Biomedical subjects

J D Waterfield

Publications and source records attributed to J D Waterfield.

At least 37 records · Page 2Linked to original sources

PubMed1991

Expression of an EL4 tumour-associated determinant on subpopulations of murine T cells in normal and lympho-proliferative autoimmune mice.

It has been demonstrated that the single autosomal recessive lpr and gld genes are responsible for the accumulation of unusual T-cell subsets. Although these subsets have been assigned to the T-cell lineage, they share certain antigenic cell surface markers with mature B lymphocytes. Consequently the maturational pathway(s) of these cells has been difficult to fit in the currently accepted models of T-cell differentiation. Previous work has determined that the YE1/19.1 monoclonal antibody (mAb), developed against the EL4 tumour line, reacts with the accumulating T cells in lpr-expressing mice. In this study we report that YE1/19.1 could also be used as a marker for the accumulating T cells in gld-expressing mice and that the hyporesponsiveness seen in gld mice correlated with these accumulating cells. We then demonstrated that the YE1/19.1 antibody also reacts with a subpopulation of neonatal thymocytes as well as a mitogen non-responsive subpopulation of 'double negative' T cells from the spleens and thymuses of non-autoimmune mice. Our findings indicate that the YE1/19.1 mAb will be a useful probe for helping in the eludication of the intra-thymic maturational pathways of T lymphocytes.

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PubMed1991

Rates of putrefaction of dental pulp in the Northwest coast environment.

Cytological stability is of interest to criminal investigators in instances where remnants of soft tissue have been preserved, since such tissue can aid in the identification of human remains, helping to determine either the sex of the individual or his or her identity. This study based on seven experiments shows that, in Northwest coast outdoor environments in both summer (three experiments) and winter (three experiments), the stability of dental pulp nuclei ranges from 4 days to 2 weeks. The seventh experiment serves to describe the morphological sequence observed in nuclear putrefaction. The specimens included human and pig extracted teeth and unextracted pig teeth. Deposition of the specimens was made both on the surface and in the subsurface (30-cm depth), and the environmental variables were recorded.

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PubMed1991

The effect of the genetic background on the development and function of accumulating YE1/19.1+ cells in lpr mice.

It has been demonstrated that the single autosomal recessive lpr gene is capable of inducing autoimmunity in various strains of mice. Moreover, it is generally accepted that this is an indirect effect of the accumulation of an unusual T lymphocyte subset. Although a thymus is essential for the initiation of the lymphadenopathy, adult thymectomy cannot delay the development of the disease. In this study we report that the degree of lymphadenopathy can be assessed utilizing the YE1/19.1 monoclonal antibody. This antibody recognizes a surface antigen found on the EL 4 tumor lines and all "double negative" nonresponsive T cells from lpr gene expressing mice. We then constructed radiation-induced chimeras to determine whether a normal thymic and extrathymic milieu had any effect on the development and function of the YE1/19.1+ T cells responsible for the lymphadenopathy. It was found that the spleens of B6-lpr----B6-lpr chimeras demonstrated a marked accumulation of the YE1/19.1 positive cells. However, the spleens of B6-lpr----B6 chimeras were shown to contain very few YE1/19.1 positive cells. These differences were also reflected in the amount of anti-DNA antibodies produced by each of the chimeras, the B6 recipients producing very little autoantibody. Once isolated by panning it was found that the cells from either chimera failed to respond to mitogenic signals. Our findings support the possibility that the lpr gene can function in the thymus and/or the periphery of the animal to limit the numbers of accumulating T cells.

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PubMed1989

Isolation and characterization of a T-suppressor factor specific for the lupus-associated autoantigen RNP-Sm.

We have previously described a monoclonal antibody, B16G, which has been found to be specific for T-cell derived suppressor factors (TsF). B16G has been shown to react with T-suppressor cells, TsF in the spleen of normal or tumor-bearing mice, the TsF produced by tumour-specific, or hapten-specific T-cell hybridomas, and with polyclonal whole human TsF isolated from tonsillar tissue. This pan-reactivity inherent to the B16G antibody suggests that it recognizes some common, shared epitope of the TsF molecule. In this study, we have used B16G as a probe to isolate a TsF-producing T-cell hybridoma, S-50, from CBA mice (H-2k) that is specific for the Lupus-associated antigen, RNP-Sm. The TsF bound specifically to RNP-Sm and inhibited the production of anti-RNP-Sm antibody cell cultures from MRL-lpr mice. SDS-PAGE analysis of purified S-50 TsF revealed a B16G-reactive band with a molecular weight of 43 kd.

