The area around Río Blanco, in the Orán department in the north of the Argentinian province of Salta, is endemic for American tegumentary leishmaniasis. In an attempt to facilitate the identification of the Lutzomyia species in this area, sequences of the gene coding for the 18S ribosomal RNA (rRNA) of sandflies caught in a Shannon trap were explored, by a combination of PCR and analysis of restriction-fragment-length polymorphism (RFLP). The products from the PCR, which employed two primers developed specifically for this study (Lu.18S 1S and Lu.18S AR), were cloned into a commercial vector (pGEM-T Easy) so that their nucleotide sequences could be investigated. In the RFLP analysis, the products of single and double digestion with the AfaI and HapII restriction enzymes were separated by electrophoresis in 3% or 4% agarose. Taken together with the results of a morphological investigation of the flies, the resultant DNA fragment patterns were sufficient to identify most of the sandflies caught as Lu. neivai. Although two other species, Lu. cortelezzii and Lu. sallesi, were collected, they were relatively rare and only identified morphologically. A single digestion of the 18S-rRNA gene sequences with AfaI or HapII appeared sufficient and useful for the identification of Lu. neivai from the north of Salta province, and for several other Lutzomyia species.

ABSTRACT. In the present study, the changes of gene expression profile in dendritic cell (DC)-derived DC2.4 cells sensitized with two allergenic chemicals were analyzed by microarray analysis to develop a basis for an in vitro assessment system of type IV allergenic chemicals. Consequently, 26 genes were significantly up-regulated, and 53 were down-regulated in both groups. Interestingly, some of upregulated genes were associated with the maturation process of DCs. A set of genes was further evaluated by real-time reverse transcription-polymerase chain reaction to identify the gene expression changes specifically induced by type IV allergy-inducible chemicals in DC2.4 cells, and 2 possible candidates, syndecan-1 (Sdc1) and smoothened (SMO) genes were identified. Thus, up-regulation of Sdc1 gene and down-regulation of SMO gene in DC2.4 cells may be diagnostic markers for the screening of type IV-allergenic chemicals. KEY WORDS: chemical, dendritic cell, microarray analysis, type IV allergy.J. Vet. Med. Sci. 70 (7): [673][674][675][676][677][678][679][680] 2008 Allergic contact dermatitis (ACD), a type IV allergy, is one of the most common inflammatory diseases of the skin with unknown genetic basis and is often an occupationally related disorder in industrialized countries with an important socio-medical impact [14,28]. At present, many chemicals are considered to have allergenic potency and thus risk assessment of such chemical substances is important. ACD has been intensively studied, and the development of an allergic hypersensitivity reaction in the skin is considered to be processes depending on the induction of specific T-lymphocyte responses [23]. At the initial step, chemical allergens exposed on the skin are recognized by Langerhans cells (LCs), the principal DC residing in the epidermis and known to play a key role in the development of ACD. Following an encounter with a chemical allergen, LCs are activated and subsequently migrate from the skin to the draining lymph nodes, undergoing a maturation process during the journey [20,22].For many years, guinea pigs have been applied for the hazard analysis of skin-sensitizing chemicals [9,26]. Recently, the local lymph node assay (LLNA) was developed in mice as an alternative approach based on the characterization of initial proliferative responses in draining lymph nodes caused by chemicals exposure [16,21,34,39], and this method is now widely used for estimation of the allergenic potency of chemical substances. Although these approaches are sensitive and reliable, more advantageous ways in terms of cost performance, safety, readiness and animal welfare are expected. More recently, in vitro assay for chemical substances with allergenic potency is extensively explored by using cultured cells, especially macrophages [5,41]. In these experiments, up-regulation of several molecules including cell surface markers were reported to be induced by chemical exposure, suggesting that these markers may be candidates for evaluating chemicals with allergenic potency [5...