Inflammation driven by tumour-specific Th1 cells protects against B-cell cancer

The immune system can both promote and suppress cancer. Chronic inflammation and proinflammatory cytokines such as interleukin (IL)-1 and IL-6 are considered to be tumour promoting. In contrast, the exact nature of protective antitumour immunity remains obscure. Here, we quantify locally secreted cytokines during primary immune responses against myeloma and B-cell lymphoma in mice. Strikingly, successful cancer immunosurveillance mediated by tumour-specific CD4+ T cells is consistently associated with elevated local levels of both proinflammatory (IL-1α, IL-1β and IL-6) and T helper 1 (Th1)-associated cytokines (interferon-γ (IFN-γ), IL-2 and IL-12). Cancer eradication is achieved by a collaboration between tumour-specific Th1 cells and tumour-infiltrating, antigen-presenting macrophages. Th1 cells induce secretion of IL-1β and IL-6 by macrophages. Th1-derived IFN-γ is shown to render macrophages directly cytotoxic to cancer cells, and to induce macrophages to secrete the angiostatic chemokines CXCL9/MIG and CXCL10/IP-10. Thus, inflammation, when driven by tumour-specific Th1 cells, may prevent rather than promote cancer

Activated dendritic cells and monocytes in HIV immunological nonresponders: HIV-induced interferon-inducible protein-10 correlates with low future CD4+ recovery

Objective: To explore monocyte and dendritic cell immune responses, and their association with future CD4+ gain in treated HIV patients with suboptimal CD4+ recovery. Design: A cross-sectional study of HIV-infected, virally suppressed individuals on antiretroviral therapy for at least 24 months; 41 immunological nonresponders (INRs) (CD4+ cell count + cell count >600 cells/μl). Ten HIV-infected antiretroviral therapy-naive and 10 HIV-negative healthy persons served as controls. CD4+ cell counts were registered after median 2.4 and 4.7 years. Methods: Monocyte, dendritic-cell and T-cell activation and regulatory T cells (Tregs) were analyzed by flow cytometry. In INR and immunological responder subgroups matched on age and nadir CD4+ cell count, upregulation of interferon-inducible protein-10 (IP-10) and indoleamine 2,3-dioxygenase in monocytes and dendritic cells and cytokines in cell supernatants were measured in vitro in peripheral blood mononuclear cells stimulated with aldrithiol-2-inactivated HIV-1. Results: The INR group displayed higher spontaneous activation of both monocytes (HLA-DR+) and myeloid and plasmacytoid dendritic cells (HLA-DR+, CD83+ and CD86+) compared with immunological responders, and this was associated with increased T-cell activation (CD38+HLA-DR+), an effector memory T-cell phenotype and activated Tregs. The IP-10 response in monocytes after in-vitro HIV stimulation was negatively associated with prospective CD4+ gain. IP-10, indoleamine 2,3-dioxygenase and cytokines levels were comparable between the groups, but inversely correlated with activated Tregs in INRs. Conclusion: HIV-infected individuals with suboptimal immune recovery demonstrated more activated monocytes and in particular dendritic cells, compared with patients with acceptable CD4+ gain. A high level of HIV-specific IP-10 expression in monocytes may be predictive of future CD4+ recovery

Activated dendritic cells and monocytes in HIV immunological nonresponders: HIV-induced interferon-inducible protein-10 correlates with low future CD4+ recovery

