Paper Title
Affinity Maturation of Anti-SIPD Sequence for Detection of Salmonella Typhi

Abstract
Over 1,61,000 deaths are being reported annually all over the world due to the causative agent Salmonella typhi. The most crucial problem of the 21st century is the emergence and evolution of MDR (Multiple Drug-Resistant) bacterial strains, contributingto a serious threat to public health. To counter this problem, one possible approach is to counter the virulence system of the bacteria. Type III Secretion System (T3SS) is a type of virulence system of bacteria that is available in most gram-negative pathogenic bacteria. T3SS consists of a needle-syringe complex affiliated with the plants, humans, and animal hosts that are responsible to transfer effectors inside the cytosol of target host cells. T3SS is consist of around 20 proteins, disarming any of those proteins can eliminate its pathogenicity. Therefore, T3SS can be used as a potential target. Most Salmonella sp. uses two types of T3SS to introduce the infection to the host cell.Tip Complex (TC) is present at the end of the T3SS needle, responsible for providing the physical contact between the host cell and bacteria. SipD (Salmonella Invasion Protein) is a crucial protein of Salmonella that is responsible for this attachment. Inhibit the activity of SipD protein will inhibit the virulence of Salmonella sp. Through the combination of computational biology and recombinant DNA technology, our aim is to perform an antibody-mediated approach using SipD protein as a target. Affinity maturation of Single-Domain Antibody (SdAb)against the SipD of S. typhiwas performed to enhance the binding affinity of antibodieswith the target antigen. With the help of Bioinformatics tools, several mutations were introduced in the antibody sequence to achieve enhanced binding affinity toward the antigen.These Anti-SipD antibodies can be used for diagnostic purposes to detect the presence of Salmonella typhi infectionin a suspected person. Keywords - SdAbs (Single-Domain Antibodies), Recombinant DNA Technology, Type III Secretion System, SipD (Salmonella Invasion Protein), Tip Complex.