Suppression of hapten-specific delayed-type hypersensitivity responses in mice by idiotype-specific suppressor T cells after administration of anti-idiotypic antibodies

Tuberculous anergic sera or purified protein derivative treatment induces modification in lymphocyte transformation of cells from patients with tuberculosis

Peripheral blood mononuclear cells from 20 purified protein derivative (PPD)-reactive (PPD+) tuberculous patients were cultured in autologous, tuberculous anergic, or normal serum. After 12 h of incubation, the serum was eliminated and lymphocyte transformation with PPD was performed. Transformation was inhibited only in cells incubated with anergic serum. In contrast, cells from 11 anergic tuberculous (PPD-) individuals recovered the ability to respond to an optimal PPD dose after treatment with high PPD concentrations followed by several washings. The cells which recovered returned to their initial anergic state when incubated with sera from anergic patients. Under both conditions, incubation with sera did not abolish the response to the mitogen phytohemagglutinin. Cells from healthy PPD+ or PPD- individuals were used as controls. The most important finding derived from serum analysis was the increased levels of specific immunoglobulins G and A in anergic patients.

Protection against a syngeneic mammary adenocarcinoma by administration of idiotypic and anti-idiotypic antibodies

A hybridoma secreting a monoclonal antibody (mAb) with specificity for tumor-associated cell surface antigens of a transplantable murine mammary adenocarcinoma (SMC-168) was prepared by fusion of syngeneic C3H/He spleen cells with SP2 myeloma cells. Mice which were pretreated with this mAb (C-73) were significantly resistant to the outgrowth of a tumorigenic dose of SMC-168 cells when compared to controls. The treated mice developed tumor-specific cell-mediated immunity, measured by leukocyte adherence inhibition (LAI), which was equal to that of mice immunized with live tumor cells. The IgG fraction from serum of mice receiving mAb C-73 contained antibodies which would bind to that mAb suggesting the presence of anti-idiotypic antibodies (anti-Id). This binding could be partially inhibited by a soluble 1-butanol cell surface extract of SMC-168. Rabbits were immunized with mAb C-73 to produce a polyclonal anti-Id. The purified and absorbed IgG fraction of this serum would bind only to mAb C-73 and not to other mAbs of the same isotype or normal C3H/HeN IgG. Binding of the rabbit anti-Id to mAb C-73 could be partially inhibited by soluble tumor-associated antigen extracted from SMC-168. Mice immunized with this polyclonal anti-Id vaccine developed tumor-specific cell-mediated immunity and were significantly resistant to the outgrowth of a tumorigenic dose of SMC-168.

Prospects for the treatment of B cell tumors using idiotypic vaccination

Manipulation of the immune system in order specifically to attack autologous tumor cell has been a distant goal, largely due to the poor definition of tumor-associated antigens. By focussing on B cell lymphomas which express a molecularly defined clonal marker, the idiotypic immunoglobulin, it has been possible to generate autologous anti-idiotypic responses which suppress individual tumors. Studies of the components of these responses are providing insight into host effector mechanisms which can be activated against tumors, and also into the many strategies adopted by the target cells in order to avoid such attack. Promising results in various animal models where tumor bearers can be treated by idiotypic immunization have led to the point where application of this approach to the treatment of certain categories of human B cell lymphoma can be considered.

Binding specificity of antiidiotypic autoantibodies to anti-DNA antibodies in humans

Human antiidiotypic antibodies to anti-DNA antibodies can be separated into at least two categories based on their binding to anti-DNA, antiidiotypic antibodies, and antigens. One type was found mainly in inactive stage of SLE. The antiidiotypic antibodies appear to be directed towards idiotype (Id) determinants in the antigen-binding sites of anti-DNA antibodies. Antibody from patient T.K. acted like a mirror image of anti-single-stranded DNA antibodies, O-81, as determined by a competitive inhibition RIA. Antibodies from patient S.U. also seemed to be Ab 2 beta and Ab 2 gamma to anti-double-stranded(ds) DNA antibodies, NE-1. Most of normal subjects, on the other hand, had antibodies that bound to the human monoclonal anti-ds DNA antibodies, NE-1, NE-13, 7F4, and O-81. The Id-anti-Id interaction was not inhibited by the addition of DNA. Thus, normal subjects had Ab2 alpha activity that recognizes Id determinants in the framework region common among anti-DNA antibodies, whereas antiidiotypic antibodies in most SLE sera appear to show Ab 2 beta and Ab 2 gamma activity. The results provide evidence that the Id network system regulates immunological tolerance to DNA in humans.

