Cockroach (CR) allergies caused by the American cockroach hyave been recognized to be repsonsible for IgE-mediated type I hypersensitivity worldwide. Per a 10 is one of the recognized main allergens of the American CR. In a previous study, we examined another American CR allergen, Per a 9 in patients with CR allergies and examined epitope sequences in this allergen. In the present study, we aimed to examine epitope sequences in the Per a 10 allergen. for this purpose, the Per a 10 gene was cloned and expressed in Escherichia coli (E. coli) systems. Our results revealed that 9 out of 16 (56.3%) sera from patients with American CR allergies reacted to Per a10, as assessed by ELISA, confirming that Per a 10 is a major allergen of the American CR. Our results also revealed that the expression of CD63 and CCR3 on passively sensitized basophils (obtained sera of patients with American CR allergies) was increased by approximately 2.3-fold, indicating that recombinant Per a 10 is functionally active. In addition, 3 immunoinformatics tools, namely the DNAStar Protean system, the Bioinformatics Predicted Antigenic Peptides (BPAP) system and the BepiPred 1.0 server were used to predict the peptides and the results revealed 8 peptides (2-12, 55-67, 98-120, 125-133, 149-160, 170-182, 201-208 and 223-227) as potential B cell epitopes of the Per a 10 allergen. Moreover, Per a 10 was predicted to have 3 T cell epitope sequences, namely 83-92, 139-147 and 162-170. The findings of our study on the CR allergen may prove to be useful in the development of peptide-based vaccine for the prevention and/or treatment of CR allergies.
Toona microcarpa Harms is a tonic, antiperiodic, antirheumatic, and antithrombotic agent in China and India and an astringent and tonic for treating diarrhea, dysentery, and other intestinal infections in Indonesia. In this study, we prepared ethyl-acetate extract from the air-dried leaves of Toona microcarpa Harms and investigated the anticoagulant activities in vitro by performing activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) assays. Antiplatelet aggregation activity of the extract was examined using adenosine diphosphate (ADP), collagen, and thrombin as agonists, and the inhibitions of factor Xa and thrombin were also investigated. Bleeding and clotting times in mice were used to determine its anticoagulant activities in vivo . It is found that Toona microcarpa Harms leaf extract (TMHE) prolonged APTT, PT, and TT clotting times in a dose-dependent manner and significantly inhibited platelet aggregation induced by thrombin, but not ADP or collagen. Clotting time and bleeding time assays showed that TMHE significantly prolonged clotting and bleeding times in vivo . In addition, at the concentration of 1 mg/mL, TMHE inhibited human thrombin activity by 73.98 ± 2.78%. This is the first report to demonstrate that THME exhibits potent anticoagulant effects, possibly via inhibition of thrombin activity.
Per a 9 is a major allergen of the American cockroach (CR), which has been recognized as an important cause of imunoglobulin E-mediated type I hypersensitivity worldwide. However, it is not neasy to obtain a substantial quantity of this allergen for use in functional studies. In the present study, the Per a 9 gene was cloned and expressed in Escherichia coli (E. coli) systems. It was found that 13/16 (81.3%) of the sera from patients with allergies caused by the American CR reacted to Per a 9, as assessed by enzyme-linked immunosorbent assay, confirming that Per a 9 is a major allergen of CR. The induction of the expression of CD63 and CCR3 in passively sensitized basophils (from sera of patients with allergies caused by the American CR) by approximately 4.2-fold indicated that recombinant Per a 9 was functionally active. Three immunoinformatics tools, including the DNAStar Protean system, Bioinformatics Predicted Antigenic Peptides (BPAP) system and the BepiPred 1.0 server were used to predict the potential B cell epitopes, while Net-MHCIIpan-2.0 and NetMHCII-2.2 were used to predict the T cell epitopes of Per a 9. As a result, we predicted 11 peptides (23-28, 39-46, 58-64, 91-118, 131-136, 145-154, 159-165, 176-183, 290-299, 309-320 and 338-344) as potential B cell linear epitopes. In T cell prediction, the Per a 9 allergen was predicted to have 5 potential T cell epitope sequences, 119-127, 194-202, 210-218, 239-250 and 279-290. The findings of our study may prove to be useful in the development of peptide-based vaccines to combat CR-induced allergies.