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Differential down-modulation of HLA class I and II molecule expression on human tumor cell lines upon in vivo transfer.

Turrini R, Merlo A, Dolcetti R, Zanovello P, Rosato A - Cancer Immunol. Immunother. (2011)

Bottom Line: Collected data showed a highly heterogeneous in vivo behavior of the various cell lines, which could alternatively down-modulate, completely abrogate or maintain unchanged the expression of either MHC-I or MHC-II molecules.Moreover, the site of injection impacted differentially on these aspects.Although such phenomena still lack a comprehensive clarification, epigenetic mechanisms are likely to be involved as epigenetic drugs could partially counteract MHC down-modulation in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology and Surgical Sciences, University of Padova, Italy.

ABSTRACT
Previous evidence from our laboratory showed that Epstein-Barr virus-immortalized lymphoblastoid B cells undergo a prominent down-modulation of HLA-II molecule expression when injected intraperitoneally in SCID mice, while HLA-I remains almost unaffected. Since this phenomenon can alter the experimental outcome of therapeutic protocols of adoptive cell therapy, we decided to evaluate the behavior of MHC antigens in a panel of cell lines belonging to the B- and T-cell lineages, as well as in epithelial tumor cell lines. Cells were administered in mice either intraperitoneally or subcutaneously and recovered 4 days later for HLA molecule expression analysis. Collected data showed a highly heterogeneous in vivo behavior of the various cell lines, which could alternatively down-modulate, completely abrogate or maintain unchanged the expression of either MHC-I or MHC-II molecules. Moreover, the site of injection impacted differentially on these aspects. Although such phenomena still lack a comprehensive clarification, epigenetic mechanisms are likely to be involved as epigenetic drugs could partially counteract MHC down-modulation in vivo. Nonetheless, it has to be pointed out that careful attention must be paid to the assessment of therapeutic efficacy of translational protocols of adoptive immunotherapy, as modulation of MHC molecules on human target cells when transferred in a mouse environment could readily interfere with the desired and expected therapeutic effects.

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a Representative cytofluorimetric analysis of DG-75, BL-41 B95.8, and Raji cell lines: expression of different markers (HLA-I for DG-75 and BL-41 B95.8 cells and HLA-II for Raji cell line) after i.p. (dotted line) or s.c. (dashed line) recovery in comparison with in vitro expression (black line). Gray areas represent the isotype controls. b HLA-I, β2-microglobulin (b2m), HLA-II, and immunoglobulins (Ig) percentage of positivity (left panels) and MFI of expression (right panels) from selected B cell lines after i.p. and s.c. injection. White and black bars refer to values of cells recovered from i.p. and s.c. sites, respectively, while gray bars show data of cells maintained in in vitro culture. The percentage of positivity for in vitro markers expression is not shown and is always 100%. Figure shows mean ± SD of at least 3 independent experiments for each cell line
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Fig1: a Representative cytofluorimetric analysis of DG-75, BL-41 B95.8, and Raji cell lines: expression of different markers (HLA-I for DG-75 and BL-41 B95.8 cells and HLA-II for Raji cell line) after i.p. (dotted line) or s.c. (dashed line) recovery in comparison with in vitro expression (black line). Gray areas represent the isotype controls. b HLA-I, β2-microglobulin (b2m), HLA-II, and immunoglobulins (Ig) percentage of positivity (left panels) and MFI of expression (right panels) from selected B cell lines after i.p. and s.c. injection. White and black bars refer to values of cells recovered from i.p. and s.c. sites, respectively, while gray bars show data of cells maintained in in vitro culture. The percentage of positivity for in vitro markers expression is not shown and is always 100%. Figure shows mean ± SD of at least 3 independent experiments for each cell line

Mentions: Based on our previous results [1], first we decided to extend the assessment of MHC-I and MHC-II expression, before in vivo administration and after ex vivo recovery, to a panel of B cell lines. Such analysis revealed that in all cases the percentage of positivity and the mean fluorescence intensity (MFI) of samples were lower after ex vivo evaluation, but no general rule could be inferred. DG-75, SH-9, Raji (this latter being reported in Fig. 1a, b as an example of this group of cells), and Daudi (which does not harbor MHC class I) cell lines completely or partially down-modulated HLA-I and HLA-II molecule expression when injected i.p. On the other hand, most of the cell lines maintained a high expression of the analyzed markers when injected s.c., with the exception of LCL and, partially, SH9, Namalwa, and Daudi cell lines (LCL and Namalwa illustrate this behavior in Fig. 1b). The only B cell lines that preserved the expression of MHC-I and MHC-II markers, after both i.p. and s.c. injection, were BL-41 and their EBV-infected counterpart (Fig. 1a, b). Expression data obtained with pan anti-HLA-I were fully confirmed by staining recovered cells with anti-β2-microglobulin antibody (Fig. 1b) and anti-HLA-A2 allele-specific antibody (where present, data not shown). Similarly, results of cytometry analyses with the use of anti-HLA-DR and anti-HLA-DQ antibodies completely overlapped those obtained with pan anti-HLA-II (data not shown).Fig. 1


Differential down-modulation of HLA class I and II molecule expression on human tumor cell lines upon in vivo transfer.

