Biomedical subjects
Publications and source records attributed to D S Cunningham.
Hereditary angioneurotic edema is a potentially fatal condition. Below is described the first reported case of the initial presentation of the condition precipitated by vaginal delivery.
The reactivity of a new monoclonal antibody to the T-cell beta chain antigen receptor (beta F1) with routinely processed paraffin sections from patients with T-cell lymphoma is described. Staining of tumour cells was seen in 36/47 cases of T-cell lymphoma. No staining was seen in any cases of B-cell lymphoma (0/21 cases), nine of which had previously been shown to react with other T-cell antibodies (MT1/UCHL1). We conclude that beta F1 is a specific marker for demonstrating a T-cell histogenesis of lymphoma and with advantages over other currently available antibodies reactive with paraffin sections.
To determine whether the tissue distribution of glutathione S-transferase (GST) isoenzymes could define the precise nature of renal injury, 13 adult kidneys were studied, using specific antibodies raised against purified isoenzymes. Basic GST stained strongly proximal convoluted tubules and some medullary tubules; acidic GST stained strongly distal convoluted tubules and medullary tubules; neutral GST stained similarly to acidic GST, but weaker, and microsomal GST stained glomerular and interstitial endothelium and collecting ducts deep in the medulla, although there was considerable variation in staining intensity among cases. It is suggested that the measurement of these isoenzymes in serum and urine may help to elucidate the localisation of tissue damage, which may be particularly valuable in patients with cyclosporine toxicity following renal transplantation.
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Attempts to immunize susceptible hosts against infection with Trypanosoma cruzi have generally not met with a high degree of success. In the present study, we used the antimetabolite mitomycin C to produce nonreplicating, attenuated culture forms of T. cruzi. Attempts to immunize highly susceptible C3H(He) mice with single or multiple inoculi of mitomycin C-treated trypanosomes 2 weeks before injection of infective blood-form trypomastigotes did not, however, lead to greater longevity in immunized mice over nonimmunized, control mice. It was determined that a single injection of 10(7) attenuated parasites induced a transient suppression of the immune response to sheep erythrocytes which was maximum on day 7, less on day 14, and undetectable by the 21st day after immunization. This immunosuppression to a heterologous antigen did not, however, appear to be the cause of the failure of the vaccination procedure to elicit protective immunity since mice immunized once with 10(7) mitomycin C-treated trypanosomes and challenged 30, 60, or 90 days later exhibited no greater longevity than control mice.
Specific-pathogen-free B6D2 F1 hybrid mice were infected intravenously with 10(7) to 10(8) viable Mycobacterium kansasii cells. The growth of the five test strains in vivo was correlated with the level of delayed hypersensitivity to a cytoplasmic protein antigen injected into the footpad. M. kansasii TMC no. 1201 and 1203 gave rise to persisting systemic infections with an early delayed hypersensitivity response (day 7) followed by a profound anergy to the cytoplasmic protein antigen injections. Strains 1204, 1214, and 1217 declined in viability relatively rapidly and failed to induce detectable levels of delayed hypersensitivity. Spleens harvested from mice infected 20 to 30 days earlier with 10(8) M. kansasii 1203 cells contained a T-cell subpopulation capable of suppressing mixed lymphocyte reactions between normal B6D2 and C3H(He) cells. On the other hand, splenic T-cells taken from M. kansasii 1214-infected mice enhanced, rather than suppressed, the indicator mixed lymphocyte reactions. The kinetics of stimulator-suppressor T-cell production within the spleens of the heavily infected mice differed as the two contrasting M. kansasii infections progressed. Such cellular interactions could well be responsible for the observed persistence of the systemic M. kansasii 1203 infection.
Specific pathogen-free B6D2 F1 hybrid mice were infected intravenously with increasing numbers of Mycobacterium kansasii TMC 1203 or 1214 and blastogenic responsiveness of the splenic T cells to phytohaemagglutinin (PHA), Con A or to a mixed lymphocyte reaction (MLR) were compared. Mice which had been infected 30 days earlier with M. kansasii strain 1203 exhibited substantial suppression whereas those infected with 1214 showed enhanced tritiated thymidine uptakes when exposed to mitogenic or allogeneic stimulation. Spleen cells harvested from mice infected 10 days earlier with either M. kansasii 1203 or 1214 exhibited substantially enhanced levels of helper T-cell activity in vitro compared with normal spleen cells. As the M. kansasii 1203 infections progressed, increasing suppressor T-cell activity was observed so that by day 30, the helper T-cell response had been largely ablated. On the other hand, the M. kansasii 1214-infected spleens exhibited little or no suppressor T-cell activity at any time during the infection. However, helper T-cell activity doubled over this same time period relative to that for the 1203-infected spleens when the responses were compared on a cell-to-cell basis.
