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Biomedical subjects

G Kraal

Publications and source records attributed to G Kraal.

At least 145 records · Page 8Linked to original sources
PubMed1988

Histochemical identification of guinea-pig macrophages by monoclonal antibody MR-1.

A monoclonal antibody is described which reacts with monocytes and macrophages of the guinea-pig. The antibody recognizes a cytoplasmic component in the majority of tissue macrophages, as detected by histochemical analysis. It reacts positively with all macrophages in lymphoid organs, including Tingible body macrophages. In addition it recognizes the cells of Von Kupffer in the liver, and macrophages in bone marrow and peritoneal cavity. In comparison to other monoclonal antibodies that have been described in the guinea-pig, MR-1 shows a unique tissue distribution. The antibody is a useful tool to discriminate macrophages by immunohistochemical methods.

Animals↗
PubMed1988

Subpopulations of lymphoid and non-lymphoid cells in bronchus-associated lymphoid tissue (BALT) of the mouse.

Lymphoid and non-lymphoid subpopulations were investigated in the lung of the mouse with immunocyto-, immunohisto- and enzyme-histochemical methods. Special attention was paid to the cell populations in bronchus-associated lymphoid tissue (BALT), which is positioned between a bronchus and an artery. In BALT, discrete T- and B-cell areas can be found. The majority of the T cells belong to the L3T4+ (T-helper) subpopulation. In the T-cell area interdigitating cells can be recognized by anti-class II antibodies as well as by specific monoclonal antibodies, NLDC-145 and MIDC-8. Macrophage subpopulations can be discriminated by location, enzyme reactivity and various macrophage-specific monoclonal antibody markers. On the outer rim of BALT macrophages are recognized by the MOMA-1 and ERTR9 antibody. Macrophages dispersed in BALT can only be discriminated with the MOMA-2 antibody. The macrophage markers F4/80 and Mac-1 show no reactivity in BALT. In lung, tissue macrophages around bronchi and blood vessels are predominantly recognized by the MOMA-1 and MOMA-2 antibody, and a minor population by the ERTR9 antibody. Alveolar macrophages show heterogeneity with the MOMA-1, MOMA-2 and NLDC-145 antibody. The relationship between alveolar macrophages and antigen-presenting cells is discussed here.

Animals↗
PubMed1987

Dendritic cells of the mouse recognized by two monoclonal antibodies.

A new monoclonal antibody, MIDC-8, is described which shows a comparable tissue distribution as the recently described NLDC-145 antibody. It recognizes interdigitating cells, veiled cells and Langerhans cells in lymphoid organs and the skin of the mouse. In contrast to NLDC-145 it recognizes a cytoplasmic component of these cell types. Its distribution is more restricted to the T cell-dependent areas than NLDC-145. Isolation of dendritic cells from lymph nodes, spleen and thymus revealed that both antibodies react with the in vitro isolated dendritic cells. The results show that these antibodies can be used to study dendritic cells in vitro and emphasize the relationship between the in vivo interdigitating cells of the T cell areas and the in vitro isolated dendritic cells.

Animals↗
PubMed1987

Rapid decrease in lymphocyte adherence to high endothelial venules in lymph nodes deprived of afferent lymphatic vessels.

Occlusion of the afferent lymph flow to the lymph node (LN) results in both flattening of the endothelium of high endothelial venules (HEV) and a severe decrease in numbers of lymphocytes in transit across the walls of the flattened HEV. In the present study we have used the in vitro lymphocyte-binding assay to investigate the ability of HEV in rat LN to bind lymphocytes at various time points after occlusion of the afferent lymph flow. In addition the specificity of T and B lymphocyte adherence to HEV of such operated LN was studied. In normal LN, lymphocytes adhered to virtually all HEV using the in vitro binding assay. However, 1 and 2 weeks after operation lymphocytes bound to only 50-60% of the HEV and by 3-6 weeks 20-30%. The total numbers of lymphocytes bound to these HEV had also diminished to 10% of the control value 3-6 weeks after operation. Morphometric analysis showed that this was not only due to a reduction in the area of HEV endothelium available for lymphocyte adherence by flattening of the high endothelial cells, but also to a strong decrease in the numbers of bound lymphocytes per unit area high endothelium. In spite of the reduction in numbers of adhering lymphocytes the T/B cell ratio did not change. The results show that the reduction in lymphocyte binding of HEV in operated LN is a rapid event, probably due to loss of high endothelial cell determinants involved in binding of lymphocytes. The decrease in lymphocyte binding clearly precedes flattening of HEV endothelium suggesting that the height of high endothelial cells is of secondary importance to lymphocyte adherence.

Animals↗
PubMed1987

The influence of oxazolone on the recirculation capacity of B and T cells.

