Neospora caninum SRS2 Protein: Essential Vaccination Targets and Biochemical Features for Next-Generation Vaccine Design

Abstract

Vaccination is a standout preventive measure to combat neosporosis among cattle herds. The present in silico study was done to evaluate the physicochemical properties and potent immunogenic epitopes of N. caninum SRS2 protein as a possible vaccine candidate. Web-based tools were used to predict physicochemical properties, antigenicity, allergenicity, solubility, posttranslational modification (PTM) sites, transmembrane domains and signal peptide, and secondary and tertiary structures as well as intrinsically disordered regions, followed by identification and screening of potential linear and conformational B-cell epitopes and those peptides having affinity to bind mouse major histocompatibility complex (MHC) and cytotoxic T lymphocyte (CTL). The protein had 401 residues with a molecular weight of 42 kDa, representing aliphatic index of 69.35 (thermotolerant) and GRAVY score of -0.294 (hydrophilic). There were 53 PTM sites without a signal peptide in the sequence. Secondary structure comprised mostly by extended strand, followed by helices and coils. The Ramachandran plot of the refined model showed 90.2%, 8.8%, 0.5%, and 0.5% residues in the favored, additional allowed, generously allowed, and disallowed regions, correspondingly. Additionally, various potential B-cell (linear and conformational), CTL, and MHC-binding epitopes were predicted for N. caninum SRS2. These epitopes could be further utilized in the multiepitope vaccine constructs directed against neosporosis.

In Silico Characterization of an Important Metacyclogenesis Marker in Leishmania donovani, HASPB1, as a Potential Vaccine Candidate

“…Although a low aliphatic index was predicted for this protein, the main focus of this study was on the extensive epitope mapping of LdHASPB1, which can be used towards multiepitope vaccine construction against VL cases in humans and dogs. The GRAVY score is an estimated mean of hydrophilicity and hydrophobicity values for individual residues, so scores over or below zero indicate hydrophobicity and hydrophilicity, respectively [ 56 ]. In addition, this protein was shown to be highly antigenic and nonallergenic with high solubility.…”

Evaluation of Protective Immune Responses Induced in BALB/c Mice and Goats by the Neospora caninum Surface SRS Proteins and Interleukin-18

“…Surface proteins from the SRS superfamily play important roles in adhesion and invasion processes, which enables them to be possible anti-parasite targets. N. caninum SRS2 has been previously demonstrated to be a potential antigen [ 4 ]. Studies are attempting to obtain an understanding of other antigens from the SRS superfamily, such as NcSRS67 [ 5 ], NcSRS29B and NcSRS29C [ 6 ], but whether these antigens confer protection against N. caninum infection has not been investigated.…”