No.1

No.1 Sept.

.

Sept.

J. germfree life gnotobiol.

3SARS-CoV-2

110(N o.01002A)(A) N o.19H 00965

Basic research on anti-viral Immunobiotics
HARUKI KITAZAWA

Emerging and re-emerging infectious diseases caused by virus like SARS-CoV-2 are required tobe addressedwith both efficient prevention and treatment strategies to protect human health. Similar str ategies should be also applied
to livestock due to the epidemic spread of viral infectious diseases such as African swine fever. In addition, the diseases
caused by indigenous viruses and bacteria are positio ned as an important problem to overcome in animal production.
Vaccines and antimicrobials have been used to protect livestock from infectious diseases, but their development is labor
intensive and time-consuming, and the risk for appearance of antimicrobial-resistant bacteria has been drastically increased.
Immunobiotics, the beneficial microbes with the ability to positively influence the immune system of the host, have emerged
as a promising alternative to modulate the defenses of human and animals from viral and bacterial infections.
In this symposium I will revise our efforts to select and characterize immunobiotics from porcine small intestine by theconstruction of an evaluation system for antiviral immunobiotics with an originallyestablished porcine small intestinal
epithelial cell line (PIE cells). Since the pig is also useful as a human model, it is expected that our research will lead to theexpansion of the food and feed immunological use of immunobiotics, which will contribute to the prevention of a wide rangeof indigenous, emerging and re-emerging viral infectious diseases, by helping to strengthen the immune functions of humanand animals.

Ack n owledgem en t s

BRAIN(No. 01002A), J SP S KAKE NH I (A; 19H 00965), J RA

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Persistent infection ofmutualistic symbiont ?

with cucumber mosaic virus: a conditional

HIDEKI TAKAHASHI

Wild perennial plants naturally growing in the field often appear to be persistently infected withviruses. However, information on the positive or negative impact of persistent viral infections on hostplants is quite limited, while the underlying molecular events leading to the persistent infection have
hardly been studied. In this study, cucumber mosaic virus (CMV), a virus with a very broad naturaland named CMV(Ho). To study
plant host range, was isolated from wild perennial, infectious cDNA
the underlying mechanism of the persistent CMV(Ho) infection in perennial
clones were generated for all genetic elements. CMV, which consists of synthetic transcripts from theand annual
infectious tripartite RNA genome copies and designated CMV(Ho)tr, multiplied in
Col-0 to a similar level as the virulent strain CMV(Y), but did not induce any symptoms inthem. The response of Col-0 to a series of reassortant CMVs between CMV(Ho)tr and CMV(Y) suggestedgene ofthat the establishment of asymptomatic phenotype of CMV(Ho) infection was maintained by
CMV RNA2. The 2b protein interacted with argonaute 4, which is known to regulate the cytosine
methylation levels of host genomic DNA. Whole genomic bisulfate sequencing analysis of CMV(Ho)trand mock-inoculated Col-0 revealed that cytosine hypomethylation in the promoter regions of 82 genes,
was induced in response to CMV(Ho)tr infection. Taken altogether, the results indicate that during, host gene expression may be epigenetically modulated bypersistent CMV(Ho) infection in
resulting from 2b-mediated cytosine hypomethylation of host genomic DNA.

*,**(*), **15in vit r oDevelopment of functional food, not relying on animal experiments but taking
into account the dynamics of food components in the human intestine
RO OSAWA*,**

There are many foods whose components contribute to the maintenance of human health, which arecollectively called "functional foods", whose beneficial effects can be confirmed in experiments on cultured
cells or animals but not in human intervention tests, or whose effects in humans cannot be explained well.
This is because there are still some aspects that we do not understand fully about what take places in ourown gut. These include the difference in microbiota between laboratory animals and human, the differencein mucosal architecture between small and large intestines, and the difference in gut microbiota between
taxonomic and functional compositions. Based on the above differences, we have developed an "intestinalmodel" system that combines two in vitro test systems: an immune intestinal model (human small intestinalmodel) and a culture model (human large intestinal model) that reproduces the intestinal microbiota of anindividual using a single vessel continuous anaerobic culture system. Using these systems, we are now
working on the development of truly effective functional foods by assessing the probiotic, prebiotic or biogenic
properties of various food ingredients, some of which are presented in the talk.

