IgG4 subclass antibodies impair antitumor immunity in melanoma
Panagiotis Karagiannis, Amy E. Gilbert, Debra H. Josephs, Niwa Ali, Tihomir Dodev, Louise Saul, Isabel Correa, Luke Roberts, Emma Beddowes, Alexander Koers, Carl Hobbs, Silvia Ferreira, Jenny L.C. Geh, Ciaran Healy, Mark Harries, Katharine M. Acland, Philip J. Blower, Tracey Mitchell, David J. Fear, James F. Spicer, Katie E. Lacy, Frank O. Nestle, Sophia N. Karagiannis
Panagiotis Karagiannis, Amy E. Gilbert, Debra H. Josephs, Niwa Ali, Tihomir Dodev, Louise Saul, Isabel Correa, Luke Roberts, Emma Beddowes, Alexander Koers, Carl Hobbs, Silvia Ferreira, Jenny L.C. Geh, Ciaran Healy, Mark Harries, Katharine M. Acland, Philip J. Blower, Tracey Mitchell, David J. Fear, James F. Spicer, Katie E. Lacy, Frank O. Nestle, Sophia N. Karagiannis
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Research Article Oncology

IgG4 subclass antibodies impair antitumor immunity in melanoma

Abstract

Host-induced antibodies and their contributions to cancer inflammation are largely unexplored. IgG4 subclass antibodies are present in IL-10–driven Th2 immune responses in some inflammatory conditions. Since Th2-biased inflammation is a hallmark of tumor microenvironments, we investigated the presence and functional implications of IgG4 in malignant melanoma. Consistent with Th2 inflammation, CD22+ B cells and IgG4+-infiltrating cells accumulated in tumors, and IL-10, IL-4, and tumor-reactive IgG4 were expressed in situ. When compared with B cells from patient lymph nodes and blood, tumor-associated B cells were polarized to produce IgG4. Secreted B cells increased VEGF and IgG4, and tumor cells enhanced IL-10 secretion in cocultures. Unlike IgG1, an engineered tumor antigen-specific IgG4 was ineffective in triggering effector cell–mediated tumor killing in vitro. Antigen-specific and nonspecific IgG4 inhibited IgG1-mediated tumoricidal functions. IgG4 blockade was mediated through reduction of FcγRI activation. Additionally, IgG4 significantly impaired the potency of tumoricidal IgG1 in a human melanoma xenograft mouse model. Furthermore, serum IgG4 was inversely correlated with patient survival. These findings suggest that IgG4 promoted by tumor-induced Th2-biased inflammation may restrict effector cell functions against tumors, providing a previously unexplored aspect of tumor-induced immune escape and a basis for biomarker development and patient-specific therapeutic approaches.

Authors

Panagiotis Karagiannis, Amy E. Gilbert, Debra H. Josephs, Niwa Ali, Tihomir Dodev, Louise Saul, Isabel Correa, Luke Roberts, Emma Beddowes, Alexander Koers, Carl Hobbs, Silvia Ferreira, Jenny L.C. Geh, Ciaran Healy, Mark Harries, Katharine M. Acland, Philip J. Blower, Tracey Mitchell, David J. Fear, James F. Spicer, Katie E. Lacy, Frank O. Nestle, Sophia N. Karagiannis

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Figure 4

Biological properties of engineered IgG1 and IgG4 antibodies recognizing the melanoma-associated antigen CSPG4.

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Biological properties of engineered IgG1 and IgG4 antibodies recognizing...
Anti-CSPG4 IgG1 and anti-CSPG4 IgG4 antibodies bind to receptors on the cell surface of (A) U937 monocytic cells, (B) primary monocytes, and (C) tumor cells. ImageStream and flow cytometric evaluations confirm IgG1 and IgG4 antibody binding to Fcγ receptors (top and middle panels) and also to the antigen CSPG4 (bottom panel) expressed on the surface of SK-MEL-28 melanoma cells. ImageStream images are shown on the left. IgG FITC, cell surface (area indicated by circle on top left of each panel) binding of antibodies on cells; BF, bright-field image of cells; IgG FITC/BF, composite image of antibody and bright-field images, confirming anti-CSPG4 antibody binding to the cell surface. Quantitative analyses are based on the acquisition of 20,000 cells. Control samples for U937 and monocytes were incubated with goat anti-human IgG (Fab′)2-FITC antibody. Control samples for antibody binding to tumor cells were human IgG1 and IgG4 isotype antibodies of irrelevant specificity. (D) Flow cytometric analysis of CSPG4 IgG1 or CSPG4 IgG4 antibody binding to a panel of tumor cell lines or primary human melanocytes. Antibody binding was detected with an anti-human IgG (Fab′)2-FITC, and specific binding was depicted by MFI values above isotype control antibody binding.