Constitutive expression of interleukin 4 in vivo does not lead to the development of T helper 2 type CD8(+) T cells secreting interleukin 4 or interleukin 5
Kj. Erb et al., Constitutive expression of interleukin 4 in vivo does not lead to the development of T helper 2 type CD8(+) T cells secreting interleukin 4 or interleukin 5, IMMUNOL LET, 68(2-3), 1999, pp. 383-390
Interleukin 4 (IL-4) has been shown to commit CD8(+) T cells to a T helper
(Th) 2 functional phenotype in vitro. To study the effects of IL-4 on CD8() T cell development in vivo we analysed the CD8(+) T cell phenotype in mic
e constitutively expressing IL-4. Purified CD8(+) T cells from uninfected o
r flu infected IL-4 transgenic (tg) animals produced no detectable IL-4 or
IL-5 after in vitro stimulation on anti-CD3 coated plates. However, CD8(+)
T cells from IL-4 tg mice could be converted into IL-4 and IL-5 producers i
n vitro in the presence of exogenous added IL-4, showing that these cells w
ere still responsive to IL-4. IL-4 tg mice also showed a delay in influenza
virus clearance from the lung, which was probably due to the observed redu
ction of total CD8(+) T cell numbers in the IL-4 tg animals since IL-4 tg C
D8(+) T cells showed normal levels of influenza-specific cytotoxicity in co
mparison to controls. Taken together these results suggest that CD8(+) T ce
lls are not necessarily switched to a Th2 phenotype by the presence of IL-4
and that some other factor(s) may be important in the switch process of CD
8(+) T cells in vivo, since the addition of IL-4 during CD8(+) T cell activ
ation in vitro leads to Th2 type CD8(+) T cells secreting IL-4 and IL-5. (C
) 1999 Elsevier Science B.V. All rights reserved.