Detection of Toxoplasma antigens and antibodies in mice infected with different strains of Toxoplasma gondii

Ketolides are a new class of macrolide antibiotics that have been shown to be active against a variety of bacteria including macrolide-resistant bacteria and mycobacteria. We examined two ketolides, HMR 3647 and HMR 3004, for their in vitro and in vivo activities against the protozoan parasite Toxoplasma gondii. In vitro, both ketolides at concentrations as low as 0.05 microg/ml markedly inhibited replication of tachyzoites of the RH strain within human foreskin fibroblasts. HMR 3004 demonstrated some toxicity for host cells after they were exposed to 5 microg of the drug per ml for 72 h. In contrast, HMR 3647 did not show any significant toxicity even at concentrations as high as 25 microg/ml. In vivo, both ketolides provided remarkable protection against death in mice lethally infected intraperitoneally with tachyzoites of the RH strain or orally with tissue cysts of the C56 strain of T. gondii. A dosage of 100 mg of HMR 3647 per kg of body weight per day administered for 10 days protected 50% of mice infected with tachyzoites. The same dosage of HMR 3004 protected 100% of the mice. In mice infected with cysts, a dosage of 30 mg of HMR 3647 per kg per day protected 100% of the mice, whereas a dosage of 40 mg of HMR 3004 per kg per day protected 75% of the mice. These results demonstrate that HMR 3647 and HMR 3004 possess excellent activities against two different strains of T. gondii and may be useful for the treatment of toxoplasmosis in humans.

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Chronic Infection with Toxoplasma gondii Does Not Prevent Acute Disease or Colonization of the Brain with Tissue Cysts Following Reinfection with Different Strains of the Parasite

Journal of Parasitology ◽

10.2307/3284421 ◽

1997 ◽

Vol 83 (3) ◽

pp. 521 ◽

Cited By ~ 39

Author(s):

Fausto Araujo ◽

Teri Slifer ◽

Steven Kim

Keyword(s):

Toxoplasma Gondii ◽

Chronic Infection ◽

Acute Disease ◽

Different Strains ◽

The Brain

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Killing of Different Strains of Toxoplasma gondii Tissue Cysts by Irradiation under Defined Conditions

Journal of Parasitology ◽

10.2307/3283255 ◽

1994 ◽

Vol 80 (5) ◽

pp. 764 ◽

Cited By ~ 45

Author(s):

J. P. Dubey ◽

D. W. Thayer

Keyword(s):

Toxoplasma Gondii ◽

Different Strains

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Clinical, parasitological, and serological characteristics of toxoplasmosis in felines (Felis catus) infected with isolates i and III of Toxoplasma gondii

Semina Ciências Agrárias ◽

10.5433/1679-0359.2019v40n6supl3p3511 ◽

2019 ◽

Vol 40 (6Supl3) ◽

pp. 3511

Author(s):

Weslen Fabricio Pires Teixeira ◽

Dielson da Silva Vieira ◽

Welber Daniel Zanetti Lopes ◽

Gustavo Felippelli ◽

Regina Maura Bueno Franco ◽

...

Keyword(s):

