Abstract:
Malaria is a global problem that affects up to 500 million people and kills hundreds of
thousands every year making it a serious global health predicament. Currently, there is
only a partially efficacious vaccine licensed for use against malaria and available
therapeutic control measures continue to be impeded by the emergence of drug-resistant
strains of Plasmodia parasites which cause high morbidity and mortality. Cutting-edge
research on anti-malarial mechanisms is intensively focused on biochemical and
molecular actors with the potential of improving vaccination and therapy against malaria.
The outcome of host-pathogen interactions, with respect to Plasmodia parasites, is
determined by an extremely delicate balance of various biomolecules, cytokines and hostspecific factors. Plasmodia parasites evade immune mechanisms and it is still unclear
what exact modulations of the immune system are required in their elimination. Proper
understanding of the intricate mechanisms underlying the immunopathogenesis of
malaria is an essential component in the development of vaccination and therapeutic
interventions. A vast array of immunopotentiating molecules like unmethylated CpG
motif oligodeoxynucleotides (ODNs) operate in concert with cytokines to mediate
resistance to infections. The CpG ODNs exert potent immunostimulatory effects via
nexus with dendritic cell Toll-like receptors (TLRs) like TLR 9 and by activating
immune cells like B-cells, plasmacytoid dendritic cells (pDCs) and NK cells. The current
project investigated cytokine-CpG motif ODN co-inoculation in BALB/c mice infected
with P. berghei ANKA strain. Two BALB/c mice groups were infected with virulent P.
berghei ANKA strain parasites, followed by five consecutive days of cytokine-involving
CpG ODN-based gene therapies. One of the P. berghei-infected mice groups received IL18-CpG ODN, and another one received IL-12-CpG ODN co-inoculation. Six other
control groups with various therapeutic regimens were involved in the study. At ten days
postinfection, all mice groups were humanely sacrificed for the extraction of EDTAtreated blood, plasma and splenocyte samples which were used to quantify a plethora of
transcription factors (TFs), physiologic biomolecules, haematological and clinical
chemistry parameters, chemokines, cytokines, immunoglobulin M (IgM) and splenocyte
recall proliferation in a multiplicity of bioassays. Analysis using one-factor ANOVA
unraveled cytokine-CpG co-immunotherapy as a strong trigger of antimalarial
mechanisms that lead to overall parasitaemia reduction, less dramatic parasitaemia trends,
milder clinico-haematological outcomes, and protective patterns in expression of TFs,
physiologic biomolecules, chemokines, cytokines, IgM, and antigen-specific splenocyte
recall proliferation. Murine recipients of the cytokine-CpG ODN co-inoculation ditherapy
manifested with increased levels of NF-kB, NFATc, IRF-5, AhR, KLF and reduced
levels of FOX-P3 and STAT-6 TFs. They also had enhanced of anti-Plasmodial activities
accompanied by elevations in adiponectin, ANGPT1, NRP-1 and Cox-2 and delevations
in Angiogenin, ANGPT2, MMP-8 and MMP-9 physiologic biomolecules. Cytokine-CpG
ODN co-injection triggered upregulated concentrations of CCL-2, CCL-5, CXCL-12,
CXCL-1, CX3CL-1, recall proliferation SI and downregulated concentrations of CCL-3,
CXCL-5, CXCL-10 and CXCL-16. Augmented quantities of IFN-γ, TNF-α, IL-17, IL23a, and IgM repressed measurements of IL-4, and IL-10 were detected with widespread
ramifications in the potential of cytokine-CpG-based DNA therapy in counteracting
malaria, other infectious diseases and medical conditions.