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In the search of therapeutic agents for emerging drug-resistant parasites, the synthesis of newer classes of 8-quinolinamines has emerged as a successful chemotherapeutic approach. We report synthesis of 8-quinolinamines bearing 5-alkoxy, 4-methyl, and 2-tert-butyl groups in the quinoline framework and their amino acid conjugates as broad-spectrum anti-infectives. 8-Quinolinamines exhibited potent in vitro antimalarial activity [IC50 = 20–4760 ng/mL (drug-sensitive Plasmodium falciparum D6 strain) and IC50 = 22–4760 ng/mL (drug-resistant P. falciparum W2 strain)]. The most promising analogues have cured all animals at 25 mg/kg/day against drug-sensitive Plasmodium berghei and at 50 mg/kg/day against multidrug-resistant Plasmodium yoelii nigeriensis infections in Swiss mice. The in vitro antileishmanial activities (IC50 = 0.84–5.0 μg/mL and IC90 = 1.95–7.0 μg/mL) comparable to standard drug pentamidine were exhibited by several of the synthesized 8-quinolinamines. At the same time, very promising antifungal activities (Candida albicans—IC50 = 4.93–19.38 μg/mL; Candida glabrata—IC50 = 3.96–19.22 μg/mL; Candida krusei—IC50 = 2.89–18.95 μg/mL; Cryptococcus neoformans—IC50 = 0.67–18.64 μg/mL; and Aspergillus fumigatus—IC50 = 6.0–19.32 μg/mL) and antibacterial activities (Staphylococcus aureus—IC50 = 1.33–18.9 μg/mL; methicillin-resistant S. aureus—IC50 = 1.38–15.34 μg/mL; and Mycobacterium intracellulare—IC50 = 3.12–20 μg/mL) were also observed. None of the 8-quinolinamines exhibited cytotoxicity and therefore are a promising structural class of compounds as antiparasitic and antimicrobials.

BACTEC 460 has now been phased out, so the search for an alternative is imperative. We have determined the activity of standard anti-tuberculosis drugs against intramacrophage Mycobacterium tuberculosis, in vitro, by using BACTEC 460 and MGIT 960 methods. The minimum inhibitory concentrations of isoniazid, rifampicin, ethambutol and streptomycin against intracellular M. tuberculosis H37Rv were found to be 0.2, 0.8, 8.0, and 5.0 μg/mL, respectively, by both methods. These results show a significant (p

Globally, vaccines have emerged as one of the most effective, safe, and cost-effective public health interventions, and are known to save 2–3 million lives, annually. However, despite various commendable efforts, a suitable human malaria vaccine is yet to see the light of the day. The lack of our complete understanding of the molecular mechanisms of pathogenesis and immune protection in malaria appears to be responsible for this state. Earlier, our laboratory has reported that Swiss mice vaccinated with Plasmodium yoelii nigeriensis-total parasite antigens soluble in culture medium and saponin, following a 100% lethal challenge, showed 60% protection. The monoclonal antibodies (MAbs) generated from the splenocytes of these vaccinated/protected mice, following characterization by in vitro merozoite invasion inhibition assay, ex vivo macrophage phagocytosis assay, and in vivo passive transfer of protection test, belonged to 2 distinct groups—a larger group of MAbs inhibited

Tuberculosis (TB) has overburdened humans for ages and continues to be a major health problem worldwide. Mycobacterium tuberculosis, a facultative intracellular pathogen, is the causative agent of human TB. M. tuberculosis has an enormous capacity to survive and multiply inside host macrophages (MΦs), which are one of the most hostile cell types of the host. MΦs play a central role(s) as an effecter cell in host defense against mycobacterial infections. Soon after the inhalation of droplet-nuclei containing M. tuberculosis by the host, MΦsare the first cells to interact with mycobacteria, leading to the onset of primary events which later ensue in the development of TB. MΦs, all by themselves, are not sufficient to provide protective immunity; they require interaction with other cells (e. g. T-cells) to mount an enhanced protective immune response against the pathogen. The cytokines such as interferon gamma and tumor necrosis factor alpha etc. Play a major role in the regulation of interactions among different cells of the immune system to augment immunity. In this review, we focus on various functional roles of cytokines which serve as a link between innate and adaptive immunity, and discuss their potential use as biomarker(s) or biosignatures for the diagnosis, to monitor the progression of disease, and to determine the success of the treatment of human TB.

