Human Parainfluenza Virus (HPIV) Type-1, which is an anti-sense ribonucleic acid (RNA) virus belonging to the paramyxoviridae family, induces upper and lower respiratory tract infections. The infections caused by the HPIV Type-1 virus are usually confined to northwestern regions of America. HPIV-1 causes infections through the virulence of the hemagglutinin-neuraminidase (HN) protein, which plays a key role in the attachment of the viral particle with the host’s receptor cells. To the best of our knowledge, there is no effective antiviral drugs or vaccines being developed to combat the infection caused by HPIV-1. In the current study, a multiple epitope-based vaccine was designed against HPIV-1 by taking the viral HN protein as a probable vaccine candidate. The multiple epitopes were selected in accordance with their allergenicity, antigenicity and toxicity scoring. The determined epitopes of the HN protein were connected simultaneously using specific conjugates along with an adjuvant to construct the subunit vaccine, with an antigenicity score of 0.6406. The constructed vaccine model was docked with various Toll-like Receptors (TLRs) and was computationally cloned in a pET28a (+) vector to analyze the expression of vaccine sequence in the biological system. Immune stimulations carried out by the C-ImmSim Server showed an excellent result of the body’s defense system against the constructed vaccine model. The AllerTop tool predicted that the construct was non-allergen with and without the adjuvant sequence, and the VaxiJen 2.0 with 0.4 threshold predicted that the construct was antigenic, while the Toxinpred predicted that the construct was non-toxic. Protparam results showed that the selected protein was stable with 36.48 instability index (II) scores. The Grand average of Hydropathicity or GRAVY score indicated that the constructed protein was hydrophilic in nature. Aliphatic index values (93.53) confirmed that the construct was thermostable. This integrated computational approach shows that the constructed vaccine model has a potential to combat laryngotracheobronchitis infections caused by HPIV-I.

The world had faced unprecedented disruptions like global quarantine and the COVID-19 pandemic due to SARS-CoV-2. To combat the unsettling situations, several effective vaccines have been developed and are currently being used. However, the emergence of new variants and the high mutation rate of SARS-CoV-2 challenge the efficacy of existing vaccines and have highlighted the need for novel vaccines that will be effective against SARS-CoV-2 variants. In this study, we exploit all four structural proteins of SARS-CoV-2 to execute a potential vaccine against SARS-CoV-2 and its variants. The vaccine was designed by utilizing the antigenic, non-toxic, and non-allergenic epitopes of B-cell and T-cell from conserved regions of viral structural proteins. To build a vaccine construct, epitopes were connected through different linkers and adjuvants to enhance the immunogenicity and specificity of the epitopes. The vaccine construct was selected through the aforementioned filters and it scored 0.6 against the threshold of 0.4 on VexiJen 2.0 which validates its antigenicity. Toll-like receptors (TLR2–4, and TLR8) and vaccine construct were docked by Cluspro 2.0, and TLR8 showed strong binding of -1577.1 kCal/mole. To assess the reliability of the docked complexes, C-IMMSIM's immune simulations over three doses of the vaccine and iMODS' molecular dynamic simulation were executed. The stability of the vaccine construct was evaluated through the physicochemical analyses and the findings suggested that the manufactured vaccine is stable under a wide range of circumstances and has the ability to trigger immune responses against various SARS-CoV-2 variants (due to conserved epitopes). However, in order to strengthen the vaccine formulation and assess its safety and effectiveness, additional studies and research are required to support the computational data of this research at In-vitro and In-vivo levels.