Anti-idiotypic antibodies as immunogens: idiotype-based vaccines

Numerous studies have documented that antibodies may regulate the immune system and form the basis of vaccines, namely anti-idiotype vaccines. Antibodies carry individual idiotype antigenic determinants against which antibodies can be formed. When the anti-idiotype recognizes the same site that recognizes the primary antigen, a mirror image or combining site antibody may be generated. Other anti-idiotypes which recognize non-combining antigenic determinants have also been used. The evidence is reviewed for the existence of a broad range of anti-idiotypes and details are given of how an anti-idiotype vaccine based on the hepatitis B surface antigen has protected against virus challenge in the most relevant animal model system, namely the chimpanzee. Furthermore, the definition of the CD4 molecule as the conserved binding site for all known human and similar immunodeficiency viruses, (in marked contradiction to their varied neutralizing properties) has led to the raising of anti-idiotypes in mice based on the CD4 receptor which have the capacity to neutralize a broad range of isolates.

Coexistence of antigen-specific and idiotype-specific suppressor T cells in mice injected neonatally with a mixture of antigen and anti-idiotype antibody

Specific tolerance to phosphorylcholine (PC) can be induced in BALB/c mice by neonatal injection with either pneumococcal C-polysaccharide (PnC) containing PC or anti-TEPC-15 idiotype (T15id) antibody which recognizes the predominant idiotype of anti-PC antibody of BALB/c mice. Suppressor T cells (Ts) induced after treatment with anti-T15id antibody react with the T15id and PnC-induced Ts cells appear to recognize PC. A brief incubation of anti-id-induced, T15id-specific Ts with PnC-induced, PC-reactive Ts resulted in complete cancellation of their suppressor functions. However, both types of Ts were present in mice neonatally injected with mixtures of PnC and anti-T15id antibody. Neutralization experiments using either PnC-induced or anti-id-induced suppressor T cells strongly suggest that only one of the Ts cell types is functionally dominant in those mice: most frequently, T15id-specific Ts cells. The suppressor function of the other population is detectable only when the predominant Ts cell population is removed by anti-id or monoclonal IgM anti-PC (SP45) plus complement. However, both suppressor activities are completely eliminated when one of the Ts populations is removed by adherence to either antigen or T15id. These results suggest that mice neonatally injected with a mixture of antigen and anti-id antibody possess both types of suppressor T cells, yet only one type is functionally dominant.

B and T lymphocytes regulated by idiotype anti-idiotype interactions inhibit delayed-type hypersensitivity to BCG in mice

Mice infected subcutaneously with 2 X 10(7) CFU of Mycobacterium bovis strain BCG (BCG) were able to mount a specific DTH response, whereas mice infected intravenously with the same dose of microorganisms were not. The suppression turned out to be mediated by id+ anti-PPD B lymphocytes, which arose very early during the infectious process and induced anti-id B lymphocytes. These cells were found at Day 4 after infection and exerted their effect by activating antigen-specific suppressor T lymphocytes, which affected the efferent phase of the DTH response. These results clearly indicate that the activation of a complex immunosuppressive circuit represents a mechanism by which BCG may interfere with the host's immune response already during the very early phases of infection.