Objective To produce comparative data on a group of Trichomonas vaginalis clonal strains with varied drug responses using identical methods and materials. Methods Five clonal strains of Trichomonas vaginalis were isolated from reference strain using agar plate technique. The variability of growth kinetic and susceptibility of clonal strain to metronidazole, tinidazole, satranidazole and nitazoxanide were observed in 96 well microtitre plate. Results Among these clonal strains there was a good correlation between rates of growth with the relative susceptibility of the strains to drugs in vitro . Regarding metronidazole, tinidazole and satranidazole susceptibility, different degrees of susceptibility were determined. However, no difference in nitazoxanide susceptibility was found between the clonal strain tested and a reference strain. Conclusions This is the first description of biological variability in clonal stock of Trichomonas vaginalis . Different degrees of drug susceptibility were determined among clonal strains tested. Further studies will be necessary to ascertain the importance of this variability in clinical infection.

Serum amyloid P-component (SAP), a pentraxin, is known to play an important role in innate immunity to microbial infections; however, nothing is known about it during tuberculosis (TB). Mice intratracheally infected with Mycobacterium tuberculosis Erdman, showed peak SAP levels (442+/-58.2 microg/ml) on day 21, which declined to background levels by day 60. Their serum interleukin-6 levels paralleled SAP levels, whereas, their serum transforming growth factor-beta levels were paradoxical. During the acute phase of infection, the SAP levels positively correlated with the lung mycobacterial load. Purified mouse SAP (1-50 microg/ml) treatment of M. tuberculosis-infected alveolar macrophages (AMs), in vitro, inhibited their intracellular mycobacterial growth; maximum inhibition (1.1 log10 CFU reduction) occurred at 10 microg/ml, and a 4-day treatment appeared optimal. Treatment of AMs with both rabbit anti-mouse SAP polyclonal antibody and mannose-derived simple sugars, separately, blocked the SAP-induced inhibition of mycobacterial growth. The mycobacterial growth inhibition appeared to be nitric oxide (NO)-dependent as NO synthase inhibitors, both aminoguanidine and N(G)-monomethyl-L-arginine, annulled it. Further, SAP treatment of infected AMs induced significant (P0.05) elaboration of nitrite (72.1+/-8.3 nM/ml), compared to the controls, and these AMs showed augmented expression of inducible NO synthase. This first study demonstrates that during murine TB the SAP levels were increased, and purified mouse SAP inhibited the intra-AM M. tuberculosis growth, in vitro, apparently via NO-dependent mechanism(s). SAP may thus contribute both to the pathogenesis and pulmonary innate immunity in TB.

Background Human tuberculosis (TB), a chronic inflammatory disease is caused by Mycobacterium tuberculosis, a facultative intramacrophage pathogen. The highly complex interactions between mycobacteria and macrophages (MΦs), characterized in part by the induction and elaboration of several cytokines including IL-1, IL-6, IL-10, IL-12 p40 and IL-12 p70 are not yet fully understood. The cytokines are known to have important bearing on the pathogenesis and host defense during TB. We thus studied different patterns of cytokines elaborated by mouse peritoneal macrophages (PMs) following their interaction with live and heat-killed, virulent and avirulent, and pathogenic and non-pathogenic mycobacteria, in vitro. Materials and methods Pathogenic M. tuberculosis H37Rv (virulent) and M. tuberculosis H37Ra (avirulent), and non-pathogenic M. smegmatis were grown in complete Middle Brook 7H9 broth. For some experiments, mycobacteria were heat-killed (80°C; 20 min). The supernatants of cultured PMs, having ingested mycobacteria for 6 h, 24 h, 4 days and 7 days, were harvested for the quantification of IL-1, IL-6, IL-10, IL-12 p40 and IL-12 p70 by using a multiplex suspension cytokine array system. Results The PMs infected with heat-killed mycobacteria, as compared to their respective live counterparts, invariably elaborated significantly (p

