Supplementary Material for: Innate Immunity Protein Tag7 Induces 3 Distinct Populations of Cytotoxic Cells That Use Different Mechanisms to Exhibit Their Antitumor Activity on Human Leukocyte Antigen-Deficient Cancer Cells

The search for new immune response mechanisms capable of controlling
immune-evasive tumor cells devoid of the MHC antigen is a challenging
task for immunologists. In this study, we found that the treatment of
human peripheral blood lymphocytes with the innate immunity protein Tag7
(PGRP-S, PGLYRP1) induces differentiation of the populations of NK
(natural killer) cells and CD8+ and CD4+ T lymphocytes that are
cytotoxic for human leukocyte antigen-negative tumor cells. These
populations employ different mechanisms of tumor cell lysis (based on
the release of granzymes in the case of NK cells and on the FasL-Fas
interaction in the case of CD8+ and CD4+ T lymphocytes) and induce
different death pathways (apoptosis or necroptosis) in tumor cells. An
analysis of genes activated in leukocyte populations after Tag7
treatment and experiments with specific inhibitors have shown that the
TREM-1 receptor expressed on the monocyte cell surface is essential for
activation of cytotoxic activity. Overall, the results of this study
provide evidence for a novel role of the Tag7 protein in the immune
response.