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Biomedical subjects

B M Goddeeris

Publications and source records attributed to B M Goddeeris.

At least 91 records · Page 5Linked to original sources
PubMed1991

Bovine afferent lymph veiled cells differ from blood monocytes in phenotype and accessory function.

Veiled cells have been prepared from bovine afferent lymph and their surface phenotype has been compared with that of blood monocytes using a panel of mAb that define bovine leukocyte Ag. It has been observed that the expression of CD1c and a putative bovine CD45R Ag is restricted within these populations to afferent lymph veiled cells (ALVC), whereas CD11b is expressed only on monocytes. The CD11a and CD11c specificities and an additional Ag defined by mAb 1LA24 (p110/75) are expressed by both cell types, although CD11a and p110/75 are found only on subpopulations of ALVC. In a comparison of accessory function, we have found that ALVC are considerably superior to blood monocytes both as stimulators in mixed leukocyte cultures and as presenters of soluble Ag to primed T cells. This superiority appears to be associated with an increased capacity to form clusters with responding lymphocytes. In addition, we have established that the capacity of ALVC to present soluble Ag to Ag-specific T cell clones resides almost exclusively in a subpopulation defined by the phenotype p110/75+ CD11a-.

Animals↗
PubMed1991

A simple and efficient method for purifying and quantifying schizonts from Theileria parva-infected cells.

An improved method for the purification of Theileria parva schizonts from infected bovine cells is described. The technique is simpler and more rapid than previously described methods and gives rise to greater yields of schizonts with negligible contamination by host-cell components. In addition, a fluorescent staining technique was developed whereby live schizonts purified from infected cells can be enumerated and sorted using the flow cytometer. An assessment of the quality of schizonts prepared according to our method as a source of RNA for the construction of parasite cDNA libraries suggests that RNA derived from these preparations is free of host nucleic acids.

Animals↗
PubMed1991

Cell surface phenotype of two cloned populations of bovine lymphocytes displaying non-specific cytotoxic activity.

Monoclonal antibodies specific for T cell differentiation antigens were tested on four cloned populations of lymphocytes derived from the peripheral blood mononuclear cells of an animal immunised with Theileria parva. The clones were defined functionally in terms of cytotoxic activity, MHC restriction and expression of messenger RNA for CD3 and T cell receptor (TCR). Two clones contained RNA transcripts for CD3, TCR-alpha and beta and were positive for CD2, CD5 and CD6; one of these was a typical CD4+ class II MHC-restricted non-cytotoxic clone while the other was a CD8+ class I MHC-restricted cytotoxic clone. By contrast, the remaining two clones had the characteristics of non-specific killer cells in that they exhibited moderate levels of non-MHC-restricted killing; they contained TCR-delta mRNA and a 1.2 kb truncated form of TCR-beta message, but they did not contain CD3 or TCR-alpha mRNA. One of these non-specific killer clones only expressed CD2 whereas the other clone only expressed CD8, but without the CD8 determinant recognised by monoclonal antibodies CC58 and BAT52. All four clones were negative for the WC1 antigen which is expressed on gamma/delta T lymphocytes.

Animals↗
PubMed1991

Characterization of a polymorphic immunodominant molecule in sporozoites and schizonts of Theileria parva.

This study examines several aspects of a polymorphic, immunodominant molecule (PIM) found in the protozoan parasite, Theileria parva. The antigen is present in all T.p. parva stocks examined, and in the related subspecies, T.p.bovis and T.p.lawrencei. It is the predominant antigen recognized by antisera from immune cattle on Western blot analysis of schizont-infected lymphocytes, and is the only antigen which has been shown to react with anti-schizont monoclonal antibodies (MoAbs) on Western blots or in immunoprecipitations. The antigen shows polymorphism in both size and expression of antibody epitopes among the different stocks of T. parva. The antigen is present in sporozoites as well as schizonts.

Animals↗
PubMed1990

A bovine class I major histocompatibility complex molecule plus a Theileria parva antigen resembles mouse H-2Kd.

Two BoT2+, BoT8+ cytotoxic T cell clones were generated from peripheral blood of a steer immunized with the intracellular protozoan parasite Theileria parva. Both cytotoxic T cell clones appeared to be restricted by the same major histocompatibility complex (MHC) molecule and were specific for the immunizing parasite clone. However, one of the two clones also recognized uninfected mouse cell lines carrying the H-2d haplotype. Inhibition of cytotoxicity with monoclonal antibodies specific for polymorphic determinants on H-2 molecules confirmed that this CTL clone recognized the H-2Kd MHC molecule. These results extend to the bovine system observations in other species that foreign MHC mimics self MHC plus antigen.

Animals↗
PubMed1990

Identification of a Theileria mutans-specific antigen for use in an antibody and antigen detection ELISA.

