Direct visualization of cytokine-producing recall antigen-specific CD4 memory T cells in healthy individuals and HIV patients
| Autor: | Robert Asaad, Bernhard O. Boehm, Magdalena Tary-Lehmann, Paul V. Lehmann, Richard Peter Trezza, Thomas Helms |
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| Rok vydání: | 2000 |
| Předmět: |
Adult
CD4-Positive T-Lymphocytes Male Time Factors Anti-HIV Agents medicine.medical_treatment Immunology Epitopes T-Lymphocyte Enzyme-Linked Immunosorbent Assay HIV Infections Biology Lymphocyte Activation Tuberculin Epitope Interferon-gamma Immune system Th2 Cells Antigen Memory cell T-Lymphocyte Subsets medicine Hypersensitivity Tetanus Toxoid Immunology and Allergy Humans Aged Skin Tests Antigens Bacterial Middle Aged Viral Load CD4 Lymphocyte Count medicine.anatomical_structure Cytokine Bacterial Vaccines Female Immunocompetence Interleukin-5 Memory T cell Viral load Immunologic Memory |
| Zdroj: | Journal of immunology (Baltimore, Md. : 1950). 164(7) |
| ISSN: | 0022-1767 |
| Popis: | We have used computer-assisted cytokine ELISA spot analysis to measure the frequencies, the type of cytokine, and the amount of cytokine produced by individual recall Ag-specific CD4 memory cells in freshly isolated blood. We studied the memory cells specific for tetanus toxoid and purified protein derivative in 18 healthy individuals and in 22 HIV-infected patients on highly active antiretroviral therapy (HAART). In healthy individuals, the frequency, cytokine signature, and cytokine production per cell of these memory cells were stable over time. Although it is presently unclear whether the maintenance of the memory T cell pool depends upon Ag persistence, cross-reactive Ag stimulation, or cytokine-driven bystander stimulations and expansions, our data strongly argue for a stable memory cell pool in healthy individuals. In HIV patients, however, the frequency of these memory cells was a function of the viral load. The decreased numbers of functional memory cells in patients with high viral loads might provide one mechanism behind the immunodeficient state. Although the cytokine output per cell was unaffected in most patients (20 of 24), in some patients (4 of 24) it was >100-fold reduced, which might provide an additional mechanism to account for the reduced immunocompetence of these patients. The ability to visualize directly and quantify the cytokine produced by the low frequency memory cells in freshly isolated blood that have been physiologically stimulated by Ag should aid comprehensive studies of the Ag-specific memory cell pool in vivo, in health and disease. |
| Databáze: | OpenAIRE |
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