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PubMed1988

Vertical development of the secondary palate in hamster embryos following exposure to 6-mercaptopurine.

Cellular aspects of vertical development of the secondary palate were examined in control and 6-mercaptopurine (6MP)-treated hamster embryos. Cross-sectional area of the palatal shelf was measured and the numbers of both epithelial and mesenchymal cells counted. Also, in 6MP-treated palates the damaged mesenchymal cells, characterized by the presence of dense bodies, were counted. DNA synthesis in both control and treated fetuses was measured by 3H-thymidine incorporation. The results indicated that both the shelf area and cell numbers increased with age in control and 6MP-treated palates. However, in controls the mesenchymal cell density and DNA synthesis showed two peaks that were absent following 6MP treatment. Unlike controls, in treated embryos the damage to mesenchymal cells became increasingly pronounced between days 10:00 and 10:12 but subsided by day 11:00 of gestation. It is suggested that a major force in the development of the initial primordia and early vertical development of the palatal shelf may be provided by a spurt of DNA synthesis in the mesenchymal cells resulting in their increased number. After 6MP treatment, depression of DNA synthesis and consequent reduction in the mesenchymal cell number and density followed by cell damage lead to retardation in the vertical development of the palatal shelves.

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PubMed1987

Antigen-specific T-cell hyporesponsiveness in MRL congenic mice can be explained by two independent cellular defects.

MRL-+, MRL-lpr and B6-lpr have been shown to be useful models in studying systemic lupus erythematosus. MRL-lpr and B6-lpr differ from their congenic counterparts by the presence and expression of the homozygous recessive lymphoproliferation (lpr) gene. One manifestation of this gene is a massive T-cell proliferation that results in a generalized lymphadenopathy in older animals. A paradox that has developed out of the work utilizing the congenic mice is that the gene responsible for lymphoproliferation also appears to be responsible for the inability of T cells to respond to proliferative signals in vitro. In this paper we investigate the basis for this hyporesponsiveness in antigen-induced activation of proliferation and antibody synthesis. We have demonstrated that spleen cells from both MRL-+ and MRL-lpr mice gave minimal stimulation in a one-way mixed lymphocyte reaction against allogeneic T cells. These findings were extended to include antigen-specific proliferation involving antigen that must be processed and presented to responder lymphocytes in a H-2 restricted manner. Thus, MRL-+ and MRL-lpr spleen cells pulsed with ferredoxin also failed to stimulate ferredoxin-primed T cells from B10.Br animals in vitro. We then investigated whether any T-cell defect(s) was also contributing to this proliferative hyporesponsiveness. T lymphocytes from the spleen of MRL-+, 2-month-old MRL-lpr, and 6-month-old MRL-lpr were tested in a one-way mixed lymphocyte reaction. It was found that only the MRL-+ T cells gave responses approaching normal, suggesting lpr gene involvement in T-cell non-responsiveness. This was confirmed by the demonstration of an age-onset T-cell proliferative hyporesponsiveness in B6-lpr mice. This lpr gene-linked non-responsiveness was also shown to extend to T-cell helper function in a positive allogeneic effect assay. We can conclude from these studies that antigenic nonresponsiveness in MRL congenic mice can be explained by two defects: the failure of antigen-presenting cells in MRL-+ and MRL-lpr mice to provide the necessary signal(s) to immunocompetent T cells, this defect not being associated with the lpr gene, and the lpr gene controlled outgrowth of a unique T-cell population that cannot respond in our assay systems.

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PubMed1986

Correction of defective IL 3 responses of T lymphocytes from autoimmune mice.

