Tm. Petro et al., Smokeless tobacco and nicotine bring about excessive cytokine responses ofmurine memory T-cells, INT J IMMUN, 21(2), 1999, pp. 103-114
To determine the influence of smokeless tobacco (ST) and nicotine on the cy
tokine phenotype of memory T-cells, splenic mononuclear cells (SPM) were ex
posed to 1:10(2) or 1:10(3) dilutions of ST extract (ST-SPM), 10 or 100 mu
g/ml nicotine (NIC-SPM), or medium (CON-SPM) during 4 days of stimulation w
ith anti-CD3. SPM were then washed extensively to remove residual ST or nic
otine and restimulated with anti-CD3 and anti-CD28 in the absence of ST or
nicotine. Expression of IL-2, IL-4, IL-10 and IFN-gamma protein and mRNA le
vels after 4 days of primary stimulation and after 24 and 48 h of restimula
tion was evaluated using ELISA and RT-PCR, respectively. After 4 days of pr
imary stimulation, SPM exposed to 100 mu g/ml nicotine sustained expression
of IL-2, IFN-gamma, IL-10 and IL-4 mRNA as opposed to CON-SPM. Restimulati
on of CON-SPM resulted in maximum re-expression of cytokine mRNA at 24 h an
d a decline by 48 h. Restimulated NIC-SPM in the absence of nicotine delaye
d maximal re-expression of IL-2, IFN-gamma, IL-IO and IL-4 mRNA until 48 h.
Heightened expression of cytokine mRNA at 48 h was paralleled by a small b
ut significant increase in production of IFN-gamma, IL-4 and IL-IO protein
by NIC-SPM as measured by ELISA. In contrast, ST-SPM did not exhibit residu
al expression of cytokine mRNA after 4 days of primary stimulation. Like NI
C-SPM, however, restimulated ST-SPM exhibited maximum IL-2, IL-4, IFN-(gamm
a), and IL-IO mRNA at 48 h. Heightened re-expression of cytokine mRNA at 48
h by ST-SPM was paralleled by increased production of IL-2, IFN-gamma, IL-
4 and IL-10 protein. These results indicate that exposure of T-cells to nic
otine, but not ST, during a primary immune response result in inordinate cy
tokine expression after 4 days. In addition, memory T-cells initially expos
ed to nicotine or ST during a primary immune response, exhibit excessive cy
tokine expression when T-cells are restimulated in the absence of nicotine
or ST. (C) 1999 International Society for Immunopharmacology. Published by
Elsevier Science Ltd.