[Autotransplantation of the spleen in rats: development, function and cytokine expression in intra-omental and subcutaneous regeneration].

The implantation of splenic tissue at different implantation sites (intraomental and subcutaneous) into one animal (Lewis rats) results in the development of splenic nodules at both sites. In a quantitative immunohistological analysis of splenic compartments such as red pulp (RP), periarteriolar lymphoid sheaths (PALS), marginal zone (MZ) and follicles (F) the T-cell reduction was related to the T(helper) cells in the MZ and T(supp/cyt) cells in the PALS. In contrast, the cell density of B cells and ED-1+ macrophages in the PALS and T(supp/cyt) cells in the MZ was increased. Significant differences between the implantation sites were restricted to CD5+ cells (thymocytes and T cells) in the MZ and OX-33+ cells (B cells with LCAB antigen) in the PALS. The reorganisation of the compartments of subcutaneous implants showed a delay of one week as compared with omental ones. Functional assays like haemolytic plaque assay, mitogen stimulation and mixed lymphocyte assay elicited an analogous delay of the functional maturation of IgM-positive B cells, a reduced proliferation of both transplant groups after pokeweed mitogen (PWM) stimulation, a decreased response after lipopolysaccharide (LPS) stimulation in solely subcutaneous replants and no differences concerning the mitogens concanavalin A (ConA) and phytohaemagglutinin (PHA). Both transplant groups showed a significantly reduced allogeneic response. The results of the functional analysis and the abnormal mRNA expression of Il-5, Il-6 (Interleukin 5 and 6), GMCSF (Granulocyte-Macrophage-Colony-Stimulation-Factor) and IFN-gamma (Interferon gamma) in subcutaneous replants indicate subtle molecular alterations (independent of a spleen-like immunoarchitecture) at this site.(ABSTRACT TRUNCATED AT 250 WORDS)