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International Congress of Immunology 2016
Abstract Book
mite ImmunoCAP. Inhibition experiments were conducted by
pre-incubating patient sera with bacterial extracts, prior to HDM
immunoblot or ImmunoCAP assay. Rabbit antibodies raised
against
S. aureus
and
E. coli
antigens were tested for reactivity
to blotted HDM extract.
Results:
The frequency of IgE sensitisation to bacterial antigens
was significantly higher in HDM allergic patients compared to
allergic subjects without HDM allergy. Specific antibody probes
detected
S.aureus
and
E.coli
antigens in immune-blotted HDM
extract. Furthermore, pre-incubation of sera from HDM allergic
patients with bacterial extract, inhibited IgE binding to bands in
blotted HDM extract, and reduced IgE binding to HDM extracts
in ImmunoCAP measurements.
Conclusion:
House dust mites are potential carriers of bacteria
responsible for the induction of IgE sensitisation to microbial
antigens.
This study was supported by the FWF-funded PhD program
MCCA.
3831
Virus infected human mast cells have a unique and potent
type 1 interferon response and selectively respond to
interferon activation
Portales, L.
1
, Oldford, S.
2
, Haidl, I.D.
1
, Marshall, J.S.
1
1
Dalhousie University, Microbiology and Immunology, Halifax,
Canada,
2
Dalhousie University, Medicine, Halifax, Canada
Mast cells are frequent at mucosal surfaces and have a sentinel
role in infection. They have been implicated in the pathogenesis
of asthma where viral infections are associated with disease
exacerbation. Type 1 interferons (IFNs) are critical for the early
response to viral infection. We therefore examined human mast
cell production of, and response to, type 1 IFNs.
Using reovirus, which infects multiple cell types, we analyzed
the IFN response of cord blood derived human mast cells
and structural cells. Mast cells expressed a wide range of IFNs
including IFNβ, IFNα1, IFNα2, IFNα4, IFNα6 and IFNα8 upon
infection. In contrast, structural cells, such as normal lung
fibroblasts had a highly restricted pattern of IFN expression.
When peripheral blood NK cells were treated with supernatants
from virus activated mast cells they demonstrated significantly
greater CD69 expression and cytotoxicity than those treated
with uninfected mast cell supernatants. These responses were
dependent on type 1 IFNs.
In vivo
, virus infected mast cells also
significantly enhanced both NK cell activation and recruitment.
Human mast cell responses to IFNα2 were also examined.
Significant production of several cytokines was observed
following IFN treatment, including VEGF-A and IL-1 receptor
antagonist, in the absence of mast cell degranulation.
These data suggest that mast cells contribute substantially to
the IFN response to viral infection at mucosal surfaces, and
that such responses activate NK cells. The subsequent mast cell
response to IFNs might potentially aid in tissue remodeling and
regulation of inflammation.
Supported by the Canadian Institutes for Health Research
278
The effect of early postnatal colonisation of newborns by
probiotic vaccine Colinfant New Born on allergy incidence
and immune system characteristics
Hrdy, J.
1
, Sukenikova, L.
1
, Novotna, O.
1
, Petraskova, P.
1
, Borakova,
K.
2
, Prokesova, L.
1
1
First Faculty of Medicine, Charles University in Prague, Institute of
Immunology and Microbiology, Prague, Czech Republic,
2
Institut
for the Care of Mother and Child, Paediatric Unit, Prague, Czech
Republic
Allergies belong to the most common diseases with steadily
increasing incidence. Probiotics are believed to prevent or
reduce allergy development. Nevertheless, the mechanism
of their beneficial effect is poorly understood. Decreased
allergy incidence was observed 5, 10, 20 years after initial
supplementation of newborns with Colinfant New Born (E.
coli O83:K24:H31). To reveal the mechanism of the action,
immune characteristics of peripheral blood regulatory T cells
(Tregs) of probiotic colonized and noncolonized children of
allergic mothers (high risk children) and noncolonized children
of healthy mothers were compared by flow cytometry. The
capacity of E. coli O83:K24:H31 to promote maturation of
dendritic cells (DC) and induce immune responses was tested
in vitro by coculture of probiotic primed DC derived from cord
blood precursors with naive CD4+. Functional characteristics
of Tregs (MFI of FoxP3, intracellular presence of regulatory
cytokines IL-10, TGF-beta) were decreased in the allergic group.
Probiotic colonized children have increased regulatory potency
of Tregs (MFI of FoxP3, regulatory cytokines) in comparison
to noncolonized children. E. coli O83:K24:H31 promotes
maturation of cord blood derived DC. The beneficial effect of
probiotics on newborn immature immune system could be, at
least partially, explained by the modulating immune function of
Tregs. Although we detected increased proportion of Tregs in
peripheral blood of allergic children, their functional properties
were decreased in comparison with Tregs of healthy children.
We suggest increased proportion of Tregs in allergic children
reflects an effort to compensate impaired function of Tregs.
This work was supported by AZV CR15-26877A and PRVOUK
P25/LF1/2.
Lymphocyte Signalling
1765
Soluble CD52 binds the damage-associated molecular
pattern protein HMGB1 to mediate T-cell suppression
through the Siglec-10 receptor
Bandala-Sanchez, E.
1
, Ngui, K.
1
, Stone, N.L.
1
, Pearce, L.A.
2
, Adams,
T.A.
2
, Harrison, L.C.
1
1
Walter and Eliza Hall Institute of Medical Research,
Population Health and Immunity Division, Parkville, Australia,
2
Commonwealth Scientific and Industrial Research Organisation
(CSIRO), Materials Science & Engineering, Melbourne, Australia
Introduction:
Activated T cells release the GPI-anchored
glycopeptide CD52, which suppresses bystander T cells by
binding the inhibitory receptor, sialic acid binding Ig-like
lectin-10 (Siglec-10) (1). Siglec-10 was reported to bind another