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J Kampinga

Publications and source records attributed to J Kampinga.

At least 37 records · Page 2Linked to original sources
PubMed1990

Inhibition of T cell responses in vitro by an antibody against a novel lymphocyte surface molecule (QCA-1).

We have identified an antigen present on the surface of lymphocytes in the rat which appears to play an important role in the preliminary stages of the immune response. This antigen, which we have called quiescent cell antigen 1 because of its apparent expression only on quiescent cells, is present on the majority of peripheral T and B cells and a small percentage of thymocytes which are located mainly in the medullary region. SDS-PAGE analysis of membrane molecules shows two bands on unreduced gels at approximately 43 and 47 kd. On reduction the bands ran at approximately 46 and 60 kd. When a monoclonal antibody against this antigen (HIS45) is present in an allogeneic mixed leukocyte reaction, it inhibits the proliferation of responding cells completely. When the antibody HIS45 is added to cytotoxic T lymphocyte mediated lysis assays it does not inhibit lysis nor does it affect the specificity of this lysis. Comparison with other antibodies which have been reported to affect lymphocyte function in rats and in other species fail to reveal any which have similar properties.

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PubMed1990

Vascular thymus transplantation in rats. Technique, morphology, and function.

A new method of thymus transplantation is introduced, in which the graft is directly connected with the recipient's vascular system. This procedure was used both in euthymic rats and congenitally athymic nude rats. At all tested intervals after transplantation thymus grafts hardly differed from the recipient's own thymus in immunohistology and lymphocyte yield. In athymic nude rats, T cell-dependent immunity, tested by mitogen- and alloantigen-induced T cell responses, as well as by antibody production and delayed-type hypersensitivity after ovalbumin administration, showed that vascular thymus grafts could generate T cell functions to euthymic control levels. We conclude that the technique of vascular thymus transplantation represents a valuable tool, either in fundamental research on thymus function, or for the purpose of immune (re)constitution.

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PubMed1990

In vitro and in vivo effects of monoclonal antibodies against T cell subsets on allogeneic and xenogeneic responses in the rat.

The Syrian hamster-to-rat represents an example of a concordant species difference, and therefore organ transplants using the hamster as the donor and the rat as the recipient are not rejected hyperacutely, as in discordant species combinations. Cellular mechanisms of xenogeneic rejection of hamster hearts by rats were studied both in vitro and in vivo, using monoclonal antibodies to rat T cell antigens. The results of this study reveal that CD4-positive cells of rats proliferated in vitro to both allogeneic stimulators and xenogeneic stimulators from a concordant strain, but required accessory cells of the responder phenotype to proliferate to discordant human stimulators. Monoclonal antibody therapy was used to prevent graft rejection in allogeneic and xenogeneic species combinations, using the rat as the recipient. Treatment with anti-CD4 antibodies was effective in prolonging allograft survival across a full MHC mismatch. No rejection occurred during antibody therapy, and long-term graft survival was achieved in 1/3 of transplanted grafts. The same monoclonal antibody therapy led to increased survival of grafts from hamster donors, but all of these grafts were rejected during therapy, and no long-term graft survival was achieved. Anti-CD8 antibody therapy, combined with anti-CD4 did not improve survival of hamster hearts in rats. Addition of cyclosporine to the anti-CD4 regimen also did not improve graft survival. Injection of an anti-T cell receptor antibody was no better than the anti-CD4 antibody in prolonging the survival times of heart grafts from the concordant xenogeneic species. These data suggest that the rejection of concordant xenogeneic tissue is not wholly a T cell-dependent phenomenon.

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PubMed1990

RT7-defined alloantigens in rats are part of the leucocyte common antigen family.

Haemopoietic cells carry a variety of cell-surface molecules, some of which are known to have allotypic variation. In rats, the RT7 alloantigenic system has been well documented using alloantisera. We have produced the first mouse hybridoma cell line secreting an antibody, HIS41, which binds to leucocytes of rat strains carrying the RT7.2 but not the RT7.1 determinant. An IgG2b isotype switch variant (HIS41.2b) of the original HIS41 (IgG1 isotype) was also made. HIS41 showed a clear and discrete binding in immunofluorescent and histological experiments and has already been used in several studies on haemopoietic cell turnover and differentiation employing PVG rats congenic for RT7. The present study addresses the question of whether the RT7 gene products are members of the L-CA family, which has been a matter of controversy over the last decade. When using HIS41 for the analysis of tissue distribution and molecular weight of RT7 gene products, a strong similarity was evident with the data reported for the L-CA detected by MRC OX-1 and MRC OX-30. These two MoAb have been reported to bind to all members of the L-CA family. All haemopoietic cells, excluding erythrocytes and the more mature stages of erythropoiesis, stained with HIS41. The molecular weights of HIS41 binding molecules on thymocytes and peripheral T cells were comparable to the L-CA precipitated by MRC OX-1. Capping and sequential immunoprecipitation studies indicated that HIS41 and MRC OX-30-binding molecules were identical. MRC OX-1, however, appeared to bind only a subset of these molecules. Thus, our study confirms the identity of RT7.2 gene products and L-CA. It also revealed a difference between MRC OX-1 and MRC OX-30 not noticed previously.

