Biomedical subjects

R Gillitzer

Publications and source records attributed to R Gillitzer.

63 records · Page 4Linked to original sources

PubMed1991

Expression of T-cell-associated serine proteinase 1 during murine Leishmania major infection correlates with susceptibility to disease.

The expression of T-cell-associated serine proteinase 1 (MTSP-1) in vivo during Leishmania major infection was analyzed in genetically resistant C57BL/6 mice and in genetically susceptible BALB/c mice. Using a monoclonal antibody as well as an RNA probe specific for MTSP-1 to stain tissue sections, we found T cells expressing MTSP-1 in skin lesions and spleens of mice of both strains. In skin lesions, MTSP-1-positive T cells could be detected as early as 3 days after infection. Most importantly, the frequency of T cells expressing MTSP-1 was significantly higher in susceptible BALB/c mice than in resistant C57BL/6 mice. These findings suggest that MTSP-1 is associated with disease-promoting T cells and that it may be an effector molecule involved in the pathogenesis of cutaneous leishmaniasis.

Animals↗

PubMed1991

Localized vs generalized pyogenic granuloma. A clinicopathologic study.

We herein report the unusual case of a previously healthy young man who had spontaneous development of multiple lobular capillary hemangiomata disseminated over the integument. Based on the observation that the single lesions exhibited (immuno)pathologic and ultrastructural features similar, if not identical, to those of late-stage pyogenic granulomas, we propose to nosologically include our patient's eruption within the disease spectrum of pyogenic granuloma. As opposed to the occurrence of localized forms of pyogenic granuloma, the disseminated eruption seen in our patient and in other patients whose cases are reported in the literature cannot be ascribed to physical trauma. As some of these latter patients suffered from an underlying malignant neoplasm, it is tempting to speculate that both exogenous (eg, trauma) and endogenous (eg, tumor cells) factors can lead to the release of mediators promoting the development of these vascular neoplasms.

Adult↗

PubMed1990

In situ localization of CD45 isoforms in the human thymus indicates a medullary location for the thymic generative lineage.

Previous work has suggested that the generative lineage within the human thymus can be defined by the selective expression of CD45 isoforms and is CD45RO- and predominantly CD45RA+. In order to physically localize these cells we have stained frozen sections of human thymus with antibodies to CD45RO (p180), and CD45RA (p205/P220), as well as with CD1 and HLA class I to define cortical and medullary areas, respectively. In the cortex, 70 to 90% of thymocytes were CD45RO+, whereas only 0.5% expressed CD45RA. Medullary cells were 30% CD45RO+, 29% CD45RA+; approximately 40% did not express detectable levels of either isoform but did express CD45 common determinants. To assess the degree of proliferation of cells expressing CD45 isoforms, we stained adjacent sections, or used double staining, with Ki67, an antibody that detects a nuclear Ag on proliferating cells. We found that CD45RA+ thymocytes are predominantly a resting medullary population with a small component in cell cycle, consistent with our analysis of human thymocytes by immunofluorescence, and with data in murine systems defining the generative lineage. To confirm that the CD1- or low, CD45RO-CD45RA+ thymocytes defined by immunofluorescence analysis were likely to have a medullary location, we analyzed the CD4/CD8 subset distribution of CD1-cells. From 80 to 90% of CD1-thymocytes are CD4+ or CD8+ single positives or CD-8- double negatives. CD1-thymocytes also include 12 to 14% CD4+8+ cells with a probable medullary location. A similar analysis of lymphocytes expressing a high density of HLA class I, which have a medullary location, confirmed the existence of CD4+8+ thymocytes in the medulla. Purified CD3-4-8- cells, previously shown to be CD1-CD45RA+, were also shown to bear a high density of HLA class I, indicating a medullary location. Correlative localization of a panel of Ag thus supports the argument for a medullary location of the thymic generative lineage.

Antigens, CD↗

PubMed1990

Endemic Kaposi's sarcoma in human immunodeficiency virus type 1-seronegative persons: demonstration of retrovirus-like particles in cutaneous lesions.

