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Journal of Tropical Medicine
Volume 2012, Article ID 132583, 8 pages
http://dx.doi.org/10.1155/2012/132583
Clinical Study

A Single Dose of Oral BCG Moreau Fails to Boost Systemic IFN- 𝛾 Responses to Tuberculin in Children in the Rural Tropics: Evidence for a Barrier to Mucosal Immunization

1Centro de Investigaciónes FEPIS, Esmeraldas Quinindé, Ecuador
2Vaccine Centre, St George’s University of London, Cranmer Terrace, London SW17 ORE, UK
3Laboratorio de Biologia Molecular, Hospital de Los Valles, Via Interoceanica Km 12.5, Cumbayá, Quito, Ecuador
4Fundacao Ataulpho de Paiva, Avenida Pedro II, 226 Sao Cristovao, 20941-000 Rio de Janeiro, RJ, Brazil
5Department of Immunology, Fundacao Instituto Oswaldo Cruz, 4365 Avenida Brasil, 21040-360 Rio de Janeiro, RJ, Brazil
6Molecular and Biochemical Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
7Colegio de Ciencias de la Salud, Universidad San Francisco de Quito, Via Interoceanica S/N y Avenida Pampite, Quito, Ecuador

Received 16 May 2011; Revised 9 September 2011; Accepted 28 September 2011

Academic Editor: Ann-Mari Svennerholm

Copyright © 2012 Maritza Vaca et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Immune responses to oral vaccines are impaired in populations living in conditions of poverty in developing countries, and there is evidence that concurrent geohelminth infections may contribute to this effect. We vaccinated 48 children living in rural communities in Ecuador with a single oral dose of 100 mg of BCG Moreau RDJ and measured the frequencies of tuberculin-stimulated peripheral blood mononuclear cells expressing IFN- 𝛾 before and after vaccination. Vaccinated children had active ascariasis ( 𝑛 = 2 0 ) or had been infected but received short- ( 𝑛 = 1 3 ) or long-term ( 𝑛 = 1 5 ) repeated treatments with albendazole prior to vaccination to treat ascariasis. All children had a BCG scar from neonatal vaccination. There was no evidence of a boosting of postvaccination IFN- 𝛾 responses in any of the 3 study groups. Our data provide support for the presence of a barrier to oral vaccination among children from the rural tropics that appeared to be independent of concurrent ascariasis.