Evidence for a regulatory idiotypic network in the in vivo response to H-2 antigens

Treatment of BALB/c mice with purified pig antiidiotype to 11-4.1 (anti-H-2Kk) monoclonal antibody has been found previously to induce the appearance of idiotype-bearing molecules (Id') in the serum of these mice, in the absence of detectable antigen-binding activity. In the present study we examined the effect of subsequent immunization of such antiidiotype-primed mice with the original H-2Kk antigen. Skin grafting of virgin BALB/c mice with BALB.K skin did not generate any detectable Id' antibodies when tested by enzyme-linked immunosorbent assay (ELISA). In contrast, grafting of antiidiotype-primed mice with BALB.K skin specifically boosted ther serum level of Id' molecules. Challenge of antiidiotype-primed mice with either B10.D2 or rat skin had no effect on the production of such Id' molecules. Absorption studies demonstrated that the majority of Id' molecules induced by H-2Kk antigenic stimulus and detected in ELISA are antigen-nonbinding molecules, thus indicating specific restimulation by the original H-2Kk antigen of nonbinding idiotype-positive B cell clones. The relevance of these findings to the existence of network interactions in the immune response to H-2 antigens is discussed.

Staphylococcus aureus-induced suppression of contact sensitivity in mice: suppressor cells elicited by polyclonal B-cell activation are regulated by idiotype--anti-idiotype interactions

Staphylococcus aureus strain Cowan I, a strong polyclonal B-cell activator (PBA), inhibited contact sensitivity to oxazolone in mice when administered 24 hr before sensitization. This suppression was mediated by idiotype-positive (Id+) B lymphocytes, which arose very early during the sensitization process and induced anti-Id B cells. These cells were found at Day 3 of the sensitization process and exerted their effect by activating antigen-specific suppressor T lymphocytes, which affected the efferent phase of the immune response. S. aureus strain Wood 46, which lacks of the ability to act as a PBA, was unable to inhibit contact sensitivity. These results indicate that PBA may play an important role in the regulation of cell-mediated immune reactions.

T suppressor cells as well as anti-hapten and anti-idiotype B lymphocytes regulate contact sensitivity to oxazolone in mice injected with purified protein derivative from Mycobacterium tuberculosis

Purified protein derivative from Mycobacterium tuberculosis inhibits contact sensitivity to oxazolone in mice when given intravenously 24 to 72 h before the antigen. Transfer experiments showed that various types of suppressor cells occurred in the lymph nodes draining the site of sensitization: (i) anti-oxazolone idiotype + B lymphocytes, found at day 3 after sensitization, transferred suppression to syngeneic recipients at the moment of their sensitization; (ii) anti-idiotype B lymphocytes, found at day 3 after sensitization, transferred suppression to syngeneic recipients when sensitization of these animals had been performed 3 days before cell transfer; (iii) T lymphocytes, found only at day 6 after sensitization, inhibited the passive transfer of contact sensitivity, indicating that they were effective on the efferent phase of the immune response. These results indicate that purified protein derivative from M. tuberculosis interferes with contact sensitivity by activating a complex and multiple immunoregulatory circuit.

Influence of subclass-specific anti-idiotypic antibodies on the kinetics of the immune response to BCG

The role of anti-idiotypic subclass-specific antibodies was analysed in the regulation of the immune response to BCG in the guinea-pig. The idiotypes to BCG were separated into subclasses and anti-idiotypes were carried out by immunizing with the purified IgG1 and IgG2 anti-idiotypes. The in vivo T cell response was recorded by tuberculin skin testing, and the in vitro response by lymphocyte stimulation testing with tuberculin. A suppressive effect was detected in cases where the animals were preimmunized with anti-idiotypic IgG2 against anti-BCG IgG1. In the B cell response, the anti-BCG IgG1 and IgG2 subclasses were also quantified by a solid-phase radioimmunoassay. There were 10 times more IgG2 antibodies than IgG1 against BCG in the guinea-pig, and this major idiotypic subclass was suppressed by the IgG2 anti-idiotype raised against anti-BCG IgG2. The minor component anti-BCG IgG1 was slightly stimulated by both IgG2 anti-idiotypes.

Auto-anti-idiotypic antibodies inhibit T-cell-mediated hypersensitivity in BCG-infected mice

It is shown that serum from mice heavily infected with BCG contains antibodies which block the cell transfer of delayed-type hypersensitivity (DTH) to purified protein derivative (PPD) when BCG-immune cells were preincubated in it. This suppressive activity is antigen specific in that the serum does not block the cell transfer of contact sensitivity to oxazolone. However, the suppressive activity is not antigen directed in that it is absorbed neither by PPD-coupled Sepharose beads nor by PPD-pulsed normal peritoneal exudate cells. On the other hand, the activity can be absorbed to BCG-immune T cells and eluted from a Sepharose column conjugated with affinity-purified mouse anti-PPD antibodies. The possibility that antireceptor antibodies arise during the BCG infection and regulate DTH reaction is discussed.

