TY - JOUR
T1 - Apoptosis following interleukin-2 withdrawal from T cells: evidence for a regulatory role of CD18 (beta 2-integrin) molecules
AU - Röpke, C
AU - Gladstone, P
AU - Nielsen, M
AU - Borregaard, N
AU - Ledbetter, J A
AU - Svejgaard, A
AU - Odum, Niels
N1 - Keywords: Antigens, CD18; Apoptosis; Cell Line; Humans; Interleukin-2; Isoantigens; Lymphocyte Function-Associated Antigen-1; T-Lymphocytes
PY - 1996
Y1 - 1996
N2 - Following a successful immune response against invading microorganisms, the majority of activated T cells is eliminated, while a minor fraction survives as memory T cells. A decline in T lymphocyte growth factors such as interleukin-2 (IL-2) appears to play a role in the elimination of previously activated T cells. Thus, removal of IL-2 from proliferating T cells not only induces growth arrest, but triggers a massive cell death due to apoptosis. While the apoptotic response involves a series of well-described events, it remains less clear how apoptosis is regulated following IL-2 withdrawal. Here, we provide evidence that CD18 molecules (beta 2-integrins) play a regulatory role in the apoptotic response following removal of IL-2 from previously activated, antigen specific CD4+ T cell lines. Thus, CD18 mAb inhibited the apoptotic response to IL-2 deprivation, whereas mAb against other adhesion molecules (CD28, CD29, CD49d, CD80, CD86) did not. Secondly, IL-2 withdrawal resulted in a retarded apoptotic response in LFA-1 (CD11a/CD18) negative T cells obtained from a leukocyte adhesion deficiency (LAD) patient, as compared to LFA-1 positive T cell lines. Thirdly, co-culture of LFA-1 positive- and negative-T cells at different ratios induced apoptotic responses that were higher than expected, had the two lymphocyte populations not been interacting and significantly higher than that seen in pure LFA-1 negative T cells. Supernatants from LFA-1 positive T cell cultures undergoing apoptosis did not induce an enhanced apoptotic responses in LFA-1 negative T cells, and, reversely, culture supernatants from LFA-1 negative T cells did not rescue LFA-1 positive cells from undergoing apoptosis. The apoptotic response was partly blocked by IL-15, a newly identified T cell growth factor. Taken together, these findings suggest that CD18 molecules (beta 2-integrins) play a regulatory role in the apoptotic response following cytokine withdrawal, and that the regulation is mediated, at least partly, through T-T cell interactions. Thus, apoptotic death following IL-2 deprivation appears to be under "social" control by surrounding T cells.
AB - Following a successful immune response against invading microorganisms, the majority of activated T cells is eliminated, while a minor fraction survives as memory T cells. A decline in T lymphocyte growth factors such as interleukin-2 (IL-2) appears to play a role in the elimination of previously activated T cells. Thus, removal of IL-2 from proliferating T cells not only induces growth arrest, but triggers a massive cell death due to apoptosis. While the apoptotic response involves a series of well-described events, it remains less clear how apoptosis is regulated following IL-2 withdrawal. Here, we provide evidence that CD18 molecules (beta 2-integrins) play a regulatory role in the apoptotic response following removal of IL-2 from previously activated, antigen specific CD4+ T cell lines. Thus, CD18 mAb inhibited the apoptotic response to IL-2 deprivation, whereas mAb against other adhesion molecules (CD28, CD29, CD49d, CD80, CD86) did not. Secondly, IL-2 withdrawal resulted in a retarded apoptotic response in LFA-1 (CD11a/CD18) negative T cells obtained from a leukocyte adhesion deficiency (LAD) patient, as compared to LFA-1 positive T cell lines. Thirdly, co-culture of LFA-1 positive- and negative-T cells at different ratios induced apoptotic responses that were higher than expected, had the two lymphocyte populations not been interacting and significantly higher than that seen in pure LFA-1 negative T cells. Supernatants from LFA-1 positive T cell cultures undergoing apoptosis did not induce an enhanced apoptotic responses in LFA-1 negative T cells, and, reversely, culture supernatants from LFA-1 negative T cells did not rescue LFA-1 positive cells from undergoing apoptosis. The apoptotic response was partly blocked by IL-15, a newly identified T cell growth factor. Taken together, these findings suggest that CD18 molecules (beta 2-integrins) play a regulatory role in the apoptotic response following cytokine withdrawal, and that the regulation is mediated, at least partly, through T-T cell interactions. Thus, apoptotic death following IL-2 deprivation appears to be under "social" control by surrounding T cells.
M3 - Journal article
C2 - 8883302
SN - 2059-2302
VL - 48
SP - 127
EP - 135
JO - HLA
JF - HLA
IS - 2
ER -