Tracking acute phase protein response during acute and chronic Toxoplasma gondii infection

Abstract

Toxoplasmosis is a disease caused by the protozoan Toxoplasma gondii, which occurs worldwide in mammals and birds. Brain is the primary target organ because Toxoplasma gondii is a ubiquitous intracellular parasite that causes most frequently life-threatening encephalitis in immunocompromised patients. Relation of tissue cysts number, histopathology score and acute phase proteins were investigated. In this study, 36 mice are infected with Me49 strain of Toxoplasma gondii. The control group has 6 healthy mice. After inoculation of Toxoplasma gondii, at 10., 15., 20., 30., 45., 60. days, 6 each mice euthanized after collection of blood samples. Hemopexin, haptoglobulin, macroglobulin, serum amyloid A and clusterin levels are determined by ELISA. Then, brain tissues were investigated histopathologically and lesions were scored. The average cyst numbers were determined by counting three samples (25 μl each) of each brain homogenate under light microscopy. Inflammatory reaction was observed on day 10 days after inoculation (d.a.i.) The lesions were characterized by perivascular mononuclear cell infiltration, focal mononuclear cell infiltration in the meninges, and glial proliferation. Tissue cysts were observed in all Toxoplasma gondii-infected groups. The highest lesion score was observed at 60 d.a.i. And the most tissue cyst number were on day 30. d.a.i. Serum levels of hemopexin, haptoglobulin, macroglobulin, serum amyloid A and clusterin were significantly higher than the control group on day 10-20., 10., 10-30., 10.,10-45 d.a.i., respectively. High level of acute phase proteins in mice on certain days infected with Toxoplasma gondii was exhibited a relationship between brain lesions and tissue cysts.

Keywords: Acute; Acute phase proteins; Chronic; Encephalitis; Toxoplasma gondii.

Fig. 1

a Toxoplasma gondii tissue cyst. Scale bar = 20 μm. b Marked perivascular cuffing of mononuclear cells (asterisk), focal gliosis (arrow head), Toxoplasma gondii tissue cyst (arrows). Hematoxylin and eosin staining. Scale bar = 200 μm. c. Higher magnification of focal gliosis. Scale bar = 50 μm. d. Anti-Toxoplasma gondii immunopositivity in foci of gliosis (arrow), also tissue cyst was stained (arrow heads). IHC. DAB chromogen with hematoxylin counterstain. Scale bar = 100 μm. e. Anti-Toxoplasma gondii immunopositivity in foci of gliosis (arrows) and perivascular cell infiltration (arrow head). IHC. DAB chromogen with hematoxylin counterstain. Scale bar = 100 μm. f. Brain section from healthy animal. Hematoxylin and eosin staining. Scale bar = 200 μm. g. The number of tissue cysts number per brain (per 25 μl per brain homogenate) in 10, 15, 20, 30, 45, 60 day after infection. Values in a column suffixed with different letters are significantly different from each other. The values represent means ± S.E.M P<0.05 h. Comparison of total numbers of inflammatory foci. Values in a column suffixed with different letters are significantly different from each other. The values represent means ± S.E.M P<0.05

Fig. 2

a Serum Amyloid A levels b Serum Haptoglobin levels c Serum Hemopexin levels d Serum α-Macroglobulin levels e Serum Clusterin levels. Statistical analysis was performed according to One-way analysis of variance and Tukey’s Multiple Comparison Test. Values in a column suffixed with different letters are significantly different from each other. The values represent means ± S.E.M. P<0.05