Enhancement of the antigen presenting cell (ARC) capacity of ALL cells, can be developed into a strategy for a vaccine therapy. So far it has been shown that CD40-crosslinking on ALL cells by NIH3T3 transfected with the CD40L coding region or by soluble CD40L (fusion protein of murine CD40L and CD8a chain) can induce expression of B7family members (B7-1/CD80; B7-2/CD86) and generation of autologous anti-ALL-specific cytolytic T-cell lines (Cardoso et al Blood 1997) that could be used for adoptive immunotherapy. Conceivably, irradiated ALL cells, rendered capable to present antigen, could be able to induce a host anti-leukemia immune response when administered to patients with a minimal residual disease. In the perspective of using CD40L-stimulated ALL cells in a clinical setting, we used a trimeric soluble CD40 Ligand (sCD40L) molecule (Alexis) and human bone marrow stroma (HBMS) to support ALL cells viability. Thawed cells, frozen at diagnosis, from 10 ALL children were cultured on HBMS in presence of sCD40L. Cell viability after 48h of culture on HMBS was high (mean 83%, range 54% - 103%). Compared to the control culture (HBMS without SCD40L), addition of sCD40L induced up-regulation of CD86 expression in 7 of 10 cases (mean percent of positive ALL cells: 48% versus 22%) and up-regulation of CD80 in 4 of 10 cases (52%, 72%, 80% and 36% versus 2%, 11%, 3% and 3%) and a slight up-regulation of CD40 in 5 of 5 cases (mean 61% versus 49%). By contrast, cell viability in cultures without stroma was poor (mean 15%) and CD40L did not up-regulate CD80 and CD86 on the few ALL cells surviving after 48h of culture. To investigate the effect of HBMS on the modulation of these molecules, we also compared the expression level of CD86, CD80 and CD40 one hour after thawing and after 48 hours culture on HBMS in absence of CD40L: HBMS increased the expression of CD86 in 6 of 14 cases (mean 14%to31%),ofCD40in8of9cases(mean29%to56%)andin 1 case, induced expression of CD80 (negative to 11%). Our data indicate that the culture of ALL cells on HBMS in presence of SCD40L modifies the ALL cells APC capacity and preserves their viability thus making them potentially available for vaccine therapy.
|Issue number||11 PART II|
|Publication status||Published - 2000|
ASJC Scopus subject areas