ISSN: 1314-6246 Kostova et al. J. BioSci. Biotechnol. 2015, 4(3): 271-283. RESEARCH ARTICLE http://www.jbb.uni-plovdiv.bg 271 Zhivka Kostova Tsvetelina Batsalova Dzhemal Moten Ivanka Teneva Balik Dzhambazov Characteristics of T-cell and B-cell immune respoonses to pollen allergens in Bulgarian patients with pollinosis Authors’ address: Faculty of Biology, Plovdiv University, Plovdiv, Bulgaria. Correspondence: Balik Dzhambazov Faculty of Biology Plovdiv University 24, Tsar Assen Str. 4000 Plovdiv, Bulgaria. Tel.: +359 32 261535 e-mail: balik@uni-plovdiv.bg Article info: Received: 30 January 2015 Accepted: 6 July 2015 ABSTRACT Characterization of the pollen allergens and identification of the main T-cell and B- cell epitopes is of crucial importance, since the clarification of the cellular and molecular mechanisms will allow long-term control of this type allergic diseases and development of safe immunotherapeutic medication. The objective of this study was to identify which pollen allergens are responsible for the T-cell activation in atopic patients with pollinosis and to determine whether the same allergens are responsible for the IgE-mediated reactions. Thirty-seven patients with pollinosis and thirteen non-allergic subjects were recruited. Peripheral blood samples were collected out of the pollen season. T-cell responses (IFN-γ production) towards different pollen allergens and levels of pollen specific IgE and IgG in the sera were measured by ELISA. The T-cell reactivity in most patients was directed towards the grass pollen B1, tree pollen I and autumn pollen B5. 70% of the allergic individuals responded to allergens from Lolium perenne, 84% to Dactylis glomerata, 11% to Phleum pratense, 65% to Betula pendula and 70% to Taxus baccata. Elevated serum levels of specific IgE in the allergic patients (p<0.01) were measured against the tree pollen I and autumn pollen, which include widespread deciduous trees (birch, willow, poplar and yew) and Artemisia absinthium, respectively. Our results show that the T- cell reactivity and antibody responses may be directed towards different or the same allergens. In addition, we propose that short synthetic peptides, which contain overlapping T- and B-cell epitopes can be used for specific immunotherapy treatment if they lack antibody recognition domains. Key words: pollen allergy, T-cell responses, B-cell responses, allergens Introduction Allergic diseases are defined as multifactorial, heterogeneous disorders caused by the interaction of environmental and genetic factors (Takai & Ikeda, 2011). Their pathogenesis is determined by the immune system – overproduction of IgE, abnormalities in the receptor for IgE or impaired Th2 cell differentiation. Sources of allergens (such as pollen) can produce or contain proteases, which are allergens. It is assumed that the proteolytic activities of these proteases are involved in the pathogenesis of the allergy by facilitating the passage of allergens through tissue barriers, breaking down different molecules, which affects the functions of cells and the immune responses (Takai & Ikeda, 2011). During the last years, the allergic diseases have become a serious health problem for most European countries, which reported a drastic increase of their distribution only for several decades, and now affected at least 20% of the population (Evans III, 1993; Burney et al., 1997; D'Amato et al., 1998; Brożek et al., 2010). There are comparatively few investigations concerning the frequency of pollen allergies in Bulgaria and specificity of the immune response of the allergic patients. Studying the range and quantity of pollen grains outdoors and indoors during the pollen seasons in 1989 and 1990, Yankova