In vivo allograft rejection in a bony fish Dicentrarchus labrax (L.): characterisation of effector lymphocytes.
Lymphoid cell subpopulations involved in allograft rejection in the teleost Dicentrarchus labrax were characterised at the ultrastructural level and quantified by using monoclonal antibodies against T- and B-lymphocytes. T-cells positive for T-cell receptor beta-chain (TcR beta) were detected by reverse transcription/polymerase chain reaction (RT-PCR) and in situ hybridisation by using RNA probes for TcR beta. Flow cytometry detected a similar percentage of T- and B-lymphocytes (around 17%) in the leucocyte-enriched fraction from allografts. Two different types of T-lymphocytes (DLT 15-immunoreactive) infiltrating the allografts were identified by cytomorphology: small cells with high nuclear/cytoplasmic ratio and cells with a higher cytoplasmic content. RT-PCR revealed a single band (513 bp) corresponding to the TcR beta. In situ hybridisation showed that TcR beta-positive cells in the grafted muscle fibres were less numerous compared with DLT 15-positive cells, as evidenced in parallel sections, suggesting that cytotoxic cells might express different TcR phenotypes. DLIg 3-immunoreactive Ig-producing lymphocytes had: 1) a high nuclear/cytoplasmic ratio or 2) a larger size similar to that of pre-plasma cells (plasma cells lacked any membrane labelling).
Romano
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N
Department of Environmental Sciences, Tuscia University, 01100 Viterbo, Italy. NROMANO@UNITUS.IT
Baldassini
M R
MR
Buonocore
F
F
Picchietti
S
S
Mastrolia
L
L
Abelli
L
L
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000648:ultrastructure*; D001492:Bass / Q000276:immunology*; D005434:Flow Cytometry; D006084:Graft Rejection; D017403:In Situ Hybridization; D007962:Leukocytes / Q000276:immunology / Q000648:ultrastructure; D016131:Lymphocyte Subsets / Q000276:immunology / Q000648:ultrastructure*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology / Q000648:ultrastructure*; D014184:Transplantation, Homologous / Q000276:immunology*
D016693:Receptors, Antigen, T-Cell, alpha-beta