Regulatory idiotypes. T helper cells recognize a shared VH idiotope on phosphorylcholine-specific antibodies

Priming of BALB/c mice with phosphorylcholine-hemocyanin (PC-Hy) induces T helper cells that are detected in splenic fragment cultures responding to immunization with trinitrophenylated PC-binding myeloma proteins, TEPC 15 (TNP-T15) and MOPC 167 (TNP-M167). Trinitrophenylation did not alter the binding site, idiotype, or isotype of the antibodies as demonstrated by binding studies. To assay idiotype-recognizing helper cells, Ly-2.2-depleted T cells from PC-Hy-primed donor mice were transferred to syngeneic athymic mice. Splenic anti-trinitrophenol fragment cultures were prepared from the nude recipients, and the response to TNP-T15 and TNP-M167 was measured by enzyme-linked immunosorbent assay. The number of responding fragments is dependent on the number of transferred primed T cells. The homing efficiency of 51Cr-labeled helper cells into the spleen of nude recipients was determined. The frequencies of T helper cells taken from PC-Hy-primed donors required for a B cell response to TNP-T15 or TNP-M167 were indistinguishable. The fine specificity of the anti-PC idiotype-recognizing T helper cells was studied by adding hapten (PC) or unconjugated myeloma proteins to fragment cultures as inhibitors at the time of immunization. PC and PC-bovine serum albumin, as well as T15 and M167, inhibited the helper function in vitro. Furthermore, free heavy chains of T15 and M167 partially inhibited T help, but free light chains of both idiotypes had no effect. These findings collectively show that T helper cells, induced by priming with antigen, recognize a shared idiotypic determination on T15 and M167 that is part of the PC binding site. The heavy chains of T15 and M167 appears to be the major structural component of this determinant. Evidently, T helper cells can recognize a shared determinant that is present on idiotypically different myeloma proteins. This determinant appears to be conserved throughout evolutionary and somatic mutations. The role of this shared, binding site-related idiotypic determinant as a regulatory idiotype in T-B cell interaction is discussed.

The assessment of anti-idiopathic antibodies as effective immunoregulatory probes in vivo

In order to increase our understanding of the potential to use anti-idiotypic antibodies as immune modulators in vivo, we extensively analysed influences induced by one such antibody (anti-Id-l) following its administration to animals of different ages, genetic backgrounds, and immunological histories. Id-l is an inter-strain idiotype associated with rat anti-Group A streptococcal carbohydrate antibodies. The intraperitoneal (i.p.) injection of anti-Id-l antibodies, prepared against Id-l+ antibodies from an HPR rat could effectively induce long-term idiotype suppression in all tested strains of rats, regardless of the age at the time of treatment, the RTl haplotype or IgG2c or k-chain allotype. Total anti-streptococcal antibodies were not suppressed by this treatment. Although long-term suppression could be induced at any age, the percentage of animals suppressed following neonatal injections was consistently less than that following adult injections of anti-idiotypic antibodies. In addition, neonatal injections of anti-Id-l or Id-l with anti-Id-l appeared to enhance Id-l production in a minority of the animals. Similar treatment of adult animals never increased Id-l synthesis, suggesting that cells associated with enhanced Id-l production in older animals are either refractory to activation-differentiation signals and/or are sequestered and no longer accessible by i.v. or i.p. routes of administration of the probe. Auto-anti-Id-l immunity induced by immunizing adult rats with heavy, light, F(ab')2 fragments or whole IgG molecules could also induce an Id-l suppressed state. We were not able to induce significant Id-l suppression if animals were immunized with antigen prior to the injection of anti-Id-l. There was evidence, however, that such treatment might lead in time to the development of some idiotype specific suppression.

