Hapten-induced B cell paralysis. II. Evidence for trivial mechanisms of tolerance

Injection into mice of a free, reactive form of the hapten (4-hydroxy-3,5-dinitrophenyl)acetyl (NNP), induces a state of specific unresponsiveness to the hapten, upon its challenge with thymus-dependent and independent carriers. This unresponsiveness is maintained in vitro. Both induction and expression of the unresponsive state were found to be independent of T cells. Analysis of the mechanisms responsible for the B cell “tolerance” demonstrated that the major cause of unresponsiveness in this system is the blockade of specific surface receptors on B cells by the hapten, abolishing the focusing function of these receptors. “Tolerant” B cells, though they were unresponsive to the antigen, could be activated to anti-hapten antibody secretion by the B cell mitogen lipopolysaccharide (LPS), which does not require Ig-mediated binding. They also became fully responsive to the antigen NNP-LPSin specific thymus-independent responses after 24 hours of in vitro incubation in the absence of tolerogen, conditions which allowdeblocking of Ig surface receptors, and, thus, restorationof the focusing function of these receptors. These results demonstrate that great care is required for a clearcutdefinition of B cell tolerance. In this example, the tolerant B cells were perfectly responsive to a competent ligand, and no indication of an altered triggering or effector processes was found. It appears that in this, as in many other cases of B cell tolerance, the systems or the animals are tolerant, whereas B cells maintain a resting nonactivated state and are fully responsive to the triggering signal. Thus, the existance oftolerance-inducing signals resulting in B cell unresponsiveness isquestioned.     

Hapten-induced B cell paralysis. II. Evidence for trivial mechanisms of tolerance.

Injection into mice of a free reactive form of the hapten (4-hydroxy-3,5-dinitrophenyl)acetyl (NNP), induces a state of specific unresponsiveness to the hapten, upon its challenge with thymus-cependent and independent carriers. This unresponsiveness is maintained in vitro. Both induction and expression of the unresponsive state were found to be independent of T cells. Analysis of the mechanisms responsible for the B cell "tolerance" demonstrated that the major cause of unresponsiveness in this system is the blockade of specific surface receptors on B cells by the hapten, abolishing the focusing function of these receptors. "Tolerant" B cells, though they were unresponsive to the antigen, could be activated to anti-hapten antibody secretion by the B cell mitogen lipopolysaccharide (LPS), which does not require Ig-mediated binding. They also became fully responsive to the antigen NNP-LPS in specific thymus-independent responses after 24 hours of in vitro incubation in the absence of tolerogen, conditions which allow "deblocking" of Ig surface receptors, and, thus, restoration of the focusing function of these receptors. These results demonstrate that great care is required for a clearcut definition of B cell tolerance. In this example, the tolerant B cells were perfectly responsive to a competent ligand, and no indication of an altered triggering or effector processes was found. It appears that in this, as in many other cases of B cell tolerance, the systems or the animals are tolerant, whereas B cells maintain a resting nonactivated state and are fully responsive to the triggering signal. Thus, the existence of tolerance-inducing signals resulting in B cell unresponsiveness is questioned.     

Cytokines in the induction and circumvention of peripheral tolerance.

Injection of deaggregated (monomeric) human gamma globulin (DHGG) into mice induces a state of immunological tolerance to subsequent challenge with immunogenic forms of HGG. Tolerance was shown to be induced in both the Th1 and Th2 CD4+ subsets. These mice fail to demonstrate antibody production, T cell proliferation, cytokine release, or T cell helper function. On the other hand, simultaneous injection of lipopolysaccharide (LPS) as well as interleukin-1 (IL-1) was capable of interfering with the induction of tolerance to DHGG. The purpose of the present study is to extend these investigations to determination of the cellular mechanisms responsible for the interference of tolerance induction in both CD4+ T cell subsets. It was demonstrated that LPS and IL-1 have differential effects on the induction of tolerance in the CD4+ subsets. As evidenced by immunoglobulin G (IgG) subclass, T helper cell function, and lymphokine secretion, coinjection of LPS with tolerogen interfered with the induction of tolerance in both subsets, whereas IL-1 interfered with the induction of tolerance exclusively in the Th1 subset. LPS and IL-1 had differential effects on the interference of the induction of tolerance in LPS-resistant mice where IL-1, but not LPS, was effective. In contrast to IL-1, IL-12 injected along with DHGG failed to interfere with the induction of tolerance in either Th1 or Th2 cells. Previous studies that demonstrated tolerance in the DHGG models induced in both the Th1 and Th2 subsets was further suggested by the demonstrations in the present study that dose-response curves for the induction of tolerance are identical in both subsets. The above findings taken together are compatible with the suggestion that tolerance induction results from the lack of cytokine production, which then prevents the expansion of Th1 and Th2 subsets following activation of the CD4+ precursor T cell. Furthermore, they support the general opinion that the expansion of these two subsets involve different cytokine pathways and that LPS and IL-1 most likely act through different cell receptors.     

