[68] ENUMERATION OF LATENTLY INFECTED CD4+ T-CELLS FROM HIV-1 INFECTED PATIENTS USING AN HIV-1 ELISPOT ASSAY

2nd International AIDS Society Conference on HIV Pathogenesis and Treatment

Paris, France - July 13 - 16, 2003

[TITLE:] ENUMERATION OF LATENTLY INFECTED CD4+ T-CELLS FROM HIV-1 INFECTED PATIENTS USING AN HIV-1 ELISPOT ASSAY

[AUTHOR(S):] V Baillat¹, JM Fondere², G Petit Jean², V Perez², J Reynes¹ and JP Vendrell^2,3
¹Laboratoire de Virologie, Hôpital Lapeyronie, Montpellier, France; ²Service des Maladies Infectieuses et Tropicales, Hôpital Guide Chauliac, Montpellier, France; and ³INSERM U 475 Immunopathologie des Maladies tumourales et Auto-immunes, Montpellier, France

IAS Conf HIV Pathog Treat 2003 Jul 13-16;2nd: Abstract No. 68
Antiviral Therapy 2003; 8(Suppl. 1):S201

[ABSTRACT:] Background: The presence of latently infected, resting CD4+ T cells carrying replication-competent HIV-1 is induced in naïve chronically infected individuals as well as in those who are receiving highly active antiretroviral therapy (HAART). These cells serve as a potential source of reactivation of viral replication and remain a major obstacle for the eradication of HIV-1.

Objectives: The enzyme-linked immunospot (ELISPOT) is adapted to detecting and enumerating HIV-1-antigen secreting cells at the single level. We applied the HIV- 1 ELISPOT assay to the enumeration of latently HIV-1-infected CD4+ T cells.

Study design: Latent infected CD4+ T cells were assessed in an in vitro model of HIV-1-infected resting CD4+ T cells as well as in 18 HAART-treated patients and in four untreated patients. Enriched CD4+ T cells were cultured with or without antibodies directed to CD3 and to CD28 T-cell receptors plus irradiated peripheral blood mononuclear cells from HIV-1–seronegative individuals. At term of culture, CD4+ T cells were tested using HIV-1 ELISPOT assay.

Results: CD4+ T cells secreting HIV-1 antigens after polyclonal activation were found in the experimental model to be 5579±4190 per million CD4+ T cells and as low as 15±6 spontaneously. In 22 patients, induced HIV-1 antigen-secreting cells were measured at 55± 108 per million CD4+ T cells. In contrast, spontaneous HIV-1- producing cells were as low as 1.6±3 per million CD4+ T cells in untreated subjects and in four treated patients.

Conclusions: As each immunospot represents one HIV-1-secreting cell, the HIV-1 ELISPOT assay is an eligible assay to enumerate HIV-1 latently infected CD4+ T lymphocytes from peripheral blood. This sensitive assay could become a useful tool for precisely evaluating latently infected CD4+ T cell frequencies.

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