Stimulation of lymph nodes with the contact allergen oxazolone had a profound effect on the recirculation capacity of IgD+ B cells and to a lesser extent of T cells when tested in an allotypic transfer system. The effect was most prominent on day 4 after stimulation and was not found with any other antigen that was tested. The impaired recirculation was correlated with a reduction of the adherence capacity of this cell population to HEV in vitro. However, the cells expressed normal levels of the MEL-14 antigen on their surface, as determined by dual-fluorescence FACS analysis. Similar effects were observed when lymphocytes were haptenized with the allergen for a short period in vitro. The treatment had no effect on the viability of the cell population nor on its capacity to react with lipopolysaccharide (LPS) and concanavalin A (Con A). When the cells were cultured for 24 h in the absence of oxazolone after either in vivo or in vitro treatment, a normal recirculation capacity was observed, indicating that the effects were reversible. The possible implications of this finding are discussed.

Animals↗
PubMed1987

Macrophages in T and B cell compartments and other tissue macrophages recognized by monoclonal antibody MOMA-2. An immunohistochemical study.

A new monoclonal antibody, MOMA-2, is described, which recognizes monocytes and macrophages in the mouse. The antibody reacts with the majority of mononuclear phagocytes in various tissues as determined by immunohistochemistry. It differs from other macrophage markers that have been described by the strong reaction with macrophages in the lymphoid organs such as the tingible body macrophages and macrophages in T cell-dependent areas. The antibody recognizes predominantly a cytoplasmic component, although a membrane component can also be demonstrated. Isolated Langerhans' cells, interdigitating cells and dendritic cells, members of the mononuclear phagocyte system that are involved in antigen presenting, stain weakly with the antibody. Because of the intense staining the antibody is very useful for defining tissue macrophages by immunohistochemistry.

Animals↗
PubMed1987

The endothelium of the high endothelial venule: a specialized endothelium with unique properties.

High endothelial venules (HEV) in lymphoid organs are specialized to facilitate the passage of lymphocytes into lymphoid parenchyma. This is accomplished by a ligand-receptor system on the endothelium and lymphocytes, which differs between lymph nodes and Peyer's patch. Experiments discussed in this paper show that other non-HEV-derived endothelial cells can acquire the characteristics of HEV and that HEV may differentiate under influences from their local micro-environments.

Animals↗
PubMed1987

Lymphocyte migration into the lamina propria of the gut is mediated by specialized HEV-like blood vessels.

Migration of lymphocytes into the lamina propria of the small intestines was studied in mice using short-term in vivo migration experiments in combination with immunocytochemistry and autoradiography. The results show that, shortly after intravenous injection, most of the lymphocytes present in the lamina propria are actually located within the capillary network of the villi. Furthermore, it was shown that lymphocytes leave the blood stream and enter the lamina propria via small blood vessels at the base of the villi. These blood vessels can be discriminated by their positive staining with MECA-325, a monoclonal antibody that is specific for high endothelial venules (HEV) in lymphoid organs. From the results it is concluded that the gut contains specialized venules at specific sites, involved in the emigration of lymphocytes, comparable to HEV in lymphoid organs. The flatness of the endothelium of these MECA-325-positive intestinal blood vessels, which is in contrast to the situation in lymphoid organs, could not be changed by inducing an intestinal inflammation. This flatness may be directly correlated to the less efficient transmigration of lymphocytes, as demonstrated in our experiments.

Animals↗
PubMed1986

Human lymphocyte-high endothelial venule interaction: organ-selective binding of T and B lymphocyte populations to high endothelium.

We wished to determine whether human lymphocytes, like their murine counterparts, show organ-specific interactions with high endothelial venules (HEV). Functional HEV-binding ability was measured by an in vitro assay of lymphocyte adherence to HEV in frozen sections of human lymphoid tissues which was adapted from rodent systems. It was found that human lymphocytes bind selectively to HEV and that, whereas mature T lymphocytes bind preferentially to HEV in peripheral lymph nodes and tonsils, B lymphocytes show preferential binding to HEV in GALT. Moreover, by analyzing the binding characteristics of T4+ and T8+ T cell populations, it was found that T8+ cells adhere preferentially to HEV in GALT and mesenteric lymph nodes and tonsil, and that T4+ cells bind slightly better to HEV in peripheral lymph nodes. The above findings indicate that organ--specific lymphocyte-endothelial cell recognition mechanisms exist also in humans, and suggest that these mechanisms play an important role in normal and pathologic lymphocyte traffic.

B-Lymphocytes↗
PubMed1986

Langerhans' cells, veiled cells, and interdigitating cells in the mouse recognized by a monoclonal antibody.

An mAb, NLDC-145, is described that specifically reacts with a group of nonlymphoid dendritic cells including Langerhans cells (LC), veiled cells (VC), and interdigitating cells (IDC). The antibody does not react with precursor cells in bone marrow and blood. Macrophages are not stained by the antibody, but a subpopulation of Ia+ peritoneal exudate cells is recognized. Possible relationships of the various nonlymphoid dendritic cell (NLDC) types are discussed.

Animals↗
PubMed1986

Antigen-induced changes in B cell subsets in lymph nodes: analysis by dual fluorescence flow cytofluorometry.

