Toxoplasma gondii SAG2, SAG3 and GRA6 alleles and single nucleotide polymorphism in congenital infections with known parasite load and clinical outcome

Author(s)

Lília Spaleta Targa ^[1] ; Emilly Henrique dos Santos ; Lidia Yamamoto ^[3] ; Gabriel Acca Barreira ; Karen Alessandra Rodrigues ; Mussya Cisotto Rocha ^[6] ; Kelly Aparecida Kanunfre ^[7] ; Thelma Suely Okay

Affiliation

^[1] Universidade de São Paulo. Faculdade de Medicina. Instituto de Medicina Tropical de São Paulo - Brasil

^[3] Universidade de São Paulo. Faculdade de Medicina. Instituto de Medicina Tropical de São Paulo - Brasil

^[6] Universidade de São Paulo. Faculdade de Medicina. Instituto de Medicina Tropical de São Paulo - Brasil

^[7] Universidade de São Paulo. Faculdade de Medicina. Instituto de Medicina Tropical de São Paulo - Brasil

• Document type: Journal article
• Source: Revista do Instituto de Medicina Tropical de São Paulo; v. 65, 2023-01-30.

Abstract

ABSTRACT 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. (AU)

• FAPESP's process: 10/15022-1 - Frequency of HLA-DQA1 and DQB1 alleles in fetuses with toxoplasmosis: association with the parasite genotype and the parasite load
• Grantee: Thelma Suely Okay
• Support Opportunities: Regular Research Grants