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B Meedendorp

Publications and source records attributed to B Meedendorp.

11 recordsLinked to original sources
PubMed1999

Towards standardization of the human cytomegalovirus antigenemia assay.

The Human Cytomegalovirus antigenemia (HCMV-Agemia) test has been accepted worldwide as a clinical tool in the diagnosis and management of HCMV-associated syndromes in immunocompromised patients. The many modifications proposed since the first description by our laboratory make standardisation of the HCMV-Agemia assay necessary to enable multicenter clinical trials. We report the initial work for standardization of the HCMV-Agemia assay. A standard protocol is proposed, the optimal distribution conditions are investigated and the results of the shipment of positive and negative test slides as well as of two sets of coded internal standard slides are discussed. The main conclusions are that standard slides can be distributed at room temperature and that the results of participating laboratories with the coded internal standard slides were strikingly similar in spite of differences in HCMV-Agemia protocols used by participating laboratories.

Antibodies, Monoclonal↗
PubMed1995

Defective bronchus-associated lymphoid tissue in long-term surviving rat lung allografts.

In a previous study we found that a local immune response did not develop in the bronchus-associated lymphoid tissue (BALT) of infected rat allografts. We hypothesized that the BALT in rat lung allografts was damaged after allotransplantation. Therefore, we investigated three prerequisites for a normal function of the BALT, i.e., its structure, the uptake of antigens, and the lymphocyte migration to the BALT in three groups of rats (n = 10 each): (1) Brown Norway(BN)-to-Lewis (LEW) allografts; (2) LEW-to-LEW isografts; and (3) normal LEW rats. All rats were immunosuppressed with CsA (injected on days 2 and 3). Six mo after transplantation the structure of the BALT and the uptake of intrabronchially injected carbon particles in the BALT were determined histologically; the migration of intravenously injected, fluoroscein-isothiocyanate labeled lymphocytes to the BALT was determined immunohistochemically. In the allografts the BALT was defective in all three investigated aspects. It was reduced in size and lymphocyte density and was largely replaced by fibrous tissue. Twenty-four h after administration no carbon particles and only a few labeled lymphocytes were found in the BALT. In contrast, in the syngeneically transplanted and nontransplanted lungs the BALT consisted of a large and dense collection of lymphocytes. In these BALTs large numbers of carbon particles and labeled lymphocytes were found. In conclusion, after allogeneic transplantation the BALT in the lung becomes defective in structure and function. The BALT is most likely damaged by rejection, since the BALT is syngeneic lung transplants was perfectly normal.

Animals↗
PubMed1994

B cells specific for bromelain-treated erythrocytes are not derived from adult rat bone marrow.

As part of an evolutionary layered hematopoietic system, the B lymphocyte compartment consists of different lineages of B lymphocytes, which evolve sequentially during ontogeny. In mice, there is ample evidence for the existence of at least two lineages, a layer of B-1 cells (Ly-1 B cells) and the evolutionary more advanced layer consisting of conventional B cells. In a previous study we were unable to detect B-1 cells in the rat as determined by phenotypic markers. Here we studied the possible existence of putative B-1 cells in the rat based on some functional and developmental characteristics as have been described for mouse B-1 cells. We show that B cells secreting antibodies that recognize bromelain-treated mouse red blood cells (BrMRBC) can be identified in rat spleen, whereas these cells (in contrast to DNP-specific B cells) are virtually absent in lethally X-irradiated and bone marrow (BM) reconstituted animals. The number of anti-rMRBC-secreting B cells could not be restored to control levels by reconstitution with fetal liver cells or by cotransfer of 10(7) cells from peritoneal cavity, lymph node or Peyer's patches or up to 2 x 10(8) splenocytes. Although our findings thus suggest that B-1 cells (or B-1 like cells) may be present in rats, formal proof for the existence of such a lineage in rats awaits definition of these cells at the progenitor level.

Animals↗
PubMed1991

Differential kinetics of various subsets of thymic bone marrow-derived stromal cells in rat chimeras.

Identification of those cells within the thymic stroma which are responsible for tolerance induction remains controversial. Evidence derived from studies of bone marrow chimeras or thymus transplants attributed this function to cells of haematopoietic origin, usually class II positive medullary dendritic cells (DC). Recent data suggest, however, that a stromal element located in the thymus cortex might be involved in negative selection. To further explore this issue we used immunohistology and immunocytology with a combination of allotype and cell type specific monoclonal antibodies (MoAb) to study the turnover of thymic stromal cells of haematopoietic origin in different rat models of allogeneic and congenic bone marrow (BM) radiation chimeras. Use of CFU-GM cultured BM inoculum for congenic recipients allowed us to distinguish between direct homing of donor myeloid cells and the delayed migration of the donor stem cell progeny after the post-irradiation recovery of the recipient. Our data indicate a heterogeneity in the turnover rate of thymic mobile stromal cells. While DC and a subset of macrophages located in the cortex as well as in the medulla (ED1+), within 4 weeks were virtually all of donor type, cortical macrophages detected by ED2 MoAbs were still incompletely replaced after a period as long as 20 weeks. Slow turnover, location and variable class II expression may imply a role for thymic cortical macrophages in (self-) tolerance induction.

Animals↗
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.

Animals↗