Selective expression of the p70 subunit of the interleukin-2 receptor on
lymphocytes from patients with infectious mononucleosis
M Kamio, T Uchiyama, T Hori, T Kodaka, T Ishikawa, R Onishi, H Uchino, N Yoneda, E Tatsumi and N Yamaguchi
First Division of Internal Medicine, Faculty of Medicine, Kyoto University,
Japan.
The lymphocytosis manifested in infectious mononucleosis (IM) during acute
phase is ascribed to a reactive expansion of CD8+ T lymphocytes caused by
Epstein-Barr virus (EBV)-infected B lymphocytes. Expression of HLA-DR
antigen on IM lymphocytes suggests that these T lymphocytes are somehow
activated in vivo. In the present study, we analyzed the interleukin-2
(IL-2) receptor expression on lymphocytes from six patients with acute IM.
Radiolabeled IL-2 binding assay revealed that IM lymphocytes from all
patients examined had a considerable number of IL-2 binding sites with an
intermediate affinity, although they did not express the IL-2 receptor
recognized by anti-Tac antibody (p55). The number of binding sites (1,070
to 4,600 sites per cell) was larger than that of a normal, resting T
lymphocyte-enriched population (650 sites per cell). Furthermore, IM
lymphocytes showed marked proliferative responses to higher concentrations
of IL-2, which were almost completely blocked by an anti-p70 IL-2 receptor
antibody, indicating that their IL-2 receptor is a functional receptor. The
results of an affinity cross-linking study seem to indicate that the IL-2
receptor expressed on IM lymphocytes is p70, the second chain of the IL-2
receptor distinct from p55. Flow cytometric analysis following
immunofluorescent staining with anti-p70 IL-2 receptor antibody confirmed
p70 expression on CD8+ HLA-DR+ lymphocytes. These data suggest that p70
IL-2 receptor expression is involved in the immune response triggered by
EBV infection.
Volume 75,
Issue 2,
pp. 415-420,
01/15/1990
Copyright © 1990 by The American Society of Hematology
