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W O Weigle

Publications and source records attributed to W O Weigle.

At least 19 recordsLinked to original sources
PubMed1997

Peripheral deletion of rheumatoid factor B cells after abortive activation by IgG.

Rheumatoid factor (RF) B cells proliferate during secondary immune responses to immune complexed antigen and antigen specific T cells, but higher affinity RFs are not detected except in patients with rheumatoid arthritis and other autoimmune diseases. Consequently, there must exist highly efficient mechanisms for inactivation of these higher-affinity RF B cell clones under normal circumstances. Exposure of transgenic mice expressing a human IgM RF to soluble human IgG in the absence of T cell help causes antigen specific B cell deletion in 2-3 days. The deletion is independent of the Fas/Fas ligand (FasL) pathway of apoptosis and is preceded by a phase of partial activation involving increase in cell size and expression of B7 and ICAM-1, and transient release of low levels of immunoglobulin. Complete B cell activation involving the formation of germinal centers and sustained high level RF secretion only occurs if T cell help is provided simultaneously. RF B cells exposed to tolerogen remain competent to secrete RF in vitro if provided with an appropriate antigenic stimulus and T cell help. Consequently, death of these cells is not preceded by anergy. Abortive activation/deletion of B cells by antigen in the absence of T cell-derived survival signals may represent the major mechanism for maintaining peripheral tolerance in B cells expressing higher affinity RF. The lack of anergy, and the potential for reactivation before death, provide a means for maintaining RF production under pathologic circumstances, such as may occur in the inflamed rheumatoid synovium.

Animals↗
PubMed1996

CD4+ T cell activation and tolerance induction in B cell knockout mice.

B cell knockout mice microMT/microMT were used to examine the requirement for B cell antigen (Ag) presentation in the establishment of CD4+ T cell tolerance. CD4+T cells from microMT mice injected with exogenous protein Ag in adjuvant responded to in vitro challenge by transcription of cytokine mRNA, cytokine secretion, and proliferation. Peripheral tolerance could be established in microMT mice with a single dose of deaggragated protein. This tolerance was manifested by a loss of T cell proliferation and cytokine production (including both T helper cell type 1 [Th1]- and Th2-related cytokines), indicating that B cells are not required for the induction of peripheral T cell tolerance and suggesting that the dual zone tolerance theory is not applicable to all protein Ags and is not mediated through Ag presentation by B cells.

Animals↗
PubMed1996

Intervention of CD4+ cell subset shifts and autoimmunity in the BXSB mouse by murine CTLA4Ig.

In the BXSB autoimmune disease-prone mouse strain, male mice develop severe lupus-like symptoms and die early in life (4-6 mo), whereas females do not. We have previously demonstrated that profound phenotypic and functional changes occur with age in CD4+ cells from BXSB males. CD4+ cells from males (4 mo old) were predominantly CD44high, CD45RBlow, and MEL-14low (activated/memory phenotypes), while the reciprocal phenotypes characteristic of naive cells were prevalent in age-matched females and young adult males (2 mo old). CD4+ cells from older males proliferated less and produced less IL-2 and IFN-gamma than cells from either females or young males in response to immobilized anti-CD3 mAb. We tested the effect of CTLA4Ig treatment on the progression of disease in BXSB males. CD4+ cells from CTLA4Ig-treated mice at 4 mo of age were predominantly CD44low, CD45RBhigh, and MEL-14high phenotypes that were identical with those observed in CD4+ cells from young (3-mo-old) females. In contrast, control male mice treated with IgG2a accumulated the CD4+ memory phenotype. CD4+ cells from 4-mo-old male CTLA4Ig-treated mice proliferated and produced IL-2 at levels similar to those of cells from females in response to immobilized anti-CD3 mAb. Furthermore, in contrast to IgG2a-treated mice, female and CTLA4Ig-treated male mice at 4 mo of age produced no anti-chromatin Abs. Three of four male mice injected with CTLA4Ig until 6 mo of age appeared healthy at 8 mo of age, whereas all five of IgG2a-treated control males died by 6 mo of age. These 8-mo-old CTLA4Ig-treated males showed variable resistance to autoimmunity as well as function and phenotype marker expression, and a less striking glomerulonephritis than 4-mo-old untreated males. The results of this study demonstrate that the rampant T cell activation and T cell dysfunction that occur in male BXSB mice by 4 mo of age are abrogated by blocking the CTLA4-dependent costimulatory signal(s). They also show that treatment with CTLA4Ig can suppress the pathogenesis of disease and increase longevity.

