Functional analysis of cloned macrophage hybridomas. VI. Differential ability to induce immunity or suppression

We previously screened a series of macrophage hybridomas derived from fusion of P388D1 (H-2d) tumor cells with CKB (H-2k) splenic adherent cells for their ability to induce I-J restricted Ts cell responses. One Ia+ macrophage clone (63) consistently induced Ag-specific, I-J-restricted Ts. To evaluate whether macrophage hybridoma 63 also induced delayed-type hypersensitivity (DTH) immunity, mice were immunized with hapten-coupled macrophage hybridoma cells. Hapten-coupled splenic adherent cells and control macrophage hybridomas induced significant primary DTH responses, whereas hapten-coupled macrophage 63 induced little or no immunity when injected into H-2 compatible hosts. However, macrophage hybridoma 63 specifically activated I-Ak, I-Ad, or I-Ed restricted T cell hybridomas/clones, in vitro in the presence of appropriate Ag. Three different strategies designed to eliminate suppressor cell activity were successfully used to demonstrate that hapten-coupled macrophage 63 could also induce in vivo immunity. First, after immunization with hapten-coupled macrophages, mice were treated with cyclophosphamide. Second, macrophage 63 was treated with anti-IJ idiotype antibody before 4-hydroxy-3-nitrophenyl acetyl hapten (NP) coupling. Finally, haptenated macrophages were injected into I-A compatible but I-J incompatible recipients. These protocols are known to inhibit the induction of Ts activity, thus these results indirectly suggest that there is stimultaneous generation of Ts activity in vivo. The latter hypothesis was tested in adoptive transfer experiments. Transfer of lymph node cells from NP-63 primed B10.BR (H-2k) mice induced immunity in naive 4R animals, whereas the same number of immune cells suppressed NP-induced DTH responses in 5R mice. The combined results indicate that a cloned macrophage line can activate both Th and Ts cells. Macrophages which induce Ts activity may be responsible for maintaining the balance of immunity vs suppression. The data support the hypothesis that IJ interacting molecules (IJ-IM) expressed on macrophages are critical for induction of suppressor cell activity.     

Immunoregulation of lysozyme-specific suppression. III. Epitope-specific amplification of immunosuppression induced by monoclonal suppressor-T-cell products

The hen egg-white lysozyme (HEL)-specific suppression induced by soluble molecules produced by a monoclonal T-cell lymphoma line (LH8-105) obtained from HEL-specific suppressor T lymphocytes has been examined. Injection of I-J+ molecules from LH8-105 cell culture supernatant (TsFa) in HEL-primed mice during the afferent phase of the response induced Lyt-2+ second order suppressor T (Ts) cells which, upon transfer into HEL-CFA-primed syngeneic recipients, inhibit the delayed-type hypersensitivity (DTH) response to HEL. Transfer of spleen cells from TsFa-injected mice primed with HEL or human lysozyme suppresses the DTH response to HEL in recipient mice whereas this response is not affected by cell transfer from ring-necked pheasant egg-white lysozyme (REL)-primed and TsFa-injected mice, indicating that induction of second order Ts by TsFa is specific for a lysozyme epitope including phenylalanine at position 3. Fine antigenic specificity of second order Ts-cell induction is confirmed by similar results obtained upon injection of TsFa in mice primed with HEL N-terminal synthetic peptide or with an analog in which, as in REL, phenylalanine has been substituted by tyrosine at position 3. The same fine antigenic specificity observed in the induction of second order Ts cells is also present in the expression of TsFe suppressive activity. The similar antigenic specificity of Tsa and Tse suggests that Tse cells could result from amplification of the Tsa cell population or these two cell subsets could reflect different maturation stages of the same cell type rather than distinct T-cell populations activated in cascade.     

Antigen-specific T cell-mediated suppression. II. In vitro induction by I-J-coded L-glutamic acid50-L-tyrosine50 (GT)-specific T cell suppressor factor (GT-T8F) of suppressor T cells (T82) bearing distinct I-J determinants.

