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 2

B cells in melanoma lesions are polarized to produce IgG4 antibodies with reactivity against tumor cells.

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B cells in melanoma lesions are polarized to produce IgG4 antibodies wit...
(A) Polarization of IgG subclasses in B cells derived from metastatic melanoma skin tumor lesions (n = 2), patient lymph nodes (n = 3), peripheral blood from patients with melanoma (n = 6), and from healthy volunteers (n = 4). Cells were cultured ex vivo, and IgG subclass expression profiles were analyzed from culture supernatants by ELISA (mean ± SD; each sample condition tested in triplicate). (B) Immunohistological evaluations confirm significantly increased IgG4+ cell infiltration in melanoma lesions (n = 10) but not healthy skin (n = 10) (***P < 0.001), and representative metastatic melanoma depicts IgG4+ cells (red; hematoxylin [blue]) (scale bar: 20 μm; original magnification, ×10). (C) Reactivity of patient B cell–derived IgG1 and IgG4 antibodies to A375 tumor cells evaluated using a cell-based ELISA. Dashed black and gray lines indicate cut-off points for IgG1 and IgG4 tumor-reactive antibodies, respectively (lines defined as 2 SDs above isotype control antibodies). (D) Immunofluorescent staining of IgG4+ (red) colocalized with S100+ (green) cells in metastatic melanoma (scale bar: 50 μm; original magnification, ×40). (E) Increased expression of IL4, IL10 and IFNG in metastatic melanomas (n = 10) compared with primary melanomas (n = 10) and healthy skin (n = 9) by comparative real-time PCR. Horizontal lines in box plots represent mean, and whiskers indicate minimum and maximum values. *P < 0.05, **P < 0.01, Kruskal-Wallis 1-way ANOVA with Dunn’s post-hoc test. (F) Cytokines IL-4, IL-10 and IFN-γ are secreted in metastatic melanoma lesion ex vivo cultures.