The induction of carrier-specific helper cell tolerance in presensitized rats.

Lewis rats rendered tolerant to sheep IgG (SGG) show a markedly reduced antibody response to the 2,4,6-trinitrophenyl (TNP) hapten when later challenged with TNP-SGG. We have previously shown that this effect is due to functional unresponsiveness in the carrier SGG-specific helper T cell population. In this paper we demonstrate that induced helper cell tolerance is also maintained through a secondary immunogenic challenge. Furthermore, rats which are primed to the carrier SGG prior to tolerance induction also show a markedly reduced anti-TNP response upon secondary immunogenic challenge with TNP-SGG. The ability to specifically suppress a secondary response in this manner was found to be relatively long lasting, since rats showed reduced responsiveness when the secondary challenge was delayed for up to 4 weeks after tolerance induction. In addition, rats primed to the hapten (TNP) prior to carrier (SGG) tolerance induction also showed a marked reduction in anti-TNP antibody following challenge with TNP-SGG. These findings imply that helper cell tolerance can be induced in rats even after priming of carrier-specific (SGG) helper cells, or hapten-specific (TNP) B cells. These results parallel our other published findings that IgE responses in presensitized rats can be overcome by helper cell tolerance.     

Differences in calcium requirements for B-cell tolerance and immunity.

Incubation of unprimed spleen B cells with high concentrations of hapten-conjugates resulted in the induction of specific unresponsiveness or tolerance to a subsequent encounter with the hapten on a potentially immunogenic carrier. This process of tolerance induction could occur in the absence of extracellular calcium. In contrast B-cell activation to both proliferation and subsequent antibody secretion is known to be calcium dependent. This means that either (1) the decisions which determine immunity and tolerance in B cells are mediated through totally distinct signalling pathways, or that (2) if tolerance and immunity depend on same common signalling events, then the commitment of B cells to switch on or off must be determined at a very early stage.     

Critical role of B cells in the development of T cell tolerance to aeroallergens

Respiratory exposure to allergen induces the development of allergen-specific CD4(+) T cell tolerance that effectively protects against the development of allergic-sensitization and T(h)2-biased immunity. The establishment of T cell unresponsiveness to aeroallergens is an active process preceded by a transient phase of T cell activation that requires T cell co-stimulation and is critically influenced by the antigen-presenting cell type. In this study we examined the role of B cells in the development of respiratory tolerance following intranasal (i.n.) exposure to a prototypic protein antigen. We found that respiratory exposure of BCR-transgenic (Tg) mice to minute quantities of cognate antigen effectively induced T cell unresponsiveness, indicating that antigen presentation by antigen-specific B cells greatly enhanced the development of respiratory tolerance. In contrast, respiratory T cell unresponsiveness could not be induced in B cell-deficient JHD mice exposed to i.n. antigen, although T cell tolerance developed in JHD mice reconstituted with B cells, suggesting that B cells are required for the induction of respiratory T cell tolerance. Respiratory exposure of BCR-Tg mice to cognate antigen induced activation of antigen-specific T cells and partial activation of antigen-specific B cells, as demonstrated by enhanced expression by B cells of class II MHC and B7 molecules but lack of antibody secretion. Our data indicate that B cells critically influence the immune response to inhaled allergens and are required for the development of allergen-specific T cell unresponsiveness induced by respiratory allergen.     