In continuing our search of potent antimalarials based on 8-aminoquinoline structural framework, three series of novel bis(8-aminoquinolines) using convenient one to four steps synthetic procedures were synthesized. The bisquinolines were evaluated for in vitro antimalarial (Plasmodium falciparum), antileishmanial (Leishmania donovani), antimicrobial (a panel of pathogenic bacteria and fungi), cytotoxicity, β-hematin inhibitory and methemoglobin (MetHb) formation activities. Several compounds exhibited superior antimalarial activities compared to parent drug primaquine. Selected compounds (44, 61 and 79) when tested for in vivo blood-schizontocidal antimalarial activity (Plasmodium berghei) displayed potent blood-schizontocial activities. The bisquinolines showed negligible MetHb formation (0.2–1.2%) underlining their potential in the treatment of glucose-6-phosphate dehydrogenase deficient patients. The bisquinoline analogues (36, 73 and 79) also exhibited promising in vitro antileishmanial activity, and antimicrobial activities (43, 44 and 76) against a panel of pathogenic bacteria and fungi. The results of this study provide evidence that bis(8-aminoquinolines), like their bis(4-aminoquinolines) and artemisinin dimers counterparts, are a promising class of antimalarial agents.

New primaquine conjugates 5-7 with glucosamine and two polymers of polyaspartamide type, poly/a,b-(N-2-hydroxyethyl-DL-aspartamide)/ (PHEA) and poly/a,b-(N-3-hydroxypropyl-DL-aspartamide)/ (PHPA), were synthesized, characterized and screened for their antimalarial activity. The conjugates differed in type of covalent bounding, length of spacer between the polymeric carrier and drug, molecular mass and drug-loading. Blood-schizontocidal activity of the prepared conjugates was tested against Plasmodium berghei infection in Swiss mice. The polymeric conjugates showed better antimalarial activity than glucosamine conjugate. U radu je opisana sinteza, karakterizacija i ispitivanje antimalarijskog djelovanja novih konjugata primakina 5-7 s glukozaminom i dva polimera poliaspartamidnog tipa, poli/a,b-(N-2-hidroksietil-DL-aspartamidom)/ (PHEA) i poli/a,b-(N-3-hidroksipropil-DL-aspartamidom)/ (PHPA). Konjugati su se razlikovali u vrsti kovalentne veze, duljini razmaknice između polimernog nosača i ljekovite tvari, molekulskoj masi i količini vezanog lijeka. Šizontocidno djelovanje pripravljenih konjugata ispitano je na miševima inficiranim Plasmodium berghei. Polimerni konjugati pokazali su jače antimalarijsko djelovanje nego konjugat s glukozaminom

