Immunotherapy-Resistant Cancer Patients Lack Critical Immune Cells

Source: Genetic Engineering & Biotechnology News, March 2023

Scientists at the Washington University School of Medicine in St. Louis report that the difference between people who do and do not respond to immunotherapy may have to do with CD5+ dendritic cells because they bear the protein CD5 on their outer surfaces. Their research showed that people with a variety of kinds of cancers, including melanoma, lived longer if they had more CD5+ dendritic cells in their tumors, and that mice that lacked CD5 on their dendritic cells were unable to respond well to immunotherapy.

The findings “CD5 expression by dendritic cells directs T cell immunity and sustains immunotherapy responses,” published in Science, suggest that a supplementary therapy designed to increase the number or activity of CD5+ dendritic cells potentially could extend the lifesaving benefits of immunotherapy to more cancer patients.

“The induction of proinflammatory T cells by dendritic cell (DC) subtypes is critical for antitumor responses and effective immune checkpoint blockade (ICB) therapy. Here, we show that human CD1c+CD5+ DCs are reduced in melanoma-affected lymph nodes, with CD5 expression on DCs correlating with patient survival,” write the investigators.
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