Abatacept↗
PubMed1995

In vivo tolerance induction and associated cytokine production by subsets of murine CD4+ T cells.

Male BXSB mice develop lupus-like disease and die early in life (4 to 5 mo) whereas female mice do not. Others have demonstrated that CD4+ cells from male mice support B cell resistance to tolerance induction to human gamma-globulin (HGG). In this study, male and female mice tolerized at 2 mo of age with deaggregated HGG and subsequently immunized with HGG in comparison with mice immunized only were tested for anti-HGG Ab responses. CD4+ cells from draining lymph nodes of these mice were tested in culture for proliferation and production of cytokine mRNA and protein in response to HGG plus APC. Tolerized male but not female mice produced anti-HGG Abs of both the IgG1 and IgG2a isotypes. HGG-stimulated CD4+ cells from immunized male and female mice that were not tolerized produced IL-2, IL-4, IL-5, IFN-gamma, and TNF-beta mRNA as well as IL-2 and IL-4 protein, whereas tolerized, immunized mice of both sexes failed to proliferate or produce either IL-2 or IL-4 or express any cytokine mRNA in response to HGG in vitro. A resistance in tolerance induction in male mice, as determined by anti-HGG Abs, was also observed at 3 mo of age. Although a resistance to tolerance was also seen in terms of proliferation in the 3-mo-old males, production of IL-2 or IL-4 protein was still not observed. Thus, all T cell subsets identified by cytokine expression profiles were tolerized not only from females but also from males, of which the latter appeared to show some resistance to tolerance induction.

Animals↗
PubMed1995

Immunologic tolerance: development and disruption.

Loss of tolerance to self-antigens is thought to have a role in a variety of common diseases. Studies in animal models of such diseases as systemic lupus erythematosus have provided new insights into how self-tolerance is broken or bypassed and how it may be restored. These and other experiments also are clarifying how self-tolerance is normally established; the T lymphocyte appears to be the dominant player.

Animals↗
PubMed1995

Human immunoglobulin (IgG) induced deletion of IgM rheumatoid factor B cells in transgenic mice.

The singular ability of immunoglobulin genes to hypermutate their variable regions, while permitting the generation of high-affinity antibodies against foreign antigens, poses a problem in terms of maintenance of immunological self-tolerance. Immunoglobulin gene hypermutation driven by a foreign antigen has the potential to generate antibodies that cross-react with self-components. Consequently, there must exist a mechanism in the periphery for inactivation of mature autoreactive B cell clones. The classical experimental system used to address this problem is the induction of tolerance to soluble, deaggregated human IgG. We have analyzed the mechanism of induction of tolerance to human IgG using transgenic mice that express a human IgM rheumatoid factor (IgM RF) on a large proportion of their B cells. Injection of deaggregated human IgG caused a specific deletion of those B cells that express an intact IgM RF on their cell surface. The degree of RF B cell deletion was proportional to the reduction in the proliferative response of splenocytes to antigen (aggregated human IgG), or to F(ab')2 fragments of anti-human IgM antibodies. Control experiments showed that IgG administration had little effect on the numbers of mouse Ig-bearing cells or their ability to proliferate to a nonspecific mitogen. Thus, the effects of IgG on the human IgM RF B cell are antigen specific and are not due to nonspecific toxic effects of the human IgG preparation. These experiments demonstrate that peripheral exposure to IgG induces deletion of reactive B cells, without any evidence for anergy, and differ from data obtained by other investigators studying tolerance to soluble protein antigens. The results imply that human Igs have distinct properties as soluble antigens, and that peripheral nonresponsiveness to IgG may be due to lymphocyte deletion.

Animals↗
PubMed1994

Maturational changes in CD4+ cell subsets and lymphokine production in BXSB mice.