Hapten-specific responses to the phenyltrimethyl-amino hapten. I. Evidence for idiotype-anti-idiotype interactions in delayed-type hypersensitivity in mice

The delayed-type hypersensitivity (DTH) reaction to the phenyltrimethylamino (TMA) hapten in mice has been investigated. TMA-derivatized syngeneic spleen cells (TMA-SC) administered s.c. in several strains of mice consistently evoked DTH reactivity, as measured by footpad swelling after challenge with the diazonium salt of TMA. DTH could be induced by low levels of anti-idiotypic antisera (anti-Id) in lieu of antigen. The DTH reaction induced by either mode was hapten-specific, could be transferred into naive recipients by viable lymph node cells but not with serum from immune mice and was not influenced by cyclophoshamide pretreatment. Unlike TMA-SC which induced DTH in all of the strains of the mice tested, anti-Id induced DTH only in strains of the Igh-1e allotype. Positive DTH reactions were induced by anti-Id in the C57.Ige strain (H-2b, Igh-1e) but not in its allotype-congenic partner C57BL/6J (H-2b, Igh-1b). Interestingly this reaction could be suppressed if relatively high amounts of anti-Id were inoculated i.v. just prior to antigen challenge. In addition, the administration of anti-Id 1 h prior to antigen challenge in TMA-SC-sensitized mice significantly blocked the DTH reaction only in the Igh-1e strains. These results demonstrate that the induction and abrogation of TMA-specific DTH by anti-Id is linked to the IgCh locus.

Preparation and characterization of the anti-idiotypic properties of rabbit anti-timothy antigen B helper factor and anti-mouse timothy IgE antisera

with AgB-primed B or T cells and injected into syngeneic X-irradiated recipients. Anti-THF and anti-Eid purified by an AgB-specific T suppressor factor (TSF) affi-gel adsorbent retain their ability to specifically initiate [3H]-thymidine incorporation of AgB-primed T cells. The data indicate that both anti-THF and anti-Eid recognize unique determinants present on AgB-specific T-helper, T-suppressor and B cells, and suggest that the receptors on AgB-specific T and B cells share cross-reactive idiotypic determinants.

Suppression of hen egg-white lysozyme (HEL)- specific delayed -type hypersensitivity responses in mice by suppressor T cells after neonatal administration of anti-idiotypic antibodies

Anti-idiotypic rabbit antiserum (anti-Id) directed to the idiotypes of anti-hen egg-white lysozyme (HEL) antibody froma single C3H mouse (No. 2) was shown to be capable of recognizing only a fraction of the anti-HEL antibody populations produced by other C3H mice. Experiments were performed to examine the effect of this particular anti-Id on the delayed-type hypersensitivity (DTH) response specific for the same protein antigen. A group of 60-day-old C3H mice which had been administered anti-Id within 24 hr after birth were tested for HEL-DTH response. The results indicated that the DTH response was completely suppressed by the anit-Id treatment. The inhibition of DTH reactivity is due to active suppression and involves the generation of suppressor T cells. Thus, the suppression induced with a single injection of anti-Id was transferable with both spleen cells and thymocytes from mice, that received anti-Id. These suppressor cells are T cells since their ability to suppress DTH is completely abrogated by treatment in vitro with anti-Thy 1.2 serum and complement.

Mechanisms of idiotype suppression. IV. Functional neutralization in mixtures of idiotype-specific suppressor and hapten-specific suppressor T cells

Specific tolerance to phosphorylcholine (PC) can be induced in BALB/c mice by neonatal injection with either pneumococcal C-polysaccharide (PnC) or anti-TEPC 15 idiotype (T15Id) antibody specific for the major idiotype (Id) of anti-PC antibody. Spleen cells from these tolerant mice exhibited T cell-mediated active suppression of anti-PC response when they were co-cultured with normal spleen cells. Suppressor cells from the PnC-injected mice appeared to bear either Lyt-1 or Lyt-2 antigens, whereas suppressor cells from anti-Id-treated mice expressed Lyt-2 antigens. Analyses of the specific receptors of these suppressor T cells, based on either adherence to PC and T15-coated petri dishes or cytolysis by rabbit anti-T15Id and monoclonal IgM anti-PC antibody with complement, revealed that receptors of PnC-induced suppressor T cells recognize PC, whereas receptors of anti-Id-induced suppressor T cells react with the T15Id. The possible interaction of the two different types of suppressor T cells was examined by co-culturing normal spleen cells with mixtures of the different suppressor cell types in various cell ratios in the presence of the T-independent PC-antigen, R36a. A brief incubation of anti-Id-induced, T15Id-specific suppressor T cells with PnC-induced, hapten-specific, and T15Id-bearing suppressor T cells resulted in complete cancellation of their suppressor function. These results suggest that idiotype network regulation may also occur among suppressor T cell population.

