School of Life Sciences

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Designing T-cell epitope-based vaccine against Eimeria infection in chicken using immunoinformatics approach.
(2021) Madlala, Thabile.; Adeleke, Matthew Adekunle.; Okpeku, Moses.
Chicken coccidiosis is the most significant ubiquitous, intestinal parasitic disease known to infect chickens globally. It is recognised for incurring significant production loss to the poultry industry, caused by single or multiple Eimeria spp. infections which threaten chicken welfare and productivity. The emergence of drug resistance in parasites and pathogenicity reversion has put pressure on the poultry industry to reduce chemoprophylactic drugs and live vaccines as preventive measures against coccidiosis. Recombinant DNA vaccines have shown promising results as an alternative option, but complete protection has not been reported highlighting the need for the design of new vaccine against this disease. In this study, Eimeria antigens Immune Mapped Protein-1(IMP1) and Microneme Protein-2(MIC2) were explored using reverse vaccinology and immunoinformatics tool to predict and design potential multiepitope vaccine candidate against coccidiosis. A total of 28 and 19 antigenic T-cell epitopes were predicted and used to construct two multiepitope vaccines with 610 and 512 amino acids for IMP1 and MIC2, respectively. The produced vaccines exhibited favoured characteristics for an ideal vaccine candidate; they were antigenic (Vaxijen score of 0.5989 and 0.5103), immunogenic (scores: 10.15 and 9 419), thermostable (instability index <40 ), and non-allergic. The presence of IFN-gamma and IL-4 inducing epitopes in the constructed vaccine enables vaccine to trigger a cellular and humoral response within the host. Molecular docking of designed vaccines with toll-like receptors (TLR4 and TLR5) to determine vaccine interaction and stability was confirmed by molecular dynamics simulation root-mean square deviation (RMDS) and root-mean-square fluctuation (RMSF) analysis. The designed vaccines induced immune response through production of cytokines and antibodies associated with tertiary response. When exposed to online immune simulation C-ImmSim, both vaccines produced potent immune response through production of IgG, Tc and Th cell and memory Bcells. The constructed multiepitope vaccine in this present study is highly promising and as such further experimental work should be done to confirm its suitability against chicken coccidiosis.
Diversity of Eimeria tenella apical membrane antigen-1 from chickens in Mpumalanga province and its in silico epitope prediction as a vaccine candidate.
(2021) Tenza, Petronella Nokukhanya.; Adeleke, Matthew Adekunle.; Fatoba, Abiodun Joseph.
Coccidiosis has been a significant challenge in the poultry industry. There is a high request for the modification of a cost-effective immunizing agent to curtail this disease. Apical membrane antigen 1 (AMA1) has been reported as a protective antigen in sub-unit vaccine development against several apicomplexan parasites such as Plasmodium falciparum, Eimeria tenella and Eimeria maxima. However, knowledge of genetic diversity in this vaccine candidate is imperative. Also, to minimize the cost and time involved in producing a vaccine, computational vaccine design has received much attention through the immunoinformatics method. Therefore, screening for the potential vaccine epitopes in AMA1 that can induce cellular and humoral immune response through the immunoinformatics technique looks promising. This investigation aimed to detect the level of genetic diversity amid Eimeria tenella Apical Membrane Antigen 1(EtAMA1) in selected farms in Mpumalanga province and predict vaccine epitopes from this antigen. Four hundred fresh faecal samples were collected from 10 selected broiler chicken farms in Mpumalanga. The samples were screened for Eimeria oocyst using a compound microscope, and samples containing oocyst were further screened for E. tenella using molecular methods. AMA1 (n=103) was amplified from positive samples for E. tenella, and resulted amplicons were sent to Inqaba Biotec for sequencing and analyzed using MEGA6.06 and DnaSP programs. The results revealed low levels of genetic diversity among Mpumalanga EtAMA1 sequences which were measured by nucleotide diversity (0.0007) diversity, haplotype diversity (0.113) and haplotype number (3). Correspondingly, the haplotype network revealed 4 haplotypes, 3 of which consist of samples from Mpumalanga. Identification of immunogenic B- and T-cell epitopes from EtAMA1 sequences was further carried out and were used to construct a multiepitope vaccine (MEV) using immunoinformatics approaches. The constructed MEV is 311 amino acids long. It was constructed by linking 6 B-cell, 3 CD8+ epitopes and 6 CD4+ epitopes with appropriate adjuvant and linkers. Both adjuvant and linkers were used to increase the immunogenicity of the MEV. The designed MEV was highly antigenic and non-allergenic. The results showed a strong binding affinity of MEV with TLR4. These results suggest that the predicted vaccine could be a significant vaccine candidate against chicken coccidiosis through further experimental validation is still necessary.