CD4+ cells are thought to play a significant role in the development of lupus-like disease in a variety of autoimmune disease-prone mouse strains. In one such strain, BXSB/MpJScR, male mice develop severe lupus-like symptoms early in life but females do not. In this study, splenic CD4+ cells from male and female BXSB mice were evaluated for age-related changes in: 1) membrane expression of CD4+ cell subset markers (1, 2, and 4 mo) and activation Ags (4 mo) and 2) the capacity to proliferate and produce cytokines (4 mo) in response to polyclonal stimuli. CD4+ cells from females of all age groups and from younger males were predominantly CD44lo, CD45RBhi, MEL-14hi, and 3G11hi (phenotypes associated with naive T cells). In contrast, 4-mo-old males were predominantly CD44hi, CD45RBlo, MEL-14lo, and 3G11lo (phenotypes associated with activated/memory T cells). Furthermore, an increased constitutive expression of the activation Ags RL388, IL-2R, and TfR was observed in CD4+ cells of 4-mo-old male BXSB mice in comparison with age-matched females. In 3-day cultures, purified CD4+ cells from 4-mo-old males proliferated significantly less than cells from age-matched females in response to plate-bound anti-CD3 epsilon (2C11i). The reduced proliferation was restored in large part by PMA and ionomycin. CD4+ cells from older males generally produced increased amounts of IFN-gamma and IL-4 and significantly less IL-2 than age-matched females in response to either stimulus (IL-2 mRNA was also decreased in response to 2C11i). Taken together, these studies suggest that profound phenotypic and functional changes occur with age in the CD4+ cells of male BXSB mice that are indicative of an activated state.

Animals↗
PubMed1994

Interleukin-10 production by splenic CD4+ cells and cell subsets from young and old mice.

We have examined whether aging is accompanied by changes in the capacity of CD4+ cells to produce IL-10, a potent immunoregulatory cytokine. Splenic CD4+ cells from young-adult and old C57BL/6NNia mice were stimulated in vitro with immobilized anti-CD3 epsilon mAb and were monitored for the release of IL-10 in short-term (3-day) cultures. In both age groups, detectable IL-10 accumulation in culture supernatants was stimulation dependent and reached a maximum level on Day 3. However, the peak IL-10 level in the old group was approximately 10-fold higher than that in the young-adult group. This age-associated difference in IL-10 production was also evident in the analysis of IL-10 mRNA levels in stimulated CD4+ cells. In contrast to these findings, the analysis of S-phase activity in the stimulated cell cultures revealed an age-related decline in this aspect of the cellular response. In studies on CD4+CD44lo and CD4+CD44hi subsets isolated from mice of various ages, we found that measurable IL-10 production segregated entirely with the CD44hi population, regardless of donor age. Taken together, our data suggest that the capacity for IL-10 synthesis by the splenic CD4+ cell pool is increased with age, and that the age-related shift toward a predominance of CD4+CD44hi cells in the peripheral tissues accounts for this quantitative change in IL-10 gene expression.

Aging↗
PubMed1994

Tolerogenicity of resting and activated B cells.

Antigen presentation by resting splenic B cells has been shown previously to induce T helper 1 cell (Th1) anergy. In contrast to expectations, it was found here that B cells treated with F(ab')2 goat anti-mouse immunoglobulin (IgM) for 24 or 48 h also presented antigen (Ag) to Th1 cells in a manner that induced dramatic Ag-specific proliferative inactivation. The tolerogenicity of the anti-Ig-treated B cells was consistent with the observation that these B cells were only slightly more efficient than resting B cells in stimulating human gamma globulin (HGG)-induced proliferation of HGG-specific Th1 cells in primary cultures. The activated B cells were, however, more efficient than resting B cells in stimulating a primary mixed leukocyte reaction, and exhibited increased expression of major histocompatibility complex class II molecules, RL388 Ag and transferrin receptor. In addition, unlike resting B cells, which expressed little detectable B7, anti-Ig-treated B cells expressed high levels of B7. The functional capacity of the B7 expressed on the activated B cells was demonstrated by the fact that the Ag-presenting capacity of these B cells was inhibited by the addition to culture of CTLA4Ig, a soluble receptor for B7. It is unlikely that the tolerogenicity of the activated B cells was due to an inability of the Th1 cells to respond to B7 signals; the Th1 clones used in the experiments, unlike the Th2 clones tested, expressed CD28, the ligand for B7. In addition, anti-CD28 monoclonal antibody inhibited the induction of Th1 cell anergy when added to cultures of Th1 cells and Ag-pulsed fixed antigen-presenting cells. Taken together, the results indicate that B cells, even when activated, do not satisfy the costimulatory requirements of the Th1 cells used here, and therefore can present Ag in a tolerogenic fashion to Th1 cells. The costimulator deficiency of activated B cells may reflect an inadequacy in the level of B7 expressed or a lack of some other molecule.