Anti-receptor antibody-induced suppression of murine H-Y-specific delayed-type hypersensitivity responses

A putative anti-H-Y receptor antiserum (ARA) was raised in C57BL/6 male mice against splenic T lymphocytes from syngeneic females immunized against H-Y antigen. When this antiserum is given i.v. to C57BL/6 females it prevents the expression of H-Y-specific delayed-type hypersensitivity (DTH). The suppressive activity in ARA was selectively retained on rabbit anti-mouse immunoglobulin columns, and could be absorbed by H-Y-immune spleen cells from C57BL/6 female mice. The abrogation of H-Y DTH reactivity was at least in part due to the generation of suppressor T cells which are generated by ARA in naive female mice. ARA-generated suppressor cells specifically inhibit the induction phase of DTH responses to the H-Y antigen, having no effect on (4-hydroxy-3-nitrophenyl)acetyl (NP)-specific cutaneous sensitivity responses or on DTH responses to minor histocompatibility antigens. Furthermore, there is a requirement for Igh gene homology between the strain producing the ARA and the strain in which the DTH response is induced. Thus, C57BL/6 ARA given to A.BY (H-2b, Igh-1e) or to B.C-8 (H-2b, Igh-1a) mice was unable to suppress homologous H-Y DTH responses in these strains. However, C57BL/6 ARA induced suppressor cells in B.C-8 mice which were capable of inhibiting H-Y DTH responses when adoptively transferred to C57BL/6 females.

Regulation by complementary idiotypes. Ig protects the clone producing it

A/He mice actively producing complementary or anti-idiotypic antibody directed against a combining site structure for phosphorylcholine (PC) have profound and long-lasting suppression of their response to PC. B cells from unresponsive mice are unresponsive in vitro, and attempts to demonstrate suppressor cells in unresponsive mice were unsuccessful. Although the process ultimately responsible for suppression has not been defined, suppression can be initiated by anti-idiotypic antibody alone and prevented by complementary Ig; i.e., by anti-PC antibody. Furthermore, a suppressed anti-PC response can be rescued by sublethal irradiation and anti-PC antibody given passively. The recovery of the suppressed response is slow and presumably results from maturation from "stem" cells, which are protected from tolerization by the passively given antibody. Thus, by extrapolation, one of the functions of secreted Ig may be to protect the clone that produces it.

Demonstration of T15 idiotype-positive effector and suppressor T cells for phosphorylcholine-specific delayed-type hypersensitivity response in CBA/N or (CBA/N X BALB/c)F1 male mice

Subcutaneous immunization of CBA/N or (CBA/N X BALB/c)F1 (NBF1) male mice, which were defective in phosphorylcholine (PC)-specific humoral antibody response, with PC-conjugated syngeneic spleen cells induced a PC-specific delayed-type hypersensitivity (DTH) response, while intravenous administration of the same cells induced PC-specific suppressor T cells for the DTH response. Treatment of PC-specific effector or suppressor T cells for the DTH response induced in NBF1 male mice with anti-T15 idiotypic antibody inactivated effector or suppressor functions of these T cells implying that PC-specific T cells in NBF1 mice expressed T15 idiotypic determinants on their surface. Enrichment of PC-specific suppressor T cells was also shown by employing anti-T15 antibody-coated dishes.