Turrini R, Merlo A, Dolcetti R, Zanovello P, Rosato A - Cancer Immunol. Immunother. (2011)

a Representative cytofluorimetric analysis of DG-75, BL-41 B95.8, and Raji cell lines: expression of different markers (HLA-I for DG-75 and BL-41 B95.8 cells and HLA-II for Raji cell line) after i.p. (dotted line) or s.c. (dashed line) recovery in comparison with in vitro expression (black line). Gray areas represent the isotype controls. b HLA-I, β2-microglobulin (b2m), HLA-II, and immunoglobulins (Ig) percentage of positivity (left panels) and MFI of expression (right panels) from selected B cell lines after i.p. and s.c. injection. White and black bars refer to values of cells recovered from i.p. and s.c. sites, respectively, while gray bars show data of cells maintained in in vitro culture. The percentage of positivity for in vitro markers expression is not shown and is always 100%. Figure shows mean ± SD of at least 3 independent experiments for each cell line
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3197938&req=5

Fig1: a Representative cytofluorimetric analysis of DG-75, BL-41 B95.8, and Raji cell lines: expression of different markers (HLA-I for DG-75 and BL-41 B95.8 cells and HLA-II for Raji cell line) after i.p. (dotted line) or s.c. (dashed line) recovery in comparison with in vitro expression (black line). Gray areas represent the isotype controls. b HLA-I, β2-microglobulin (b2m), HLA-II, and immunoglobulins (Ig) percentage of positivity (left panels) and MFI of expression (right panels) from selected B cell lines after i.p. and s.c. injection. White and black bars refer to values of cells recovered from i.p. and s.c. sites, respectively, while gray bars show data of cells maintained in in vitro culture. The percentage of positivity for in vitro markers expression is not shown and is always 100%. Figure shows mean ± SD of at least 3 independent experiments for each cell line
Mentions: Based on our previous results [1], first we decided to extend the assessment of MHC-I and MHC-II expression, before in vivo administration and after ex vivo recovery, to a panel of B cell lines. Such analysis revealed that in all cases the percentage of positivity and the mean fluorescence intensity (MFI) of samples were lower after ex vivo evaluation, but no general rule could be inferred. DG-75, SH-9, Raji (this latter being reported in Fig. 1a, b as an example of this group of cells), and Daudi (which does not harbor MHC class I) cell lines completely or partially down-modulated HLA-I and HLA-II molecule expression when injected i.p. On the other hand, most of the cell lines maintained a high expression of the analyzed markers when injected s.c., with the exception of LCL and, partially, SH9, Namalwa, and Daudi cell lines (LCL and Namalwa illustrate this behavior in Fig. 1b). The only B cell lines that preserved the expression of MHC-I and MHC-II markers, after both i.p. and s.c. injection, were BL-41 and their EBV-infected counterpart (Fig. 1a, b). Expression data obtained with pan anti-HLA-I were fully confirmed by staining recovered cells with anti-β2-microglobulin antibody (Fig. 1b) and anti-HLA-A2 allele-specific antibody (where present, data not shown). Similarly, results of cytometry analyses with the use of anti-HLA-DR and anti-HLA-DQ antibodies completely overlapped those obtained with pan anti-HLA-II (data not shown).Fig. 1

Bottom Line: Collected data showed a highly heterogeneous in vivo behavior of the various cell lines, which could alternatively down-modulate, completely abrogate or maintain unchanged the expression of either MHC-I or MHC-II molecules.Moreover, the site of injection impacted differentially on these aspects.Although such phenomena still lack a comprehensive clarification, epigenetic mechanisms are likely to be involved as epigenetic drugs could partially counteract MHC down-modulation in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology and Surgical Sciences, University of Padova, Italy.

ABSTRACT
Previous evidence from our laboratory showed that Epstein-Barr virus-immortalized lymphoblastoid B cells undergo a prominent down-modulation of HLA-II molecule expression when injected intraperitoneally in SCID mice, while HLA-I remains almost unaffected. Since this phenomenon can alter the experimental outcome of therapeutic protocols of adoptive cell therapy, we decided to evaluate the behavior of MHC antigens in a panel of cell lines belonging to the B- and T-cell lineages, as well as in epithelial tumor cell lines. Cells were administered in mice either intraperitoneally or subcutaneously and recovered 4 days later for HLA molecule expression analysis. Collected data showed a highly heterogeneous in vivo behavior of the various cell lines, which could alternatively down-modulate, completely abrogate or maintain unchanged the expression of either MHC-I or MHC-II molecules. Moreover, the site of injection impacted differentially on these aspects. Although such phenomena still lack a comprehensive clarification, epigenetic mechanisms are likely to be involved as epigenetic drugs could partially counteract MHC down-modulation in vivo. Nonetheless, it has to be pointed out that careful attention must be paid to the assessment of therapeutic efficacy of translational protocols of adoptive immunotherapy, as modulation of MHC molecules on human target cells when transferred in a mouse environment could readily interfere with the desired and expected therapeutic effects.

Show MeSH
Related in: MedlinePlus