Animals↗
PubMed1993

In vivo induction of tolerance in murine CD4+ cell subsets.

The induction of tolerance in mice to preparations of deaggregated human gamma globulin (DHGG) results in in vitro antigen-specific unresponsiveness in CD4+ T cells as well as in both the T helper 1 (Th1) and Th2-like subpopulations. Whereas both CD45RB(hi) and CD45RB(lo) cells from lymph nodes of HGG/complete Freund's adjuvant-immunized mice (control) proliferated in vitro to HGG, both subpopulations from mice previously tolerized with DHGG failed to respond. Furthermore, CD4+ T cells from control, but not from DHGG-injected mice, secreted high levels of interleukin 2 (IL-2) after in vitro stimulation with HGG. Although significant levels of IL-4 in supernatants of control CD4+ cells stimulated with HGG were detected in some, but not all, experiments, significant levels of IL-4 were never detected in supernatants of HGG-stimulated tolerant CD4+ cells. The demonstration that serum IgG1 anti-HGG is preferentially produced in a few tolerant mice that exhibit a leaky tolerant state suggests that tolerance induction may be more difficult to induce in IL-4- than in IL-2-producing cells.

Animals↗
PubMed1993

Th1 cell anergy and blockade in G1a phase of the cell cycle.

Human gamma-globulin (HGG)-specific Th1 cells exposed to HGG presented by chemically fixed spleen cells are blocked in G1a phase when challenged subsequently with HGG. The present study made use of the G1a blocker n-butyrate to further examine the relationship between tolerance induction and cell cycle progression. Th1 cells from primary cultures containing n-butyrate together with HGG and immunogenic, nonfixed APC lost their ability to proliferate or secrete IL-2 in HGG-stimulated secondary cultures. In contrast to their lack of responsiveness to secondary Ag challenge, Th1 cells exposed to n-butyrate and HGG proliferated normally in secondary cultures stimulated with IL-2. The suppressive effects of n-butyrate appear to require TCR occupation; Th1 cells exposed to n-butyrate in the absence of HGG did not lose their ability to proliferate in Ag-stimulated secondary cultures. In addition, although both HGG-presenting APC and IL-2 stimulate Th1 cell cycle progression into G1a, only HGG-presenting APC induced Th1 cell anergy in conjunction with n-butyrate. Unlike n-butyrate, drugs that blocked Th1 cell cycle progression in G0, G1b, or S/G2 phases did not inhibit subsequent Ag-specific proliferation by Th1 cells. Thus it appears that n-butyrate-induced G1a sequestration, in association with TCR occupancy, induces Th1 cell anergy.

Animals↗
PubMed1993

The age-associated increase in IFN-gamma synthesis by mouse CD8+ T cells correlates with shifts in the frequencies of cell subsets defined by membrane CD44, CD45RB, 3G11, and MEL-14 expression.

The mouse model system was used to evaluate age-associated changes in the subset composition and function of the splenic CD8+ T cell pool. In response to stimulation with plate-bound anti-CD3 epsilon mAb, CD8+ cells from old C57BL/6NNia mice produced greater levels of IFN-gamma than cells from young-adult controls. This age-associated difference was apparent at the levels of both IFN-gamma mRNA accumulation and cytokine release, and was established within the first major cell cycle in culture. In addition, the capacity to produce IFN-gamma appeared to increase gradually with age as evidenced by studies on CD8+ cells from intermediate aged mice. In contrast to these findings, the peak S-phase responses by stimulated CD8+ cells from old mice were significantly reduced relative to young-adult controls. Immunophenotypic analyses of membrane CD44, CD45RB, 3G11, and MEL-14 expression by splenic CD8+ cells from young-adult, intermediate-aged, and old mice revealed an age-associated decrease in the frequencies of cells that expressed low levels of CD44 and high levels of CD45RB, 3G11, and MEL-14, whereas the reciprocal phenotypes increased with age. The correlated analysis of all four subset markers identified a composite phenotype (CD44loCD45RBhiMEL-14hi3G11lo/hi) which, based on past functional studies, is a candidate phenotype for naive cells. This "naive" phenotype dominated the CD8+ cell pool of young-adult mice but decreased in frequency with age. In contrast to the CD44lo cell group, the CD44hi cell fraction, which is associated with preactivated/memory CD8+ cells, was found to be uniformly 3G11lo but expressed heterogeneous levels of CD45RB and MEL-14, perhaps defining multiple subsets within the memory population. All of these latter subsets increased in frequency with age. Finally, we found that when CD8+ cells were fractionated based on CD44 expression the capacity to release measurable levels of IFN-gamma segregated entirely with the CD44hi fraction, irrespective of donor age. Together, these findings support the hypothesis that aging is accompanied by dramatic shifts in the subset compositions of splenic CD8+ cell pools, which contribute significantly to their increased capacity to produce IFN-gamma at the population level.

