1. ¹Grupo de Inmunobiología y Biología Celular, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá, Colombia
2. ²Grupo de Ciencias Básicas Médicas, Universidad de los Andes, Bogotá, Colombia
3. ³Laboratorio de Parasitología Molecular, Departamento de Microbiología, Pontificia Universidad Javeriana, Bogotá, Colombia
4. ⁴Departamento de Biología Molecular, Instituto de Parasitología y Biomedicina López Neyra, CSIC, Granada, Spain
5. ⁵Fundación Clínica Abood Shaio, Bogotá, Colombia

Correspondence: Dr C Puerta, Laboratorio de Parasitología Molecular, Departamento de Microbiología, Facultad de Ciencias, Pontificia Universidad Javeriana, Carrera 7a No 43-82, Edificio 52, Oficina 608, Bogotá, Distrito capital 1, Colombia. E-mail: cpuerta@javeriana.edu.co

Received 10 January 2008; Revised 18 September 2008; Accepted 21 September 2008; Published online 28 October 2008.

Abstract

Trypanosoma cruzi kinetoplastid membrane protein-11 (KMP-11) is able to induce protective immunity in mice. In humans, T-cell immunity during Chagas disease has been documented using parasite antigens allowing the identification of specific CD8⁺ T cells. However, little is known about the CD4⁺ T-cell response during the evolution of the disease. In this paper, the induction of a natural CD4⁺ T-cell response against the KMP-11 protein in T. cruzi infected humans was studied to assess whether this parasite-derived protein could be processed, presented and detected as a major histocompatibility complex class II restricted epitope. The results show that helper T cells from 5 out of 13 chagasic patients specifically produced interferon- after exposure to the KMP-11 antigen, whereas healthy donors and non-chagasic cardiopathic patients did not respond. This is the first description of T. cruzi KMP-11 protein recognition by CD4⁺ T cells in chronic chagasic patients.