Biomedical subjects

R M Gorczynski

Publications and source records attributed to R M Gorczynski.

At least 109 records · Page 6Linked to original sources

PubMed1990

Antigenic variation in Leishmania mexicana following infection of immunized mice leads to relative sparing of suppressor determinants.

Intravenous immunization of BALB/c mice with irradiated Leishmania mexicana slows the growth of a subsequent intradermal inoculation of virulent parasites. Prior subcutaneous immunization with irradiated parasites before i.v. immunization blocks the protective effect of the latter. Parasites harvested from vaccinated mice grow more slowly in naive mice than the initial inoculated clone, and have a diminished capacity to immunize mice against this initial clone when used as (irradiated) i.v. immunogen. However, parasites harvested from vaccinated mice are as effective as the initial clone in blocking protection when used as subcutaneous immunogen. Understanding the nature of this differential response in expression of protecting/suppressor determinants in parasites harvested from vaccinated or naive mice will likely be important to developing a suitable vaccination strategy for human use.

Animals↗

PubMed1990

Comparison of endotoxins and cutaneous burn toxin as immunosuppressants.

Endotoxins of E. coli, S. typhosa and Ps. aeruginosa were injected i.p. into mice a few days before administration of the antigen sheep erythrocytes (SE). Antibody-forming cells (AFC) to SE were later enumerated in relation to dose of endotoxin given. In comparison a toxic lipid protein isolated from burned skin (cutaneous burn toxin or CBT) was similarly applied and found to be more inhibitory of the immune response than any of the three endotoxins. Considering the 50 per cent inhibitory doses on a molar basis CBT was found to be 1000 fold more immunosuppressive than the most inhibitory endotoxin. As the immune suppression which follows severe thermal injury involves failure of interleukin 2 (IL2) function, as a critical index of survival, the CBT was tested for its effects on the culture of a human IL2-dependent cell line in the presence of IL2. CBT inhibited the growth of these cells, however, endotoxin had no effect on their proliferation. Thus CBT, which arises by a thermally induced polymerization of skin lipid protein, is specific to burn injury and has a direct inhibitory effect on the immune response.

Animals↗

PubMed1990

Conditioned enhancement of skin allografts in mice.

Healthy A/J mice grafted with either BALB/c or C57BL/6 tail skin routinely reject these grafts with a mean survival time (MST) of 12-14 days. Low dose cyclophosphamide, Cy (50 mg/kg) on the day of engraftment can enhance survival of both grafts (MST 17-20 days). If mice are given three weekly intravenous injections of BALB/c peripheral blood prior to grafting, specific enhancement of BALB/c but not C57BL/6 grafts results (MST 18 and 12 days, respectively). Mice given several ip treatments with Cy in association with a novel taste (saccharin, Sacc) in their drinking water also show a conditioned immunosuppression if subsequently exposed to Sacc alone. Such mice given BALB/c or C57BL/6 skin grafts and re-exposed to Sacc also show prolonged survival of these skin allografts (MST 16-17 days). If conditioned mice are also treated, by pretransplant donor-specific transfusion, to develop a state of specific suppression of allograft immunity, then subsequent grafting with BALB/c or C57BL/6 grafts coupled with re-exposure to Sacc lead to a further prolonged survival of grafts specifically in the BALB/c mice (MST 29 days).

Animals↗

PubMed1989

IL-2 secretion is pertussis toxin sensitive in a T lymphocyte hybridoma.

Interaction of specific ligands with TCR initiates a cascade of biochemical events which leads to expression of high affinity IL-2R and subsequent IL-2 secretion. Activation of phospholipase C (PL-C) is considered to be a key event in the initiation of this cascade. However, in addition to this PL-C-dependent pathway, PL-C-independent pathways have been hypothesized. Identification of the steps constituting these PL-C-independent pathways has been difficult because activation of PL-C and the subsequent cascade of events mask the effects of such pathways. Specific inhibitors for PL-C, or mutants defective in, the PL-C pathway would facilitate delineation of alternative activation pathways. We have identified a murine pork insulin/IAd-specific T cell hybridoma, B8P3.11, in which perturbation of the B8P3.11 TCR by either Ag in association with Ia, anti-CD3 antibodies, or a mitogenic lectin does not induce increases in myo-inositol 1,4,5-triphosphate production or cytosolic free calcium, yet it does lead to IL-2 secretion. Treatment of B8P3.11 with pertussis toxin, at concentrations which ADP-ribosylate GTP-binding proteins, inhibits IL-2 secretion. Thus, signal transduction resulting in IL-2 secretion by B8P3.11 likely involves a G protein. In contrast, TCR/ligand interaction activates the PL-C-dependent pathway in LBRM 331A5, a T cell lymphoma. Furthermore, pertussis toxin treatment, which blocks IL-2 secretion by B8P3.11, does not alter IL-2 secretion by LBRM 331A5. However, similar pertussis toxin substrates are present in both cells. Therefore, B8P3.11 T cells should help to elucidate PL-C-independent activation pathways.