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PubMed1990

Kinetics of thymocyte regeneration in adult adriamycin treated rats: evidence for an exclusive role of bone marrow derived cells.

This paper describes a new, less toxic and more selective approach to study the adult thymus. An adriamycin (ADR), sparing bone marrow (BM) stem cells and nontoxic to cells that are not in cycle during treatment, was used as a depleting agent in conjunction with vascular thymus transplantation. We were able to deplete the thymus of thymocytes without damaging its microenvironment as witnessed by intact antigen profiles of stromal cells. Two models were used in this study, (1) regeneration after ADR induced depletion with or without BM reconstitution either systemically or intrathymically and (2) thymocyte turnover or regeneration in vascularly transplanted thymi. In the latter model either normal thymus was grafted into ADR treated recipient or ADR depleted thymus was grafted into normal recipient. These experiments clearly show that intact BM function is a prerequisite for intact continued cellularity of the adult thymus. Although the resident thymocyte population possesses some limited proliferating potential, it clearly does not seem to have a permanent self-renewing capacity of intrathymic stem cells.

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PubMed1989

Cellular requirements for renal allograft rejection in the athymic nude rat.

This study has examined the ability of adoptively transferred CD4+ and CD8+ T cells to mediate rejection of a fully allogeneic DA renal graft in the PVG nude rat. Transfer, at the time of transplantation, of naive CD4+ T cells caused rapid graft rejection and primed CD4+ cells were several times more potent. In contrast, naive or specifically sensitized CD8+ cells were entirely ineffective at mediating renal allograft rejection. Whereas nonrejecting grafts showed only a mild cellular infiltrate, rejecting grafts in CD4+ reconstituted animals showed a substantial infiltrate and many of the infiltrating cells had a phenotype (MRC OX8+, MRC OX19-), consistent with NK cells. Experiments using a mAb (HIS 41) against an allotypic determinant of the leukocyte common antigen confirmed that the majority (greater than 80%) of the cellular infiltrate in rejecting grafts derived from the host rather than from the CD4+ inoculum. Infiltrating mononuclear cells, obtained from rejecting allografts 7 d after transplantation in CD4+-injected PVG nude hosts, showed high levels of in vitro cytotoxicity against not only kidney donor strain Con A blasts but also third-party allogeneic Con A blasts, as well as against both NK and LAK susceptible targets. When splenocytes from nontransplanted nude PVG rats were tested in vitro they also demonstrated high levels of lytic activity against both NK and LAK susceptible targets as well as allogeneic Con A blasts, which were not susceptible to lysis by spleen cells from euthymic rats. These findings suggest that injected CD4+ cells may cause renal allograft rejection by the recruitment of extrathymically derived, widely alloreactive cells into the kidney in this model of graft rejection.

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PubMed1989

A monoclonal antibody to a determinant of the rat T cell antigen receptor expressed by a minor subset of T cells.

A hybridoma producing the monoclonal antibody HIS42 was isolated from a fusion between spleen cells from a BALB/c mouse immunized with rat thymocytes and the fusion partner SP2/0. This antibody recognizes a minor subset of T cells in every haplotype of rat tested so far. The subpopulation of HIS42 positive T cells contains both CD4+ and CD8+ cells, in the same ratio as found in the peripheral T cell population. When bound to Sepharose beads, HIS42 induces T cell proliferation in the presence of interleukin-2. In contrast to lymph node T cells, a number of thymocytes were found to express HIS42 only in the cytoplasm or together with membrane expression. Most bright HIS42 surface labelled thymocytes were also positive for MRC OX-44, a marker predominantly identifying mature thymocytes. SDS-PAGE analyses of the membrane molecules immunoprecipitated by HIS42 show two bands on unreduced gels. One of these bands (85 kd) runs as two separate bands at 35 and 48 kd on reduction. The other much weaker broad band (approximately 100 kd) is hardly affected by reduced conditions. Taken together these data suggest that HIS42 is directed against a determinant on the rat T cell receptor for antigen, which is common to a small number of T cells.

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PubMed1989

A novel lymphocyte surface antigen recognized by the monoclonal antibody HIS45.

A hybridoma producing the monoclonal antibody HIS45 was isolated from a fusion between spleen cells from a Balb/c mouse immunized with rat bone marrow cells and the fusion partner SP2/0. This antibody recognizes a determinant present on the majority of peripheral T and B cells and a small percentage of thymocytes. In a xenogeneic mixed leucocyte reaction HIS45 completely inhibits the proliferation of responding cells. HIS45 does not inhibit natural killer cell-mediated lysis. Comparison with other antibodies which have been reported to effect lymphocyte function fail to reveal any which have similar properties.

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PubMed1989

Peripheral T cells in diabetes prone (DP) BB rats are CD45R-negative.

