Page 29 - Biennial Report 2018-20 Jun 2021

allergic reactions. We have demonstrated that protease activity is important for PAR-2/STAT-3
axis in dendritic cells (DCs) leading to T cell priming towards Th2 milieu by Per a 10 activated DCs.

Allergen immunotherapy (AIT) represents a disease modifying and curative approach for
treatment of allergic diseases. However, immunotherapy (IT) with allergen extracts carries an
inherent risk of sensitizing the individual with other allergens and may lead to adverse allergic
reactions. Studies on in-vivo murine model demonstrated recombinant Per a 10 and its derived
T cell epitopes as safe and efficacious approach for immunotherapy. Peptide immunotherapy
(PIT) using T cell epitopes (T-P8 and T-P10) demonstrates efficacy in murine model of allergic
hypersensitivity and possess potential for treatment of cockroach allergy. PIT is associated with
synergistic action of immunological responses including Th2 to Th1 switching, production of
blocking antibodies as well as regulatory pathways involving T regulatory function.

TLR-5 ligand- FlaA have been studied to possess immunomodulatory potential in skewing the
allergic Th2-dominated phenotype towards T regulatory and Th1 response resulting in tolerance
generation against any antigen. Therefore, fusion proteins containing TLR-5 ligand Per a 10 /
immunodominant peptides from Periplaneta americana has properties for ameliorating allergic
diseases

Fusion proteins were able to activate and potentiate dendritic cells by enhanced expression of
co-stimulatory markers on DCs (CD80, CD86 and CD83) and increased production of IL-6
production. Enhanced levels of IL-10, IFN-ү and TNF-α in fusion proteins containing T cell
epitopes suggest a potential for immunomodulation of DC-mediated T cell polarization towards
Th1 and T regulatory cells.

In addition, airway inflammation model was established in Balb/c mice using cockroach extract
and major allergen, Per a 10. Lower levels of cellular infiltrates, allergen specific IgE and high
levels of blocking antibody, IgG2a was observed in the mice treated with fusion proteins
compared to the group of mice treated alone with Per a 10 or a mixture of FlaA-Per a 10. BALF
and splenocytes cells showed strong induction of T regulatory cells (CD4 and Foxp3) along with
enhanced IFN-ү, TNF-α, IL-10 (Th1/Treg IL-10) and reduced Th2 cytokines (IL-4, IL-5 and IL-13) in
the mice lungs treated with FlaA-Per a 10, FlaA-PT1 and FlaA-PT3 followed by reduced bronchial
infiltration. The results suggest overall improvement in allergic features in the groups treated
with fusion proteins containing flagellin fused with allergen or its T cell epitopes compared to
the single components

GST (Per a 5) is a clinically relevant cross reactive allergen from Periplaneta. Per a 5 exhibits up
to 65% immune reactivity with cockroach hypersensitive sera and demonstrates cross reactivity
with fungal and mite GSTs. Bioinformatic analysis reveals phylogenetic similarity and
evolutionary conservation of Per a 5 with GSTs belonging to mite, fungal and helminth GSTs.
Presence of co-sensitizing cross reactive allergens in tropical regions may enhance risk of
associated clinical manifestations. Further analysis of its B and T cell epitopes has therefore been
undertaken to devise safe and efficacious therapeutic modalities.

CYSTEINE PROTEASE A MAJOR ALLERGEN FROM PHASEOLUS VULGARIS

Red kidney bean or Phaseolus vulgaris is a commonly consumed legume of Indian population
due to its high nutritional values. It contains eight major IgE-binding proteins two of which were
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