Animals↗

PubMed1989

Neuroleptic and anti-depressant drug treatment abolishes conditioned immunosuppression in mice.

Mice previously exposed to cyclophosphamide in the presence of saccharin-flavored water will show a decreased antibody response to challenge with sheep erythrocytes if simultaneously they are again given saccharin to drink. These mice also show conditioned taste aversion. Treatment of conditioned animals with chlorpromazine or amitriptyline after challenge with erythrocytes in the presence of saccharin reduced the degree of immunosuppression and, though to a lesser degree, the conditioned taste aversion.

Amitriptyline↗

PubMed1989

Altered virulence and vaccination properties of Leishmania parasites grown in infected vaccinated mice.

BALB/c mice, which are normally highly susceptible to growth of Leishmania mexicana parasites in vivo, can be vaccinated with avirulent temperature-sensitive mutants of L. mexicana so that challenge with virulent organisms results in markedly diminished growth of the latter. Parasites extracted from the lesions which do appear in these mice are able to produce active infection in secondary hosts, although the rate of progression of these lesions is slower than that seen with the original virulent cloned organism. Interestingly, when irradiated parasites from the secondary hosts are themselves used to vaccinate naive BALB/c mice, less protection is seen than when irradiated virulent organisms from the initial infecting clone are used. These data suggest that when infection does take place in mice vaccinated with avirulent clones of parasite, the organisms which develop in lesions in these animals are substantially modified from those present in the initial infecting inoculum.

Animals↗

PubMed1988

Interactions between lymphoid cells and a thymic stromal cell line in vitro.

In the present study, we have optimalized the adherence assay to allow monitoring of the level of contact between thymocytes and a thymic epithelial cell line, E-5, in vitro. This type of interaction is not MHC-restricted, thus is unlikely to participate in the education of thymocytes to self. It was also shown that adherence does not vary from strain to strain, except for B6lpr/lpr immunodeficient mice which showed a markedly decreased adherence. This might be caused by the high level of L3T4-, Lyt-2- thymocytes in these mice (Davignon et al., 1985), since enriched double negative cells were shown not to adhere to E-5 cells. Preliminary characterization of adhering thymocytes suggests an heterogeneous mature phenotype. These cells appear around day 16 of fetal life and increase gradually until birth to remain constant throughout life. On the basis of contact duration, two populations of adhering thymocytes exist: one spontaneously detached after 1.5 hr, refractive to further adherence and the other which adheres for up to 14 hr. Contact between lymphoid and E-5 cells was shown to induce PHA responsiveness.

Animals↗

PubMed1988

Effect of neonatal injection with antibodies to Leishmania mexicana on its growth in adult infected mice.

Mice inoculated with monoclonal antibodies (MAb) directed to Leishmania mexicana antigens were not protected from growth of a subsequent challenge infection; this was the case even when those antibodies were capable of inhibiting parasite growth in vitro. However F(ab')2 fragments of one antibody (1E1) were protective in vivo. When neonatal mice were injected with MAb and subsequently infected as adults, the animals were more susceptible to parasite growth than uninjected controls. This increased susceptibility could be adoptively transferred with Lyt-1+ cells. Separate groups of animals were immunized with different MAb to L. mexicana, and parasite growth in these animals was studied. In no case was parasite growth altered, though these mice did produce specific antibodies directed against the immunizing MAb (anti-idiotypic antibodies). When neonatal mice were injected with these latter reagents, they were found to be more resistant to challenge infection than control animals. This resistance was associated with an enhanced ability of spleen cells from these mice to produce, on stimulation with parasite antigens in vitro, a factor rendering normal macrophages cytocidal for L. mexicana.

Age Factors↗

PubMed1987

Immunization with Leishmania-specific T cell not B cell lines or hybridomas can modulate the response of susceptible mice infected with viable parasites.

Monoclonal antibodies (mAb), T cell lines, and T or B cell hybridomas were prepared from BALB/c, CBA, or E1 mice infected with Leishmania mexicana. Various mAb were produced which inhibited the growth and motility of parasites in vitro. T cell lines (hybridomas) were screened for their ability to release interleukin 2 on specific antigen exposure. Passive transfer of mAb or T cell lines to infected adult mice caused little perturbation of parasite growth. Recipient naive mice were immunized with purified Ig or irradiated cells from these sources and were subsequently infected with viable parasites. Only preimmunization with T cell lines (hybridomas) led to exacerbation of parasite growth, although enzyme-linked immunosorbent assays could detect the production of anti-idiotype antibodies in mAb (B cell hybridoma)-immunized mice. Either nylon wool-purified T cells or serum Ig from T cell-immunized mice could be used to immunize further naive recipients for protection against parasite growth. These data have implications for the development of anti-idiotype vaccines for Leishmania antigens.