MRL-+ and MRL-lpr congenic mice differ by the presence and expression of the homozygous recessive lymphoproliferation (lpr) gene. One manifestation of this gene is a massive T cell proliferation that results in a generalized lymphadenopathy in older animals. Interleukin 3 (IL 3), a recently described lymphokine, has been shown to influence lymphocyte differentiation. It was possible that abberrant IL 3 production was the mechanism responsible for the lpr controlled lymphadenopathy. Consequently, in this paper we tested the MRL congenic mice for their ability to produce IL 3. We report that the T lymphocytes from MRL-+ and MRL-lpr could neither respond to pokeweed mitogen in the induction of proliferation nor produce IL 3. Moreover, IL 3 was not produced constitutively nor could be induced at any time period up to 5 days in vitro. This hyporesponsiveness was shown to be controlled at the accessory cell level. Addition of T cell-depleted peritoneal exudate cells from normal major histocompatibility complex (MHC) compatible mice was able to restore the ability to secrete IL 3 in response to pokeweed mitogen in MRL-+ and young MRL-lpr mice. The defect in the accessory cells could be overridden by two means: the incorporation of phorbol myristate acetate in the induction system and preincubation of the cells in tissue culture.

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PubMed1986

Isolation of functional polyclonal TsF from MRL-lpr spleens using monoclonal antibody absorbance.

We have previously described a monoclonal antibody, B16G, which has been found to be specific for T-cell derived suppressor factors (TsF). B16G has been shown to react with T-suppressor cells, TsF in the spleens of normal or tumor-bearing mice, the TsF produced by a tumor-specific T-cell hybridoma, and with polyclonal whole human TsF isolated from tonsilar tissue. This panreactivity inherent to the B16G MAb has made it clear that it recognizes some common, shared epitope of the TsF molecule. In this study we have used B16G as a probe to isolate TsF from the spleens of MRL-lpr mice and compare the activity with these factors isolated from the spleens of an MHC compatible nonautoimmune strain, CBA. We find that equivalent quantities of functional TsF are isolable from both strains and thus, it can be concluded that the associated oligoclonal B-cell activation characteristic of MRL-lpr mice is not due to a polyclonal T-suppressor cell deficit, nor to the ability of TsC in these mice to produce soluble, functional TsFs. The molecular and biochemical characteristics of these TsFs are discussed.

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PubMed1986

Delineation of two defects responsible for T-cell hyporesponsiveness to concanavalin A in MRL congenic mice.

MRL-lpr mice and their congenic counterparts MRL-+ spontaneously develop an autoimmune disease that resembles systemic lupus erythematosus in humans. The two strains, although congenic, differ by a considerable number of disease parameters, reflecting the expression of the lpr autosomal recessive gene. One paradox that has developed out of the work utilizing the congenic mice is that the gene responsible for lymphoproliferation also appears to be responsible for the inability of T cells to respond to proliferative signals in vitro. In this paper we investigated a possible lpr gene-encoded macrophage defect in these mice. It was found, however, that both the MRL-+ and MRL-lpr mice failed to divide in response to Con A, the lack of division correlating with an inability to secrete the growth promoter interleukin-2. In MRL-+ mice and young MRL-lpr mice this non-responsiveness was corrected by the addition of normal CBA PEC. The defect could not be explained by a failure of MRL-+ or MRL-lpr peritoneal exudate cells to quantitatively or qualitatively provide a source of interleukin-1 to Con A-activated T cells or by the possibility that the peritoneal exudate cells were blocked in their function by the presence of sera-derived autoantibodies and/or immune complexes on their membranes. We postulate that the inability of T cells to proliferate in MRL congenic mice can be explained by two defects: the failure of antigen-presenting cells in MRL-+ and MRL-lpr to provide the necessary signals to immunocompetent T cells, this defect not being associated with the lpr gene, and the lpr gene controlled outgrowth of a unique T-cell population that cannot respond in our assay system.

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PubMed1983

Presence of host-reactive T cells in lymphohaematopoietic chimeras.

