitamin C and 1.5 gm β glucan per kg dry pelleted feed were observed. The present study indicates the immunomodulation of immunostimulants through I-IFN or I-IFN mediated protective effect in L. bata.