Purified piroplasms of Theileria mutans were used to immunize BALB/c mice to generate monoclonal antibodies (MoAbs). The MoAbs recognized an antigen of a relative molecular mass of 32 kDa in Western blots. This antigen was also recognized by sera from cattle which had recovered naturally from experimental tick-transmission or infections induced by the blood stages of T. mutans. The MoAbs did not react, in indirect immunofluorescence or enzyme-linked immunosorbent assays (ELISA), with the common haemoparasites of cattle, namely, T. parva, T. annulata, Babesia bigemina, B. bovis, Anaplasma marginale, Trypanosoma congolense, T. vivax or T. brucei. An antigen capture ELISA was established with two of the MoAbs which recognized different epitopes on the 32 kDa molecule. Using this test it was possible to detect circulating antigens or immune complexes in sera collected from cattle during the acute or chronic phases of infection. When the purified 32 kDa protein was used as antigen in a micro-ELISA to detect circulating antibodies in both experimental and field cattle sera, it was found that the titres of antibodies ranged between 1:20 and 1:10,240. Results of this study indicate that the antigen and immune complex capture assays and the antibody detection ELISA can be complementary in the immunodiagnosis of acute and chronic T. mutans infections. Moreover, the tests are useful in the differential diagnosis of the disease and for epidemiological studies.

Animals↗
PubMed1990

Strain specificity of bovine Theileria parva-specific cytotoxic T cells is determined by the phenotype of the restricting class I MHC.

To determine whether the major histocompatibility complex (MHC) phenotype of cattle could affect the parasite strain specificity of immunity to Theileria parva by influencing the antigenic specificity of Theileria-specific cytotoxic T lymphocytes (CTL), we investigated the parasite strain specificity of Theileria-specific CTL clones derived from cattle of different class I MHC phenotypes. Thirty-one class I-restricted CTL clones were generated from four cattle immunized with the Muguga stock of T. parva. The MHC restriction and parasite strain specificities were determined for each clone utilizing as targets, parasitized cell lines of different MHC phenotypes and cloned cell lines containing different parasite strains. CTL clones restricted by the same MHC determinant had similar parasite strain specificities. On the other hand, clones restricted by different MHC determinants exhibited different parasite strain specificities. This was true whether the clones were generated from the same animal or from different cattle and tested on a target cell line expressing both MHC determinants. These results provide strong evidence that differences in the strain specificities of CTL derived from animals immunized with the same parasite stock, are determined by the class I MHC phenotype of the immunized animal.

Animals↗
PubMed1989

Phenotypic characterization of Theileria parva schizonts by two-dimensional gel electrophoresis.

Biosynthetically radiolabelled Theileria parva schizonts were purified from bovine lymphoblastoid cells and their proteins were analyzed by two-dimensional gel electrophoresis and autoradiography. The protein spot patterns of schizont proteins from three stocks of T. parva parva indicated that the phenotypic diversity among the stocks was minimal, with the Mariakani and Uganda stocks being identical and the Muguga stock showing only a few differences in minor spots. Comparison of the spot patterns of schizonts of three T. parva subspecies showed that T.p. parva and T.p. bovis differed in only one protein and thus could not be reliably distinguished on the basis of their protein differences. However, T.p. lawrencei showed several protein differences and could be distinguished easily from the other subspecies. Differences in schizont-protein spot patterns were also seen when two different cell lines were infected with the same Theileria stabilate, when one cell line was infected with two different stabilates of the same stock and when uncloned and cloned infected cell lines were used. These results suggest the possibility that selection of phenotypically different parasites could occur in vivo or in vitro.

Animals↗
PubMed1989

Protein changes in bovine lymphoblastoid cells induced by infection with the intracellular parasite Theileria parva.

Protein and glycoprotein changes induced in bovine lymphoblasts by infection with Theileria parva were analyzed by high-resolution two-dimensional gel electrophoresis. Uninfected and infected cloned bovine T and B lymphoblasts were biosynthetically labeled with [35S]methionine and their two-dimensional autoradiographic patterns were compared with each other and with the pattern obtained using purified labeled schizonts. Ten proteins were found in infected cells which were not present in uninfected cells, and seven of these were detected in preparations of purified schizonts. Four glycoproteins were detected on the surface of infected cells labeled with [3H]borohydride while a major glycoprotein present on uninfected cells disappeared or was reduced in infected cells. Other minor changes in protein and glycoprotein patterns were also observed.

Animals↗
PubMed1989

Infection of bovine T cell clones with genotypically distinct Theileria parva parasites and analysis of their cell surface phenotype.