The presence of autoreactive lymphocytes was investigated in murine lymphohaematopoietic chimeras. In this report we demonstrate the presence of precursors of host-reactive cytotoxic effector T lymphocytes in parent leads to F1 chimeras. Lymphocytes from these chimeras display cytotoxic activity towards the non-shared major histocompatibility complex (MHC) antigens of the host following activation with the polyclonal T-cell activator concanavalin A. These host-reactive cells were found despite the apparent absence of lymphocytes demonstrating autoreactivity in other experimental systems: mixed lymphocyte reaction, cell-mediated lympholysis, positive allogeneic effect and negative allogeneic effect. Animals possessing precursors of these cytotoxic effector cells also possess precursors of cytotoxic effector cells capable of generating an MHC-restricted anti-minor histocompatibility antigen response. The results are discussed in reference to the role of the thymus in effecting self non-self discrimination.

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PubMed1982

T-cell responses to minor histocompatibility antigens.

We have investigated the helper and cytotoxic T-cell response to minor histocompatibility antigens and generated long term antigen-specific cell lines to them. Antigen-specific activity was selected for by regular restimulation with irradiated cells bearing the antigens in the presence of interleukin 2, so that alloreactivity to other cell surface antigens was gradually lost. Helper T cells cultured over several months were active in vivo and in vitro, but the culturing method eventually selected for cytotoxic T cells at the expense of helper T cells, with concomitant changes in the proportions of cells expressing the Lyt phenotypes. Individual long term cultures of cytotoxic T cells specific for minor histocompatibility antigens were restricted by either H2K or D but not both. Helper T cells to minor histocompatibility antigens derived directly from primed F1 mice did not show restriction to the priming parental haplotype. This is consistent with antigen reprocessing by the F1 antigen presenting cells such that populations of helper T cells restricted by both parental H-2 haplotypes were primed. F1 cytotoxic T cells were restricted to the parental H-2 haplotype used for in vitro boosting, irrespective of which H-2 was used for in vivo priming.

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PubMed1981

Fine specificity mapping of two allospecific T cell lines: recognition of private specificities in the H-2 IA subregion.

Two allospecific T-cell lines, C.C3.11.75 (H-2d anti-H-2k) and B6.C.7.76 (H-2b anti-H-2d) established from mixed lymphocyte cultures, were selected by continuous antigenic stimulation over several years. Both cell lines proliferated to alloantigen, provided allohelp to B cells in the humoral antibody response, and one of them showed cytolytic activity. Using spleen cells from various congenic mouse strains, the specificity of antigen recognition was examined in order to examine whether there is a correlation between T cell function and antigen recognition. Results showed that in all functional assays. This shows that there is no obligatory correlation between T cell function and antigen recognition and may suggest that the T cell receptor repertoire is biased towards recognizing private specificities.

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PubMed1981

Experimentally induced transplantation tolerance. I. Dissociation of effector lymphocytes specific for alloantigens by neonatal tolerance induction.

Neonatal tolerance was induced in CBA mice to alloantigens expressed by lymphoid cells of the A/Sn strain. 50% of the grafted animals maintained viable skin grafts for greater than 120 days and thus were considered operationally tolerant. However, splenic lymphocytes from these animals were capable of in vitro activation of DNA synthesis in response to the tolerizing alloantigens. Likewise, the spleen contained precursors of cytotoxic effector cells capable, upon activation, of similarly recognizing the major histocompatibility complex alloantigens used for tolerance induction. In contrast, in vivo graft-versus-host (GVH) effector function was absent, suggesting a possible dissociation of cells involved in the in vitro cell-mediated lympholysis and the in vivo GVH. Determination of potential serum-blocking factors as a possible mechanism of graft survival in these tolerant animals proved negative.

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PubMed1981

Lymphocyte-mediated cytotoxicity against allogeneic tumour cells. IV. Fine specificity mapping and characterization of concanavalin A-activated cytotoxic effector lymphocytes.