The effect of second signals on the induction of B cell tolerance: failure of helper T cells to block tolerance induction

The effect of carrier-primed helper T (Th) cells and T cell-replacing factors on the induction of hapten-specific tolerance in B cells from adult mice has been tested. The 2,4,6-trinitrophenyl conjugate of human gamma-globulin (TNP17HGG) was used as tolerogen in an in vitro tolerance induction system. Tolerance was assessed by the subsequent induction of plaque-forming cell responses using TNP-Brucella abortus and trinitrophenylated sheep red blood cells (TNP-SRBC) plus SRBC-primed Th cells as T-independent (TI) and T-dependent (TD) forms of TNP, respectively. B cells that respond to the different forms of TNP appear to be distinct B cell subpopulations. TNP17HGG induced TNP-specific tolerance in B cells responsive to TI and TD forms of the antigen, although more tolerogen was required to induce unresponsiveness in the TD antigen-reactive B cells. The presence of antigen nonspecific T cell-replacing factors during tolerance induction had no effect on the induction of unresponsiveness in either TI or TD antigen-responsive B cells, although these factors were able to support primary anti-TNP responses in T-depleted B cell populations to subtolerogenic doses of TNP-HGG. Populations of irradiated lymphocytes enriched for HGG-specific Th cells also had no effect on tolerogenesis in TI or TD antigen-responsive B cells, although priming of TD antigen-responsive B cells occurred at subtolerogenic doses of tolerogen. The inability of these Th cells to modulate B cell unresponsiveness was not due to their inability to exert helper function at higher concentrations of HGG. Thus, in this system, tolerance susceptibility is an intrinsic property of B lymphocytes, i.e. immunogenicity vs. tolerogenicity of signals is not determined by a "second signal" provided by Th cells.     

The induction of hapten-specific T cell tolerance using hapten-modified lymphoid membranes. II. Relative roles of suppressor T cells and clone inhibition in the tolerant state.

The cellular nature and specificity of suppressor cells and the mechanisms of tolerance to 2,4-dinitrophenyl-l-fluorobenzene (DNFB) in mice was investigated. Mice tolerized with hapten-modified self membrane, i.e. dinitrophenylated spleen cells (DNP-SC), generated suppressor cells as shown by their ability to transfer unresponsiveness to normal animals. Such suppressor cells were specific for DNFB as they did not interfere with sensitization of normal animals with 2,4,6-trinitro-1-chlorobenzene (picryl chloride). These suppressor cells were of the thymus-derived lymphocyte (T cell) lineage as (a) their activity was abolished by treatment with anti-Θ serum plus complement, and (b) these cells could not be raised in T cell-deprived mice. Kinetic studies of the development of tolerance showed discrepancies between the rate of induction of unresponsiveness in the donor (“phenotypic” tolerance) and the ability to transfer tolerance. One day after receiving 5 × 10 DNP-SC mice were phenotypically tolerant but could not serve as the donors of suppressor cells. 7 days after tolerization with DNP-SC mice were still fully tolerant and also contained suppressor cells, which were no longer demonstrable 14 days after tolerization when mice were still phenotypically tolerant. The ability to transfer tolerance was eliminated by pretreatment with cyclophosphamide (Cy). We postulate that two independent mechanisms of tolerance occur after tolerization with DNP-SC - the rapid induction of clone inhibition and the slower, transient induction of suppressor T cells. Cy had no effect on clone inhibition but eliminated the precursors of suppressor T cells.     

Lipopolysaccharide prevents apoptosis and induces responsiveness to antigen receptor cross-linking in immature B cells.

Unlike mature B cells, immature B cells are not activated in response to antigen receptor cross-linking. To examine the mechanisms underlying this unresponsiveness, we have studied the effects of reagents that have been shown to alter the responses of immature B cells to antigen receptor stimulation. Bacterial lipopolysaccharide (LPS) is a polyclonal B-cell activator, and has been shown to interfere with B-cell tolerance induction in vivo and in vitro. Here we show that LPS can also overcome the unresponsiveness of immature B cells to stimulation with anti-receptor (anti-mu) antibodies. LPS synergizes with anti-mu to induce a proliferative response that exceeds the response of immature B cells to LPS alone. Moreover, pretreatment of immature cells with LPS allows them to proliferate in response to subsequent stimulation with anti-mu antibodies. This induction of responsiveness to anti-mu requires exposure to LPS for at least 8 hr. Although the mechanisms of induction are not fully understood, one component of the LPS effect appears to involve enhancement of immature B-cell survival in culture. Neonatal splenic B cells undergo spontaneous apoptosis at a much higher rate than mature B cells, but we have found that LPS causes a dramatic inhibition of apoptosis, even when it is present for only the first 8 hr of culture. The ability of LPS to promote survival of immature B cells and allow them to proliferate in response to antigen receptor stimulation provides a system for investigation of the biochemical mechanisms of unresponsiveness and tolerance susceptibility.     

