title: Detection of MHC class II transcripts in lymphoid tissues of the common carp (Cyprinus carpio L.).
abstract: In all vertebrates studied to date, the expression of MHC class II genes is known to be restricted to a limited number of tissues and cell types. In order to have a better understanding of the function of the equivalent genes in teleost fish, the distribution of MHC class II beta transcripts (Cyca-DAB) in the common carp (Cyprinus carpio L.) was investigated. RNA was isolated from tissues and leucocytes, cDNA was produced, and amplification of the Cyca-DAB genes was carried out by PCR. Of the organs with known immunological function, the highest level of Cyca-DAB transcription was found in the thymus. Despite their expected different cellular organization, total blood, head kidney, spleen and the second segment of the gut had similar Cyca-DAB expression levels. No class II transcripts were detected in the skeletal muscle. The studies carried out with leucocytes isolated from the lymphoid tissues point to a direct correlation between the levels of expression and the amounts of surface immunoglobulin positive (sIg+) cells present in the different cell fractions. However, thymus leucocytes did not follow this correlation since the highest level of class II expression was found in a thymocyte fraction that contained very low numbers of Ig+ cells. In PBL the Ig+ cells were highly positive whereas the Ig- were weakly positive. Adherent leucocytes shown to be class II positive, although adherent cells from PBL show a lower level of expression compared to those from the spleen and head kidney.
authors.affiliation: Wageningen Agricultural University, The Netherlands.
authors.forename: P N
authors.initials: PN
authors.lastname: Rodrigues
authors.forename: T T
authors.initials: TT
authors.lastname: Hermsen
authors.forename: J H
authors.initials: JH
authors.lastname: Rombout
authors.forename: E
authors.initials: E
authors.lastname: Egberts
authors.forename: R J
authors.initials: RJ
authors.lastname: Stet
mesh_terms: D000818:Animals; D001483:Base Sequence; D002347:Carps / Q000276:immunology*; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D000949:Histocompatibility Antigens Class II / Q000032:analysis* / Q000235:genetics; D016130:Immunophenotyping; D007962:Leukocytes / Q000737:chemistry / Q000145:classification; D008221:Lymphoid Tissue / Q000737:chemistry / Q000276:immunology; D008969:Molecular Sequence Data; D011947:Receptors, Antigen, B-Cell / Q000235:genetics; D014018:Tissue Distribution / Q000235:genetics / Q000276:immunology; D014158:Transcription, Genetic / Q000276:immunology*
chemical_list: D000949:Histocompatibility Antigens Class II; D011947:Receptors, Antigen, B-Cell