Toxoplasma Gondii ◽

Clinical Signs ◽

Nasal Secretion ◽

Felis Catus ◽

Type I ◽

Parasitic Disease ◽

Subclinical Infection ◽

Clinical Symptomatology ◽

Lack Of Information ◽

Different Strains

Toxoplasmosis is a parasitic disease caused by the protozoan Toxoplasma gondii, characterized by a clinical or subclinical infection attributed mainly to the isolate of the parasite responsible for the infection. Although domestic felines are considered the only urban hosts of this parasite and, consequently, the animals responsible for perpetuating T. gondii cycle in this environment, there is still a lack of information regarding the potential of different strains/isolates of this parasite and appearance of clinical signs during infection in domestic felines. In this context, the objective of the present study was to evaluate the clinical, parasitological, and serological characteristics of toxoplasmosis in felines infected with T. gondii isolates type I (RH strain) and III (P strain). Twelve healthy and serologically negative felines were selected for T. gondii (IgG titer < 16). These animals were divided into three experimental groups, GI: (P1, P2, P3, and P4) inoculated with 600 cysts of T. gondii (P strain), GII: (RH1, RH2, RH3, and RH4) inoculated with 2 × 105 tachyzoites (RH strain), and GIII: (C1, C2, C3, and C4) uninoculated. From the seventh day before (day ?7) to the 70th day after inoculation (DAI), the animals were observed daily to verify the occurrence of alterations in the digestive, nervous, locomotor, cardiorespiratory, and urinary systems, as well as skin and appendages. The clinical signs most observed in felines inoculated with T. gondii were apathy, hyporexia, shivering, nasal secretion, ocular secretion, and diarrhea. The results obtained in this study allow inferring that T. gondii isolate type I (RH strain) was more pathogenic to feline species than isolate type III (P strain), although both showed clinical symptomatology in all infected animals.

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Detection and Characterization of Circulating Antigens in Acute Experimental Infections of Mice with Four Different Strains of Toxoplasma gondii

Zentralblatt für Bakteriologie ◽

10.1016/s0934-8840(11)80054-x ◽

1990 ◽

Vol 272 (4) ◽

pp. 526-534 ◽

Cited By ~ 4

Author(s):

Andreas Hassl ◽

Horst Aspöck

Keyword(s):

Toxoplasma Gondii ◽

Experimental Infections ◽

Circulating Antigens ◽

Different Strains

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Effects of iNOS inhibitor on IFN-γ production and apoptosis of splenocytes in genetically different strains of mice infected with Toxoplasma gondii

The Korean Journal of Parasitology ◽

10.3347/kjp.2004.42.4.175 ◽

2004 ◽

Vol 42 (4) ◽

pp. 175 ◽

Cited By ~ 9

Author(s):

Ki-Man Kang ◽

Gye-Sung Lee ◽

Jae-Ho Lee ◽

In-Wook Choi ◽

Dae-Whan Shin ◽

...

Keyword(s):

Toxoplasma Gondii ◽

Inos Inhibitor ◽

Ifn Γ ◽

Different Strains

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Oral oocyst-induced mouse model of toxoplasmosis: effect of infection with Toxoplasma gondii strains of different genotypes, dose, and mouse strains (transgenic, out-bred, in-bred) on pathogenesis and mortality

Parasitology ◽

10.1017/s0031182011001673 ◽

2011 ◽

Vol 139 (1) ◽

pp. 1-13 ◽

Cited By ~ 62

Author(s):

J. P. DUBEY ◽

L. R. FERREIRA ◽

J. MARTINS ◽

RIMA McLEOD

Keyword(s):

Toxoplasma Gondii ◽

Protective Efficacy ◽

Human Leukocyte ◽

Mouse Strains ◽

Type I ◽

Knock Out ◽

Leukocyte Antigen ◽

Immune Parameters ◽

Acute Toxoplasmosis ◽

Different Strains

SUMMARYHumans and other hosts acquire Toxoplasma gondii infection by ingesting tissue cysts in undercooked meat, or by food or drink contaminated with oocysts. Currently, there is no vaccine to prevent clinical disease due this parasite in humans, although, various T. gondii vaccine candidates are being developed. Mice are generally used to test the protective efficacy of vaccines because they are susceptible, reagents are available to measure immune parameters in mice, and they are easily managed in the laboratory. In the present study, pathogenesis of toxoplasmosis was studied in mice of different strains, including Human Leukocyte Antigen (HLA) transgenic mice infected with different doses of T. gondii strains of different genotypes derived from several countries. Based on many experiments, the decreasing order of infectivity and pathogenicity of oocysts was: C57BL/6 background interferon gamma gene knock out (KO), HLA-A*1101, HLA-A*0201, HLA-B*0702, Swiss Webster, C57/black, and BALB/c. Mice fed as few as 1 oocyst of Type I and several atypical strains died of acute toxoplasmosis within 21 days p.i. Some Type II, and III strains were less virulent. The model developed herein should prove to be extremely useful for testing vaccines because it is possible to accurately quantitate a challenge inoculum, test the response to different strains of T. gondii using the same preparations of oocysts which are stable for up to a year, and to have highly reproducible responses to the infection.

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