Genetic characterization of resistance and virulence genes in Enterococcus species from animal isolates in Durban.
(2018) Eberechi, Phoebe Nnah.; Adeleke, Matthew Adekunle.; Zishiri, Oliver Tendayi.
Misuse of antimicrobials in animal agriculture has given rise to strains of bacteria that are resistant to multiple antibiotics. Enterococci bacteria have emerged among such antibiotic-resistant strains of bacteria and infections due to antibiotic-resistant bacteria is one of the world’s critical health challenge. Enterococci are gut commensal bacteria but are currently confirmed pathogenic bacteria responsible for so many hospital-acquired infections like urinary tract infections. The aim of this research was to detect the occurrence of Enterococcus species in chickens, cats, and dogs; their phenotypic and genotypic resistance to antibiotic drugs and virulence genes. Isolation of Enterococcus species was done using microbiological culture methods and confirmed using specific primers through Polymerase Chain Reaction (PCR). Presumptive Enterococcus growth on bile esculin agar was positive for 94% of all the isolates. Overall, 77.3% of the isolates were positive for Tuf gene (Enterococcus genus-specific gene). Enterococcus faecalis was detected at a higher frequency (40.4%; P <0.05) compared to Enterococcus faecium (8.5%). All the Enterococcus isolates were susceptible to High-Level Gentamicin on antimicrobial susceptibility test. Enterococcus species in chickens exhibited higher resistance to the antibiotics than the pets. Highest resistance was observed in Quinupristin/Dalfopristin (89.4%) followed by Vancomycin (87.9%), Rifampicin (85%), Ampicillin (76.6%), Erythromycin (72.3%), and Tetracycline (64.5%). Chloramphenicol (24.8%), High-Level Streptomycin Resistance (24.1%), and Ciprofloxacin (14.2%). Eighty-four percent (84%) of the Enterococcus isolates expressed multidrug resistance (MDR). Three of the four resistance genes screened were detected: 21.3%, 7.8% and 4.3% for Kanamycin, Streptomycin, and Vancomycin resistance genes respectively. Gentamicin resistance gene was absent in all the isolates. PCR detection of virulence gene showed highest prevalence in EfaA gene at 88.7% frequency followed by GelE (82.3%), ccf (81.6%), Esp (26.2%) and CylA (25.5%). All E. faecalis and E. faecium detected harbored multiple virulence genes. These findings show that chickens, cats, and dogs can be colonized by pathogenic Enterococci which harbor resistance and virulence genes and are multidrug resistant. It is therefore important that antibiotics are used prudently in animal husbandry to mitigate emergence and transfer of Enterococci pathogens to humans via food chain and direct contact of pets by their owners.
Genetic characterization of robustness and fitness traits in South African indigenous chickens.
(2016) Mtungwa, Nokwanda.; Zishiri, Oliver Tendayi.; Adeleke, Matthew Adekunle.
Abstract available in PDF file.
Prevalence of Staphylococcus aureus and its antimicrobial resistance and virulence genes in pet dogs of Durban: the risks of reservoir populations.
(2017) Brouckaert, Mary-Anne Frances.; Adeleke, Matthew Adekunle.; Zishiri, Oliver Tendayi.
Abstract available in pdf.

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