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G Kraal

Publications and source records attributed to G Kraal.

At least 127 records · Page 7Linked to original sources
PubMed1989

Macrophage subset repopulation in the spleen: differential kinetics after liposome-mediated elimination.

Different macrophage subsets can be discriminated in the well defined compartments of the mouse spleen by specialized functions and the presence of specific surface determinants. Red pulp macrophages, marginal zone macrophages, and marginal metallophilic macrophages are eliminated simultaneously within 24 hr by a single injection with liposome-entrapped dichloromethylene diphosphonate (DMDP). After such elimination, these subsets show a striking difference in their kinetics of reappearance: Red pulp macrophages are back in normal numbers after 1 week, the marginal metallophilic macrophages take 2 weeks to regain fully their position at the border of the marginal zone and periarteriolar lymphocyte sheath, but it takes over 1 month for complete reappearance of the marginal zone macrophages. Marginal zone lymphocytes, also affected by treatment with the liposome-entrapped drug, reappeared in the marginal zone within 2 weeks, indicating that marginal zone macrophages are not required for their localization and/or retention there. Approximately 2 weeks after treatment, all cells in the spleen have returned to normal numbers with the exception of marginal zone macrophages, which can be found only sporadically at that time. The results indicate that these macrophage subpopulations must have different precursor requirements. The differential reappearance of the macrophages creates the possibility of studying lineage analysis and will help to unravel the precise function of the marginal zone macrophages and marginal metallophilic macrophages in particular.

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PubMed1989

Histological changes in the spleen and liver of C57BL/6 and A/J mice during Plasmodium chabaudi AS infection.

The level of resistance to infection in inbred mice with the murine malaria species Plasmodium chabaudi AS is genetically determined. Resistant C57BL/6, which are able to eliminate the parasite by 4 weeks, develop marked splenomegaly and survive the infection. Susceptible A/J mice, which succumb to infection (mean survival time = 10 days), develop only minimal splenomegaly. In order to determine if gross differences in the organization, number, and type of spleen cells are related to the outcome of infection with P. chabaudi AS, the development of splenomegaly was examined by enzyme and immunohistochemical methods during the first week after infection. Cryostat sections of spleens removed from normal animals of both strains and at 4 and 7 days after intraperitoneal infection with 10(6) parasitized erythrocytes were stained for enzyme (acid phosphatase and nonspecific esterase) and immunohistochemistry with conventional monoclonal antibodies against T cells, B cells, and macrophages as well as with novel rat anti-mouse monoclonal antibodies which define discrete subpopulations of macrophages in the mouse spleen. The livers of normal and infected animals of each strain were also examined. The results of this study demonstrate (1) differences between normal, uninfected B6 and A/J mice in the organization and number of one subpopulation of macrophages in the spleen, the marginal metallophilic macrophages, and (2) marked histological changes in the spleen and liver during the course of infection in both resistant C57BL/6 and susceptible A/J mice. These changes include depletion of cells from the marginal zone of the spleen which, in the case of the marginal metallophilic macrophages, appears to be more severe in susceptible A/J mice.

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PubMed1989

An antigen expressed by murine CD8+ T cells and activated B cells.

A monoclonal antibody, H1F5, is described that reacts with a subset of Lyt-2 (CD8) mouse T cells and LPS-activated B cells. In both lymph nodes and spleen of BALB/c mice, the H1F5 antigen is coexpressed approximately on 20%-30% of the CD8+ T cells and approximately on 91% of LPS-activated B cells. In the thymus, few cells (less than 1%) are positive for the marker, but no correlation could be demonstrated with markers for mature T cells such as MEL-14 and PNA expression. Elimination of H1F5+ cells by complement lysis led to a 30%-50% reduction of specific lysis as measured in a primary allo CTL, indicating that the cytotoxic effector cells are injured. The relationship of this marker and other antigenic determinants on lymphocytes is discussed.

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PubMed1989

Interferon-gamma-increased adherence of lymphocytes to high endothelial venules.