Objective: To explore monocyte and dendritic cell immune responses, and their association with future CD4+ gain in treated HIV patients with suboptimal CD4+ recovery. Design: A cross-sectional study of HIV-infected, virally suppressed individuals on antiretroviral therapy for at least 24 months; 41 immunological nonresponders (INRs) (CD4+ cell count 600 cells/μl). Ten HIV-infected antiretroviral therapy-naive and 10 HIV-negative healthy persons served as controls. CD4+ cell counts were registered after median 2.4 and 4.7 years. Methods: Monocyte, dendritic-cell and T-cell activation and regulatory T cells (Tregs) were analyzed by flow cytometry. In INR and immunological responder subgroups matched on age and nadir CD4+ cell count, upregulation of interferon-inducible protein-10 (IP-10) and indoleamine 2,3-dioxygenase in monocytes and dendritic cells and cytokines in cell supernatants were measured in vitro in peripheral blood mononuclear cells stimulated with aldrithiol-2-inactivated HIV-1. Results: The INR group displayed higher spontaneous activation of both monocytes (HLA-DR+) and myeloid and plasmacytoid dendritic cells (HLA-DR+, CD83+ and CD86+) compared with immunological responders, and this was associated with increased T-cell activation (CD38+HLA-DR+), an effector memory T-cell phenotype and activated Tregs. The IP-10 response in monocytes after in-vitro HIV stimulation was negatively associated with prospective CD4+ gain. IP-10, indoleamine 2,3-dioxygenase and cytokines levels were comparable between the groups, but inversely correlated with activated Tregs in INRs. Conclusion: HIV-infected individuals with suboptimal immune recovery demonstrated more activated monocytes and in particular dendritic cells, compared with patients with acceptable CD4+ gain. A high level of HIV-specific IP-10 expression in monocytes may be predictive of future CD4+ recovery

SH2D2A modulates T cell mediated protection to a B cell derived tumor in transgenic mice.

BACKGROUND: T cell specific adapter protein (TSAd), encoded by the SH2D2A gene, modulates signaling downstream of the T cell receptor (TCR). Young, unchallenged SH2D2A-deficient C57BL/6 mice exhibit a relatively normal immune phenotype. To address whether SH2D2A regulates physiologic immune responses, SH2D2A-deficient TCR-transgenic BALB/c mice were generated. The transgenic TCR recognizes a myeloma-derived idiotypic (Id) peptide in the context of the major histocompatibility complex (MHC) class II molecule I-E(d), and confers T cell mediated resistance to transplanted multiple myeloma development in vivo. PRINCIPAL FINDINGS: The immune phenotype of SH2D2A-deficient C57BL/6 and BALB/c mice did not reveal major differences compared to the corresponding wild type mice. When challenged with myeloma cells, Id-specific TCR-transgenic BALB/c mice lacking SH2D2A displayed increased resistance towards tumor development. Tumor free TCR-transgenic SH2D2A-deficient mice had higher numbers of Id-specific single positive CD4+ thymocytes compared to TCR-transgenic wild-type mice. CONCLUSION: Our results suggest a modulatory role for SH2D2A in T cell mediated immune surveillance of cancer. However, it remains to be established whether its effect is T-cell intrinsic. Further studies are required to determine whether targeting SH2D2A function in T cells may be a potential adjuvant in cancer immunotherapy

Enhanced Gut-Homing Dynamics and Pronounced Exhaustion of Mucosal and Blood CD4+ T Cells in HIV-Infected Immunological Non-Responders

Immunological non-responders (INR), a subgroup of people living with HIV (PLHIV) who fail to restore CD4 + T cell numbers upon effective antiretroviral treatment, have impaired gut mucosal barrier function and an inferior clinical prognosis compared with immunological responders (IR). The contribution of gut-homing and exhaustion of mucosal T cells to the INR phenotype was previously unknown. Flow cytometry analysis of mononuclear cells from peripheral blood and ileal and colonic lamina propria showed that INR had higher fractions of gut-homing CD4 + T cells in blood compared with IR. In addition, gut-homing cells were more likely to display signs of exhaustion in INR. The increased CD4 + T cell exhaustion in INR was ubiquitous and not restricted to subpopulations defined by activation, differentiation or regulatory T cell markers. In INR, colon CD4 + T cell exhaustion correlated negatively with the fraction of CD4 + T cells in the same compartment, this was not apparent in the ileum. The fraction of exhausted mucosal CD4 + T cells correlated with I-FABP and REG3α, markers of enterocyte damage. We conclude that alterations of gut-homing and exhaustion of T cells may contribute to impaired gut immune and barrier functions associated with immunological non-response in PLHIV

Small changes in thymocyte proportions in <i>SH2D2A</i>-deficient mice.

