Harnessing Immune Evasion Strategy of Lymphatic Filariae: A Therapeutic Approach against Inflammatory and Infective Pathology

Human lymphatic filariae have evolved numerous immune evasion strategies to secure their long-term survival in a host. These strategies include regulation of pattern recognition receptors, mimicry with host glycans and immune molecules, manipulation of innate and adaptive immune cells, induction of apoptosis in effector immune cells, and neutralization of free radicals. This creates an anti-inflammatory and immunoregulatory milieu in the host: a modified Th2 immune response. Therefore, targeting filarial immunomodulators and manipulating the filariae-driven immune system against the filariae can be a potential therapeutic and prophylactic strategy. Filariae-derived immunosuppression can also be exploited to treat other inflammatory diseases and immunopathologic states of parasitic diseases, such as cerebral malaria, and to prevent leishmaniasis. This paper reviews immunomodulatory mechanisms acquired by these filariae for their own survival and their potential application in the development of novel therapeutic approaches against parasitic and inflammatory diseases. Insight into the intricate network of host immune-parasite interactions would aid in the development of effective immune-therapeutic options for both infectious and immune-pathological diseases

Antifilarial actions of green tea extract and a synthetic heterocyclic thiazolidine derivative, Im8 compound in experimental mouse model

753-757In spite of the advances in drug development and research against human lymphatic filariasis following the WHO mandate to address the disease-associated socioeconomic burden, diethylcarbamazine (DEC, N, N-diethyl-4-methyl-1-piperazine carboxamide) is the only available antifilarial drug to date. The major obstacle for further development of antifilarial drugs is the lack of validation of candidate drugs in the experimental animal models. Both, green tea extract and a synthetic heterocyclic thiazolidine derivative (Im8; 2-chloro-N-(4-phenylthiazol-2-yl), showed efficacy of antifilarial action in our earlier in vitro study and hence, they were screened in the present study for their antifilarial potential in the BALB/c mouse filariasis model. Mice were treated with 25 mg/kg dose of either Im8 or green tea extract or DEC or only with their respective vehicles. The untreated mice served as controls. Following insertion of the micropore chamber laden with microfilariae (Mf) of Brugia malayi, the drug or vehicle was administered s.c. in mice at 12 h intervals as 4 doses. After 12 h of administration of the last dose, the micropore chambers were removed to determine the action of the treatments as the loss of Mf motility. The green tea extract showed a significant antifilarial action and Im8 showed relatively less but significant antifilarial action as compared to the respective vehicle controls. Both the green tea extract and Im8 showed higher activity than that was exerted by DEC. These results revealed a greater efficacy of green tea and thiazolidine derivative, Im8 as the novelantifilarial agents in the experimental mouse model of filariasis

Implications of Fragment-Based Drug Discovery in Tuberculosis and HIV

Tuberculosis (TB) remains a global health problem and the emergence of HIV has further worsened it. Long chemotherapy and the emergence of drug-resistance strains of Mycobacterium tuberculosis as well as HIV has aggravated the problem. This demands urgent the need to develop new anti-tuberculosis and antiretrovirals to treat TB and HIV. The lack of diversity in drugs designed using traditional approaches is a major disadvantage and limits the treatment options. Therefore, new technologies and approaches are required to solve the current issues and enhance the production of drugs. Interestingly, fragment-based drug discovery (FBDD) has gained an advantage over high-throughput screenings as FBDD has enabled rapid and efficient progress to develop potent small molecule compounds that specifically bind to the target. Several potent inhibitor compounds of various targets have been developed using FBDD approach and some of them are under progression to clinical trials. In this review, we emphasize some of the important targets of mycobacteria and HIV. We also discussed about the target-based druggable molecules that are identified using the FBDD approach, use of these druggable molecules to identify novel binding sites on the target and assays used to evaluate inhibitory activities of these identified druggable molecules on the biological activity of the targets