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.