Search PubMed⌕ Search

Biomedical subjects

E S Raveche

Publications and source records attributed to E S Raveche.

At least 37 records · Page 2Linked to original sources
PubMed1985

Comparison of response to stem cell differentiation signals between normal and autoimmune mouse strains.

Normal DBA/2 and autoimmune NZB mice were studied with regard to signals eliciting differentiation and division of bone marrow stem cells. Irradiated (NZB X DBA/2)F1 mice were repopulated with various combinations of T-depleted bone marrow from NZB and DBA/2 mice. In response to the repopulation signal of irradiation, recipients of autoimmune NZB marrow initially demonstrated expansion of LY-5+ lymphoid and hemopoietic cells, particularly of the B cell lineage. The greater the proportion of NZB marrow, the higher the percentage of lymphoid cells observed 2 wk post-repopulation. B cells (ThB-positive cells) were increased in disproportionate numbers in recipients of NZB marrow, even those that had received as little as 20% NZB bone marrow cells. However, by 2 mo, the initially observed increase in lymphoid cells in recipients of NZB marrow was no longer observed. Up to 6 mo post-repopulation, cytogenetic analysis revealed that irradiated recipients were repopulated in the same proportion of DBA/2: NZB as was in the injected marrow. Endogenous colony formation assays indicated that recipients of 100% NZB, 80% NZB, and 20% NZB marrow all had greater numbers of splenic endogenous colonies than did recipients of DBA/2 marrow alone. These studies indicated that autoimmune NZB marrow repopulated irradiated mice in the proportion in which it was injected, but there was a disproportionate early increase in cells of the B lineage as well as a disproportionate increase in splenic colony formation.

Animals↗
PubMed1985

Role of T cells in sex differences in syngeneic bone marrow transfers.

Transferred marrow cells will proliferate in normal mice not exposed to irradiation or any other type of stem cell depletion when five consecutive transfers of 40 million cells are given. Approximately 25% of the mitotic cells are of male donor origin observed cytogenetically in all of the female recipient spleens and marrow analyzed from two weeks to one and one-half years after transfusions. Male donor stem cells are accepted and form a stable component of the self-renewing stem cell pool. In contrast, only 5% female cells are found in male recipients. This sex difference in engraftment is not hormonal since castration of recipients does not alter the percentage of donor cells. Rigorous T depletion of female donor bone marrow, however, increases the percentage of donor engraftment to the level observed when male marrow, either whole or T depleted, is transferred to female recipients. The success of T-depleted female stem cells to seed male recipients is observed in both C57BL/6, a responder strain in which females readily respond to the H-Y antigen as manifest by skin graft rejection, and CBA/J, a strain in which females do not readily respond to H-Y. In addition, recipient nude BALB/c males, which lack a thymus, fail to accept whole bone marrow from BALB/c females. However, male bone marrow cells seed BALB/c nude females. These studies demonstrate that the poor engraftment of female cells in transfused male recipients is abrogated by the removal of T cells from the donor female marrow.

Animals↗
PubMed1984

Studies of immune defective RIII/AnN mice.

The present study advances our knowledge of the newly described immunodeficient RIII/AnN mouse. This strain was found to have markedly reduced spleen size and low serum levels of IgM, IgA, IgG1, IgG2 alpha, and IgG2 beta. Studies of F2 and backcross mice demonstrated that the defective immunoglobulin production was due to multiple genes: a dominant gene for low IgA and recessive genes for the others. RIII mice, like xid-bearing mice, had a markedly reduced splenic plaque-forming cell (PFC) response to Type III pneumococcal polysaccharide; however, unlike xid-bearing mice, the RIII/AnN mice produced substantial serum antibody responses to pneumococcal polysaccharide, polyriboinosinic . polyribocytidylic acid, and trinitrophenyl--Ficoll. In addition, spleen cells from RIII/AnN mice proliferated normally when stimulated with anti-mu, whereas those from xid mice did not. Thus, RIII/AnN mice represent a model of hypogammaglobulinemia and restricted immunodeficiency. They differ from other immunodeficient mice, and should assist in the analysis of immunodeficiency, autoimmunity, and regulation of class-specific immunoglobulin production.

