ICI 2016_Abstract Book

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International Congress of Immunology 2016 Abstract Book
between the remaining Irf8-/- progenitors and their wild-type
counterparts. Nevertheless, the enhancer landscapes of Irf8-/-
progenitors were significantly distinct from those of wild-type
cells, with the enhancer landscapes of Irf8-/- GMPs, MDPs, and
cMoPs all remaining similar to that of wild-type GMPs. IRF8
was required particularly for the establishment of enhancers
common in monocytes and DCs. These results illustrate that
enhancer establishment and gene expression are dynamically
and hierarchically regulated by transcription factors during
mononuclear phagocyte development.
1506
Batf2/Irf1 induces inflammatory responses in classically
activated macrophages, lipopolysaccharides, and
mycobacterial infection
Roy, S.1,2 , Guler, R.3,4, Parihar, S.P.3,4, Schmeier, S.5, Kaczkowski, B.1,2,
Nishimura, H.1,2, Shin, J.W.1,2, Negishi, Y.1,2, Ozturk, M.3,4, Hurdayal,
R.3,4, Kubosaki, A.1 , Kimura, Y.1, de Hoon, M.J.L.1,2, Hayashizaki, Y.2,6,
Brombacher, F.3,4, Suzuki, H.1,2
1RIKEN Center for Life Science Technologies, Yokohama, Japan,
2Riken Omics Science Center, Yokohama, Japan, 3University of Cape
Town/Institute of Infectious Disease and Molecular Medicine (IDM),
Division of Immunology, Cape Town, South Africa, 4International
Centre for Genetic Engineering and Biotechnology (ICGEB), Cape
Town Component, Cape Town, South Africa,5Massey University,
Institute of Natural and Mathematical Sciences, North Shore
City, New Zealand, 6 Riken Preventive Medicine and Diagnosis
Innovation Program (PMI), Yokohama, Japan
Basic leucine zipper transcription factor Batf2 is poorly
described, whereas Batf and Batf3 have been shown to play
essential roles in dendritic cell, T cell, and B cell development
and regulation. Batf2 was drastically induced in IFN-γ-activated
classical macrophages (M1) compared with unstimulated or IL-
4-activated alternative macrophages (M2). Batf2 knockdown
experiments from IFN-γ-activated macrophages and
subsequent expression profiling demonstrated important roles
for regulation of immune responses, inducing inflammatory
and host-protective genes Tnf, Ccl5, and Nos2. Mycobacterium
tuberculosis (Beijing strain HN878)-infected macrophages
further induced Batf2 and augmented host-protective Batf2-
dependent genes, particularly in M1, whose mechanism was
suggested to be mediated through both TLR2 and TLR4 by
LPS and heat-killed HN878 (HKTB) stimulation experiments.
Irf1 binding motif was enriched in the promoters of Batf2-
regulated genes. Coimmunoprecipitation study demonstrated
Batf2 association with Irf1. Furthermore, Irf1 knockdown
showed downregulation of IFN-γ- or LPS/HKTB-activated host-
protective genes Tnf, Ccl5, Il12b, and Nos2. Batf2 deficiency
in mice resulted in resistance to M. tuberculosis infection with
reduced immunopathology. Conclusively, Batf2 is an activation
marker gene for M1 involved in gene regulation of IFN-γ-
activated classical macrophages, as well as LPS/HKTB-induced
macrophage stimulation, possibly by Batf2/Irf1 gene induction.
Taken together, these results underline the role of Batf2/Irf1 in
inducing inflammatory responses in M. tuberculosis infection.
2879
The effects of transgenic expression of a T-box molecule,
eomesodermin, in naive T cells on their activation and
exhaustion status
Eshima, K., Misawa, K., Noma, H., Iwabuchi, K.
Kitasato University School of Medicine, Department of
Immunology, Sagamihara, Japan
A T-box family transcription molecule, Eomesodermin (Eomes),
controls effector function of CD8+ CTLs. Eomes is expressed
in effector or memory CD8+ T-cells, but is also found in
“exhausted” cells, although its precise roles there remain to be
fully delineated. In order to determine the relevance of Eomes
in T-cell activation statuses, we developed Eomes-transgenic
mouse using human CD2 promoter/enhancer. In Eomes-Tg
mouse, the number of peripheral T-cells was smaller than
that in wild type mice. This was accompanied with decreased
expression of CD127 and Bcl-2 in Tg mature T-cells, which is
frequently observed in exhausted T-cells. It was also noticed
that higher proportion of peripheral CD8+ T-cells in Eomes-Tg
mice expressed some of exhausted T-cells markers, such as,
PD-1, LAG-3, or TIM-3, suggesting that part of exhausted T-cell
phenotypes may result from higher expression of Eomes. As
for other activation markers, expression of CD44, CD122, Ly-6C
was also up-regulated on Eomes-Tg CD8 + T-cells. By utilizing
Tg-TCR, it was suggested that optimal expression of many of
these markers, except for CD122, still requires TCR-stimulation.
Transgenic expression of Eomes alone may not be adequate
for provision of functional activity to CD8+ T-cells, either, since
CD44lo+ CD8+ T-cells from Eomes-Tg did not produce IFN-γ or
exert cytotoxicity until antigenically primed. Collectively, these
results imply that Eomes induction alone may be insufficient for
proper CTL differentiation and that Eomes expression without
TCR stimulation might induce exhausted phenotypes.
2692
Deciphering the importance of H3K27me3 demethylation
during early CD8 + T cell responses against influenza A virus
Li, J., Olshansky, M., Turner, S.
University of Melbourne, Department of Microbiology &
Immunology, Melbourne, Australia
The acquisition and maintenance of cytotoxic CD8+ T cell
(CTL) function in response to influenza virus infection is partly
regulated by co-ordinated changes in chromatin structure,
histone modifications and binding of transcription factors.
Developmental or lineage-defining genes in stemcells and CD4+
T cells are bivalently marked by the repressive trimethylated
lysine 27 (H3K27me3) and activating trimethylated lysine 4
(H3K4me3) on the H3 histone. In naïve CD8+ T cells, we have
also shown that a number of bivalent genes rapidly resolve to
a transcriptionally permissive state when differentiated into
virus-specific effector and memory T cells (Russ et al., 2014).
To understand how the early removal of the repressive mark,
H3K27me3, defines immediate transcriptional responses of
bivalent genes, naive CD8+ T cells were stimulated with the
SIINFEKL peptide for 3, 5 and 24hrs. Whole-genome H3K27me3
chromatin-immunoprecipitation-sequencing (ChIP-seq) and