New primaquine conjugates 5-7 with glucosamine and two polymers of polyaspartamide type, poly/a,b-(N-2-hydroxyethyl-DL-aspartamide)/ (PHEA) and poly/a,b-(N-3-hydroxypropyl-DL-aspartamide)/ (PHPA), were synthesized, characterized and screened for their antimalarial activity. The conjugates differed in type of covalent bounding, length of spacer between the polymeric carrier and drug, molecular mass and drug-loading. Blood-schizontocidal activity of the prepared conjugates was tested against Plasmodium berghei infection in Swiss mice. The polymeric conjugates showed better antimalarial activity than glucosamine conjugate., U radu je opisana sinteza, karakterizacija i ispitivanje antimalarijskog djelovanja novih konjugata primakina 5-7 s glukozaminom i dva polimera poliaspartamidnog tipa, poli/a,b-(N-2-hidroksietil-DL-aspartamidom)/ (PHEA) i poli/a,b-(N-3-hidroksipropil-DL-aspartamidom)/ (PHPA). Konjugati su se razlikovali u vrsti kovalentne veze, duljini razmaknice između polimernog nosača i ljekovite tvari, molekulskoj masi i količini vezanog lijeka. Šizontocidno djelovanje pripravljenih konjugata ispitano je na miševima inficiranim Plasmodium berghei. Polimerni konjugati pokazali su jače antimalarijsko djelovanje nego konjugat s glukozaminom

The immunomodulatory effects of opioids are known in various infections. However, little is known about the effects of opioids in tuberculosis (TB). In the present study, we report the effects of morphine in Mycobacterium smegmatis infection in mice and macrophages. Morphine exerted a dose-dependent suppression of infection in vivo: 50 and 100 mg/kg morphine exerted significant (P

The neuroimmunomodulatory effects of opiates during microbial infections are now well known; however, not much is known during leishmaniasis. Here, we report the effects of morphine on purified approximately 12-kDa component of Leishmania donovani amastigote antigen (LDAA-12)-induced colony-stimulating factor (CSF) production by mouse peritoneal macrophages (PMs) in vitro. Low concentrations (1 x 10(-9) and 1 x 10(-11) M) of morphine significantly (P0.05) augmented the production of CSFs, whereas high concentrations (1 x 10(-3) and 1 x 10(-5) M) inhibited CSF production. Morphine exerted a similar concentration-dependent biphasic effect on the LDAA-12-induced elaboration of granulocyte (G)-macrophage (M)-CSF (GM-CSF) and M-CSF by PMs in their conditioned medium, as quantified by using enzyme-linked immunosorbent assay. Furthermore, selective agonists of mu-(DAGO) and delta-(DPDPE) opioid receptors also, respectively, augmented and inhibited the production of CSFs. Pretreatment of PMs with naloxone (1 x 10(-5) M) significantly (P0.05) blocked the augmenting effect of morphine. In contrast, at 1 x 10(-5) M, naloxone lacked any effect on the inhibitory effect of morphine; however, its 100-fold higher concentration partially blocked it. This study, apparently for the first time, demonstrates that morphine, via surface opioid receptors, biphasically modulates the LDAA-12-induced CSF production by PMs, in vitro. These results thus show the implications of opiate abuse on the outcome of therapeutic interventions in areas where both visceral leishmaniasis and drug abuse are rampant.

An estimated 300-500 million new infections and 1.5-2.7 million deaths attributed to malaria occur annually in the developing world, and every year tens of millions of travelers from countries where malaria is not transmitted visit countries with malaria. Because the parasites that cause malaria have developed resistance to many antimalarial drugs, new methods for prevention are required. Intraperitoneal injection into mice of one dose of 150 ng (approximately 7.5 micrograms per kg body weight) recombinant mouse interleukin-12 (rmIL-12) 2 days before challenge with Plasmodium yoelii sporozoites protects 100% of mice against malaria. We report that one subcutaneous injection of 10 micrograms/kg recombinant human IL-12 (rhIL-12) 2 days before challenge with P. cynomolgi sporozoites protected seven of seven rhesus monkeys. Protection was associated with marked increases in plasma levels of interferon-gamma (IFN-gamma), and relative increases of lymphoid cell messenger RNA coding for IFN-gamma and several other cytokines. We speculate that rIL-12 protects monkeys through IFN-gamma-dependent elimination of P. cynomolgi-infected hepatocytes. This first report of rIL-12-induced protection of primates against an infectious agent supports assessment of rhIL-12 for immunoprophylaxis of human malaria.