Agammaglobulinemia↗
PubMed1984

Genetic studies in NZB mice. VI. Association of autoimmune traits in recombinant inbred lines.

Because recombinant inbred lines, which are homozygous at most loci, can have any combination of parental genes, the numbers and the association of genes responsible for traits can be suggested by examining phenotypic distribution in these lines. Such studies, reported herein, uncovered two major families of nonlinked genetic loci whose interactions underlie autoimmune abnormalities in NZB mice. One family of genes leads to antibodies to murine leukemia virus, ssDNA, and erythrocytes, as well as to defective tolerance to bovine gamma-globulin. The other group of genes leads to polyclonal B cell activation, stem cell abnormalities, endogenous murine leukemia virus expression, and NTA. These studies help explain previously observed dissociations between the traits associated with these two groups of genes. Such genetic analyses provide the basis for future molecular biologic studies of the genes and gene products that underlie autoimmune disease.

Animals↗
PubMed1983

Comparison of stem-cell recovery in autoimmune and normal strains.

The capacity of NZB stem cells to proliferate in vivo was evaluated in two systems which required repopulation of peripheral organs. In both types of depletion systems, stem-cell repopulation after cyclophosphamide treatment or adoptive transfer repopulation in lethally irradiated hosts, it was found that NZB stem cells were hyperproliferating. The increase in proliferating cells was most pronounced in the spleens of NZB mice treated with high-dose cyclophosphamide and in lethally irradiated F1 mice reconstituted with NZB T-cell-depleted bone marrow. Thus, upon a stimulus to repopulate, NZB marrow stem cells will hyperproliferate in peripheral organs resulting in an increase in cell number. The abnormality in the marrow cells can be observed in young NZB mice when their marrow cells are in an environment which requires recovery and division.

Animals↗
PubMed1983

Analysis of thymocyte subpopulations following treatment with sex hormones.

Sex steroids were found to affect both murine and avian immune systems. Female and male (NZB X NZW)F1 mice were castrated at 2 weeks of age and given Silastic implants containing either dihydrotestosterone or estradiol. Four weeks following treatment, the thymuses were studied for cell cycle kinetics and for the presence of various cell surface antigens using fluorescein-conjugated antisera and flow cytometric techniques. Estradiol therapy resulted in an increase in mature thymocytes, that is, thymocytes that had decreased peanut agglutinin receptors and decreased Thy 1 antigens on their surfaces. Additional studies with anti-Lyt 1 and 2 indicated that these mature thymocytes were of the "helper" rather than the "suppressor" phenotype. Estradiol therapy resulted in an increase in the percentages of proliferating cells in the spleen and a decrease in the percentages of proliferating cells in the thymus. In contrast, in the avian system, estradiol had little effect on proliferation in immunological organs. Dihydrotestosterone was a potent inhibitor of proliferation in the avian bursa. These results indicate that sex hormones have specific effects on different immune cell subpopulations. In the murine system the male is the heterogametic sex but in the avian system the female is the heterogametic sex. Based upon the present and previous studies, we suggest that the primary modulating hormone for immunological sex effects in the mammal is estrogen, whereas in the bird it is androgen.

Animals↗
PubMed1983

Induction of autoimmunity in normal mice by thymectomy and administration of polyclonal B cell activators: association with contrasuppressor function.