Aging↗
PubMed1993

Patterns of cytokine gene expression by CD4+ T cells from young and old mice.

We have analyzed the patterns of induced cytokine gene expression and cell cycle activity by CD4+ cells from mice, and have examined how these response patterns change during the aging process. CD4+ cells were isolated from spleens of young adult and old C57BL/6NNia mice and were stimulated in vitro with plate-bound anti-CD3 epsilon mAb. The cells were then assessed over time for the capacity to accumulate transcripts for IL-1 alpha, IL-1 beta, IL-2, IL-3, IL-4, IL-5, IL-6, IFN-gamma, TNF-alpha, and TNF-beta; to secrete IL-2, IL-3, IL-4, IL-5, IL-6, and IFN-gamma; and to progress through S phase. Before the first major cell division in culture (< 32 h), stimulated CD4+ cells of the old group contained similar peak levels of IL-2, TNF-alpha, and TNF-beta transcripts relative to young adult controls, whereas IL-3, IL-4, IL-5, and IFN-gamma transcripts accumulated to significantly higher peak levels in the old group. These findings were consistent with the patterns of cytokine secretion later in culture (24 to 72 h): the peak IL-2 levels were similar between age groups, but the old group exhibited an enhanced capacity to release IL-3, IL-4, IL-5, and IFN-gamma. In contrast, CD4+ cells of the young group were superior in the hyper-expression of the housekeeping gene, rpL32, before cell division and in the levels of S phase activity throughout 3-day cultures. Similar analyses of CD4+ cells from mice of intermediate ages showed that the alterations in cytokine profiles occurred gradually from young adulthood to old age, whereas the reductions in proliferative capacity were late life changes. Consistent with previous reports, we found that the splenic CD4+ cell group also underwent a progressive, age-dependent increase in the proportions of cells expressing high levels of membrane CD44 (a phenotype associated with memory or effector cells). Moreover, the analysis of IL-3, IL-5, and IFN-gamma production by isolated CD4+CD44lo and CD4+CD44hi cells revealed that the capacity to produce these cytokines segregated predominantly with the CD44hi subset, regardless of donor age. Taken together, our data suggest that gradual age-associated shifts in the subset composition of the splenic CD4+ cell pool underlie progressive changes in the patterns of cytokine gene expression by this cell group.

Aging↗
PubMed1993

Aging and lymphokine production by T cell subsets.

From sexual maturity to old age, the mammalian immune system undergoes progressive changes, some of which may predispose individuals to infectious, neoplastic and degenerative diseases. These age-associated changes are prominent in the T lymphocyte compartment and encompass both the CD4+ and CD8+ T cell subpopulations. In this review, we focus on the mouse model system and summarize current information on the existence of functionally distinct subsets within each of the CD4+ and CD8+ cell subpopulations. We describe how the representation of these subsets is altered during the aging process, with consequent changes in the lymphokine production repertoires and other functional attributes of the T cell pool. Lastly, we present evidence showing that similar changes occur in aging humans and discuss the potential impact of these changes on immune responsiveness in late life.

Aging↗
PubMed1993

The expression of CD45RB on antigen-responsive CD4+ lymphocytes: mouse strain polymorphism and different responses to distinct antigens.

