To assess the role of cAMP on the growth and proliferation of Toxoplasma in HL-60 cells we tested the effect of exogenous cAMP and cAMP analogues to the co-culture system of Toxoplasma and HL-60 cells. cAMP, dbcAMP, and br-cAMP stimulated the growth of Toxoplasma at a specific concentration, i.e., 10(0) mM, 10(0) mM, and 10(-1) mM, respectively. There were differences in growth induction kinetics and in the rate of promotion. These results were further verified by treating the co-culture with adenylate cyclase activator, pNHppG, cAMP phosphodiesterase activators, imidazole and A23187, and cAMP phosphodiesterase inhibitors, IBMX, compound 48/80, and theophylline, separately. When the cytosolic cAMP levels increased by the reagents mentioned above, Toxoplasma in the cytoplasm of HL-60 cells stimulated to proliferate more rapidly with concentration-dependent modes compared to the control, and vice versa. It is suggested that some mechanisms are activated by the high levels of cAMP in the cytoplasm, which result in the stimulation of Toxoplasma proliferation.
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Cyclic-nucleotide signalling in protozoa Matthew K. Gould, Harry P. de Koning FEMS Microbiology Reviews.2011; 35(3): 515. CrossRef
Schizophrenia Susceptibility Genes Directly Implicated in the Life Cycles of Pathogens: Cytomegalovirus, Influenza, Herpes simplex, Rubella, and Toxoplasma gondii C.J. Carter Schizophrenia Bulletin.2009; 35(6): 1163. CrossRef
Culture of tissue-cyst forming strain of Toxoplasma gondii and the effect of cyclic AMP and pyrimidine salvage inhibitors W Y Choi, S K Park, H W Nam, D J Kim The Korean Journal of Parasitology.1994; 32(1): 19. CrossRef
Metabolic inhibitors which act in the process of pyrimidine salvage influenced on the uracil incorporation into nucleic acids of Toxoplasma. Inhibitors of dihydrofolate reductase, pyrimethamine and methotrexate, and inhibitors of thymidylate synthase, fluoro-uridine, fluoro-dUMP and fluoro-uracil, diminished isotopic uracil uptake in dose-dependent manners. Azauridine which suppresses de novo pyrimidine biosynthesis did not affect the salvage even in a relatively high dose. These results suggested that the activation of uracil salvage should be closely related with the function of TMP biosynthetic enzymes. The pattern of thymidine uptake had no differences between control HL-60 cells and Toxoplasma infected cells, which did not reflect the specific proliferation of Toxoplasma. It can be exploited to characterize the effects of various compounds related with the proliferation of Toxoplasma, especially its DNA synthesis.
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Culture of tissue-cyst forming strain of Toxoplasma gondii and the effect of cyclic AMP and pyrimidine salvage inhibitors W Y Choi, S K Park, H W Nam, D J Kim The Korean Journal of Parasitology.1994; 32(1): 19. CrossRef
This study was aimed to observe the direct and lymphokine-activated cell mediated cytotoxic effects against Trichomonas vaginalis by mouse peritoneal macrophages.
Cytotoxicity was measured as release of 3H-thymidine from prelabeled protozoa, and tested in U-bottom microtiter plates. A 0.1 ml suspension of labeled protozoa (2 x 10(5)/ml) was placed in each well, followed by 0.1 ml of a suspension containing increasing numbers of peritoneal cells. After a 24 hr incubation at 37 degrees C, 0.1 ml of the supernatant was collected and counted in liquid scintillation counter. Mouse peritoneal macrophages had appreciable level of spontaneous cytotoxicity against T.
vaginalis at the effector to target cell ratios from 5:1 to 50:1. Treatment of macrophages with lymphokine, produced by PHA-stimulated spleen cells, increased the cytotoxicity in comparison with resident macrophages against T. vaginalis.
The degree of macrophage activation for the killing was not dependent upon the lymphokine concentration. Peritoneal cells adherent to plastic displayed significant levels of cytotoxicity against T. vaginalis. This study indicates that mouse peritoneal macrophages are spontaneously cytotoxic for T. vaginalis and lymphokine increases the cytotoxicity by activating macrophages to kill T. vaginalis.
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Trichomoniasis Jae-Sook Ryu Hanyang Medical Reviews.2010; 30(3): 213. CrossRef
Proinflammatory Cytokine and Nitric Oxide Production by Human Macrophages Stimulated with Trichomonas vaginalis Ik-Hwan Han, Sung Young Goo, Soon-Jung Park, Se-Jin Hwang, Yong-Seok Kim, Michael Sungwoo Yang, Myoung-Hee Ahn, Jae-Sook Ryu The Korean Journal of Parasitology.2009; 47(3): 205. CrossRef
Trichomonas vaginalis and trichomoniasis in the Republic of Korea Jae-Sook Ryu, Duk-Young Min The Korean Journal of Parasitology.2006; 44(2): 101. CrossRef
The role of nitric oxide as an effector of macrophage-mediated cytotoxicity against Trichomonas vaginalis G C Park, J S Ryu, D Y Min The Korean Journal of Parasitology.1997; 35(3): 189. CrossRef
Cytotoxicity of lymphokine activated peritoneal macrophages against Trichomonas vaginalis K Yoon, J S Ryu, D Y Min The Korean Journal of Parasitology.1991; 29(4): 381. CrossRef
Paragonimus westermani is a tissue migrating parasite in the early stage until arriving at lung, and most of the parasites spend their life spans there. Considerable immune responses including activation of macrophages are taken place during the residence of parasites in the host.