Animals↗

PubMed1987

T cell-derived factor alone or in combination with immunosuppressive drugs augments prolongation of allogeneic skin graft survival in mice receiving donor-specific transfusion.

Limiting dilution cytotoxicity or proliferation assays were performed with cells taken from A/J mice pretransfused with BALB/c blood. The data obtained indicate that donor-specific transfusion decreased both the frequency of reactive precursors and their proliferative potential after activation. Additional studies implied that these changes may be associated with a serum- or cell-mediated antigen-specific suppressive mechanism. Further manipulations aimed at preferentially sparing or enhancing the activity of suppressor T cells prolonged skin graft survival in pretransfused mice and led to the presence of suppressor T cells in the spleen of such mice, which were active upon adoptive transfer. These manipulations included the use of pretransplant donor-specific transfusion, administration of ALS or cyclosporin-A, or the use of posttransplant injection with a T suppressor activating factor (SAF). Optimum graft survival was associated with combined treatment when using transfusion, SAF, and cyclosporin-A.

Animals↗

PubMed1987

Role of natural killer (NK) cells in the production of the murine T lymphocyte allorecognition repertoire.

Limiting dilution cultures of alloreactive (anti-H2Kb) CTL were established from thymocyte or spleen cell pools of C3H/HeJ and their congenic bg/bg partner, or of SJL/J and their congenic bg/bg partner. CTL populations in these cultures were assayed for cross-reactive lysis of a panel of splenic Con A blasts of H2Kbm mutant mice. There was some slight elevation of frequency of CTLp in the thymocyte lymphoid pool of bg/bg mice; more strikingly, the repertoire of anti-H2Kb specificities was clearly altered in both strains in the bg/bg animals. There was apparently an increased diversity (more specificities represented at higher frequencies) in the thymocyte pool and a decreased diversity in the spleen cell CTLp pool in animals with the bg/bg marker. Similar shifts in the allorecognition repertoire of normal C3H/HeJ mice were produced by inoculation of neonatal mice with a rabbit anti-NK heteroantibody (antiasialo GM1). Preabsorption of this serum such that it lost anti-NK activity also abolished this effect of in vivo neonatal injection. Furthermore, injection of bg/bg bone marrow-reconstituted C3H/HeJ (bg/+) mice with a C3H spleen cell-derived NK line also caused a shift in the allorecognition repertoire toward that seen in the normal littermate control animals.

Animals↗

PubMed1987

Cyclosporin alters the induction of allospecific tolerance in vivo.

CBA mice were made hyporesponsive to A/J alloantigens by either neonatal inoculation of (CBA X A)F1 hybrid lymphoid cells or by intravenous injection of adult mice with A/J bone marrow cells. Specific alloreactivity was assessed in vitro by induction of anti-A/J cytotoxic T lymphocytes (CTL) or in vivo by skin graft rejection. Cyclosporin A given at the same time as the tolerance-inducing regimen of F1 (or parental) lymphoid cells abolished the hyporesponsiveness normally induced by these injections.

Animals↗

PubMed1987

Analysis of lymphocytes in, and host environment of, mice showing conditioned immunosuppression to cyclophosphamide.

Mice were subjected to repeated exposures to cyclophosphamide: saccharin (conditioned) or cyclophosphamide:saccharin followed by saccharin only (conditioned:extinguished). Animals in the former group but not the latter subsequently showed diminished IgG antibody-forming cells (AFC) after challenge with sheep red blood cells followed by reexposure to immunologically inert cues (saccharin). When these animals were used as irradiated recipients of syngeneic spleen lymphocytes, reconstituted irradiated conditioned mice showed augmented IgG AFC on transfer of naive spleen cells and reexposure to saccharin. The expected diminished IgG AFC response was seen when cells from conditioned mice were transferred. However, the latter cells gave augmented IgG AFC when transferred to naive irradiated mice. Both of the effects seen with cells from conditioned animals (increased IgG AFC in control recipients; decreased IgG AFC in conditioned mice reexposed to saccharin) were regulated by adoptively transferred T cells in the spleen cell population.

Animals↗

PubMed1987

Behavioral trait associated with conditioned immunity.

