The expansion of CD8 lymphocytes using T cell receptor variable gene products during HIV infection

Abstract

Fresh peripheral blood was obtained from HIV-infected subjects and from age-matched healthy controls. Single-, two- and three-colour flow cytometry was performed using FITC-labelled MoAbs directed against the following TCR Vβ subfamilies: V2, V3, V5a, V5b, V5c, V6, V8, V12, V13.3, V17, V19, alone or in combination with PE-labelled CD4, CD8, HLA-DR, CD28, CD38 and with Peridinin-chlorophyll A protein (PerCP)-conjugated CD8. The percentages of each Vβ subfamily did not differ in HIV+ patients compared with healthy controls. However, we were able to find in four patients (one CDC group II, one group III and two group IV) an expansion of a TCR Vβ subfamily (V3 in two, V5a and V19 in one patient). These cells were mainly CD8+. Three-colour flow cytometry allowed us to define that the expanded Vβ+, CD8+ T lymphocytes were characterized by the low/intermediate expression of activation markers (HLA-DR, CD28, CD38). In some HIV+ patients there is an expansion of T cells expressing a TCR Vβ subfamily; the nature of this expansion may be related to factors that are still unknown, such as the genetic background of each individual and the antigenic specificity of T cells. These populations may be relevant in the host response to the virus and in disease progression.