However, concerning the immunologic defense mechanisms of the host against this parasite, only a few document is available so far. In this study, the cytotoxic effect of peritoneal macrophages under the presence of antibody and/or complement against metacercariae of P. westermani was investigated in vitro. Metacercariae were collected from the crayfish, Cambaroides similis and hatched out in Tyrode solution (pH 7.4). Plastic adherent cells from normal or infected rat (Wistar) peritoneal exudates were used as experimental macrophages. Polyclonal antibodies were obtained from infected rats and a cat. Cat IgG was fractioned with ion exchange chromatography. Fresh rabbit complement was used according to experimental scheme.
Various combinations of peritoneal macrophages, normal or infected rat serum, complement and cat IgG were incubated at 36 degrees C in 5% CO2 incubator for 6, 14, 24 and 48 hours.
The results obtained were as follows: 1. P. westermani infection activated peritoneal macrophages non-specifically and this activation induced increases of cell adherence and cytotoxicity on metacercariae. 2. In the presence of infected rat serum the antibody-dependent cell-mediated cytotoxicity of peritoneal macrophages on metacercariae was significantly increased and showed a peak at 6-hour incubation. But the cytotoxic effect was markedly reduced after inactivation of complement and heat-labile IgE antibody by the heating of infected serum at 56 degrees C for 30 minutes. 3. The highest cytotoxic effect (100%) of concomitant incubation with IgG and complement showed 24 hours after incubation, although cell adherence was relatively low at 6-hour incubation and 0% at 24-hour incubation. 4. Coordinative functions of complement with serum and IgG were effective in cell adherence and in cytotoxicity, but it is not clear the independent role of complement on the macrophage-mediated cytotoxicity in this study. With these results it is assumed that P. westermani infection can induce the non-specific activation of peritoneal macrophages, and serum antibodies including IgE antibody might enhance the cytotoxicity by macrophages.
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Effects of anti-IgE mAb on serum IgE, FcεRII/CD23 expression on splenic B cells and worm burden in mice infected with Paragonimus westermani M H Shin, H K Min The Korean Journal of Parasitology.1997; 35(1): 47. CrossRef
Changes of IgE production, splenic helper and suppressor T lymphocytes in mice infected with Paragonimus westermani D Y Min, J S Ryu, M H Shin The Korean Journal of Parasitology.1993; 31(3): 231. CrossRef
Blastogenesis of splenic lymphocytes to specific antigens and PHA in Paragonimus westermani infected mice D Y Min, M H Shin, R Choi The Korean Journal of Parasitology.1992; 30(1): 43. CrossRef
Antibody-dependent rat macrophage-mediated damage to the excysted metacercariae of Paragonimus westermani in vitro P R Chung, J K Chang, C T Soh The Korean Journal of Parasitology.1991; 29(1): 43. CrossRef
Surgically collected cystic fluid of Taenia solium metacestodes from patients of intracranial cystic lesion were compared in their protein composition with those from naturally infected pigs in Cheju Do, Korea and Ecuador. In non-denaturing discontinuous-polyacrylamide gel electrophoresis (disc-PAGE), no discernible differences were recognized in banding patterns between the cystic fluids from Cheju Do and Ecuador, and between the cystic fluids from pigs and human lesions except wider bands that corresponded to human albumin and gamma-globulin (in 4 of 9 patients). In reducing SDS-PAGE, bands in the cystic fluid from Ecuador showed the same banding pattern with that from Cheju Do but two bands of 21 and 17 kDa were stained darker.
Cystic fluids from patients revealed the same protein compositions of the major protein bands of 94, 64, 15, 10 and 7 kDa as in the cystic fluid of pig origin, but human albumin (66 kDa), heavy and light chains of gamma globulin (55 and 22.5 kDa) were contaminated in 4 of 9 cystic fluids.
Human CSF proteins seem to have been contaminated during cystic fluid collection. In any cystic fluid from patients, the major protein component was 150 kDa which was subdivided into 15, 10 and 7 kDa in reducing SDS-PAGE.
Status of intestinal protozoan and helminthic infections was surveyed in mestizo population living in rural parish of Palmar and its nearby recintos(villages). Three of the surveyed villages were at the Pacific coast and 5 villages were in inner pasture land, located about 100 km west of Guayaquil, the second largest city in Ecuador. One stool sample was examined by one cellophane thick smear for helminth ova and one direct smear stained with Lugol's iodine solution for protozoan cysts. Of 325 persons examined, 66.1% were positive for any ova or cyst. The positive rates were: 18.1% for Ascaris lumbricoides, 19.4% for Trichuris trichiura, 0.6% for hookworm, 3.7% for Hymenolepsis nana, 1.8% for Taenia sp., 19.4% for Entamoeba histolytica, 28.6% for Entamoeba coli, 5.5% for Endolimax nana, 1.5% for Iodamoeba buetschlii, 11.1% for Giardia lamblia and 0.6% for Chilomastix mesnili. Poor supply of potable water was considered the main cause of high prevalence of intestinal protozoan infections.
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