Abstract
Purpose::
The P30 is the major antigenic protein of Toxoplasma gondii. Immune response in animal models has showed that recognition by antibodies preferentially occurs at the carboxy end peptides of the protein. Recognition pattern of peptides by human serum antibodies is unknown. We aimed to determine what peptides from the P30 protein were recognised by human infected with Toxoplasma
Methods::
We performed an immunoenzymatic assay with serum from patients with different clinical forms. We use 9 peptides from the amino and the carboxy end derived from the P30 protein of Toxoplasma gondii.
Results::
Initial assays with serum from congenital, ocular and chronic asymptomatic toxoplasmosis indicated that they only recognized the peptides from the carboxy end of the protein and that serum from patients with ocular toxoplasmosis gets a higher absorbance against the peptide Pep17 compared to the other serum with congenital or chronic asymptomatic infection. We then tested the peptide Pep17 in 32 patients with toxoplasmosis; 13 without ocular infection, 13 with inactive chorioretinal scars and 6 with active ocular infection. All serum recognised this peptide and there were not differences in the absorbencies levels between groups.
Conclusions::
As occurs in mouse the human serum antibodies are addressed against the carboxy terminal peptides of P30 major protein. We are currently working on to the cellular immune response against the same peptides in order to determine if there is dichotomy between humoral and cellular immune response during the ocular infection of human toxoplasmosis.
Keywords: toxoplasmosis • immunomodulation/immunoregulation • chorioretinitis