Recirculating lymphocytes specifically adhere to and migrate through endothelium lining high endothelial venules (HEV), using specific and non-specific receptor-ligand systems. Interferons (IFN) profoundly affect the traffic of lymphocytes. Therefore the effects of interferon-gamma (IFN-gamma) on lymphocytes with respect to their interaction with HEV endothelium in lymph nodes were studied using the frozen section assay. In addition the organ-specificity of T- and B-lymphocyte adherence to HEV was investigated. Lymphocytes from spleen and peripheral lymph nodes showed increased binding to HEV of up to 35% compared to control lymphocytes after in vivo administration of IFN-gamma. The specificity of their binding did not change in terms of T:B-cell ratios. Increased adherence was also found by preincubation of lymphocytes with IFN-gamma in The enhanced binding was not due to increased expression of Mel-14 homing receptors and LFA-1 molecules on T and B lymphocytes, as shown by fluorescence-activated cell sorter analysis and antibody-blocking studies in the frozen section assay. Apparently IFN-gamma induces an additional Mel-14-independent and LFA-1-independent adhesion mechanism on lymphocytes.

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PubMed1989

Lymphocyte migration in the spleen: the effect of macrophage elimination.

To study the influence of macrophages on the migration and distribution of lymphocytes in the spleen, macrophages were eliminated from the spleen of mice by injection of liposomes in which DMDP was encapsulated. This leads to an elimination of macrophages in both the red pulp and marginal zone of the spleen within 1-2 days. In these animals the distribution of lymphocytes was determined by transfer of either syngeneic fluoresceinated or Ly 5 congeneic cells. It was found that after elimination of the macrophages the number of lymphocytes immigrating into the spleen had decreased, although a comparable mode of compartimentalization was found with an initial localization in the marginal zone and a subsequent distribution into the white pulp. After this elimination spleen macrophage subsets return with different kinetics, and in this way the influence of the red pulp macrophages, the marginal zone macrophages and the marginal metallophilic macrophages on lymphocyte immigration and redistribution could be investigated. A quantitative decrease of immigration was still found when red pulp and marginal metallophilic macrophages had repopulated their compartments, but was only fully restored when the last population to repopulate the spleen after treatment with DMDP-liposomes, the marginal zone macrophages, had returned. Experiments with isolated T and B cells showed that the elimination of macrophages had a profound effect on the localization of B cells in the white pulp, whereas it hardly affected T cells.

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PubMed1988

Splenic microenvironment of the CBA/N mouse: immunohistochemical analysis using monoclonal antibodies against lymphocytes and nonlymphoid cells.

CBA/N mice carry an X-linked immune-deficiency gene, leading to a defect in the ability to form antibodies against T-independent type 2 antigens. By using immunohistochemistry, the organization of the spleen of the immune-deficient male (xid) CBA/N F1 and the normal female F1 were compared. Staining with antilymphocyte markers showed that the total number of cells in the various T- and B-cell areas was smaller in the xid mouse, resulting in very small white pulp compartments. Fewer B cells were seen in the marginal zone. When the spleens of the F1 mice were examined for macrophage markers, the rings of marginal-zone macrophages and the ring of marginal metallophilic macrophages were much thinner in the xid mouse. In particular, the marginal-zone macrophages are thought to play a role in the response against thymus-independent type 2 antigens, and their small numbers in the xid mouse are suggestive of a role for the microenvironment in the defects in these mice.

Animals↗
PubMed1988

Memory B cells express a phenotype consistent with migratory competence after secondary but not short-term primary immunization.

The cell surface phenotype of dinitrophenol (DNP)-specific memory B cells, defined by their capacity to transfer IgG responses into syngeneic irradiated recipients, was assessed using two markers of relevance to lymphocyte migratory properties: (i) peanut agglutinin, which binds to terminal galactosyl residues expressed at high levels by several nonmigrating lymphocyte subsets and, among lymph node B cells, is highly specific for germinal center cells; and (ii) MEL-14, a monoclonal antibody specific for lymphocyte surface receptors required for migration from the blood into peripheral lymph nodes. At various times after primary or secondary immunization with DNP-keyhole limpet hemocyananin (KLH), lymph node B cells were separated by fluorescence-activated cell sorting on the basis of staining with PNA and/or MEL-14, and the presence of B-memory cells in each fraction was assessed by adoptive transfer with antigen (DNP-KLH) and helper T cells. One week after immunization, most of the memory sorted in the PNAhi population, confirming a previous report by R. F. Coico, B. S. Bhogal, and G. J. Thorbecke (J. Immunol. 131, 2254, 1983) that early memory B cells or their precursors are contained within the germinal center cell population, a population which is known to be MEL-14- and migratory-incompetent. Six weeks after primary stimulation, however, the bulk of memory cells, unlike germinal center cells, were MEL-14hi. After secondary immunization, memory was still predominantly MEL-14+ and PNAlo, although in some experiments adoptive responses were transferred by all sorted fractions. The results are consistent with the hypothesis that antigen-specific B cells initially undergo local (sessile) differentiation and proliferation in germinal centers, where they develop the capacity for adoptive transfer of antigen-specific secondary responses, but that with continued development their long-lived memory-containing progeny express a phenotype permitting their reentry into the recirculating lymphocyte pool.

