Cevayir Coban

Malaria parasites within red blood cells digest host hemoglobin into a hydrophobic heme polymer, known as hemozoin (HZ), which is subsequently released into the blood stream and then captured by and concentrated in the reticulo-endothelial system. Accumulating evidence suggests that HZ is immunologically active, but the molecular mechanism(s) through which HZ modulates the innate immune system has not been elucidated. This work demonstrates that HZ purified from Plasmodium falciparum is a novel

Toll-like receptors (TLRs) recognize malaria parasites or their metabolites; however, their physiological roles in malaria infection in vivo are not fully understood. Here, we show that myeloid differentiation primary response gene 88 (MyD88)-dependent TLR signaling mediates brain pathogenesis of severe malaria infection, namely cerebral malaria (CM). A significant number of MyD88-, but not TIR domain containing adaptor-inducing IFN-beta (TRIF)-deficient or wild-type (WT) mice survived CM caused

DNA vaccines can induce both humoral and cellular immune responses in animals. Some DNA vaccines are already licensed for infectious diseases such as West Nile virus encephalitis in horses. When used in humans, however, DNA vaccines suffer from lower immunogenicity profiles. Although the reasons for this are poorly understood, various hypotheses have been proposed. This review aims to provide better understanding of the molecular and immunological mechanisms by which DNA vaccines work and how su

Although DNA vaccines are already in use for treatment of some animal diseases, they suffer from lower immunogenicity in humans which limits their effectiveness. Thus, recent studies have been focused on strategies to improve the immunogenicity of DNA vaccines. However, there is little known about the molecular and immunological mechanisms by which DNA vaccines work. It has long been the central dogma that DNA vaccine immunogenicity can be attributed to its immunostimulatory CpG motifs acting as

Hemozoin (malaria pigment) has been implicated in the modulation of immune responses during malaria infection. This study was designed to evaluate the effect of purified hemozoin on the in vitro activation of myeloid dendritic cells. Our study also revealed that in addition to enhancing the maturation of dendritic cells, hemozoin also greatly promotes immunoglobulin G2a antibody responses when coadministered with a DNA vaccine plasmid encoding Pfs25, a Plasmodium falciparum transmission-blocking

DNA vaccines, in general, have been found to be poorly immunogenic in nonhuman primates and humans as compared with mice. As the immunogenicity of DNA plasmids relies, to a large extent, on the presence of CpG motifs as built in adjuvants, we addressed the issue of poor immunogenicity by inserting recently identified CpG oligonucleotides (ODN) optimal for human (K-type or D-type CpG ODN) into the backbone of plasmid VR1020. We found that plasmid DNA containing K-type CpG motifs or D-type CpG mot

Malaria transmission-blocking vaccination can effectively reduce and/or eliminate transmission of parasites from the human host to the mosquito vector. The immunity achieved by inducing an antibody response to surface antigens of male and female gametes and parasite stages in the mosquito. Our laboratory has developed DNA vaccine constructs, based on Pfs25 (a Plasmodium falciparum surface protein of 25 kDa), that induce a transmission-blocking immune response in mice (C. A. Lobo, R. Dhar, and N.

Hemozoin, a bio-crystalline substance, is a hemin detoxification by-product of malaria parasites. The role of hemozoin crystals in host immune system modulation by malaria parasites, and how they interact with the immune system has been enigmatic. Here, we summarize recent progress in our understanding of how hemozoin might be interacting with the host immune system. In particular, the potential application of hemozoin crystals as an adjuvant may provide insights into the molecular mechanisms in

Since the introduction of DNA vaccines two decades ago, this attractive strategy has been hampered by its low immunogenicity in humans. Studies conducted to improve the immunogenicity of DNA vaccines have shown that understanding the mechanism of action of DNA vaccines might be the key to successfully improving their immunogenicity. Our current understanding is that DNA vaccines induce innate and adaptive immune responses in two ways: (1) encoded protein (or polypeptide) antigen(s) by the DNA pl