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Trypanosoma cruzi releases a factor (SCAF) when grown in vitro which decomplements normal mouse, human, and guinea pig sera. The production and potency of SCAF was dependent on the density of cultured parasites, parasite viability and proliferative capacity, and duration of culture. The in vitro interaction between SCAF and serum complement (C') occurred rapidly and was complete within 30 min of mixing. The administration of SCAF to normal mice resulted in up to 50% reduction in hemolytic C' activity, whereas SCAF had no effect on the C' levels in mice infected wit T. cruzi for more than 10 days. The active moiety of SCAF was shown to be a nonproteinaceous substance(s) with a molecular weight of approximately 23,000 daltons.
Peripheral blood leukocytes from patients serologically positive for Chagas' disease were examined for their ability to respond to heterologous antigens in vitro. It was found that mononuclear cells from chagasic patients had greatly reduced ability to respond to sheep erythrocytes (SRBC) as compared with peripheral blood mononuclear cells (PBMC) from control subjects. The reduction in anti-SRBC antibody activity was independent of antigen dose and was not a result of differences in antibody response kinetics. Depletion of plastic-adherent result of differences in antibody response kinetics. Depletion of plastic-adherent cells from the PBMC of patients did not affect the suppressed state of the nonadherent lymphocytes. No relationship was evident between the duration of Trypanosoma cruzi infection and the degree of humoral responsiveness.
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Serum from mice infected with Trypanosoma cruzi (SSS) is known to interact with normal spleen cells to induce an immunosuppressed condition and activate splenic suppressor cells. The induction of immunosuppression by SSS was shown to be independent of, and precede the activation of, suppressor cells. Suppressor-cell activation, however, was demonstrable only after the induction of immunosuppression. Furthermore, mice that were given two aliquots of SSS at different intervals of time, exhibited suppression of humoral responses of similar duration and magnitude, regardless of the SSS transfer regimen, whereas both the length and degree of suppressor-cell activity was critically dependent on the interval of time between SSS transfers. SSS interacted with spleen cells via a trypsin-sensitive membrane site which was regenerable within a 4- to 5-hr period, yet the suppressive effects of SSS on spleen cells following interaction was resistant to treatment with trypsin. The interaction between SSS and spleen cells during brief adsorption protocols leads to immunosuppression only because extensive washing of SSS-treated spleen cells did not reverse the immunosuppression process, but did prevent the development of detectable suppressor cells. The phenomenon of suppressor-cell activation was further distinguished from immunosuppression in that supernates from culture of spleen cells derived from SSS-treated mice or T. cruzi-infected contained a factor that activated suppressor cells, but did not directly induce a state of suppression in the responding cell population.
In vitro antisheep erythrocyte (SRBC) and antitrinitrophenyl (TNP) antibody responses of spleen cells obtained from C57BL/6 mice infected with Trypanosoma cruzi were reduced as early as 6 days postinfection and not detectable after 18 days of infection. Lymph node cells had normal antibody responses to SRBC and TNP in vitro until the 11th day of infection, after which responses were diminished. By day 31 of infection, lymph node cells were unresponsive to both SRBC and TNP in vitro. Not only were the antibody responses of spleen and lympho node cells to T-cell-dependent and -independent antigens progressively reduced as the period of infection increased, but in addition, the effect of lymphoid cell density and antigen dose on antibody production underwent several sequential changes. As the infection advanced, low densities of cultured lymphoid cells and low doses of antigen were ineffective in eliciting a detectable immune response, whereas high densities of lymphoid cells and high doses of antigen resulted in responses approximately equivalent to that observed with normal cells under the same conditions. Results of cell mixing studies have shown that a plastic-adherent, macrophage-like cell plays a major role in the suppressed humoral responses observed in this host-parasite system.
Spleen cells from normal mice and mice infected with Trypanosoma cruzi undergo mitogen-induced lymphoblast transformation in different ways. Some of these differences may be interpreted as suppression of the blastogenic response, whereas others cannot. Close examination of the culture conditions has enabled us to discriminate between in vivo-induced suppression and in vitro-determined (artifactual) suppression. Regardless of the type of suppression observed, it was shown to be dependent on duration of culture, length of labeling period, dose of mitogen, density of spleen cells, and method of expressing lymphoblast transformation data. The titration of mitomycin C-treated spleen cells from infected mice into cultures of normal spleen cells revealed two, separate, regulatory activities of spleen cells from infected mice as follow: (1) an enhancing effect which appeared late in infection and was obtained with low input of cells, and (2) a suppressive effect which appeared early in infection and was obtained with high input of cells. The enhancing effect was mediated by cells with properties characteristic of T-lymphocytes, whereas macrophages were found to be responsible for the suppressive effects.