Animals↗
PubMed1988

Marginal metallophilic macrophages in the mouse spleen: effects of neonatal injections of MOMA-1 antibody on the humoral immune response.

To investigate the role of the marginal metallophilic macrophages in the humoral immune response, mice were injected from birth with the monoclonal antibody MOMA-1, which reacts specifically with these cells. Multiple injections led to a drastic reduction in the number of cells but not to a complete elimination of the macrophage subpopulation. In these animals the humoral immune response against a Thymus-independent (TI) type 1 antigen was not disturbed but the responses against Thymus-dependent (TD) and T1 type 2 antigens were reduced as determined by specific antibody forming cells and serum titers. The results are discussed in relation to earlier findings that in the adult situation elimination of all macrophages in the marginal zone using DMDP encapsulated liposomes led to a reduction in the response to only TI type 2 antigens.

Animals↗
PubMed1988

The effects of bacterial lipopolysaccharide (LPS) on high endothelial venules and interdigitating cells in mouse lymph nodes.

Migration of lymphocytes into lymph nodes is directly controlled by interaction of lymphocytes with the high endothelial venules (HEV), located in T cell-dependent areas of lymph nodes. Little is known about the mechanisms that regulate the activity of the HEV and the specificity of interaction with lymphocytes in various lymphoid organs. It has been suggested that the non-lymphoid interdigitating cells (IDC) play a role in maintaining the integrity of T cell areas. We therefore wished to determine whether the function of the HEV could be influenced by disturbing the integrity of the T cell area. This was assayed in mice by injecting bacterial lipopolysaccharide (LPS) in the hind footpad. The T cell-dependent areas of mouse popliteal lymph node were studied using immunohistochemistry, and attention was paid to the HEV specificity using short-term in vivo localization assays and in vitro lymphocyte binding assays. After LPS administration, apparent changes in the number of interdigitating cells and T cells in the draining lymph node were found. In addition, interdigitating cells lost their typical dendritic appearance. However, after LPS treatment, neither size, localization nor receptor specificity for lymphocyte subsets of HEV differed from control HEV. Although administered subcutaneously in the footpad, the effect of LPS on T cells and IDC was much more dramatic in the spleen than in the draining lymph nodes. This points to a difference in the processing of the endotoxin in the two organs.

Animals↗
PubMed1988

Murine hybrid cell lines expressing the NLDC-145 dendritic cell determinant.

Dendritic cells play an important role as accessory cells in the immunological defense system. Investigations into the biological functions of this population have been limited by the difficulties encountered in isolating sufficient numbers of cells, and therefore different approaches have been described to immortalize accessory cell populations. In this report, four murine hybrid cell lines (H1-H4) are described that were produced by fusion of in vitro isolated dendritic cells and a tumor cell. The hybrid lines are characterized by the expression of the dendritic cell specific marker NLDC-145, Ia expression and the absence of macrophage or T cell markers. The cell lines have no phagocytic activity and are functionally active as accessory cells. The expression of the NLDC-145 antigen in vitro was found to be inducible. These NLDC-145-positive cell lines will be useful for the further characterization of the NLDC-145 antigen and in the study of dendritic cell and lymphocyte interactions.

Animals↗
PubMed1988

The interaction of interdigitating cells and lymphocytes in vitro and in vivo.

To investigate the role of the NLDC-145 antigenic determinant on interdigitating cells in T-cell dependent areas of lymphoid organs, rosettes were isolated from interdigitating cells and lymphocytes from lymph nodes. By using allotypic mixtures it was established that these rosettes represented pre-existing associations of interdigitating cells and lymphocytes. Phenotypic analysis of the lymphocytes showed that most cells in these rosettes were T cells. After antigenic stimulation, an increase of helper T cells and of B cells associated with the rosettes was found. Incubation of the rosettes with the NLDC-145 antibody did not alter the composition of the rosettes. By neonatal injection of the NLDC-145 antibody, the influence of the antigen on T-cell differentiation and antigen presenting was investigated. Although the antibody could be detected easily on interdigitating cells and thymus cortex of injected animals, no direct influence of long-term injections of the antibody from birth on antigen presentation and T-cell differentiation was found.

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