Different stocks and stabilates within a stock of Theileria parva were analysed for genotypic differences and for their effect on the expression of host cell surface antigens following infection of BoT8+ T lymphocyte clones. The parasites were characterized in vitro by hybridization of T. parva-specific DNA probes to Southern blots of endonuclease-digested DNA from the infected T cell clones. Phenotypic changes in the host lymphoblastoid cells before and after infection were examined using lineage-specific monoclonal antibodies which reacted with the differentiation antigens BoT2, BoT4, Bo6, BoT8 and a null cell marker on bovine T cells. Expression of Class I and Class II major histocompatibility complex (MHC) antigens on the cell populations was also assessed. Results of this study indicate that genotypically different parasites exist among and within T. parva stabilates and that the expression of Bo6, BoT8 and the null cell marker was differentially altered by infection with parasites from different stocks or from different stabilates of the same stock. Expression of Class II antigens was significantly increased after infection. Moreover, clones that were derived from the same cell line but had genotypically distinct T. parva parasites, also showed differences in expression of Bo6 and BoT8 and the null cell marker.

Animals↗
PubMed1988

T-cell clones in immunoparasitology.

Cell-mediated immunity (CMI) is important in many parasitic infections. Stimulation by parasite-specific antigens can induce clonal expansion of parasite-specific T-cells which may act by direct cytotoxic action or by indirect effects on other cells such as natural killer cells or antibody-producing B-cells (Box 1). In many cases however, the precise effector functions and the identity of antigens that elicit protective responses in parasitic infections are poorly defined. Analysis of proliferative and cytotoxic activities of subcloned cultures of T-cells stimulated with parasite antigens can provide some clues about the importance of CMI, but, as this review shows, much more precise information can be obtained by analysis of the response of cloned T-cell cultures.

Journal Article↗
PubMed1988

Bovine T cells, B cells, and null cells are transformed by the protozoan parasite Theileria parva.

The target cells for infection and transformation by Theileria parva were investigated. Peripheral blood mononuclear cells were reacted with monoclonal antibodies specific for bovine leukocyte differentiation antigens, sorted into subpopulations with a fluorescence-activated cell sorter, and infected in vitro with T. parva sporozoites. Infected cells were cultured at limiting dilution, and transformed clones were screened with monoclonal antibodies. The results indicated that B cells, T cells (including BoT4+ and BoT8+ cells), and null cells but not monocytes or neutrophils were transformed in vitro after infection with T. parva. After transformation, peripheral blood T cells and T-cell clones retained expression of most or all of the T-cell differentiation antigens including the mature T-cell marker recognized by monoclonal antibody IL-A27, BoT2, and BoT4 or BoT8, and some cells acquired a low level of expression of BoT4, BoT8, or the null cell marker recognized by monoclonal antibody IL-A29. T. parva-transformed null cells retained expression of the IL-A29 determinant and acquired expression of BoT2 and BoT8 but not the IL-A27 determinant or BoT4. T. parva-transformed B cells in most instances lost expression of surface immunoglobulin and never acquired expression of the IL-A27 determinant, BoT2, BoT4, or BoT8, although some cells acquired a low level of expression of the null cell marker recognized by monoclonal antibody IL-A29. Further studies on cell lines and clones grown in vitro from populations isolated from T. parva-infected cattle suggested that the majority of the in vivo T. parva-transformed cells were of T-cell origin.

Animals↗
PubMed1987

Bovine cytotoxic T cell clones which recognize lymphoblasts infected with two antigenically different stocks of the protozoan parasite Theileria parva.

The Muguga and Marikebuni stocks of Theileria parva differ on the basis of cross-protection and in their schizont antigen profile determined with a panel of parasite-specific monoclonal antibodies. The phenotype and specificity of six cytotoxic T cell clones generated from an animal immunized against T. parva (Marikebuni) were investigated. All six clones had the BoT2+ BoT4- BoT8+ phenotype, were dependent on both specific antigen and T cell growth factor for proliferation and were restricted by determinants on class I major histocompatibility complex molecules. The clones killed target cells infected with either the Muguga or Marikebuni stocks of the parasite; the target cell lines tested included T cell clones which were infected in vitro with the two parasite stocks and subsequently recloned. The specificity of these cytotoxic T cell clones contrasts with that of T cell clones generated previously from animals immunized against T. parva (Muguga), in that the latter were specific for target cells infected with the Muguga stock of the parasite. Moreover, one of the clones generated against T. parva (Marikebuni) was restricted by the same major histocompatibility complex molecule as the Muguga-specific T cell clones. The difference in parasite strain-specificity between the two sets of clones appears to reflect the capacities of the two parasite stocks to cross-protect, since animals immunized against T. parva (Marikebuni) are protected against challenge with T. parva (Muguga) whereas a proportion of animals immunized with T. parva (Muguga) are susceptible to challenge with T. parva (Marikebuni). Another difference between the two sets of T cell clones was that those generated against T. parva (Marikebuni) only killed a proportion of cells of a given cell line in a 4-h cytotoxicity assay, whereas Muguga-specific T cells invariably kill the majority of cells. However, despite this partial killing, the clones markedly inhibited growth of parasitized cell lines when cultured with them for a period of 5 days.

Animals↗