In order to gain insight into the role of polyclonal B cell activation in the development of autoimmunity, non-autoimmune mice were given chronic injections of polyclonal B cell activators (PBA). In addition, to assess the contribution of T cell regulation of such PBA-induced B cell hyperactivity, the additional effect of postnatal thymectomy was studied. Mice that were postnatally thymectomized and given PBA (LPS +/- poly rI X rC) thrice weekly were found to have elevated levels of IgG and significantly increased serum concentrations of anti-ssDNA. This anti-DNA production was greater than that observed with PBA alone or with thymectomy alone. The entire experiment was repeated with different non-autoimmune mice with the same result. Numbers of proliferating cells in the spleens of the mice in the various groups were analysed by flow cytometry. The number of cells in S+G2+M phases of the cell cycle was significantly increased by PBA or thymectomy alone as well as by the combination. As a result, B cell proliferation was not sufficient to result in maximal anti-ssDNA; an additional T cell defect was required. This was further studied in an in vitro assay for suppressor and contrasuppressor activity. In three separate experiments, mice which were clinically autoimmune were found to have defective suppressor function and the presence of abnormal contrasuppressor activity, whereas non-autoimmune controls had normal suppressor function and no contrasuppressor function. These results indicate that the combination of PBA and thymectomy can most easily induce autoimmunity. The autoimmune state so induced in non-autoimmune strains was associated with a failure of normal suppressor function and the abnormal presence of contrasuppressor function. These results have important implications for spontaneously occurring autoimmune diseases.

Animals↗
PubMed1982

Frequency of B lymphocytes responsive to anti-immunoglobulin.

The frequency of murine B lymphocytes that respond to antibodies directed against membrane IgM was measured. These anti-mu antibodies induced all, or almost all, resting B cells to enlarge over the first 24 h of stimulation. This probably represents the transition from the resting state (G0) to active transit through the cell cycle. In contrast, only a fraction of these cells, approximately 60% for BDF1 mice, continued through the cell cycle into S phase. This is consistent with previous experiments that had suggested there were some types of B cells that did not proliferate in response to anti-mu. The results presented here demonstrate that many, perhaps all, of these nonresponding B cells, both from normal mice and from mice with the xid defect, actually do respond to the presence of anti-mu by going through early parts of the cell cycle. These cells appear to become blocked at some point before the beginning of S phase, perhaps requiring a signal from a T cell or a macrophage to continue through the cell cycle. Thus, the role of antigen may be to prepare all B cells for proliferation. Different subpopulations of B cells may then require different regulatory signals before actually proliferating or before differentiating into antibody-secreting cells.

Animals↗
PubMed1982

Cell cycle analysis of lymphocyte activation in normal and autoimmune strains of mice.

The spontaneous spleen cell proliferation and the proliferation induced by in vivo or in vitro stimulation with such polyclonal B cell activators (PBA) as LPS, poly rI.rC, and anti-mu were studied in normal and autoimmune mice. The various murine models of autoimmunity differ in the level of naturally occurring splenic cellular hyperactivity as well as in the ability of their spleen cells to be further stimulated in vitro by polyclonal stimulators. Both the NZB strain and the MRL/Ipr strain had markedly increased numbers and percentages of spontaneously proliferating spleen cells, whereas the BXSB strain did not. Nonautoimmune strains were found to have very small numbers of activated cells in the spleen. However, such normal strains could be induced in vivo to mimic the natural splenic hyperactivity observed in older NZB and MRL/Ipr autoimmune strains by the injection of polyclonal B lymphocyte stimulators. In contrast, old hyperactive NZB mice were not further induced to undergo proliferation by in vivo administration of such stimulators. Density-separated, T depleted, spleen cells of normal and autoimmune mice were stimulated in vitro with PBA in 48-hr cultures. Cells from old MRL/Ipr and NZB mice were abnormal in both the anti-mu response and the LPS response; BXSB mice had normal anti-mu responses. These studies suggest that there is no prerequisite for spontaneous splenic hyperactivity in the development of autoimmunity. In addition, different PBA stimulate separate subsets of B cells that differ in their state of activation in the various autoimmune strains. Finally, different B cell subsets appear to be abnormal in different types of autoimmune mice.