The induction of new suppressor T cells (Ts2) by suppressive extracts (TsF) from L-glutamic acid50L-tyrosine50 (GT) nonresponder mice was examined. Incubation of normal spleen cells with allogeneic GT-TsF for 2 days in vitro led to the generation of Ts2 cells able to suppress subsequent responses to the immunogen GT-methylated bovine serum albumin (GT-MBSA) in vivo. This induction occurred efficiently when TsF donor and target cells differed at all of H-2, including the I-J subregion. B10.BR (H-2k) GT-TsF, adsorbed on, then acid eluted from GT-Sepharose and anti-I-Jk [B10.A (3R) anti-B10.A (5R)]-Sepharose in a sequential fashion could induce BALB/c (H-2d) spleen cells to become Ts2 only if nanogram quantities of GT were added to the purified GT-TsF. This indicates a requirement for a molecule or molecular complex possessing both I-J determinants and antigen (GT)-binding specificity, together with GT itself, for Ts2 induction. The induced Ts2 are I-J+, since their function can be eliminated by treatment with anti-I-Jk plus C. These I-J determinants are coded for by the precursor of the Ts2 and do not represent passively adsorbed, I-J coded TsF, since anti-Ijk antiserum [(3R X DBA/2)F1 anti-5R] which cannot recognize the BALB/c (I-Jd) TsF used for induction still eliminates the activity of induced A/J (I-Jk) Ts2. These data provide further evidence for and information about the minimum of two T cells involved in antigen-specific suppressor T cell systems.     

A primary in vitro antibody assay for antigen-specific T-suppressor factor: cross-suppression of TNP-specific antibody responses by TMA-specific TsF1

We have previously shown that phenyltrimethylammonium (TMA)-specific, first-order suppressor T cells (Ts1) and soluble factors extracted from these cells (TsF1) can suppress delayed-type hypersensitivity (DTH) responses. The TsF1, as monitored in the DTH system, was characterized and found to be a single-chain, antigen-binding, I-J+, and Id+ molecule. To monitor TsF1 in an efficient manner, an in vitro antibody system was developed. The studies show that in vitro stimulation of naive A/J spleen cells with the thymic-independent antigen, Brucella abortus, to which TMA and trinitrophenol (TNP) or fluorescein (FL) are coupled (TMA-BA-TNP or TMA-BA-FL), induces significant numbers of anti-TNP or anti-FL plaque-forming cell (PFC) responses. The addition of TMA-specific TsF1 results in the cross-suppression of 30-50% of the total anti-TNP and FL PFC responses. This activity is antigen (TMA) dependent since suppression occurs only when the TMA ligand is present in the culture media. Analysis of the TNP-specific PFC responses in nonsuppressed cultures revealed that 20-35% of the PFC bear the cross-reactive idiotype(s) (CRI) normally associated with anti-TMA antibodies. In cultures containing TMA-TsF1, CRI+PFC are suppressed by 90-100% while the CRI-PFC are suppressed only by 10-30%. Our studies further show that an induction-phase, antigen-binding, CRI+, and I-J+ single-chain factor is responsible for the observed in vitro suppression. The possibility of utilizing this assay to monitor a variety of antigen-specific suppressor factors is discussed.     

Modulation of SLE induction in naive mice by specific T cells with suppressor activity to pathogenic anti-DNA idiotype.

T cells (CD8+) with specific suppressor activity against anti-dsDNA antibody (16/6 Id+) were generated in vitro. The cells were established from BALB/c-enriched T cells exposed in vitro to silica beads coated with the pathogenic anti-DNA idiotype, 16/6. The idiotype specificity of the suppressor cells was demonstrated by (a) specific induction of a decrease in proliferative response of T helper cell lines specific for the pathogenic idiotype (16/6 Id), when exposed to the idiotype, with no effect on T cell lines with other specificities, e.g., against human IgM or synthetic polypeptide. (b) Effectively suppressing in vitro antibody production of anti-16/6 antibody, employing 16/6-primed B cells and specific helper T cell line. The 16/6 Id-specific Ts cells were found to be MHC restricted. Weekly intravenous injections of 10(7) 16/6 Id-specific Ts cells given to BALB/c mice at different stages of experimental SLE disease prevented the clinical, serological, and pathological manifestations. This effect was characterized by decreased titers of autoantibodies (e.g., anti-DNA, anti-Sm antibodies) in the sera, by abolishment of the proteinuria, leukopenia, and the increased ESR, followed by decreased immunoglobulin deposition in the kidneys. Treating the mice with control IgM-specific T cells did not affect the above parameters. These studies demonstrate the ability to generate Ts cells specific for pathogenic idiotypes. The method might be employed therapeutically to modulate the course of autoimmune conditions.     

Ocular immune responses. I. Priming of A/J mice in the anterior chamber with azobenzenearsonate-derivatized cells induces second-order-like suppressor T cells

We studied the cellular immune responses to ocular anterior chamber (AC) priming of mice. A/J mice primed subcutaneously with azobenzenearsonate-coupled spleen cells (ABA-SC) manifested delayed-type hypersensitivity (DTH) in the form of footpad swelling when challenged 5 days later with the diazonium salt of ABA. Mice inoculated with ABA-SC in the anterior chamber at the time of subcutaneous priming, however, were tolerant to ABA. Subconjunctival inoculation with ABA-SC did not tolerize; rather it primed for DTH. Antibodies against ABA were not detectable in significant amounts in mice made tolerant by AC inoculation. The AC-induced tolerance was shown to result from hapten-specific T cell-mediated suppression. Suppressor T cells (Ts) arising from AC priming suppressed the efferent limb of the immune response and did not bear detectable cross-reactive idiotype (CRI) surface receptors. In these phenotypic and functional respects, AC-induced Ts differed from first-order Ts (Ts1) that result from i.v. priming. The results are discussed with respect to immune privilege and the anterior chamber of the eye.     