Inbred strains of mice were tested for their activity in an open field. Animals selected for high or low activity ("tails" of the normal distribution) were further inbred through nine generations (brother x sister) with further selection at each generation. Reciprocal skin grafts between the two groups were performed to ensure that little/no genetic drift occurred. Using a cyclophosphamide:saccharin conditioning paradigm (R. Ader & N. Cohen (1975) Psychosom. Med. 37, 333-342) we show that mice preselected for high activity in an open field were those in which it was most easy to demonstrate conditioned immunosuppression. There was no difference in the conditionability of the two groups as assessed by taste aversion. By use of a cross-fostering design we conclude that immunological conditioning (in adult mice) can be affected by a characteristic of the nursing mother which is associated with activity in an open-field trial.

Animals↗

PubMed1987

Conditioned immunosuppression in young versus aged mice: differences in cells and responses to environmental stimuli lead to altered conditioning in aged animals.

Aged mice (greater than 20 months of age) show a decreased immune response after antigen challenge compared to their young counterparts. In this study aged mice were also found to show a diminished conditioned immunosuppression after associative learning trials with cyclophosphamide and saccharin, followed by immune stimulation in the presence of saccharin, when compared to young (10 weeks) syngeneic mice. Adoptive transfer experiments in which cells from nonconditioned or conditioned young or aged mice were injected into irradiated conditioned young or aged syngeneic mice (exposed or not exposed to conditioned stimuli) revealed the following: (1) There was an altered responsiveness of normal cells injected into conditioned aged mice (reexposed to cues) compared to the response in young recipients; (2) Cells from conditioned young mice failed to show conditioned immunosuppression on adoptive transfer to irradiated conditioned aged mice; (3) Cells from conditioned aged mice failed to show conditioned immunosuppression on adoptive transfer to irradiated conditioned young mice; (4) The changes seen in spleen cells from conditioned aged mice (relative to similar cells from young mice) were to be found in the T cell population of these animals. These data are consistent with the idea that during aging changes in both the responding cells and the conditioned environment, along with the interaction of these, produce a decreased ability to document conditioned immunosuppression of antibody responses.

Aging↗

PubMed1987

Diversity in the lymphocyte recognition repertoire is altered during ageing.

A variety of experiments is discussed, all of which indicate that a major alteration in the degree of diversity of both the B and T lymphocyte recognition repertoire occurs during ageing. This seems to be in part caused by alterations intrinsic to mature lymphocyte precursors themselves, and their responsiveness to environmental signals (e. g. MHC restriction), and in part due to changes in the host differentiation environment. Other changes which contribute to a decline in immune performance with age include altered accessory cell function/activity and alterations in e. g. the affinity of lymphocyte target interactions.

Aging↗

PubMed1986

Interleukin-1-like activity in human cerebrospinal fluid.

Cerebrospinal fluid (CSF) samples were obtained from patients undergoing myelography, who were subsequently diagnosed as having degenerative neck or back disease with no significant CNS inflammation. Using a mitogen co-stimulation assay with mouse thymocytes, or interleukin-1 (IL1) dependent interleukin-2 (IL2) secreting tumour cell line, these CSF samples were shown to contain an IL1-like activity, with predominant activity located in molecules with size 15 kDa and 30 kDa (Sephadex size chromatography). The results are discussed in light of data implicating a role for IL1 in other physiological functions.

Animals↗

PubMed1986

Do sugar residues contribute to the antigenic determinants responsible for protection and/or abolition of protection in Leishmania-infected BALB/c mice?

Intravenous inoculation of irradiated virulent promastigotes of Leishmania mexicana, or intradermal inoculation of avirulent temperature-sensitive clones of the same parasite, can protect BALB/c mice from progressive disease when challenged with parental organisms. However, if animals are prechallenged s.c. with irradiated parental parasites before (or shortly after, i.e., within 10 days) any other immunization regime is used, the s.c. challenge effectively suppresses development of protective immunity. The role of N-linked sugars on promastigotes in providing the determinants responsible for protection and/or suppression of protection in these assays has been examined. Growth of parasite in 2 micrograms/ml tunicamycin has no effect on incorporation of [3H]leucine but decreases incorporation of [3H]mannose by some 40 to 50%. Such tunicamycin-treated avirulent clones or irradiated virulent organisms are now unable to induce a protective response. However, tunicamycin-treated parental parasites given s.c. could still suppress the protection seen when irradiated parasites were given i.v. as immunogen. Tunicamycin-treated avirulent organisms given s.c. subcutaneously unlike the untreated avirulent clones, now also caused suppression of protection. These data suggest that the determinants responsible for development of protective immunity to L. mexicana in BALB/c mice are dependent on N-linked glycoproteins for their expression, unlike the determinants responsible for suppression of that protection. By using swainsonine as an alternative inhibitor of N-linked glycoprotein synthesis, the data additionally suggest that no complex processing of N-linked sugars takes place to reveal the immunogenic determinants in this system.

Alkaloids↗