Aging↗
PubMed1982

Studies of the induction of anti-DNA in normal mice.

Injection of PBA has previously been demonstrated to induce anti-DNA. In the present study, we found that the combination of neonatal thymectomy and chronic administration of PBA (LPS + poly rI . rC) led to significantly higher anti-DNA levels than either PBA or thymectomy separately. These results suggested that a thymic regulatory process normally serves to suppress anti-DNA after chronic PBA exposure. Indeed, antigen-nonspecific suppressor function was found to be deficient in such thymectomy + PBA-treated mice. In addition, the cells of such mice in vitro interfered with the development of normal suppressor function by control cells.

Animals↗
PubMed1982

The human autologous mixed lymphocyte reaction. II. Analysis of activation and proliferation.

In this study, we have used cell cycle analysis as an independent measure of proliferation and the 4F2 marker to enumerate activated T cells. T-cell proliferation increased gradually throughout the 7-day culture. The degree of proliferation correlated very strongly (r = 0 . 827, p less than 10(-4)) with the degree of T-cell activation as demonstrated by the expression of the 4F2 marker. However, many more T cells became activated during the AMLR than were proliferating. Thymidine incorporation correlated well (r = 0.956, p less than 10(-4)) with numbers of proliferating cells as determined by cell cycle analysis. Adherent cells (M phi) induced fewer T cells to express 4F2 and to proliferate than did (B + null) cells. However, proportionately, M phi induced much more activation than proliferation in comparison to (B + null) cells. Additional analyses of cell cycle and the 4F2 marker for activated cells indicated that a very small percentage of responder T cells (less than 1%) respond initially to signals from autologous non-T cells. Moreover, there is a three-day delay before substantial proliferation and activation takes place, providing time for amplification and suppressive regulatory processes. Ultimately, between 5 and 30% of the initial T cells are capable of proliferating in the AMLR and up to 90% of the cells may become activated. Thus, many cells become activated (and are therefore capable of secreting immune regulatory factors or otherwise participating in immune responses) than proliferate. These results provide a basis for analysing defects in the AMLR in association with various disease states.

Autoantigens↗
PubMed1981

Genetic studies in NZB mice. V. Recombinant inbred lines demonstrate that separate genes control autoimmune phenotype.

The genetic basis for autoimmunity in NZB mice has been investigated through analysis of recombinant inbred lines produced by mating NZB mice with two different non-autoimmune strains. Several genes (at least six) were found to be necessary for the production of eight traits characteristic of the NZB mice that were studied. No fundamental genetic defect (an "autoimmunity gene") was identified that could give rise to the various autoimmune traits studied. This study strongly suggests that NZB disease results from the actions of several separate genes that together result in the characteristic manifestations of autoimmunity.

Animals↗
PubMed1981

T cell abnormalities in NZB mice occur independently of autoantibody production.

By means of a series of crosses and backcrosses, ZB.CBA/N mice were prepared bearing largely NZB autosomal genes, but having X chromosomes derived only from CBA/N mice. The CBA/N X chromosome carries a gene, xid, that is associated with the lack of a B cell subset necessary for most of the spontaneous autoantibody production by NZB mice. These ZB.CBA/N mice failed to develop autoantibodies to T cells, erythrocytes, or DNA. The availability of mice that were mostly NZB, but which failed to make autoantibodies, especially anti-T cell antibodies, allowed us to study possible T cell regulatory defects in NZB mice in the absence of either antibodies reactive with such T cells or other autoantibodies. We found that such mice had derangements of T cell regulation as did the NZB mice. These observations strongly suggest that the t cell abnormalities of NZB mice are not caused by the B cell hyperactivity of these mice, but rather represent independent defects. Thus, NZB mice appear to have primary defects in both the B cell population and the T cell population. Whether or not these are separate, or derive from a common precursor cell abnormality, remains to be determined.

Animals↗
PubMed1981

Analysis of NZB hyperdiploid spleen cells.