Induction of delayed-type hypersensitivity to azobenzenearsonate by a monoclonal anti-idiotype antibody

Azobenzenearsonate (ABA)-specific sensitivity was induced in A/J mice by injecting a monoclonal anti-idiotype reagent, 14A, directed against a determinant present on a minor subpopulation of immunoglobulin molecules within the anti-ABA antibodies of A/J mice. Sensitivity was transferrable by purified T cells and this was abrogated by treating the cells with 14A, rabbit anti-mouse immunoglobulin and complement, not by treatment with only the last two reagents. The transfer was restricted by the K-end of the major histocompatibility complex.

Enhancing effect of murine anti-idiotypic serum on the proliferative response specific for poly(LTyr, LGlu)-poly(DLAla)--poly(LLys)[(T,G)-A--L]

Murine anti-idiotypic serum against C3 H.SW anti-poly(LTyr, LGlu)-poly(DLAla)--poly(LLys)[(T,G)-A--L] antibodies was elicited in C57BL/6 mice. The effect of the anti-idiotypes on the proliferation of primed lymph node cells was investigated. The anti-idiotypic serum stimulated the proliferative response of the (T,G)-A--L-specific lymph node cells as well as of nylon wool-enriched T cells. In the presence of suboptimal doses of (T,G)-A--L, the addition of the anti-idiotypes enhanced the proliferation to the levels obtained with the optimal dose of (T,G)-A--L itself. These results suggest the existence of shared idiotypic determinants between antibodies and the (T,G)-A--L-specific proliferative T cells.

Autoregulation of immune responses via idiotype network interactions

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Transferable suppression and intrinsic unresponsiveness in delayed-type hypersensitivity to sheep red blood cells of mice: two distinct mechanisms?

In mice rendered unresponsive in DTH by the i.v. infection of 10(9) SRBC, two forms of specific unresponsiveness could be distinguished, referred to as intrinsic unresponsiveness and suppression. Suppression could be transferred by splenic T cells. It was short-lived and sensitive to cyclophosphamide (Cy, 100 mg/kg i.v.) given after sensitization. On the other hand, intrinsic unresponsiveness was not transferable by either serum or spleen cells. It was long-lived and resistant to Cy (200 mg/kg i.v.) given after sensitization. Induction of both transferable suppression and intrinsic unresponsiveness depended on Cy-sensitive (200 mg/kg i.v.) precursors. Since no evidence for clonal deletion could be obtained, it is suggested that unresponsiveness in general is mediated by complex cellular interactions which are readily perturbed in transfer experiments. In this way, cell recipients would end up possessing incomplete regulatory circuits, intact circuits still being present in donor animals.

Elicitation of delayed-type hypersensitivity responses to poly(L-Tyr,LGlu)-poly(DLAla)--poly(LLys) by anti-idiotypic antibodies

The in vivo effect of murine anti-idiotypic serum against C3H.SW anti-poly(LTyr,LGlu)-poly(DLAla)-(LLys) [(T,G)-A--L] antibodies on delayed type hypersensitivity responses to (T,G)-A--L was studied. Anti-idiotypic serum could challenge DTH responses in C3H.SW mice transferred with antigen-sensitized T cells. The elicitation activity was shown to be antigen and strain specific. With H-2-compatible (but allotype different) strain combinations of (T,G)-A--L-educated T cells and recipients, we were able to show that the biological effect of the anti-idiotypic serum is expressed on the first antigen-sensitized idiotype-positive radioresistant T cell, but not on the proliferating normal cells of recipient origin that participate in the efferent phase of delayed-type hypersensitivity responses to (T,G)-A--L.

Selective suppression of the major idiotypic component of an antihapten response by soluble T cell-derived factors with idiotypic or anti-idiotypic receptors

Evidence is presented for the selective suppression of the major idiotypic component of the humoral response to the phenylarsonate hapten by soluble factors derived from T cells (TsF). The existence of TsF with anti-idiotypic receptors was also demonstrated. It was found that TsF with idiotypic and anti-idiotypic receptors coexist in cultures of spleen cells prepared from idiotypically suppressed, hyperimmunized mice. By gel filtration the molecular weight of each factor was found to be 50,000-100,000. Each is sensitive to trypsin and is bound to a column containing anti-H-2a antibodies. Evidence is discussed which suggests the possibility of mutual stimulation of suppressor T cells with idiotypic and anti-idiotypic receptors.