Bacterial superantigens induce T cell unresponsiveness in B cell-deficient mice

Bacterial superantigens such as staphylococcal enterotoxin B (SEB) cause in vivo a profound and long-lasting state of unresponsiveness in ligand-reactive T cells. To test whether presentation of SEB by small resting B cells to ligand-reactive T cells is essential for the induction of T cell unresponsiveness, we analyzed the effect of SEB in B cell-deficient mice. We observed T cell deletion and T cell unresponsiveness in both B cell-deficient mice and control mice. We conclude that presentation of SEB by resting B cells is not a prerequisite for the induction of T cell unresponsiveness in vivo.     

Injection of mouse thyroglobulin and/or adult thymectomy do not break tolerance to thyroglobulin during the lupus like graft versus host disease in mice

In a previous paper (Gleichmann, van Elven & van der Veen, 1982), it had been reported that, in contrast to lupus like autoantibodies such as anti-DNA, autoantibodies to mouse thyroglobulin (MTg) were not detectable in serum of F1 mice suffering from a lupus like graft versus host disease (GVHD) (GVH F1). In the present paper, possible explanations for this restricted autoantibody formation during the potent allogeneic stimulation were investigated. The main question was whether the natural level of circulating MTg was too low to induce the formation of anti-MTg antibodies in GVH F1 mice. Existence, in the F1 mice studied, of B cells capable of producing anti-MTg antibodies was demonstrated by injection of lipopolysaccharide (LPS) and exogeneous MTg. However, MTg injected into various F1 mice at the onset of the GVH reaction (GVHR) failed to overcome the lack of antibody formation to MTg even though the GVHR led to a severe lupus like disease. Furthermore, adult thymectomy (ATx) of either the recipients, the donors, or both also did not break tolerance to MTg during the GVHR, irrespective of administration of exogeneous MTg. Thus, neither intravenous injection of MTg nor ATx, designed to remove T suppressor (TS) cells, is adequate to enable an autoantibody response to MTg during lupus like GVHD. Hence, the non-specific T cell help that causes lupus like GVHD seems to be intrinsically insufficient to trigger the Tg reactive B cells. We suggest that globular proteins, such as Tg, require specific T cell help. In the presence of only non-specific T help, self-antigens such as DNA seem to be more apt than globular proteins to provide an effective signal 1 to the corresponding autoreactive B cells.     

Orally induced tolerance. Definition at the cellular level

Several elements of the phenomenon of oral tolerance were examined. It was shown that whereas intragastric (i.g.) exposure of mice to the T-dependent antigens ovalbumin (OVA), bovine serum albumin, and human gamma globulin severely compromised the ability to respond to a subsequent challenge with the homologous antigen, i.g. treatment with T-independent antigens such as dinitrophenylated Ficoll, polyvinylpyrrolidone and bacterial lipopolysaccharide (LPS) did not induce anergy. Furthermore, mice parenterally primed to OVA were not only refractory to the induction of oral tolerance with OVA, but displayed an anamnestic response following i.g. treatment with the antigen. In a final line of investigation, it was shown that whereas mice administered OVA orally lost specific T cell functions such as the ability to (a) provide helper activity; (b) proliferate in response to antigen, and (c) mediate delayed-type hypersensitivity, such animals possessed OVA-specific functional B cells as evidenced by the ability to respond to OVA when the antigen was administered either linked to a recognizable carrier or in conjunction with LPS.     

T cell tolerance and autoimmunity

A functional immune system requires a T cell repertoire that is extremely diverse so as to allow for the elimination of all possible pathogens. However, the production of an immense T cell repertoire also increases the likelihood of generating autoreactive T cells. The immune system must therefore also incorporate a means of silencing or eliminating autoreactive T cells, while minimally sacrificing T cell diversity. The induction and maintenance of T cell unresponsiveness to self antigens is thus defined as T cell tolerance. This review provides an overview of the T cell tolerance mechanisms invoked in the thymus and in the periphery to prevent the induction of autoimmunity. Factors that can influence the induction of tolerance and autoimmunity are also discussed.     

The insulin receptor as a universal marker of activated lymphocytes.