Changes in the representation and surface phenotype of defined B cell subsets in murine lymph nodes stimulated with keyhole limpet hemocyanin or sheep red blood cells have been analyzed by two-color immunofluorescence fluorocytometric analysis. Shortly after immunization with either antigen there is a dramatic increase in both the frequency and absolute number of IgM+, IgD+ B cells, which is followed by the formation of germinal centers. Germinal center cells, as soon as they appear on day 3 after primary immunization, bind high levels of peanut agglutinin, bear low levels of surface IgM but no detectable surface IgD, and are characterized by lack of staining with MEL-14, a monoclonal antibody which recognizes a lymphocyte surface receptor involved in lymphocyte homing. The level of I-A and H-2K region-encoded surface antigens on early germinal center cells is higher than on PNAlo B cells. During the first 7 days of the germinal centers there is a progressive decrease in the average level of H-2K but not of Ia antigens. A similar decrease was observed for ThB. It is confirmed that the germinal center cell population contains the majority of antigen-binding cells in the stimulated lymph node. These findings indicate that B cells are recruited nonspecifically to antigen-stimulated lymph nodes, and that the antigen-specific cells then selectively participate in the formation of germinal centers where they undergo specific differentiation events.

Animals↗
PubMed1986

A surface molecule on guinea pig lymphocytes involved in adhesion and homing.

A monoclonal antibody, CT 4, which recognizes an antigenic determinant on the majority of guinea pig lymphocytes, was tested for its ability to interfere with adherence and homing capacity of lymphocytes. Incubation with F(ab')2 fragments of the antibody blocks the in vitro binding to high endothelial venules (HEV) of both peripheral lymph nodes and Peyer's patches. When tested in vivo using a short-term homing assay with radiolabeled cells also a reduction of migration into the spleen was observed. Fluorescence-activated cell sorter analysis of lymph node cells showed a separation into duller and brightly positive cells whereas in the thymus the bright population is absent. Thymus cells adhere less effectively to HEV and this binding can only marginally be blocked by CT 4 incubation. The results suggest a role of CT 4 in adhesion processes.

Animals↗
PubMed1986

The differential effects of bacterial lipopolysaccharide (LPS) on splenic non-lymphoid cells demonstrated by monoclonal antibodies.

In the present study, the effect of LPS on different splenic non-lymphoid cells was investigated. Marginal zone (MZ) macrophages, marginal metallophils and interdigitating cells (IDC) were demonstrated using specific monoclonal antibodies in a two-step immunoperoxidase procedure in combination with enzyme histochemistry. The results indicate that the number of marginal zone macrophages decreases markedly after LPS treatment, but is followed by a rapid repopulation as observed by monoclonal antibody staining and selective uptake of FITC-Ficoll. Marginal metallophils are normally located at the inner border of the marginal sinus and can specifically be identified by the monoclonal antibody MOMA-1. Following LPS stimulation, many MOMA-1-positive cells were present in the corona and central parts of the follicles, with decreasing numbers near the marginal sinus. These findings strongly suggest that LPS induces a migration of marginal metallophils towards the follicle centres. Most of the tangible body macrophages in the follicle centres appeared to be slightly MOMA-1-positive, which indicates that marginal metallophils may, at least under certain circumstances, differentiate into tangible body macrophages. In the inner PALS, many interdigitating cells, NLDC-145-positive cells, can be found. The number of NLDC-145-positive cells was shown to be severely decreased at later time-intervals after LPS administration, resulting in an almost unstained inner PALS at 2 days. In contrast to the above-mentioned splenic non-lymphoid cells, the red pulp macrophages are only minimally affected by LPS.

Acid Phosphatase↗
PubMed1986

Marginal metallophilic cells of the mouse spleen identified by a monoclonal antibody.

A monoclonal antibody, MOMA-1, is described that recognizes the marginal metallophilic macrophages in the mouse spleen. The cells are localized at the marginal sinus forming a ring around the periarteriolar lymphocyte sheath and follicular areas at the inner side of the marginal zone. They show high non-specific esterase activity and can be distinguished from the marginal zone macrophages by antibody staining and the lack of FITC-Ficoll uptake. The relationship of MOMA-1-positive cells with other macrophage populations is discussed.

Acid Phosphatase↗
PubMed1985

The selective localization of B lymphocytes in the spleen and the role of complement receptors.

The role of complement receptors on the localization of T and B cells in the spleen of mice was studied using short-term homing experiments in cobra venom factor (CoF)-treated animals. The localization ratio of B and T cells in the spleen of CoF-treated mice decreased significantly compared to control recipients. No changes could be found in the relative distribution of resident T and B cells in the spleen or other lymphoid organs of CoF-treated animals and when their spleen or lymph node cells were transferred, the localization pattern was normal. When cells were incubated in serum prior to transfer a disturbed localization ratio in the spleen of untreated recipients was observed. This was due to a blockade of complement receptors as determined by the inability of the incubated cells to form EAC rosettes. No blockade of EAC rosettes and no changes in localization ratios upon transfer could be observed when the cells were incubated in functionally C3-depleted serum. The results suggest a role for the complement-receptor on B cells in the initial localization in the spleen, whereas no influence upon the selective localization in high endothelial venules-bearing organs was found.

Animals↗