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J H Fechner

Publications and source records attributed to J H Fechner.

28 records · Page 2Linked to original sources
PubMed1994

Immunity to MHC class I antigen after direct DNA transfer into skeletal muscle.

Plasmid cDNA encoding the alpha-chain of either membrane-bound (pcRT.45) or secreted (pcRQ.B3) RT1Aa MHC class I Ag were transferred to Lewis (RT1(1)) rat skeletal muscle by direct injection. Rats were challenged 7 days later with an ACI (RT1a) heterotropic heart transplant, and cardiac allograft survival, RT1Aa-specific antibody levels, and frequency of ACI-specific CTL were monitored. Graft rejection was accelerated by > or = 2 days in an Ag-specific and dose-dependent manner in pcRT.45-injected rats. The pcRQ.B3-injected rats also rejected grafts more rapidly; however, graft rejection was accelerated by only 1 day, and graft infiltrates were less pronounced than in pcRT.45-injected rats. Injection of pcRT.45 resulted in an increase in ACI-specific CTL precursor frequency 3 days post-transplant, whereas there was no significant change in rats pretreated with pcRQ.B3 injection. Compared with rats injected with a control plasmid encoding firefly luciferase, transfer of pcRT.45 resulted in an increase in RT1Aa-specific IgG and IgM antibody 3 days after heart transplantation. Transfer of pcRQ.B3 resulted in a similar mean increase in RT1Aa-specific IgG and IgM antibody after transplantation, but the variability from rat to rat was greater, with some animals exhibiting strong priming, and others showing little or no priming by gene injection. Our results suggest that skeletal muscle can express either membrane-bound or secreted MHC class I Ag after gene transfer, but that the membrane-bound form is more immunogenic than the secreted form in the high responder Lewis rat. Direct DNA transfer to skeletal muscle provides a rapid and specific approach to studying immunity to allogeneic MHC Ag.

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PubMed1994

Use of donor serum to prevent passive transfer of hyperacute rejection.

Organ transplantation in presensitized recipients continues to be contraindicated for heart and kidney recipients due to the risk of hyperacute rejection, which has no known treatment at this time. We tested whether donor serum, which contains soluble MHC class I antigen, is able to neutralize the effect of anti-donor antibody in the recipient and prevent hyperacute or accelerated rejection. A rat model of passive immunization was used to test the role of anti-donor antibody in hyperacute rejection. Seven of 10 recipients of hyperimmune serum (HyS), derived from Lewis rats (RT1l) following 3 ACI (RT1a) skin grafts, developed hyperacute or accelerated rejection. Intravenous injection of ACI serum prior to the HyS administration prevented hyperacute rejection in all recipients tested. When third-party (Wistar-Furth, RT1u) serum was given to Lewis rats injected with HyS, hyperacute rejection was not abrogated. When examining the mechanism of this effect, a simple antibody blocking phenomenon was found to be unlikely since flow cytometry analysis showed that ACI serum needed to be present at > or = 256-fold excess compared to HyS to block anti-ACI antibody binding to RT1.Aa+cells by 50%. We tested whether the RT1.Aa class I antigen in ACI serum had other biologic properties that resulted in the prolonged graft survival. However, removal of RT1.Aa antigen from ACI serum prior to use in the passive transfer model did not abrogate the graft prolongation observed previously. These data suggest that components of donor serum other than MHC class I antigen may be useful for preventing the antibody-mediated component of hyperacute rejection.

Animals↗
PubMed1993

Activation of HLA-A2-specific memory B cells in severe combined immunodeficient mice.