Although resting, rat thymus-derived spleen lymphocytes do not bear insulin receptors, these receptors emerge upon the membrane of alloimmune rat T cells subsequent to skin grafting. These studies examine conditions that permit the emergence of lymphocyte insulin receptors upon T or B-enriched rat lymphocyte populations. Allogeneic stimulation was accomplished in vivo by skin grafting from (Lewis × Brown Norway)F₁ (LBN) to Lewis male rats or by Graft-vs.-host (GVH) reaction established by intraperitoneal injections of 2 × 10⁸ Lewis leukocytes each week for a total of four injections into LBN animals. In vitro allogeneic stimulation was provided by one-way mixed lymphocyte cultures between the same strains. Lastly, both T and B-enriched populations were interacted with mitogens concanavalin A (Con A), phytohemagglutinin (PHA-P), and lipopolysaccharide (LPS). The T-enriched populations were highly enriched for T lymphocytes (90%) and macrophage-depleted while B-enriched populations contained nearly 85% B cells. Insulin receptors emerged upon T-enriched cell populations consequent to allogeneic skin grafting with saturability, specificity and high affinity (k_d = 1.1 nM) as well as after GVH. Responder strain lymphocytes developed an insulin receptor during allogeneic mixed lymphocyte cultures within 72 h of initiation. Specific insulin-binding sites also appeared upon T-enriched populations after culture with PHA-P and Con A but not LPS. Conversely, B cells developed an insulin receptor after interactions with LPS but not PHA-P or Con A. Anti-Ig and complement but not rat anti-T cell antibody abrogated the ability of LPS to induce an insulin receptor on B-enriched cells. Binding specificity was demonstrated by the inhibition of [¹²⁵I]-labeled insulin in the order porcine insulin ? desalanine insulin > proinsulin ? desoctapeptide insulin with growth hormone exhibiting no such inhibition. These data demonstrate that a true insulin receptor appears upon both T and B cells consequent to activation. The lymphocyte insulin receptor is a universal marker of cellular activation as it is not restricted to clone or species and may be applied to B and T lymphocytes of mouse, rat and man.     

Cellular events in protein-tolerant inbred rats. IV. The mechanism of immunogen-maintained tolerance.

The ability of immunogens to maintain or extend a state of unresponsiveness was investigated in unbred rats using a human serum albumin (HSA) model of tolerance. Rats initially challenged with immunogen within two weeks of high or low dose tolerance induction by tolerogen (soluble HSA) remained hyporesponsive even a year and a half later and in some cases became less responsive following a subsequent challenge. An inhibitory effect of immunogen on escape from tolerance was formally demonstrated: in comparison with an unchallenged group, tolerant rats which received a second immunogen challenge 6 months after the first, synthesized less antibody; this antibody underwent a gradual decline in affinity after each challenge which suggested that higher avidity B cells were progressively lost. In addition, immunogen-maintained tolerant rats (a) had demonstrable helper T cell activity among their thoracic duct lymphocytes on adoptive transfer, (b) did not produce a significant increase in antibody synthesis after receiving peripheral T cells and (c) provided no evidence that suppressor cells were playing a role. The results suggested that the mechanisms of tolerance induction by tolerogen and tolerance maintenance by immunogen are fundamentally different.     

Antigen-presenting cells and tolerance induction

T cell tolerance induction to foreign and self-antigens has occupied research since the beginning of the understanding of the immune system. Much controversy still exists on this question even though new methods became available to investigate immunoregulatory mechanisms. Antigen-presenting cells play a pivotal role in transferring information from the periphery of the organism to lymphoid organs. There, they initiate not only the activation of naive T cells but seem to deliver important signals which result in T cell unresponsiveness with antigen-specific tolerance induction.     

Suppression of the murine anti-trimellityl (TM) IgE response: induction of B cell tolerance by conjugates of TM and polyvinyl alcohol

It was previously shown that administration of conjugates of trimellitic anhydride with polyvinyl alcohol (TM-PVA) could suppress the IgE anti-TM immune response of mice sensitized with a TM-ovalbumin conjugate. In the present study, the existence of TM-specific B cell tolerance was shown by cell transfer experiments in which splenic B cells from mice treated with TM-PVA failed to interact with either the helper T (Th) cells of carrier primed recipients or with Th cells derived from carrier-primed donors. In contrast to previous findings from this laboratory indicating that tolerogenic conjugates of PVA and the 2,4-dinitrophenyl group led to both B cell tolerance and activation of suppressor T (Ts) cells, no evidence was obtained for the induction of Ts cells by TM-PVA. Thus, the induction of demonstrable Ts cells by hapten-PVA conjugates may depend on some property conferred by the haptenic group.     