In 1984, Greek physicians reported on the clustering of cases of Kaposi's sarcoma (KS) on the Peloponnesus peninsula. To gain more insight into its pathogenesis, we studied the seroepidemiologic and clinicopathologic characteristics of 12 Greek KS patients (eight male/four female) five of whom were residents of an endemic area on the Peloponnesus. These patients were in good general health with ages ranging from 48 to 80 years, had no clinical signs of immunodeficiency, and combined the features of both classic and epidemic KS in that they displayed not only involvement of acral areas but also widespread mucocutaneous lesions. Routine laboratory data were within normal limits; no patient had HTLV-1 and HIV-1/2 antibodies, but all patients had antibodies to several herpesviruses. The histopathology was characteristic of KS with the peculiar feature of a dense infiltrate composed predominantly of CD4+ T lymphocytes. Immunoenzymatic/morphologic studies of the KS cells were consistent with their origin from lymphatic endothelium. Outstanding ultrastructural findings were tubuloreticular structures and cylindrical confronting cisternae, structures that are indicative of an ongoing viral infection. Indeed, extensive electronmicroscopic studies resulted in the detection of retrovirus-like particles in close association to KS cells in five of 12 patients. This in situ observation opens the possibility that this retro-virus contributes to KS development.

Antibodies, Viral↗

PubMed1990

A reliable method for simultaneous demonstration of two antigens using a novel combination of immunogold-silver staining and immunoenzymatic labeling.

We have developed a reliable and sensitive immunohistochemical staining technique which allows the simultaneous demonstration of two different antigens expressed in or on the same cell (referred to as mixed labeling), together with the evaluation of the general histopathological appearance of the tissue. The staining procedure combines a three-step (streptavidin-biotin) immunogold-silver staining (IGSS) with a three-step immunoenzymatic labeling. For this purpose, we investigated the compatibility of IGSS with various substrates of peroxidase or alkaline phosphatase (AP). Highly reliable and discernible mixed labeling was achieved only after initial labeling with IGSS followed by AP labeling using the substrates naphthol AS-MX phosphate/Fast Blue or naphthol AS-BI phosphate/New Fuchsin, respectively. To ensure utmost specificity, we applied FITC-conjugated mouse monoclonal antibodies and rabbit anti-FITC immunoglobulins visualized by AP-labeled immunoglobulins and the respective substrate in a final step. This novel approach provides an excellent means for demonstration of immunocompetent cells and unequivocal determination of the percentage of specific cell subsets in infiltrated tissue. The advantages of this method, as compared with double immunofluorescence or double immunoenzymatic labeling, were investigated and are discussed.

Antibodies, Anti-Idiotypic↗

PubMed1989

Definition of the thymic generative lineage by selective expression of high molecular weight isoforms of CD45 (T200).

Selective expression of CD45 isoforms distinguishes naive and memory T cells in peripheral blood. Paradoxically, although the most recent thymic emigrants are CD45R+ CD45 p180-, the majority of thymocytes are CD45 p180+. Speculating that the small subset of thymocytes selectively expressing only the high molecular weight isoforms of CD45 constitute the thymic generative lineage giving rise to peripheral T cells, we characterized the phenotypic and functional properties of CD45 p180- thymocytes. All cells bearing CD45 p180 were removed by rigorous depletion or all CD45R+ thymocytes were removed in a parallel depletion. CD45R- thymocytes were essentially the same in phenotype and CD4/CD8 subset distribution as unfractionated thymus, and dissimilar to naive peripheral blood lymphocyte (PBL) T cells. In contrast, CD45 p180- thymocytes, mainly CD45R+, were CD1- CD38- pgp 1+, corresponding closely to the phenotype of naive CD45R+ PBL T cells. This subset is enriched in CD4+ or CD8+ single positives, includes a high proportion of CD4-8- thymocytes which are predominantly CD3-, and appears to have a medullary location. Approximately 40%-50% of CD45 p180- thymocytes expressed a high density of CDw29 (4B4), which in the periphery is expressed at high density only on CD45 p180+ memory T cells and at low density on CD45R+ naive T cells. However, the expression of high density CDw29 in the absence of CD45 p180 indicates a close resemblance to fetal lymphocytes and suggests an essential role for CDw29 in both the least and the most mature of T cells. If CD45 p180- thymocytes constitute the generative lineage and CD45 p180+ cells are commited to intrathymic death, then the CD45 p180- subset should have enhanced proliferative potential. By combining depletion methods with a limiting dilution assay for clonogenic potential, we found that 100% of the clonogenic precursors present in unfractionated thymus were CD45R+ CD45 p180- cells. This indicates that the CD45 p180+ majority of thymocytes has a very limited capability for proliferation consistent with a commitment to intrathymic death. The clonogenic potential of CD45 p180- thymocytes indicates a greater functional resemblance to PBL T cells than to CD45 p180+ thymocytes. In so far as clonogenic potential in vitro reflects generative potential in vivo, expression of high molecular weight CD45 isoforms appears to define the generative thymic lineage. Our working hypothesis proposes that expression of CD45 p180 implements the mechanism for eliminating thymocytes with self-reactive receptor specificities.

