Toxoplasma gondii SAG2, SAG3 and GRA6 alleles and single nucleotide polymorphism in congenital infections with known parasite load and clinical outcome
DOI:
https://doi.org/10.1590/S1678-9946202365008%20Keywords:
Toxoplasmosis, Congenital toxoplasmosis, Genotyping, Single nucleotide polymorphism, Parasite load, Parasite burdenAbstract
Amniotic fluid DNA samples were genotyped by multilocus-nested-PCR-RFLP, but only three of 11 markers amplified 113 of 122 (92.6%) samples, resulting in 12 untyped and 101 partial non-archetypal genotypes. The 101 typed samples were subdivided into four groups: G1 with 73 samples (5’and 3’ SAG2 allele I + SAG3 allele III + GRA6 allele III), 53 had parasite load ≤ 102 parasites/mL (43 asymptomatic, 10 mild infections), 17 had load > 102 and ≤ 103 (one mild, 13 moderate and three severe), and three had load > 103 parasites/mL (three severe); G2 with 22 samples (5’and 3’ SAG2 allele I + SAG3 allele III), all parasite load levels ≤ 102 parasites/mL (18 asymptomatic and four mild); G3 with five samples (5’ and 3’ SAG2 allele I + SAG3 allele II), parasite load ≤ 102 parasites/mL (three asymptomatic and two mild); G4 with one sample (5’ and 3’ SAG2 allele II + SAG3 allele II + GRA6 allele I), a parasite load < 102 parasites/mL in an asymptomatic infant. After DNA sequencing, restriction sites confirmed SAG2, SAG3 and GRA6 alleles in 98.7%, 100% and 100% of the cases, respectively, while single nucleotide polymorphisms confirmed 90% of 5’-SAG2 allele I; 98.7% of 3’-SAG2 allele I; 98% of SAG-3 allele III, but only 40% of GRA6 allele III results. For the moment, partial non-archetypal genotypes of parasites did not show any relationship with either parasite load in amniotic fluid samples or clinical outcome of infants at the age of 12 months.
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Copyright (c) 2023 Lília Spaleta Targa, Emilly Henrique dos Santos, Lidia Yamamoto, Gabriel Acca Barreira, Karen Alessandra Rodrigues, Mussya Cisotto Rocha, Kelly Aparecida Kanunfre, Thelma Suely Okay
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Funding data
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Fundação de Amparo à Pesquisa do Estado de São Paulo
Grant numbers 2010/15022-1