Pattern recognition receptors (PRR) such as Toll-like receptors, NOD-like receptors, RIG-I helicase receptors, and C-type lectin receptors play a critical role in innate immunity as a first line of defense against invading pathogens through recognition of pathogen and/or damage-associated molecular patterns. Genetic makeup of birds is known to play a role in resistance or susceptibility to various infectious diseases. Therefore, the present study was carried out to elucidate the differential expression of PRR and some of the cytokine genes in peripheral blood mononuclear cells of indigenous chicken breeds such as Ghagus and Nicobari and an exotic chicken breed, White Leghorn (WLH). The stability of expression of reference genes in peripheral blood mononuclear cells of 3 breeds was first determined using NormFinder and BestKeeper programs. NormFinder determined B2M and G6PDH reference genes as the best combination with stability value of 0.38. Out of total 14 genes studied, expression of ten genes was found to be significantly different among 3 breeds after normalization with these reference genes. Ghagus breed showed higher level of expression of TLR1LB, TLR7, NOD1, NOD5, B-Lec, IFNβ, IL1β, and IL8 genes when compared to Nicobari breed. Further, Ghagus showed higher expression of TLR1LB, MDA5, LGP2, B-Lec, IL1β, and IL8 genes as compared to WLH breed. Higher expression of LGP2 and MDA5 genes was observed in Nicobari compared to the WLH breed while higher expression of TLR7, NOD1, NOD5, and IFNβ genes was observed in WLH as compared to Nicobari breed. No difference was observed in the expression of TLR1LA, TLR3, B-NK, and IFNα genes among 3 breeds. Study revealed significant breed effect in expression profile of PRR and some of the cytokine genes and Ghagus breed seems to have better expression profile of these genes linked to the innate immunity when compared to the WLH and Nicobar breeds.

Chicken Mx protein confers resistance against viral infections including avian influenza virus. Mx protein is one of the strong antiviral proteins induced by interferon system. Different alleles of chicken Mx gene have been shown to vary in their antiviral activity against influenza virus. A non-synonymous mutation at position 2032 of chicken Mx gene responsible for variation of amino acid (Ser to Asn) in Mx protein is responsible for negative to positive antiviral activity of Mx protein.In the present study it was analyzed that SNP at G2032A in chicken Mx gene in two Indian native chicken breeds, Aseel, Kadaknath and compared with White Leghorn layer. A total of 90 samples, including 50 of White Leghorn and 20 each from native chicken breed were screened for SNP at position 2032 of Mx gene by using real time multiplex allele specific PCR. The resistant allele (A) frequency is higher than susceptible allele in all three chicken breeds investigated. Among the breeds, the resistant allele frequency (A) is higher in White Leghorn (0.95) followed by Aseel (0.75) and Kadaknath (0.625). Homozygous to resistant allele (AA) is the major genotype in White Leghorn whereas heterozygous to both alleles is the major genotype in Kadaknath. Variations in the gene frequency might have emerged from varying degree of selection pressure the different breeds had undergone. In future, the resistant genotype could be selected in modern breeding programs to improve the genetic status for disease resistance against viral infections.