EBV+ tumors exploit tumor cell-intrinsic and -extrinsic mechanisms to produce regulatory T cell-recruiting chemokines CCL17 and CCL22.

The Epstein-Barr Virus (EBV) is involved in the etiology of multiple hematologic and epithelial human cancers. EBV+ tumors employ multiple immune escape mechanisms, including the recruitment of immunosuppressive regulatory T cells (Treg). Here, we show some EBV+ tumor cells express high levels of the chemokines CCL17 and CCL22 both in vitro and in vivo and that this expression mirrors the expression levels of expression of the EBV LMP1 gene in vitro.

Tumors establish resistance to immunotherapy by regulating T recruitment via CCR4.

Background: Checkpoint inhibitors (CPIs) such as anti-PD(L)-1 and anti-CTLA-4 antibodies have resulted in unprecedented rates of antitumor responses and extension of survival of patients with a variety of cancers. But some patients fail to respond or initially respond but later relapse as they develop resistance to immune therapy. One of the tumor-extrinsic mechanisms for resistance to immune therapy is the accumulation of regulatory T cells (T) in tumors.

Novel Piperidinyl-Azetidines as Potent and Selective CCR4 Antagonists Elicit Antitumor Response as a Single Agent and in Combination with Checkpoint Inhibitors.

The C-C chemokine receptor 4 (CCR4) is broadly expressed on regulatory T cells (T) as well as other circulating and tissue-resident T cells. T can be recruited to the tumor microenvironment (TME) through the C-C chemokines CCL17 and CCL22. T accumulation in the TME has been shown to dampen the antitumor immune response and is thought to be an important driver in tumor immune evasion.

Discovery of a Potent and Selective CCR4 Antagonist That Inhibits T Trafficking into the Tumor Microenvironment.

Recruitment of suppressive CD4 FOXP3 regulatory T cells (T) to the tumor microenvironment (TME) has the potential to weaken the antitumor response in patients receiving treatment with immuno-oncology (IO) agents. Human T express CCR4 and can be recruited to the TME through the CC chemokine ligands CCL17 and CCL22. In some cancers, T accumulation correlates with poor patient prognosis.

CCR4 Antagonists Inhibit T Trafficking into the Tumor Microenvironment.

Recruitment of naturally occurring suppressive CD4, CD25, and FOXP3 regulatory T cells (T) to the tumor microenvironment (TME) has the potential to weaken the antitumor response in patients receiving treatment with immuno-oncology (IO) agents. Human T express CCR4 and can be recruited to the TME through the C-C chemokines CCL17 and CCL22. We have recently developed a series of potent, orally bioavailable small molecule antagonists of CCR4 that can block recruitment of T into the TME.

IgE⁺ memory B cells and plasma cells generated through a germinal-center pathway.

Immunoglobulin E (IgE) antibodies are pathogenic in asthma and allergic diseases, but the in vivo biology of IgE-producing (IgE(+)) cells is poorly understood. A model of the differentiation of IgE(+) B cells proposes that IgE(+) cells develop through a germinal-center IgG1(+) intermediate and that IgE memory resides in the compartment of IgG1(+) memory B cells. Here we have used a reporter mouse expressing green fluorescent protein associated with membrane IgE transcripts (IgE-GFP) to assess in vivo IgE responses.

Antigen-bearing dendritic cells regulate the diverse pattern of memory CD8 T-cell development in different tissues.

Memory T cells of the effector type (T(EM)) account for the characteristic rapidity of memory T-cell responses, whereas memory T cells of the central type (T(CM)) account for long-lasting, vigorously proliferating memory T-cell responses. How antigen-stimulated (primed) T cells develop into different memory T-cell subsets with diverse tissue distributions is largely unknown. Here we show that after respiratory tract infection of mice with influenza virus, viral antigen associated with dendritic cells (DCs) was abundant in lung-draining lymph nodes (DLN) and the spleen for more than a week but was scant and transient in nondraining lymph nodes (NDLN).

B7-H1 (PD-L1) on T cells is required for T-cell-mediated conditioning of dendritic cell maturation.

Studies have shown that T-cell-dendritic cell (DC) interaction is required for efficient DC maturation. However, the identities of the molecules that mediate the interaction in vivo are largely unknown. Here, we show that maturation of DCs as well as CD8 T-cell responses were impaired in B7-H1-deficient (B7-H1(-/-)) mice to influenza virus infection.

Loss of IL-7R and IL-15R expression is associated with disappearance of memory T cells in respiratory tract following influenza infection.

Following influenza virus infection, memory CD8 T cells are found in both lymphoid and nonlymphoid organs, where they exhibit striking differences in survival. We have assessed persistence, phenotype, and function of memory CD8 T cells expressing the same TCR in the airways, lung parenchyma, and spleen following influenza virus infection in mice. In contrast to memory CD8 T cells in the spleen, those residing in the airways gradually lost expression of IL-7R and IL-15R, did not respond to IL-7 and/or IL-15, and exhibited poor survival both in vivo and in vitro.