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Immature B cells are susceptible to apoptosis due to ligation of surface immunoglobulin receptors. The WEHI 231 cell line represents a useful model to study the mode of action of factors preventing apoptosis. In this work we investigated the protective effects of multi-species lactoferrins in anti-mouse Ig-induced WEHI 231 cell death. Bovine milk-derived lactoferrin (bLF), recombinant human lactoferrin expressed in Chinese hamster ovary cells - rhLF(CHO) or in human endothelial kidney cells - rhLF(HEK), and recombinant mouse lactoferrin expressed in Chinese hamster ovary cells - rmLF(CHO), were used. Goat-anti-mouse Ig antibodies were used to induce cell apoptosis. Survival of WEHI 231 cells in culture was measured using the colorimetric MTT method. Expression of signalling molecules and subunits of interleukin 2 receptor was determined by the RT PCR method. The results showed that anti-mouse Ig antibodies inhibited cell growth in a dose-dependent manner. The lactoferrins alone had no effect on the cell survival. The cells exposed to LFs, prior to anti-Ig treatment, were rescued to a significant degree from cell death. Determination of the signalling molecule expression revealed almost complete suppression of caspase-3 and NF-κB1 by bLF in untreated cells, as well as deep suppression of caspase-3, block of Fas, and 4-fold increase of NF-κB1 in cells incubated with bLF prior to anti-Ig treatment. In addition, differential changes in the expression of interleukin 2 subunits upon bLF treatment were found, indicating a process of cell differentiation. In conclusion, we showed that LF-induced cell differentiation in immature B-cell line WEHI 231 was correlated with partial protection of the cells from anti-Ig-induced cell death. [ABSTRACT FROM AUTHOR]

In the present study, we have examined the kinetics and magnitude of expression of the CD28 and CD152 molecules on unstimulated and anti-CD3+rIL-2-stimulated peripheral blood CD4+ and CD8+ T cells in patients with chronic lymphocytic leukaemia (B-CLL) and controls. The mean percentages of both CD3+/CD4+/CD28+ and CD3+/CD8+/CD28+ cells were significantly lower in B-CLL than in controls before culture, decreased rapidly, reaching their lowest levels between 24 and 48 h, and returned to basal levels after 72 h of culture. In controls, the lowest proportions of CD3+/CD4+/CD28+ and CD3+/CD8+/CD28+ cells were found after 24 h and returned to prestimulation levels after 48 h of stimulation. We observed significantly higher proportions of unstimulated CD3+/CD4+/CD152+ and CD3+/CD8+/CD152+ cells in B-CLL patients than in controls. The highest percentages of CD3+/CD4+/CD152+ and CD3+/CD8+/CD152+ cells were observed in controls after 72 h, and in B-CLL patients after 24 h, and remained statistically higher after 48, 72 and 96 h of stimulation. CD152?molecule expression returned to prestimulation levels after 96 h of culture in controls, and after 120 h in B-CLL patients. The abnormal kinetics and levels of CD28 and CD152 expression on T cells in B-CLL may lead to a state of hyporesponsiveness or anergy and could be one of the mechanisms of immune deficiency in this disease. [ABSTRACT FROM AUTHOR]