Concanavalin A (Con A)-activated cytotoxic lymphocytes have been investigated, mapping the genetic differences between the P815 target and the effector cells required for cell-mediated lympholysis to occur. The target antigens recognized during the effector phase and the phenotype of the killer cell population(s) were also determined. It was found that Con A could activate a population of primed cytotoxic lymphocytes capable of killing target cells that were identical at the major histocompatibility complex (MHC) but differed at other background genes. Thus, after in vivo priming with DBA/2, B10.D2 lymphocytes cultured with Con A were capable of killing the P815 target. Unprimed B10.D2 cells, however, would not. Studies on the involvement of the MHC indicated that differences in the H-2K through H-2S, as well as differences in H-2D and H-2L alone could cause lysis. This killing could not be accounted for by additional differences at Qa-2, a MHC-linked locus. However, the contribution of other similar non-MHC linked loci could not be excluded. Cold target competition experiments indicated that MHC encoded alloantigens were involved as recognition structures on the target cell surface. Antisera plus complement depletion of cytotoxic effector function demonstrated that the cytotoxic cells had the cell surface phenotypes Thy 1.2+, Lyt 2.2+ and natural killer (NK) 1.1-. We conclude that Con A polyclonally activates population(s) of T cells that express antigen-specific cytotoxicity through clonally distributed recognition receptors intrinsic to their membranes when lectin is omitted from the cytotoxic assay.

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PubMed1980

Is self tolerance H-2 restricted?

An individual's immune system must be capable of responding to a wide variety of antigens, but must not react against tissues of the individual itself. The specificity of this 'self tolerance' is determined early in life and recent work has dealt with the mechanisms by which self tolerance is maintained. We report here a study designed to determine whether products of the major histocompatibility complex are involved in the induction of self tolerance; in particular, whether the induction of self tolerance in the mouse is H-2 restricted. H-2 restriction refers to the finding that mouse T cells generally recognize foreign antigens only when presented in association with the products of H-2 alleles. We questioned whether T-cell precursors are made tolerant directly by antigen alone, or whether the antigen must be associated in the cell membrane with an appropriate H-2 molecule. We find that T-cell tolerance to 'self' membrane components does not seem to be H-2 restricted and discuss the possibility that this apparent lack of H-2 restriction is due to antigen processing.

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PubMed1979

Continuously proliferating allospecific T cells. I. Specificity of cooperation with allogeneic B cells in the humoral antibody response to sheep erythrocytes.

Allospecific mouse T cells, positively selected in one-way mixed lymphocyte culture were maintained for 3 yr in tissue culture by sequential restimulation. Such proliferating T cells were tested for their ability to induce a positive allogeneic effect: activating B cells in an in vitro primary humoral response to sheep erythrocytes. It was found that such T lymphocytes could function as helper cells. Helper activity was shown to be specific in that the B cells activated had to share major histocompatibility complex (H-2) antigens with the strain used for selection of the cell line. Intra H-2 mapping showed that antigens coded in the IAk subregion played an important role in the induction of the positive allogeneic effect. Supernatant factors could substitute for the allogeneic T cells in activation of the in vitro humoral response. However, such supernates exhibited no strain specificity. Therefore, the specificity seen in the positive allogeneic effect is presumably a consequence of the alloantigenic recognition receptors intrinsic to the T cells, and not to any biologically restricting properties of the allogeneic effect factor itself.

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PubMed1978

Effect of membrane stabilizing agents on induction of the immune response. II. Inhibitory effects on lymphocyte activation by B-cell mitogens parallel toxicity.

The effect of three membrane stabilizing compounds, chlorpromazine, imipramine and lidocaine, on mouse spleen cells was investigated. Cellular activation by the B-cell mitogen lipopolysaccharide (LPS) was found to be inhibited. Suppressing doses also inhibited back ground DNA-synthesis and the number of background plaque forming cells. However, the degree of suppression caused by all three of the membrane stabilizing agents tested, parallelled the decline of viable cells in the cultures. It is concluded that the drug induced inhibition of LPS activation was due solely to the toxicity of the compounds.

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PubMed1978

Presence of alloantigen-reactive cells in neonatally tolerized mice.

Neonatally induced fully tolerant mice possess cytotoxic effector cells, specific for the tolerizing antigens, which can be induced by polyclonal T cell activators in vivo (Con A) on in vitro (poly A:U). Therefore, clonal deletion of specific effector cells is eliminated as the mechanism by which skin grafts are retained in tolerized mice.

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