title: Histamine H4 receptor agonists have more activities than H4 agonism in antigen-specific human T-cell responses.
abstract: Histamine not only mediates immediate allergic reactions, it also regulates cellular immune responses. H4R is the most recently identified histamine receptor (HR). In the present study, we examined the in vitro effect of histamine and H4R agonists on the responses of human T cells to purified protein derivative from Mycobacterium tuberculosis (PPD) and to Cry j1, the major allergen of Cryptomeria japonica pollen. Dimaprit, clobenpropit and clozapine, which are H4R agonists, dose-dependently blocked both PPD-induced interferon-gamma and Cry j1-induced interleukin-5 production by both peripheral blood mononuclear cells (PBMCs) and antigen-specific T-cell lines. However, the addition of thioperamide, an H3R/H4R antagonist, as well as a mixture of d-chlropheniramine, famotidine and thioperamide, did not reverse the inhibition. Pretreatment of PBMCs with SQ22536 and 8-bromoadenosine-3',5'-cyclic monophosphorothioate, Rp-isomer, had varying abilities to reverse the inhibitory effects of H4R agonists, except for clobenpropit. Moreover, the addition of H4R agonists induced annexin-V expression on PBMCs, especially in CD19(+) and CD4(+) cells. cDNA microarray analysis revealed that, among 16,600 genes tested, increased expression following treatment with clozapine was seen in 0 x 8% of the genes, whereas decreased expression was seen in 3 x 0% of the genes. These results suggest that H4R agonists inhibit antigen-specific human T-cell responses, although H4R does not appear to be important for this effect. In addition, the present study indicated that there may be orphan receptors or HR subtypes which can bind dimaprit, clobenpropit and clozapine, and that can exert an inhibitory effect on antigen-specific cellular responses via a cAMP/cAMP-dependent protein kinase-dependent, apoptotic pathway.
authors.affiliation: Department of Otolaryngology-Head & Neck Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sugata
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Okano
authors.forename: Tazuko
authors.initials: T
authors.lastname: Fujiwara
authors.forename: Rie
authors.initials: R
authors.lastname: Matsumoto
authors.forename: Hisashi
authors.initials: H
authors.lastname: Hattori
authors.forename: Miki
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nishibori
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nishizaki
mesh_terms: D000262:Adenylyl Cyclases / Q000502:physiology; D000485:Allergens / Q000276:immunology; D052179:Antigens, Plant; D017209:Apoptosis; D002478:Cells, Cultured; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D015870:Gene Expression / Q000276:immunology; D006632:Histamine / Q000494:pharmacology; D017442:Histamine Agonists / Q000494:pharmacology*; D006633:Histamine Antagonists / Q000494:pharmacology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010940:Plant Proteins / Q000276:immunology; D012333:RNA, Messenger / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000819:agonists* / Q000276:immunology; D011968:Receptors, Histamine / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D000074040:Receptors, Histamine H4; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D014373:Tuberculin / Q000276:immunology
chemical_list: D000485:Allergens; D052179:Antigens, Plant; C065290:Cry j I protein, Cryptomeria japonica; D018984:Epitopes, T-Lymphocyte; C418607:HRH4 protein, human; D017442:Histamine Agonists; D006633:Histamine Antagonists; D015848:Interleukin-5; D010940:Plant Proteins; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D011968:Receptors, Histamine; D000074040:Receptors, Histamine H4; D014373:Tuberculin; D006632:Histamine; D007371:Interferon-gamma; D000262:Adenylyl Cyclases