Analysis of cytotoxic T lymphocyte response in rejecting allografted canine kidneys.

The involvement of cytotoxic T lymphocytes (CTL) in the rejection process of allografted canine kidneys was studied. The frequency of donor-specific (precursor) CTL was determined with a sensitive limiting dilution assay. Longitudinal sampling of peripheral blood and kidney aspiration biopsies were used to obtain information on the CTL response toward the graft. An accurate analysis of CTL kinetics in both kidney and peripheral blood of allografted dogs appeared to be technically possible. During the first days after transplantation precursor CTL (CTLp) frequencies decreased in both blood and kidney. A minimum CTLp frequency of 5-15% of the pretransplant value was reached in the peripheral blood at day 4 after transplantation. The cause of this decrease, which was observed in all 5 allografted dogs is discussed. CTLp frequencies increased after day 4 and showed an exponential rise in the kidney before serum creatinine increased due to loss of kidney function caused by rejection. The data obtained with the quantitative study of CTL show that rejection of a canine kidney allograft is accompanied by a rise in CTL numbers in the kidney. The methodology developed permits extensive functional analysis of cellular processes in allografted organs.

Influence of a skin allograft on frequencies of CTL precursor in peripheral blood of the dog.

Alloantigen-specific cytotoxic T lymphocytes (CTL) and their precursors (CTL-P) have been determined in the peripheral blood of skin allografted dogs. CTL-P frequencies increased rapidly after transplantation and reached maximal values after complete rejection of the skin allograft. Differences in the time response kinetics of CTL-P frequencies between recipients were not correlated with the length of graft survival. The CTL-P frequencies declined after days 13-20 and appeared still to be elevated 30 days after rejection of the graft.

Why tuberculosis control in an unstable country is essential: desperate TB patients embrace DOTS in Angola.

After decades of war, the tuberculosis situation in Angola is alarming. The author describes his experiences with the implementation of a DOTS TB programme adapted to the difficult circumstances in a town partly inhabited by displaced people. The high motivation of both patients and health care workers is an important factor for its successful implementation. The need for international support of tuberculosis control programmes also in war-ridden countries is stressed.

Tuberculosis and pregnancy--a provincial study (1990-1996).

BACKGROUND: Several studies suggest that physiological changes in pregnancy mimic early symptoms of tuberculosis. If true, this could influence the diagnostic delay of the disease and the outcome of pregnancy. METHODS: From the register of the Public Health Centre, all female patients with culture-proven tuberculosis aged between 22 and 35 years in the Province of Zeeland in the period 1990-1996 have been identified. Data on symptoms, delay, therapy and outcome of the pregnancy have been collected. Risk factors for an early diagnosis have been identified. RESULTS: In nearly one-third of the patients with tuberculosis (n = 14), it has been possible to make a presumptive diagnosis on the basis of a chest X-ray only. Patients with tuberculosis associated with pregnancy are more likely than their non-pregnant counterparts to have non-specific symptoms which are, at most, moderate (p = 0.002). Diagnosis has also been hampered by non-cavernous, smear-negative presentation of the disease. In addition, women with pulmonary tuberculosis associated with pregnancy are more likely to postpone having a chest X-ray taken (p = 0.02), which contributes to the delay. CONCLUSION: As the clinical features of tuberculosis in pregnancy are moderate, a high index of clinical suspicion is necessary. Nevertheless, the favourable outcome suggests that (if all risk factors are taken into account) lung tuberculosis in pregnant women in The Netherlands can be discovered sufficiently early within the limits of the current screening programme to prevent harm to mother or child.

[Connection between 2 tuberculosis outbreaks demonstrated after 8 years by DNA-fingerprinting of the causative mycobacteria]. / Verband tussen 2 tuberculose-explosies na 8 jaar bewezen door DNA-'fingerprinting' van de oorzakelijke mycobacteriën.

OBJECTIVE: To determine the possible connection between two outbreaks of tuberculosis at an 8-year interval by DNA fingerprinting of the causative mycobacteria. DESIGN: Descriptive. SETTING: Regional Public Health Services Zeeland and Noord-Holland, the Netherlands. METHOD: The source patients of the tuberculosis explosions in an island in the province of Zeeland (28 persons infected) and an island of the Noord-Holland area (36 persons infected) were identified in 1986 and 1994 respectively. In 1994. spoligotyping was performed on dead bacteria from the suspected source from 1986. to analyse the chain of transmission. RESULTS: Identical spoligotyping patterns of the source patients proved the transmission of a Mycobacterium tuberculosis strain from a father to his son around 1986. Lack of a positive Mantoux test in the son prohibited prevention of the 1994 explosion. CONCLUSION: Thanks to the applicability of spoligotyping on non-vital mycobacteria this DNA method contributed retrospectively to demonstration of a connection between two out-breaks of tuberculosis at an 8-year interval.

Canine MHC-class II antigens on B and T lymphocytes.

MHC-class II antigens on canine lymphoid cells were detected with monoclonal antibodies (Mabs). On the basis of reactivity with resting or activated T lymphocytes two groups of Mabs were reported earlier. Non-activated T lymphocytes expressed MHC-class II antigens recognized by the first group whereas the second group recognized only MHC-class II antigens on activated T lymphocytes. In this study we analysed the reactivity pattern of both groups of Mabs with purified canine B lymphocytes. One- and two-colour immunoflowcytometric analysis, immunoprecipitation, immunohistology and MLC inhibition were performed. The Mabs which only reacted with activated T lymphocytes appeared to stain also purified sIg+ lymph node cells. Two-colour fluorescence and immunohistology confirmed the reactivity of these Mabs with B lymphocytes. Immunoprecipitation showed the bimolecular structure of these antigens. It was concluded that two subsets of MHC-class II antigens can be detected on canine lymphoid cells. One subset showed an aberrant distribution being expressed on both nonactivated and activated T and on B lymphocytes. The second subset of MHC-class II antigens could only be detected on B lymphocytes and activated T lymphocytes, a distribution pattern similar to that found in most other species, for instance man.

Class II antigens on canine T lymphocytes.

A panel of crossreactive anti-human, -mouse and -rat MHC class II monoclonal antibodies (Mabs) was used to examine MHC class II antigen expression on canine T lymphocytes by cytofluorometry. The presence of MHC class II antigens was demonstrated on activated T lymphoblasts as well as on non-stimulated peripheral blood T lymphocytes. A number of anti-MHC class II Mabs reacted only with activated T lymphoblasts. Immunoprecipitation studies confirmed the Ia-like or MHC class II molecular character of the antigens on canine T cells. The expression of MHC class II antigens on peripheral blood T lymphocytes appeared to be not induced by stimulation of the T cells, as purified T lymphocytes of specific pathogen free dogs reacted with anti-MHC class II Mabs. Moreover, the study indicates that MHC class II antigen expression is present in the neonatal thymus. Lectin stimulated and allogeneically stimulated T lymphoblasts showed a stronger expression of MHC class II antigens in comparison with non-stimulated T cells.

Cell-mediated cytotoxicity toward class I and class II antigens on canine T and B lymphoblasts.

Cellular cytotoxicity generated in vitro has been studied with canine T and B lymphoblasts as target cells. B lymphocytes were isolated by rosetting with protein A labeled sheep red blood cells and stimulated with sepharose bound protein A. Such highly purified stimulated B lymphoblasts appeared to be useful target cells for cellular cytotoxicity. Cold target inhibition studies and limiting dilution analysis revealed that B lymphocytes did not carry targets for cytotoxic T lymphocytes (CTL) which were not present on PHA stimulated T lymphoblasts.