Epidermal cells in activation of suppressor lymphocytes: further characterization

Intravenous administration of hapten-coupled, high-density (density greater than 1.077) epidermal cells (HD-EC) to mice results in the appearance of transferable splenic T suppressor (Ts) cells as assayed in adoptive transfer experiments. Depletion of I-A bearing cells from the HD-EC population before hapten coupling prevents these cells from inducing Ts cell formation, whereas depletion of Thy-1-bearing cells from the HD-EC cell preparation has no effect. When HD-EC are adhered to glass for 2 hr, the ability to induce Ts cell formation resides in the adherent population. Exposure of HD-EC to a dose of ultraviolet radiation (UVR) that largely abrogates the ability of hapten-coupled EC to immunize mice for a DTH response does not affect the ability of these cells to activate Ts cells. Treatment of mice with i.p. administration of 20 mg/kg of cyclophosphamide 2 days before EC harvesting abrogates the ability of HD-EC from these mice to induce Ts cell formation. HD-EC from B10.A(3R) (I-Jb) but not B10.A(5R) (I-Jk) mice induce Ts cell formation in B10.A(3R) mice, demonstrating that the ability to do so is restricted by the I-J locus. Transmission electron microscopy of adherent HD-EC populations demonstrated that two cell types were present. One type had the characteristics of keratinocytes; the other was monocyte-like and resembled Langerhans cells or indeterminate cells in many aspects. Immunoelectron microscopy revealed this second cell type to bear I-A/I-E antigen. These cells were T-200 positive and Mac-1 negative by immunoperoxidase staining. Extensive examination by light and electron microscopy failed to reveal any dermal components in the EC populations; however, a very small degree of dermal contamination cannot be excluded. Thus, EC that activate afferent-acting Ts cells are high-density, I-A+, Thy-1-, I-J restricted, glass adherent, and functionally UVR resistant and cyclophosphamide sensitive.     

Regulation of cell-mediated immunity in cryptococcosis. II. Characterization of first-order T suppressor cells (Ts1) and induction of second-order suppressor cells

Cryptococcosis patients frequently have high levels of cryptococcal antigen in their body fluids, and the levels of circulating antigen can generally be used to predict the patient's recovery, with high or rising antigen titers indicating a poor prognosis and low or decreasing levels a good prognosis. In a previous study, we reported on a murine model for studying the effects of cryptococcal antigen on host defense mechanisms. In that work, we demonstrated that an i.v. injection of cryptococcal antigen (CneF) into CBA/J mice, to simulate the antigenemia known to occur in human cryptococcosis, induced a population of T suppressor cells (Ts1) in the lymph nodes (LN). Upon adoptive transfer, the Ts1 cells specifically suppressed the afferent limb of the delayed-type hypersensitivity (DTH) response to cryptococcal antigen. In the present study, we show that the precursors of the Ts1 cells are sensitive to low-dose cyclophosphamide treatment and that the phenotype of the Ts1 cells is Lyt-1+, Ia+ (I-J+). LN cells from CneF-injected mice or a soluble factor derived therefrom can induce in the spleens of recipient mice a second-order suppressor cell population that suppresses the efferent limb of the DTH response. The cells that induce the second-order or efferent suppressor cells have the same phenotype as the cells that appear to suppress the afferent limb of the DTH response. The findings in this study indicate that a complex regulatory mechanism is responsible for the observed suppression of the DTH response in this infectious disease model. Furthermore, the suppressive circuit thus far defined for cryptococcal antigen is similar to the antigen-specific suppressor cell pathway outlined for certain chemically defined haptenic systems.     