The levels of CD45RB expression by HGG-specific CD4+ cells residing in the Ag-draining lymph nodes of HGG-primed CBA/CaJ mice were analyzed. When sorted populations of CD4+, CD45RBhi, and CD4+, CD45RBlo cells were cultured with HGG and Ag-presenting cells, the majority of the proliferative response was found in the CD45RBlo fraction early after in vivo priming (Day 6), and this pattern remained stable through 12 days postpriming. To determine whether this segregation of responsiveness was consistent in other mouse strains, HGG-primed C57BL/6J mice were similarly analyzed. In contrast to findings with the CBA/CaJ strain, the CD4+, CD45RBhi cell fraction obtained from C57BL/6J mice was the predominant responding population early after in vivo priming (Day 6); however, there was a parallel increase in responsiveness of CD4+, CD45RBhi, and CD4+, CD45RBlo cells by Day 12. Thus, there was not a decrease in CD45RBhi expression with a concommitant increase in CD45RBlo expression in CD4+ cells proliferating to HGG. Despite the heterogeneity in CD45RB expression by the primed CD4+ cells of the two strains, the entire proliferative response to HGG early after priming resided in the fraction bearing high levels of membrane CD44, thus arguing for the existence of CD45RBhi, CD44hi and CD45RBlo, CD44hi cells during the early phase of the response. In both mouse strains the CD4+, CD45RBhi subset of primed lymph node cells produced significant levels of IL-2 in response to HGG and APC, whereas no significant IL-2 or IL-4 production was detectable in HGG-stimulated CD45RBlo cells of either strain. The CD4+, CD45RBhi subset also proliferated more vigorously in response to polyclonal activation than the CD4+ CD45RBlo fraction. To examine whether the patterns of CD45RB expression on HGG-primed cells from C57BL/6J mice were common to other antigens, the response profiles were examined after in vivo priming with a second antigen, KLH. In contrast to studies with HGG as the Ag, the proliferative response to KLH in C57BL/6J mice was evenly divided among the CD45RBhi and CD45RBlo fractions on Day 8 after priming, but shifted markedly to the CD45RBlo fraction by Day 12 after priming. Taken together, these data show that the patterns of CD45RB expression on primed populations of CD4+ cells can exhibit mouse strain polymorphism and can differ depending on the choice of antigen for immunization.

Animals↗
PubMed1992

Identification and characterization of the effector region within human C5a responsible for stimulation of IL-6 synthesis.

Human C fragment C5a is known to be a proinflammatory mediator and more recently shown to be a potent modulator of both humoral and cell-mediated immunity. We recently reported that natural and recombinant C5a induces the synthesis of IL-6-specific mRNA and secreted protein from human monocytes. Our studies using analogue peptides that are homologous to the carboxyl-terminal sequence of human C5a, indicate that the "effector" site for inducing IL-6 synthesis resides within the C-terminal region (C5a (70-74)) of the C5a molecule. C5a peptides containing the exact sequence of the natural factor were found to retain full agonist activity but exhibited low potency (0.01-0.1% of intact C5a). It was also shown that amino acid substitutions in the C5a peptides by aromatic/hydrophobic residues, outside the immediate effector site, resulted in analogue peptides with a substantial increase in potency relative to the most active natural peptide (C5a (56-74)). Moreover, these peptides approach the potency of natural C5a for induction of IL-6. Taken together, these results suggest that the inflammatory and immunoregulatory activities associated with C5a may, in part, be due to the synthesis of IL-6.

Amino Acid Sequence↗
PubMed1992

B cell presentation of a tolerogenic signal to Th clones.

Lightly irradiated (950 R) splenic B cells were inefficient, in comparison to unseparated spleen cells, in stimulating antigen-specific proliferation of Th1 clones specific for human gamma globulin (HGG). This inefficiency was due to antigen-specific inactivation: Th1 clones preincubated with HGG and lightly irradiated B cells or mitomycin C-treated B cells were unable to proliferate to HGG in secondary cultures. In contrast to Th1 clones, Th2 clones proliferated well in response to B cell APC, and showed no decrease in their subsequent antigen-induced proliferative capacity after exposure to lightly irradiated B cells and HGG. However, preincubation of Th2 with lightly irradiated B cells and HGG did inactivate the capacity of Th2 to provide help for antibody production in secondary cultures. These results suggest that under certain conditions B cells may present antigen to Th1 and Th2 cells in a tolerogenic rather than an immunogenic manner.

Animals↗