<p>(A) The graphs show the mean number of thymocytes (upper panel) and splenocytes (lower panel) with SD from <i>SH2D2A</i>-deficient C57BL/6 (7–16 weeks) and BALB/c (11–20 weeks) mice and corresponding age-matched controls. Student’s paired t-test showed no significant differences between the groups. (B, C) Thymocytes (B) and splenocytes (C) from C57BL/6 and BALB/c mice with indicated genotypes were labeled with anti-CD4 and -CD8 mAbs and their expression were monitored by flow cytometry. (B) The percentage of double negative (DN – upper left), double positive (DP – lower left), single positive (SP) CD4+ (upper right) and CD8+ (lower right) thymocytes is indicated for each genotype. (C) The percentage of CD4+ and CD8+ splenocytes is indicated in each group. (B, C) The median values are shown as lines in the diagrams P-values were calculated by the Mann-Whitney U test, p-values are indicated only when significant (p < 0.05). (D) Freshly isolated splenic CD4+ T cells were labeled with indicated mAbs prior to flow cytometry analysis. One representative experiment of at least four experiments performed on splenic CD4+ T cells from C57BL/6 mice (8–16 weeks old) is shown.</p

<i>SH2D2A</i>-deficient mice have increased numbers of Id-specific TCR–transgenic SP CD4+ thymocytes.

<p>The graphs represents from the left; “UC” –unchallenged mice, i.e. control Id-specific TCR-transgenic mice that did not receive tumor cells, wild-type (<i>SH2D2A</i>+/+) and <i>SH2D2A</i> deficient (<i>SH2D2A</i>−/−) mice that had to be sacrificed due to development of large tumors (tumor volume > 1 cm³) (T = tumor) or that was tumor free at the end of the experiment 70 days after tumor inoculation (TF = tumor free). These tumor-free mice never had a palpable tumor during the course of the experiment, or they had a tumor that never reached 1 cm³ and that disappeared prior to the end of the experiment. The median values are shown as lines in the diagrams. (A, B) Thymocytes from mice with indicated genotypes were labeled with anti Id-TCR (GB113), anti-CD4 and anti-CD8 mAbs and their expressions were monitored by flow cytometry. The total number of Id-specific TCR-transgenic (GB113+) double positive (DP, CD4+ CD8+) and single positive CD4+ (SP, CD4+ CD8−) thymocytes is indicated for each genotype. (C) The diagram display the number of GB113+ CD4+ T cells in the tumor-draining lymph node of the same mice as in A and B. Of note is that the number of GB113+ CD4+ T cells in unchallenged mice is very low due to the small size of the draining lymph node in the absence of tumor challenge. (D) The GB113+ CD4+ T cells from the draining lymph node were labeled with anti-CD69 mAb, and their expression was monitored by flow cytometry. The diagram shows the median fluorescence intensity (MFI) of CD69 divided by the MFI of isotype control in GB113+ CD4+ T cells. P values were calculated with two-tailed Mann-Whitney U test. Ns = non-significant.</p

TCR transgenic <i>SH2D2A</i> −<b>/</b>− mice are resistant towards transplanted myeloma.

<p>Non-transgenic BALB/c and Id-specific TCR-transgenic (Id-TCR) BALB/c mice with (+/+) or without (−/−) <i>SH2D2A</i> expression were injected subcutaneously with low dose MOPC315 cells (160 000 cells). Tumor development was followed by palpation. (A, B) A tumor-free mouse was defined as a mouse that did not have a palpable tumor during the course of the experiment. The plots display tumor-take for (A) non-transgenic BALB/c mice with (n = 9) or without (n = 11) <i>SH2D2A</i> expression and (B) Id-specific TCR-transgenic BALB/c mice with (n = 23) or without (n = 23) <i>SH2D2A</i> expression. P values were calculated with two-tailed log rank test. Ns = non-significant.(C, D) Splenic CD4+ T cells were isolated from surviving tumor-free mice and stimulated <i>in vitro</i> with Id-positive F9 cells. Cells were labeled with GB113, recognizing the Id-specific transgenic TCR, and anti-CD69, CD44, CD62L or CD25 mAbs, prior to and after 24, 48 and 72 hours in culture with Id-positive cells. (C) FACS plots gated on GB113+ CD4+ T cells from one representative experiment are shown. (D) The diagram show the median value of the MFI (median fluorescent intensity) of CD69 at the indicated time points (n = 11) with SD. P-values were calculated with two-tailed, unpaired student t test, * indicate significant differences (at 48 hours: p = 0,003; at 72 hours: p = 0,03).</p

Characterization of <i>SH2D2A</i>-deficient Id-specific TCR-transgenic CD4+ T cells.

