Immunogenicity and Protective Efficacy of Brugia malayi Heavy Chain Myosin as Homologous DNA, Protein and Heterologous DNA/Protein Prime Boost Vaccine in Rodent Model

Abstract

We earlier demonstrated the immunoprophylactic efficacy of recombinant heavy chain myosin (Bm-Myo) of Brugia malayi (B. malayi) in rodent models. In the current study, further attempts have been made to improve this efficacy by employing alternate approaches such as homologous DNA (pcD-Myo) and heterologous DNA/protein prime boost (pcD-Myo+Bm-Myo) in BALB/c mouse model. The gene bm-myo was cloned in a mammalian expression vector pcDNA 3.1(+) and protein expression was confirmed in mammalian Vero cell line. A significant degree of protection (79.2%±2.32) against L3 challenge in pcD-Myo+Bm-Myo immunized group was observed which was much higher than that exerted by Bm-Myo (66.6%±2.23) and pcD-Myo (41.6%±2.45). In the heterologous immunized group, the percentage of peritoneal leukocytes such as macrophages, neutrophils, B cells and T cells marginally increased and their population augmented further significantly following L3 challenge. pcD-Myo+Bm-Myo immunization elicited robust cellular and humoral immune responses as compared to pcD-Myo and Bm-Myo groups as evidenced by an increased accumulation of CD4+, CD8+ T cells and CD19+ B cells in the mouse spleen and activation of peritoneal macrophages. Though immunized animals produced antigen-specific IgG antibodies and isotypes, sera of mice receiving pcD-Myo+Bm-Myo or Bm-Myo developed much higher antibody levels than other groups and there was profound antibody-dependent cellular adhesion and cytotoxicity (ADCC) to B. malayi infective larvae (L3). pcD-Myo+Bm-Myo as well as Bm-Myo mice generated a mixed T helper cell phenotype as evidenced by the production of both pro-inflammatory (IL-2, IFN-γ) and anti-inflammatory (IL-4, IL-10) cytokines. Mice receiving pcD-Myo on contrary displayed a polarized pro-inflammatory immune response. The findings suggest that the priming of animals with DNA followed by protein booster generates heightened and mixed pro- and anti-inflammatory immune responses that are capable of providing high degree of protection against filarial larval invasion.

Exploring the out of sight antigens of SARS-CoV-2 to design a candidate multi-epitope vaccine by utilizing immunoinformatics approaches

“…In this study, the designed vaccine construct is about 51 kDa. The pcDNA3.1 has been exhibited high efficacy for in vivo expression of different recombinant proteins with different sizes from 14 to 73 kDa [98] , [99] , [100] . Also, high expression of recombinant proteins with sizes ranged from 14 to 51 kDa have been reported for pET-28a vector [101] , [102] .…”

Immunization with Brugia malayi Myosin as Heterologous DNA Prime Protein Boost Induces Protective Immunity against B. malayi Infection in Mastomys coucha

“…Therefore, to further enhance the protective efficacy of earlier identified Bm-Myo, we cloned Bm-Myo in mammalian expression vector and used this plasmid construct (DNA vaccine) to immunize BALB/c mice with homologous DNA as well as DNA/protein prime boost which demonstrated better protection than when recombinant myosin was employed [21]. Findings also demonstrated that priming with DNA construct followed by protein boosters elicited more robust humoral and cellular immune responses and provided higher rate of protection against L3 in the peritoneal cavity of mice than when DNA vaccination was followed by DNA vaccine booster.…”

“…The recombinant plasmid pcDNA3.1-Myo (Myo-pcD) was constructed as described earlier [21]. In brief, bm-myo (accession number AY705730) gene was cloned in mammalian expression vector pcDNA 3.1(+) (Invitrogen, USA) at BamHI/XhoI restriction sites and plasmid was isolated by Endo-free plasmid isolation kit (Qiagen, Germany) for immunizing M .…”

“…malayi larval (L3) challenge [21]. Filarial parasites are known to down-regulate the host immune response and inhibit antigen presentation for their survival and therefore protective immunity to filarial infections requires co-ordination of both Th1 and Th2 type of responses [22].…”

Highlighting the Relevance of CD8+ T Cells in Filarial Infections

“…Studies in TCR transgenic mice have also shown that the O. volvulus antigens O v ALT-2 and O v NLT-1 exert suppressive effects on CD8 + T cell proliferation and cytokine release ( 37 ). Recently, heterologous prime-boost vaccination administration of B. malayi heavy chain myosin induced enhanced CD8 + T cell expansion in mouse spleen ( 38 ). Although CD8 + T cell levels are elevated during filarial infections, it may be that CD8 + T cell-mediated immunity is most relevant at the initial stages of the infections when the parasite is establishing itself in the host.…”