Diabetes prone BB (DP BB) rats are known to develop insulin dependent diabetes mellitus. In addition, a number of other immune abnormalities have been observed, like severe T lymphopenia, lack of CD8+ T cells, and lack of RT6+ T cells. Here we report double-labelling studies of lymph node T cells using MRC OX-32 (CD45R), and demonstrate that this T cell subset is absent in young adult DP BB rats. Since both RT6 and MRC OX-32 antigens are only expressed by mature peripheral T cells, it is tempting to speculate that the peripheral T cell pool of DP BB rats consists only of immature peripheral T cells, i.e. recent thymic emigrants.

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PubMed1989

Thymic epithelial antibodies: immunohistological analysis and introduction of nomenclature.

During the Workshop "The Thymus. Histophysiology and Dynamics in the Immune System', Rolduc, april 1989, a special workshop was hold to characterize monoclonal antibodies (mAb) to thymic epithelial cells (TEC) in thymus of man, mice, and rat. Twenty-five TEC-specific mAb's were evaluated for their immunohistological staining patterns on reference thymus, thymuses during ontogeny, various other organs (all tissues obtained from the species against the mAb was raised) and thymuses of other species. In this report only immunohistological results of reference thymuses and thymuses of other species are described. Based on the staining patterns on reference thymuses, mAb could be subdivided in 5 main groups. It is proposed to use these clusters of thymic epithelial staining patterns (CTES) to designate individual mAb, awaiting the possible incorporation in existing CD nomenclature for leucocyte differentiation antigens. The present immunohistological approach will be extended by additional analysis for which a protocol was designed. The ultimate goal of this TEC-mAb workshop is to get well-characterized reagents in the analysis of TEC-associated molecules with putative function in intrathymic T-cell processing.

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PubMed1989

Turnover of ED2-expressing macrophages in the thymus cortex of rats.

To investigate the turnover of thymic ED2+ cortical macrophages, vascular thymus transplantation in RT7-congenic rats were performed. Thymus graft cell suspensions were analyzed using ED2 in combination with congenic markers. Immunohistology of thymus graft sections was performed to demonstrate the immigration and persistence of these macrophages at several time points after transplantation. In contrast to other mobile thymus cells like thymocytes and interdigitating cells, most ED2+ cortical macrophages showed a slow turnover rate. At 76 days after transplantation more than 30% of ED2+ macrophages were still of donor origin. The migration properties of these macrophages are discussed in relation to their presumed role in thymocyte maturation and proliferation.

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PubMed1989

Organotin-induced thymus atrophy concerns the OX-44+ immature thymocytes. Relation to the interaction between early thymocytes and thymic epithelial cells?

After single oral application of the organotin compound di-n-butyltindichloride (DBTC) to rats, a reversible dose-dependent thymus weight reduction is observed. This is maximal at day 4 and recovers to the control value approximately at day 9 after administration. In this study the changes in thymocyte subpopulations after a single oral dose of 15 mg DBTC/kg body weight were analysed by immunohistology. Thymus glands of exposed rats were collected at day 1,2,3,4,5,7 and 9 after DBTC dosing and frozen sections were screened for various thymocyte differentiation antigens. Staining by mAb HIS-44 that labels a subset of cortical thymocytes showed that the thymus atrophy was restricted to the cortex. Here a time-dependent decrease of labelling by CD2 (OX-34), CD8 (OX-8), CD4 (ER-2), and CD5 (OX-19) was observed. In contrast, the number of cortical OX-44+ cells increased from day 2 to day 5. This increase can reflect an increase of CD4-CD8- double-negative thymocytes or of macrophages. However, most of these OX-44+ cells were negative for acid phosphatase, which is present in most macrophages. We concluded that these OX-44+ cells were mainly CD4-CD8- thymocytes and that the thymocyte subpopulation of this phenotype, i.e. CD4-CD8-OX-44+, may be the target cell for DBTC. It is discussed whether DBTC might disturb the interaction of early thymocytes and thymic epithelium, probably by an interaction with the CD2 antigen.

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PubMed1988

Implantation of cultured thymic fragments in congenitally athymic (nude) rats. Ultrastructural characteristics of the developing microenvironment.

Cultured thymic fragments correspond to the thymic microenvironment depleted of lymphocytes and dendritic cells. When these fragments are implanted under the kidney capsule of congenitally athymic rats, lymphocytes and dendritic cells of host origin enter the graft and induce thymus-dependent immunity in the recipient. This paper describes the ultrastructure of the fragments and the changes that occur during the restoration of normal thymic architecture. At the end of the culture period of 6-9 days and in the early stages after implantation, the grafts consist of keratin-containing epithelial cells of unusual morphology that can be labelled with antibodies raised against the epithelium of the mid/deep cortex and the subcapsule/medulla. Normal thymic architecture develops, including nerves and blood vessels, as lymphocytes populate the environment, and by 4-6 weeks the epithelial cells are the same phenotypically and ultrastructurally as those found in normal rat thymus. However, some areas without lymphocytes still contain the atypical epithelial cells seen before implantation. Large multinucleated giant cells are also present with a few associated epithelial cells of subcapsular/medullary phenotype. In conclusion, the cultured thymic fragments contain a hitherto unknown precursor epithelial cell with an atypical ultrastructure and phenotype that is not seen in normal development.

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