In the present study, the effects of Trypanosoma cruzi and the T. cruzi-induced serum suppressor substance (SSS) on antibody responses were compared. Although infection with T. cruzi led to an alteration in T cell helper activity and a reduced specific B cell precursor frequency, SSS did not have a similar effect on either of these cell populations. The characteristics of the altered T cell helper activity was further investigated, and it was found that helper activity appeared earlier in infected mice than in normal or SSS-suppressed mice, and less antigen was required for optimal elicitation of T helper cells in infected mice. The potency of T cell helper activity also was shown to differ, and in the order T. cruzi-infected 6E normal 6E SSS-suppressed mice. It was found that spleen cells from T. cruzi-infected mice elaborated more potent specific helper factors than spleen cells from normal or SSS-suppressed mice, but did not produce a detectable nonspecific helper factor in vitro. Finally, the addition of B cells from low-dose primed, T. cruzi-infected mice to cultures of normal spleen cells resulted in subnormal responses to the priming antigen (sheep erythrocytes) but not to another unrelated antigen (trinitrophenyl-haptenated Brucella abortus), whereas similarly sensitized B cells from normal or SSS-suppressed mice caused no such effect.
Serum from mice infected with Trypanosoma cruzi-suppressed (=SSS) lipopolysaccharide (LPS)-, phytohemagglutinin (PHA)-, and concanavalin A (Con A)-induced lymphoblast transformation when added to cultures of spleen cells or lymph node cells. This serum maximally suppressed blastogenic responses in spleen cell and lymph node cell cultures that contained supportive fetal bovine serum concentrations of 2% and 4%, respectively. Preincubation of lymphoid cells with SSS for 18 to 48 hr prior to initiation of the blastogenesis assay led to suppression of LPS-, PHA-, and Con A-induced proliferation at the optimal concentration of supportive fetal bovine serum (5%), whereas adsorption of lymphoid cells with SSS at 4 C for 30 min before stimulation with mitogen led to suppression of LPS-induced proliferation in spleen cells only. There was a close temporal correspondence between the induction and manifestation of suppression to the T-cell mitogens (PHA and Con A), but the manifestation of suppression preceded the induction of suppression to the B-cell mitogen (LPS) by approximately 12 hr. The SSS-induced suppression of proliferative responses, except in spleen cell cultures stimulated with LPS, was shown to be dependent on the presence of macrophages during the preincubation and stimulation phases of the assay system. The combined results of experiments in which macrophages were preincubated with SSS, or in which macrophages from the spleen were cultured with lymphocytes from the lymph nodes and vice versa (before and after preincubation with SSS), clearly demonstrated the presence of SSS-activated suppressor cells in the spleen, but not in the lymph nodes. Furthermore, the activation of these suppressor macrophages was reliant upon interactions with splenic lymphocytes.
C57BL/6 mice exhibit low parasitemias and often survive Trypanosoma cruzi infections, whereas C3H(He) mice die during the acute phase with relatively high parasitemias. The present study showed that both strains of mice develop nonspecific immunosuppression to challenge with sheep erythrocytes during the course of infection. Several major differences in immunosuppression-related phenomena between the two strains of mice were determined, yet there is no apparent relationship between immunosuppression and resistance to T. cruzi. Both the number of direct plaque-forming cells and the titer of 2-mercaptoethanol-sensitive agglutinating antibody were significantly lower on day 11 for C57BL/6 mice and day 9 for C3H(He) mice. The number of indirect plaque-forming cells and the titer of mercaptoethanol-resistant agglutinating antibody were reduced by day 36 of infection in C57BL/6 mice and 13 days postinfection in C3H(He) mice. In both strains the degree of humoral response suppression of mice increased concomitant with the period of infection, but was not correlated with the changes in spleen cell numbers. Preliminary experiments designed to explore the mechanism underlying the induction and maintenance of immunosuppression in this hostparasite model disclosed the presence of suppressor substance in the serum of T. cruzi-infected mice. The passive transfer of serum from infected mice to syngeneic recipients elicited a state of immunosuppression to sheep erythrocytes, but did not diminish anti-erythrocyte activity in allogeneic recipients. The induction of immunosuppression in normal mice was further found to be dependent on the interval between serum transfer and challenge with antigen. No quantitative differences existed between the magnitude of suppressed humoral responses in mice infected for varying lengths of time and recipients of serum collected from similarly infected mice.