Cloning, Sequencing and In Silico Analysis of Omp C of Salmonella Typhimurium

Salmonella Typhimurium is an important pathogen having a broad host range. In human population it causes mostly gastroenteritis but there are reports in which it was found to be responsible to cause several lethal diseases like endocarditis and meningitis. Poultry products are the major sources of this organism in India as these are consumed at various stages of cooking. The available vaccines have their own limitations such as short-term immunity. Outer membrane proteins have shown some promising potential, so in the present study Omp C of Salmonella Typhimurium was cloned and sequenced to explore the possibility of development of r-DNA vaccine against Salmonella Typhimurium for poultry. The sequence of Omp C was studied for antigenic indexing, epitope mapping, and MHC mapping using various bioinformatic tools. The ORF analysis revealed a complete coding region of approximately 1000？bp. Five major and 13 minor B-cell epitopes were identified having an antigenic index of 1.7. The sequences also showed major histocompatibility complex (MHC) class I and class II binding region indicating a potential of eliciting cell-mediated immune response. The findings indicate that Omp C may be proven as promising candidate for development of r-DNA vaccine against Salmonella Typhimurium. 1. Introduction Salmonellosis is a major foodborne illness and life-threatening problem worldwide caused by various serovars of Salmonella among which Salmonella Typhimurium is one of the most important serovars. In developing countries like India where the hygienic conditions are not very good salmonelloses have became major problem related to human health and poultry products are known to be significant reservoir for Salmonella and most important source to human infections [1, 2]. The available vaccines for poultry in India are not very effective [3, 4]. The backyard poultry practices are very common in India so there is always a possibility of transfering of Salmonella Typhimurium from poultry to human populations where it can cause serious health problems [5, 6]. There is an emergent need of better vaccine for poultry against salmonellosis. In last few years Omps have been studied and have shown their immunopotential [7–9]. Few of them have been characterized [10]. In earlier report Omp C has been studied [11], and it was found that Omp C was expressed during high salt concentration which was equivalent to human serum [12]. It was found be thermostable [13] and resistant for proteolysis [14]. This finding indicates that Omp C may be proven as an efficient candidate for vaccine