An in vitro system for the generation of suppressor cells and the requirement for B cells in their induction

An in vitro method for the generation of effector suppressor cells (Ts3) was developed. By utilizing this protocol, it was possible to investigate both the cellular and genetic requirements for suppressor cell induction. It was determined that populations containing Ts3 cells can be induced after a 4-day culture of spleen cells and antigen. These Ts3 cells are similar to Ts3 cells generated by in vivo immunization. Both populations are I-J+, bind NP hapten, bind NP hapten, bear receptors which share NPb idiotypic determinants with anti-NP antibodies, function during the effector phase of the immune response, and require activation with Ts2 cells. Generation of Ts3-containing populations required both nylon wool-nonadherent T cells and a nylon-adherent, B cell-enriched population from an Igh-identical donor. T cells cultured with antigen alone or with syngeneic macrophages and antigen did not develop suppressive activity. Lytic treatment of the nylon-adherent population with a B cell-specific monoclonal antibody (J11d) removed the ability to generate suppressor cells. These results imply that the induction of suppressor T cells requires B lymphocytes, and that this induction process is dependent on Igh-linked gene products.     

Interaction of idiotype-specific T suppressor factor with the hapten-specific third-order T suppressor subset results in antigen-nonspecific suppression

The interaction between the third-order T suppressor (Ts3) cell and the idiotype (Id)-specific second-order Ts factor (TsF2) was studied in the phenyltrimethylamino (TMA) hapten system. The experimental system which we used allowed the independent analysis of induction and activation requirements of Ts3. The procedure consisted of inducing the Ts3 in vivo and activating the enriched T-cell populations containing Ts3 in vitro with TsF2. The suppressive potential was then tested in mice previously primed for delayed-type hypersensitivity responses which were also treated with cyclophosphamide to deplete Ts3 and other drug-sensitive Ts cell types. Using this experimental system, it was found that the Id-specific TsF2 was required for the in vitro activation of Ts3. Furthermore, the TsF2 activated only the homologous and not heterologous antigen-primed Ts3-containing T cells and moreover, the target of TsF2 was found to be the Ts cells bearing hapten-specific receptors. Once the TMA hapten-specific Ts3 was activated with TsF2, the ensuing suppression was antigen nonspecific. The data demonstrate that the Ts3 represents a final effector Ts cell type in the TMA system.     

B-cell-mediated regulation of delayed-type hypersensitivity

We obtained immune sera from mice which received suppressor B cells induced in vitro, injected them into immunized mice, and measured suppression of the delayed-type hypersensitivity (DTH) of these recipient mice. In the recipients, effector-phase suppressor T (Ts) cells were induced, and the action of these Ts cells was antigen-nonspecific. The suppressive material of the sera was adsorbed on a Sepharose column coated with anti-mouse immunoglobulin antibody and acid elution of the column yielded the elute fraction that showed significant suppressive activity. The suppressive activity of the sera was also adsorbed by an antigen-coated Sepharose column, and the eluate from the column had suppressive activity. Moreover, we established antigen-specific monoclonal antibodies, some of which suppressed the DTH in an H-2-nonrestricted way. The isotype or specificity of the antibodies was not related to the suppression, because suppressive and nonsuppressive antibodies belonged to the same immunoglobulin isotype and because the antibodies that recognized the same epitope had different suppressive activities. The Fc portion was not the functional site, because the F(ab')2 fragment had the activity. The suppressive antibody induced effector-phase Ts cells, which had the anti-idiotypic receptor. These findings suggested that antigen-specific antibodies in the immune sera mediated the suppression of DTH by the induction of effector-phase Ts cells in vivo and the idiotype of the antibody stimulated the anti-idiotypic receptor of these Ts cells.     

Genetic and biological characterization of a T suppressor cell induced by anti-idiotypic antibody

The cellular and molecular characteristics of anti-idiotype-induced suppression have been investigated. We have shown that i.v. immunization of A/J or C.AL-20 mice with rabbit antibodies against the major cross-reactive idiotype on A/J anti-ABA antibodies induces splenic suppressor T cells (Ts) able to suppress T cell-mediated cytolytic and delayed-type hypersensitivity responses to ABA. In these studies, we compare the T suppressor activity manifested by anti-Id-induced suppressor cells with that described previously after conventional antigen priming. Results indicate that i.v. injection of anti-idiotypic antibodies primes for efferent level Ts; in contrast, i.v. administration of ABA-coupled cells induces afferent level suppressor cells. Soluble cell lysates, containing suppressor factor(s) derived from these anti-idiotype-induced Ts, can also mediate suppression of T cell immune responses in an efferent manner. Factor-mediated suppression is MHC-unrestricted and is also observed in mice pretreated with cyclophosphamide, suggesting that this activity is analogous to third-order suppression. Furthermore, this factor suppresses the T cell-mediated DTH and CTL responses in an antigen-nonspecific but Igh-restricted manner. These latter results suggest that the cellular elements conferring antigen specificity and Igh restriction are separate. The implications of these findings to the relationship between idiotypic elements, antigen-binding structures, and Igh restriction elements on immunoregulatory T cells are discussed.     

Regulatory mechanism of delayed-type hypersensitivity in mice. IV. