Enzymatic Activity of Grass Native Allergenic Extracts Is Eliminated in Depigmented Allergoids
Transcript of Enzymatic Activity of Grass Native Allergenic Extracts Is Eliminated in Depigmented Allergoids
J ALLERGY CLIN IMMUNOL
FEBRUARY 2013
AB110 Abstracts
SUNDAY
401 Depigmented-Polymerized and Native Extracts of BirchPollen Exhibit Different IgG Epitopes Specific to Bet v1 and Bet v 2
Jer�onimo Carn�es, Ma Angeles L�opez Matas, Ma Teresa Gallego, Tamara
Aranda, Mar�ıa Morales, Jos�e Ram�on Leonor, Victor Miguel Iraola; Labo-
ratorios LETI, S.L., Tres Cantos, Spain.
RATIONALE: Induction of allergen specific IgG antibodieswith capacity
to block allergen-IgE interaction has been suggested as mechanism for
clinical efficacy, and long term benefit of allergen specific immunotherapy.
Induction of these blocking antibodies by depigmented-polymerized
allergoids (Dpg-Pol) has been demonstrated previously. The objectives
of this study were to investigate the epitope specificity of IgG antibodies
induced byDpg-Pol and native unmodified allergen extracts of birch pollen
(Betula alba).
METHODS: Sera from rabbits immunized with native and Dpg-Pol
extracts of birch pollen were obtained, and specific IgG to birch, Bet v
1 and Bet t v 2 were measured by ELISA. Linear synthetic peptides of
12 aa, overlapping 6 aa, of Bet v 1 and Bet v 2 were covalently bound to a
cellulose membrane, incubated with rabbit sera and with the secondary
antibody, and developed by chemiluminiscence.
RESULTS: Serum samples from rabbits immunized with native birch
pollen extracts recognised 11 epitopes from Bet v 1, while serum samples
from Dpg-Pol-immunized animals recognised 8. For Bet v 2, 8 epitopes
were recognized by IgG from animals immunized with native extracts, and
9 epitopes from Dpg-Pol immunized animals. There are some epitopes
recognized by both extracts, but some of them are recognized only by the
Dpg-Pol extract.
CONCLUSIONS: Depigmented-polymerized birch pollen allergen
extract stimulates the synthesis of specific IgG antibodies which recognize
common but also novel epitopes from the major allergens Bet v 1 and Bet
v 2, which may be part of the mechanism of action of this treatment when
used for allergen immunotherapy.
402 Enzymatic Activity of Grass Native Allergenic Extracts IsEliminated in Depigmented Allergoids
Victor Miguel Iraola, Jos�e Ram�on Leonor, Mar�ıa Morales, Ma Angeles
L�opez Matas, Ma Teresa Gallego, Jer�onimo Carn�es; Laboratorios LETI,
S.L., Tres Cantos, Spain.
RATIONALE: Different enzymes, that could be involved in the patho-
genesis of allergy, have been described in pollen extracts. Besides,
enzymatic activity is considered as a relevant issue for the stability of
allergen extracts. It has been demonstrated that Depigmented-polymerized
(Dpg-Pol) extracts have a reduced enzymatic activity compared to their
respective native extracts in mites, but there was no information regarding
pollens. The objectives of this study were to characterize and to compare
the enzymatic activity of both type of extracts from different species of
grasses
METHODS: Native and their corresponding Dpg-Pol extracts of pollen
of Dactylis glomerata, Festuca elatior, Lolium perenne, Phleum pratense,
and Poa pratensis were manufactured, and characterised by Lowry and
SDS. The gelatinolytic activity was determined by Gelatin zymography
in reduced and non-reduced conditions, the Cysteine protease activity
by using the L-1460 peptide (Pyr-Phe-Leu-pNa) as substrate and papain
as the standard , and 19 different enzymatic activities by the Api-Zym
system.
RESULTS: Gelatinolitic activity was detected, in non-reduced condi-
tions, in native extracts mainly around 45, 65 and above 100 kDa bands,
but not in their respective Dpg-Pol extracts. In the same way, cysteine
protease and most of the enzymatic activities detected by Api-Zym in the
native extracts are importantly or totally inactivated in the Dpg-Pol
extracts.
CONCLUSIONS: Different enzymes, including pollen proteases, are
present in intact grass pollen extracts. Chemical modification (depigmen-
tation-polymerization) eliminates most of the enzymatic activity present in
native extracts, suggesting a higher stability in these extracts
403 Characterizing the 12 Amb a 1-U Ragweed AllergyImmunotherapy Tablet Adverse Event Profile in Adults withRagweed-Induced Allergic Rhinoconjunctivitis
Jennifer Maloney, MD1, Gary D. Berman, MD, FAAAAI2, David I.
Bernstein, MD, FAAAAI3,4, Bobby Q. Lanier, MD, FAAAAI5, Amarjot
Kaur, PhD1, Nancy Liu, PhD6, Hendrik Nolte, MD, PhD1; 1Merck Sharp
& Dohme Corp., a subsidiary of Merck & Co., Inc, Whitehouse Station,
NJ, 2Allergy and Asthma Specialists, Minneapolis, MN, 3University of
Cincinnati, Cincinnati, OH, 4Bernstein Clinical Research Center, LLC,
Cincinnati, OH, 5North TX Institute for Clinical Trials, Fort Worth, TX,6Merck, Whitehouse Station, NJ.
RATIONALE: Ragweed allergy immunotherapy tablet (AIT) efficacy
trials suggest 12 Amb a 1-U as the optimal dose for patient self-
administration at home. A large trial was conducted to supplement and
support the safety profile.
METHODS: Adults with ragweed pollen–induced ARC with/without
asthma were randomized 2:1 to 28 days’ treatment with ragweed AIT
12 Amb a 1-U or placebo. The trial occurred outside ragweed season. Dose
1 of study medication was administered at the physician’s office; subse-
quent doses were taken at home. The primary objectivewas to characterize
the adverse event (AE) profile of AIT 12 Amb a 1-U.
RESULTS: 610 subjects were randomized to AIT 12 Amb a 1-U and
304 to placebo. 240 (39.4%) and 64 (21.1%) subjects receiving AIT and
placebo respectively reported treatment-related AEs; the most common
were local application-site reactions in the mouth, throat, and ear. Of these
treatment-related AEs, approximately 96% were mild or moderate in
severity. No serious treatment-related AEs were reported with AIT
treatment. 2.8% of AIT subjects discontinued due to treatment-related
AEs vs 0.7% receiving placebo (P50.029). Two systemic allergic reac-
tions developed: one subject receiving active treatment self-administered
epinephrine appropriately, and proceeded to the ER; one subject receiving
placebo with history of latex hypersensitivity presumably reacted to
inadvertent latex exposure. No new safety signals emerged.
CONCLUSIONS: In this study, AEs observed with ragweed AIT 12 Amb
a 1-U were primarily local application-site reactions and were predomi-
nantly mild or moderate in severity. Ragweed AIT may hold potential for
more convenient at-home allergy immunotherapy dosing.