Induction of immunity and tolerance in vitro by hapten protein conjugates. II. Carrier independence of the response to dinitrophenylated polymerized flagellin

The response to dinitrophenylated polymeric flagellin (DNP POL) in vitro, unlike that to DNP monomeric flagellin (DNP MON) or erythrocyte antigens does not require the presence of T cells. It was thus proposed that antigens with repeating determinants, like DNP POL, may immunize B cells without the cooperation of the usual helper cells. Since carrier specificity in secondary anti-hapten responses is based upon the cooperation of carrier-reactive T cells and hapten-reactive cells, the requirement for carrier-reactive cells in the response to “thymus-independent” DNP POL and “thymus-dependent” DNP MON was investigated. Using flagellin-primed spleen, the anti-DNP response to DNP MON was enhanced, but not that caused by DNP POL. Furthermore, there was no carrier specificity in the anti-DNP responses with DNP POL, which elicited similar responses in spleen cells primed with various DNP proteins, whereas DNP MON only immunized spleen cells which were primed with that carrier. Carrier-hapten cooperation has also been demonstrated by the suppressive effect of unconjugated carrier on the anti-hapten response to carrier hapten conjugates. Neither the induction of tolerance to flagellin, the carrier, nor the presence of free flagellin in vitro suppressed the anti-DNP response to DNP POL. In contrast, both these manoeuvres suppressed the anti-flagellin response to DNP POL, and both the anti-DNP and anti-flagellin responses elicited by DNP MON. Thus, by several criteria, there was no cooperation between carrier-reactive and hapten-sensitive cells in the genesis of the response to DNP POL. Spleen cell suspensions deprived of their content of phagocytes responded normally to DNP POL. Thus, since T cells, carrier-reactive cells and phagocytes are not needed for the induction of a response to DNP POL, this antigen immunizes B cells directly. The use of this simple system should facilitate our understanding of the mechanism of binding of antigen molecules to the surface of B cells in the process of immunization.     

Characterization of self-reactive T cells that evade tolerance in hepatitis B e antigen transgenic mice

Previous studies of hepatitis B e antigen (HBeAg)-expressing transgenic (Tg31e) mice have indicated that the degree of T cell tolerance was epitope specific. For example, T cells specific for residues 120–131 of HBeAg are profoundly tolerant, whereas a proportion of T cells specific for residues 129–140 escape tolerance induction in B10. S × B10-Tg31e mice. To understand the basis for differential tolerance towards two T cell sites on the same self antigen, we characterized T cell recognition of HBeAg by primary T cells and T cell hybridomas derived from HBeAg-Tg and non-Tg mice. The self-reactive T cells surviving in B10-Tg31e mice exhibited a unique fine specificity, albeit still focussed on HBeAg residues 129–140, which could be distinguished from the HBeAg-specific T cell repertoire in non-Tg B10 mice. Further, self-reactive T cells were comprised predominantly of Th2-type cells that preferentially evaded tolerance induction as compared to their Th1 counterparts. Because HBeAg may act as a tolerogen during the vertical transmission of chronic hepatitis B virus (HBV) infection, these results suggest that a predominance of HBeAg-specific Th2 cells expressing a limited repertoire may influence the initiation or the maintenance of the HBV chronic carrier state.     

Mechanisms of IgE tolerance: dual regulatory T cell lesions in perinatal IgE tolerance.

The mechanisms of genetic control of IgE responses are exercised at different immuno-physiological levels. This study centered upon the development of IgE lineage-specific regulatory T cells. Herein, we demonstrate the following points: (a) perinatal administration of soluble self IgE molecule or self IgE complexed with foreign antigen induces IgE tolerance as manifested by antigen-specific IgE unresponsiveness and a generalized IgE immunodeficiency, and the induction of IgE tolerance does not affect antigen-specific IgG1, IgG, and IgA responses; (b) inducibility of perinatal IgE tolerance is correlated with complete absence of endogenously secreted IgE in the neonates; and the state of persistent IgE tolerance also does not correlate with the presence of high levels of circulating anti-IgE autoantibodies; (c) The lesions induced during the ontogeny of IgE antibody system do not appear to result from an imbalance of production of interleukin 4 and interferon-gamma by T helper Th2 and Th1 cells in antigen-stimulated cultures; the dual immunoregulatory lesions in T cell subsets are demonstrated: clonal anergy/deletion of CD4+ IgE Th cells and the presence of CD8+ IgE suppressor cells induced by perinatal IgE treatment. We propose that antigen/interleukin 4 activated B cells are controlled by IgE lineage-specific regulatory T cells which recognize self IgE determinant(s) on IgE committed B cells. Life-long IgE tolerance ensues as a result of a new steady state of IgE lineage-specific CD4+ and CD8+ T cell subsets.