Antigens, Differentiation↗

PubMed1988

Decreased production of interferon in whole blood cultures derived from patients with psoriasis.

Patients suffering from psoriasis show many alterations with respect to their immune system as documented by in vitro test systems. In the present study we investigated the in vitro production of interferons (IFN) of leukocytes from psoriatic patients to stimulation with a variety of IFN inducers. Furthermore, the lymphoproliferative responses were tested. Whole blood cultures of 30 psoriatic patients showing moderate to severe disease activity and 21 cultures from healthy controls were stimulated with the mitogens PHA, ConA, and PWM, with PPD and Tetanus Antigen as IFN gamma inducers and with C. parvum, PolyI-PolyC, and Herpes simplex virus as inducers of IFN alpha. Interferon activity was tested in the supernatant of 48-h cultures by using an antiviral assay. Lymphoproliferation was assayed in 5-d cultures in parallel. Psoriatic patients showed a significantly decreased IFN production to all the stimuli tested. There were no significant differences in the lymphoproliferative responses; only the response to PWM was slightly decreased. The decreased IFN production by leukocytes from psoriatic patients seems to be very remarkable since increased susceptibility to infections is not generally known in these patients.

Cells, Cultured↗

PubMed1987

Production of interferon and lymphoproliferative response in whole blood cultures derived from patients with atopic dermatitis.

Enhanced susceptibility to viral infections has been reported repeatedly in atopic dermatitis (AD). A difference in the capacity to produce interferons (IFN) in response to viral antigens may be the cause. In the present study we investigated the in vitro IFN production of leukocytes from AD patients in response to different stimuli. Furthermore, the lymphoproliferative responses were tested. The patients showed moderate to severe disease activity. Whole blood cultures of 25 AD patients and 21 healthy nonatopic controls were stimulated with the mitogens phytohemagglutinin (PHA), concanavalin A (ConA), and pokeweed mitogen (PWM), with tuberculin derivative (PPD) and tetanus antigen as IFN-gamma inducers, and with C. parvum, poly I-poly C, and herpes simplex virus (HSV) as inducers of IFN-a. Lymphoproliferation was assayed in 5-day cultures in parallel. In AD no significant difference of the IFN production was found in comparison with the controls with any stimuli tested. The lymphoproliferative response of leukocytes of patients with AD was significantly decreased upon stimulation with PHA, Con A, PWM, and PPD. We suggest that in AD the described susceptibility to viral infections is not due to an altered capability of leukocytes to generate IFN.

Antigens↗

PubMedDate not supplied

Liposomal doxorubicin in the treatment of AIDS-associated Kaposi's sarcoma: clinical, histological and cell biological evaluation.

AIDS-associated Kaposi's sarcoma (KS) in eight patients was treated with the systemic application of liposomal doxorubicin (20 mg/m2 per cycle). After six cycles of treatment a significant regression of KS was observed in all patients. Tumour volume was reduced from 556 +/- 635 mm3 before therapy to 42 +/- 134 mm3 after therapy as determined by ultrasonography of selected tumours. Histological examination revealed a reduction of tumour-like structures and the absence of KS spindle cells in involved areas after therapy. In vitro experiments with KS-derived cell cultures, which most likely represent the KS spindle cells, suggested that liposomal doxorubicin may cause regression of KS via two different mechanisms: (i) by highly specific inhibition of KS spindle cell proliferation and (ii) by induction of monocyte chemoattractant protein-1 expression in KS spindle cells, which may result in increased recruitment of phagocytic cells (monocytes/macrophages) into the lesions. A cooperative action of both mechanisms may explain the high efficacy of liposomal doxorubicin in the treatment of AIDS-KS.

Acquired Immunodeficiency Syndrome↗