In order to study the cell types involved in the hyperdiploidy characteristic of NZB mice, flow cytometric techniques, which measure te DNA content of individual cells, have been used together with standard cytogenetic analysis. The aneuploid cells present in NZB mice were found to be clonally derived. These cells were of large size relative to nonaneuploid cells. They could not be removed by lysis with anti-Thy 1 plus complement nor were they present in the nylon-wool column nonadherent fraction, both of which are characteristic of T cells. By further cytotoxic analysis, the aneuploid cells were found not to express Ly-5 nor NK surface antigens, found on natural killer cells. The aneuploid cells had increased quantities of cell surface H-2 antigen. This marked susceptibility to lysis with anti-H-2 serum was associated with one or more extra copies of chromosome 17, which carries the H-2 complex. A large proportion of these cells also expressed surface Ia and Ig. The aneuploid cells found in the spleens of older NZB mice derive from bone marrow stem cells. Neonatally thymectomized and lethally irradiated NZB X DBA/2 recipients of anti-Thy-1 treated young NZB bone marrow cells ultimately developed aneuploid spleen cells. Such cells are not found in intact or thymectomized NZB Z DBA/2 mice nor in recipients of DBA/2 marrow. Finally, congenic NZB mice carrying the CBZ/N xid failed to develop aneuploidy. Taken together, these studies suggest that the aneuploid cell is a bone marrow-derived stem cell destined to differentiate into the B cell subset lacking in CBA/N mice.

Aneuploidy↗
PubMed1980

Genetic studies in NZB mice. IV. The effect of sex hormones on the spontaneous production of anti-T cell autoantibodies.

Hybrid NZB X NZW or NZB X DBA/2 females have markedly accelerated development of autoimmunity when compared with their respective male littermates. This difference is attributable to the ability of male sex hormones to retard the expression of autoimmunity. In contrast to the sex differences in expression of autoimmunity in F1 mice, parental NZB males and females have only minor differences in disease expression. We have been investigating the basis for the difference in anti-T cell antibody production between NZB and F1 mice. In this study, the appearance of antibodies cytotoxic for T cells (NTA) was studied in NZB and DBA/2 mice and in their F1 hybrids and backcross progeny. A major sex difference in NTA production was observed in the F1 hybrids; females produced more NTA than did males. Castration of males led to a marked increase in NTA production. Furthermore, the NTA production of castrated male and female F1 mice was significantly suppressed by administration of testosterone in Silastic capsules. In contrast to the studies in F1 mice, we found little difference between intact male and female parental NZB mice at any age studied. Furthermore, NZB mice of both sexes who were given androgen-containing capsules at 2 weeks of age failed to demonstrate a decrease in NTA production. This result suggested an androgen insensitivity in NZB mice with regard to NTA production. This insensitivity, which appears to be a recessive trait, may help to explain why NZB mice do not manifest the sex differences in disease expression observed in the F1 hybrids.

Animals↗
PubMed1980

Murine thymic androgen receptors.

Studies in mice indicate that sex hormones influence the immune system. In general females are more immunocompetent than males and the administration of androgens can suppress antibody formation in females. New Zealand Black (NZB) mice manifest a lack of sex difference in the production of certain autoantibodies and the failure of androgen administration to suppress these antibody levels. To further analyze this phenomenon, androgen receptors were studies in the thymus of NZB and a non-autoimmune strain (C57Bl/6). Specific thymic androgen receptors were found in both NZB and C57Bl/6 mice. The dissociation constant and concentration of specific dihydrotestosterone receptors was determined in thymic cytosol by Scatchard plot analysis. There were no substantial differences in the binding parameters between sexes and between strains. In conclusion, both autoimmune and control strains have similar high affinity thymic androgen receptors. Therefore, the immune androgen insensitivity observed in NZB mice is not the result of a lack of high affinity thymic androgen receptors.

Animals↗