T-cell receptor Vβ repertoire of CD8+ T-lymphocyte subpopulations in cutaneous leishmaniasis patients from the state of Rio de Janeiro, Brazil

Raquel Ferraz, Clarissa Ferreira Cunha, Maria Inês Pimentel, Marcelo Rosandiski Lyra, Armando Oliveira Schubach, Sérgio Coutinho Furtado de Mendonça, Alda Maria Da-Cruz, Alvaro Luiz Bertho

In human cutaneous leishmaniasis (CL), the immune response is mainly mediated by T-cells. The role of CD8+ T-lymphocytes, which are related to healing or deleterious functions, in affecting clinical outcome is controversial. The aim of this study was to evaluate T-cell receptor diversity in late-differentiated effector (LDE) and memory CD8+ T-cell subsets in order to create a profile of specific clones engaged in deleterious or protective CL immune responses. Healthy subjects, patients with active disease (PAD) and clinically cured patients were enrolled in the study. Total CD8+ T-lymphocytes showed a disturbance in the expression of the Vβ2, Vβ9, Vβ13.2, Vβ18 and Vβ23 families. The analyses of CD8+ T-lymphocyte subsets showed high frequencies of LDE CD8+ T-lymphocytes expressing Vβ12 and Vβ22 in PAD, as well as effector-memory CD8+ T-cells expressing Vβ22. We also observed low frequencies of effector and central-memory CD8+ T-cells expressing Vβ2 in PAD, which correlated with a greater lesion size. Particular Vβ expansions point to CD8+ T-cell clones that are selected during CL immune responses, suggesting that CD8+ T-lymphocytes expressing Vβ12 or Vβ22 are involved in a LDE response and that Vβ2 contractions in memory CD8+ T-cells are associated with larger lesions.