Receptor-mediated targeting of toxins to intraerythrocytic parasite Plasmodium falciparum. surolia@jncasr.ac.in

Macromolecular Conjugate and Biological Carrier Approaches for the Targeted Delivery of Antibiotics

For the past few decades, the rapid rise of antibiotic multidrug-resistance has presented a palpable threat to human health worldwide. Meanwhile, the number of novel antibiotics released to the market has been steadily declining. Therefore, it is imperative that we utilize innovative approaches for the development of antimicrobial therapies. This article will explore alternative strategies, namely drug conjugates and biological carriers for the targeted delivery of antibiotics, which are often eclipsed by their nanomedicine-based counterparts. A variety of macromolecules have been investigated as conjugate carriers, but only those most widely studied in the field of infectious diseases (e.g., proteins, peptides, antibodies) will be discussed in detail. For the latter group, blood cells, especially erythrocytes, have been successfully tested as homing carriers of antimicrobial agents. Bacteriophages have also been studied as a candidate for similar functions. Once these alternative strategies receive the amount of research interest and resources that would more accurately reflect their latent applicability, they will inevitably prove valuable in the perennial fight against antibiotic resistance.

Antimalarial activity of granzyme B and its targeted delivery by a granzyme B-single-chain Fv fusion protein

We present here the first evidence that granzyme B acts against Plasmodium falciparum (50% inhibitory concentration [IC50], 1,590 nM; 95% confidence interval [95% CI], 1,197 to 2,112 nM). We created a novel antimalarial fusion protein consisting of granzyme B fused to a merozoite surface protein 4 (MSP4)-specific single-chain Fv protein (scFv), which targets the enzyme to infected erythrocytes, with up to an 8-fold reduction in the IC50 (176 nM; 95% CI, 154 to 202 nM). This study confirms the therapeutic efficacies of recombinant antibody-mediated antimalarial immunotherapeutics based on granzyme B.

Triclosan: a shot in the arm for antimalarial chemotherapy

In order that malaria be successfully contained, it is important that one has a clear understanding of the normal physiology and biochemistry of the parasite essential to its survival in its human host. Until very recently, the conventional approaches to antimalarial chemotherapy have consistently been plagued with the uncanny ability of the parasite to evolve resistance to drugs. The recently discovered plasmodial fatty acid biosynthetic pathway as well as its inhibition by triclosan that classifies it as belonging to type II, provide with a very crucial breakthrough to the crusade against malaria. How triclosan could tilt the balance in favor of the human hosts of the malarial parasite in a malarial condition is discussed.