<p>(A) Thymocytes from Id-specific TCR-transgenic mice with indicated genotypes (9–15 weeks old) were labeled with anti-transgenic TCR (GB113), anti-CD4 and -CD8 mAbs. Expression of CD4 and CD8 on GB113+ thymocytes was monitored by flow cytometry. The mean average percentage with SD of double positive (DP), double negative (DN), single positive (SP) GB113+ CD4+ and CD8+ thymocytes is indicated for each genotype (n = 3). (B) Splenocytes from normal (<i>SH2D2A</i>+/+) and age-matched <i>SH2D2A-</i>deficient (<i>SH2D2A</i>−/−) mice (6–14 weeks old) were labeled with anti-CD4 and GB113 and expression was monitored by flow cytometry. Diagrams show the frequency of CD4+ T cells (left diagram) and the percentage of CD4+ T cells that express the Id-specific transgenic TCR (GB113+) (right diagram). The median values are shown as lines in the diagrams. (C) CFSE labeled CD4+ T cells from TCR transgenic <i>SH2D2A</i>+/+ (upper diagram) and <i>SH2D2A</i>−/− (lower diagram) were harvested after 24, 48 and 72 hours in culture with Id-positive F9, labeled with GB113 antibody. The CFSE dilution in GB113+ CD4+ T cells was measured by flow cytometry; grey area - CFSE profiles after 24 hours, open area (black line) - CFSE profiles after 48 hours and open area (stippled line) - CFSE profiles after 72 hours. One representative experiment out of four is shown. (D) Unlabeled CD4+ T cells from <i>SH2D2A</i>+/+ and <i>SH2D2A</i>−/− mice were cultivated as in C. Prior to and after 24, 48 and 72 hours, cells were stained with GB113 in addition to CD69, CD44, CD62L or CD25 mAbs to assess T cell activation by flow cytometry. FACS plots gated on GB113+ CD4+ T cells from one representative experiment of at least three are shown.</p

How do CD4+ T cells detect and eliminate tumor cells that either lack or express MHC class II molecules?

CD4+ T cells contribute to tumor eradication, even in the absence of CD8+ T cells. Cytotoxic CD4+ T cells can directly kill MHC class II positive tumor cells. More surprisingly, CD4+ T cells can indirectly eliminate tumor cells that lack MHC class II expression. Here, we review the mechanisms of direct and indirect CD4+ T cell-mediated elimination of tumor cells. An emphasis is put on T cell receptor (TCR) transgenic models, where anti-tumor responses of naïve CD4+ T cells of defined specificity can be tracked. Some generalizations can tentatively be made. For both MHCIIPOS and MHCIINEG tumors, presentation of tumor-specific antigen by host antigen-presenting cells (APCs) appears to be required for CD4+ T cell priming. This has been extensively studied in a myeloma model (MOPC315), where host APCs in tumor-draining lymph nodes are primed with secreted tumor antigen. Upon antigen recognition, naïve CD4+ T cells differentiate into Th1 cells and migrate to the tumor. At the tumor site, the mechanisms for elimination of MHCIIPOS and MHCIINEG tumor cells differ. In a TCR-transgenic B16 melanoma model, MHCIIPOS melanoma cells are directly killed by cytotoxic CD4+ T cells in a perforin/granzyme B-dependent manner. By contrast, MHCIINEG myeloma cells are killed by IFN-γ stimulated M1-like macrophages. In summary, while the priming phase of CD4+ T cells appears similar for MHCIIPOS and MHCIINEG tumors, the killing mechanisms are different. Unresolved issues and directions for future research are addressed