Differential expression of the cytokine receptors for human interleukin (IL)-12 and IL-18 on lymphocytes of both CD45RA super(+) and CD45RO super(+) phenotype from tonsils, cord and adult peripheral blood

• Published in: Clinical and experimental immunology 2004-12, Vol.138 (3), p.460-465
• Main Authors: Bofill, M, Almirall, E, Mcquaid, A, Pena, R, Ruiz-Hernandez, R, Naranjo, M, Ruiz, L, Clotet, B, Borras, F E
• Format: Article
• Language: English
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1111/j.1365-2249.2004.02651.x

The objective of this study was to demonstrate the variable expression of cytokine receptors on naive versus memory human CD4 super(+) T cell subpopulations in tonsillar tissue, cord blood and adult blood. We prove that the receptors for both interleukin (IL)-12 and IL-18 are expressed exclusively on memory T cells. This observation was seen not only on the CD45RO super(+) memory T cells but also on a significant percentage of the CD45RA super(+), CD62L super(-), CD27 super(-) and CCR7 super(-) populations. Furthermore, CD45RA super(+) CD62L super(+), CD27 super(+) or CCR7 super(+) CD4 super(+) T cells that expressed IL-12R beta 1 and IL-18R alpha did not express CD31, a marker for recent thymic emigrants. We reveal that cord blood lymphocytes do not express IL-12R beta 1 whereas IL-18R alpha expression was detected at low levels. Importantly, the IL-12R beta 2 signalling chain, which is absent in all resting T cells, was up-regulated in both CD45RA super(+) and CD45RO super(+) T cells as a result of stimulation with anti-CD3 and anti-CD28 in vitro. This observed up-regulation was, however, restricted to 80% of the total CD4 super(+) population. Finally, a very small proportion of the CD4 super(+) CD45RO super(+) tonsillar T cells expressed the IL-12 and IL-18 receptors, thereby establishing the differential expression of these receptors between peripheral and tonsillar memory T cell subpopulations.