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Pursuit and development ofJCM 5805 research

YUTA KOMANOJCM 5805 (LC-Plasma) is a unique lactic acid bacteria which activates plasmacytoid
dendritic cells (pDC) which play important roles in the immune system. It is known that LC-Plasma acts
on TLR 9 in pDC and induces the production of antiviral factors such as interferon- . It has been reported
that LC-Plasma supplementation activated pDC and reduced the cumulative number of incidence days ofinfluenza-like symptoms in healthy subjects.
It is well-known that high intensity exercise increases the risk of upper respiratory tract infections
which is caused by a temporary decrease in immunity "open window phenomenon". This phenomenon was
thought to be closely related to the decrease in natural killer cells, but the details were unknown.
Therefore, we proceeded with research to clarify the relation between exercise and dendritic cells, anduniversity athletic club students study showed that the activity of dendritic-cell decreased after exercise.
And it was shown that LC-Plasma supplementation significantly increased pDC activity and decreased
the cumulative number of days of cold illness and subjective symptoms. More interestingly, it was also
shown that the cumulative number of days of fatigue was significantly suppressed with LC-Plasma
supplementation. In additional human study, it was confirmed a significant improvement in sympathetic
and parasympathetic balance (LF/HF) and maintain of testosterone concentration. These results suggestthat LC-Plasma prevent deterioration of physical condition and accumulation of fatigue during highintensity exercise by maintaining immune function.
At the seminar, I would like to introduce food development focusing on LC-Plasma research.

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J. germfree life gnotobiol.

Modulation of antibody production in the small and large intestine by gut
microbiota
MASATO TSUDA and AKIRA HOSONO

Immunoglobulin (Ig) A secreted in the intestine plays roles in the maintenance of intestinal homeostasis in the faceof the exposure to invading pathogens, food-derived antigens and commensal microbiota. The primary sites to generate
IgA-producing B cells are Peyer’s patches (PPs) which are the part of gut-associated lymphoid tissue. In PPs, theactivated B cells undergo class-switch recombination to be IgA+ B cells by aid of follicular helper T cells and folliculardendritic cells. On the other hand, there are GALT in the large intestine such as cecal patches (CePs) and colonic patches
which have a similar structure to PPs, their precise immunological roles as well as regulatory mechanisms remain largely
unknown. We have been conducted our research focusing these points. We demonstrated that CePs have more IgG2b+ Bcells and few IgA+ B cells than those in PPs from BALB/c mice with normal gut microbiota. Gut microbiota via myeloid
differentiation factor 88 signaling contribute to generation of IgG2b+ B cells in CePs. IgG2b antibodies produced byCePs have a large capacity to bind microbiota, whereas IgA antibodies produced by PPs are reactive to microbiota as
well as dietary antigens. Our data suggest that CePs have a different antibody production profile compared to PPs.

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J. germfree life gnotobiol

Gut microorganisms induce Peyer’s patch-dependent maternal IgA
in milk-Discovery of gut microorganisms-Peyer’s patch-mammary gland axisTOMONORI NOCHI

Improving breastfeeding quality increases mammalian health across generations. Although the interorgan network among
distinct tissues has been implicated in maintaining essential behaviors, including breastfeeding, most details remain unknown.
We discuss the essential role of Peyer’s patches (PPs), a secondary lymphoid tissue in the small intestine, in breastfeeding.
Specifically, PPs constitute an important source of plasma cells, recruited from the mammary glands, to produce maternal IgA,
which is transferred from the mother to the offspring through breastfeeding. A more significant advance in this study was that
Bacteroides acidifaciens and Prevotella buccalis, both belonging to Bacteroidales, were identified as essential bacteria inthe gastrointestinal tract for stimulating the immune functions in PPs to produce maternal IgA in milk. Our results provide
significant insights into the development of novel strategies for transferring sufficient amounts of maternal IgA to the next
generation via breastfeeding.

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J. germfree life gnotobiol.

Chirality of amino acids modifies immune reactions to bacteria
JUMPEI SASABE

Chirality is a property that a subject does not overlap with its mirror image. Among chiral molecules
such as sugars and amino acids, organisms maintain homeostasis by using one of the enantiomers
selectively. While organisms use L-amino acids in most biological processes, bacteria have large
capacity to utilize D-amino acids. Bacteria synthesize variety of D-amino acids and utilize the aminoacids not only as integral components of the cell wall but also as functional molecules to modulate
synthesis of the cell wall. Mammals recognize and respond to diverse microbial products, including
fragments of the cell wall, however, the impact of free microbial D-amino acids on host physiology at
the host-microbial interface is not well understood.
In this talk, I will introduce the background of amino acid chirality and discuss 1) what sort of Damino acids are produced by gut microbiota, 2) how mammals respond to such microbial D-aminoacids, and 3) whether such responses influence host immune development.

J. germfree life gnotobiol.

J. germfree life gnotobiol.

Lactococcus lactis

ibobody production in the small and large intestine by gut microbiota--