Peripheral blood leukocytes of all five HLA-A2-sensitized patients produced significant levels of human IgG (> or = 0.25 micrograms/ml) following polyclonal activation in vitro, but PBLs from only one patient (K.H.) who had been transfused recently (< 4 weeks) produced detectable anti-HLA-A2 IgG. PBLs from this in vitro responder and from one in vitro nonresponder (L.G.) were transferred intraperitoneally into SCID mice. A low level (range, 5-40 ng/ml) of human anti-HLA-A2 IgG was detected in the serum of the mice without additional stimulation. This anti-HLA-A2 IgG response was boosted (range, 40-200 ng/ml) when mice received a human skin xenograft or an early challenge with x-irradiated human leukocytes intraperitoneally. Although the anti-HLA antibodies produced were specific for HLA-A2, the boosting of anti-HLA-A2 IgG production did not require the expression of the HLA-A2 protein, since either HLA-A2-negative skin xenografts or HLA-identical x-irradiated PBLs enhanced the production of anti-HLA-A2 IgG. Dose-response of transferred PBLs and kappa:lambda composition of individual mouse anti-HLA-A2 production suggested that low-frequency human memory B-cell clones were stimulated to proliferate and/or triggered to become high Ab secretors by skin graft or PBL boost.

Animals↗
PubMed1992

Chronic human skin graft rejection in severe combined immunodeficient mice engrafted with human PBL from an HLA-presensitized donor.

Mice with severe combined immunodeficiency (C.B-17 scid [SCID]) accepted xenografts of adult human peripheral blood leukocytes injected intraperitoneally as evidenced by production of human immunoglobulin (IgG and IgM), and circulation of human leukocytes in peripheral blood. SCID mice also accepted human split-thickness skin xenografts. Passenger leukocytes present in small numbers in such skin grafts could also recirculate in host peripheral blood and make detectable levels of human immunoglobulin. To test the immunocompetence of the transferred human PBL, SCID mice received a human skin xenograft from a second donor (HLA-mismatched with the PBL donor) either before (n = 6) or after (n = 23) xenografting of PBL. Skin was monitored daily for signs of rejection, and rejection was scored by histology 3-4 weeks after the second graft (PBL or skin) was placed. Of 19 SCID injected with PBL from an HLA presensitized patient (L.G.), 7/19 (37%) rejected a subsequent HLA-mismatched skin xenograft. Two of six SCID (33%) rejected a previously established skin xenograft when PBL were administered afterward. The rejection of the human skin was chronic, of relatively late onset (3-4 weeks), and was characterized grossly by contraction, glassy surface, and thickening. Histopathologic examination showed lymphocyte infiltration into the dermis with endothelial cell cuffing and destruction of capillaries, as well as lymphocyte tagging of the basal epidermis, hyperkeratosis, lymphocyte exocytosis and single epidermal cell necrosis. Immunostaining with monoclonal antibody to human CD2 or mouse CD3 revealed that human, but not mouse T lymphocytes were tagging the dermis/epidermis junction and infiltrating the epidermis of rejecting skin grafts. We conclude that a form of human skin graft rejection may be reproduced in an SCID mouse. The immune status of the transferred cells (sensitized vs. normal) and the lymphocytes ability to recirculate in SCID peripheral blood appear to be factors limiting the rejection process.

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PubMed1989

Localization of prolactin binding sites in ring dove brain by quantitative autoradiography.

Specific binding sites for prolactin have been previously detected and characterized in ring dove brain membranes. In order to map the distribution of these sites, specific binding of 125I-ovine prolactin was examined in slide-mounted sections of 6 male and 6 female ring dove brains by in vitro film autoradiography and densitometry. Analysis of 34 brain regions revealed a sex-specific pattern in specific binding activity. Although no significant sex differences were observed in any individual brain region, a trend in this direction was observed in the preoptic area. Specific binding levels in which the lower limit of the 99% confidence interval was greater than zero were detected in choroid plexus, medial habenula, lateral mesencephalic nucleus, hippocampus, parahippocampal area, preoptic area and 4 hypothalamic sites: paraventricular nucleus, ventromedial nucleus, suprachiasmatic nucleus, and tuberal region. Autoradiographic analysis of specific binding in cerebellum, ventromedial hypothalamus, and hippocampus/parahippocampus yielded relative differences that closely approximated those obtained in binding studies on tissue homogenates from these regions. These results suggest possible sites of prolactin action in altering behavioral state and neuroendocrine function in this species.

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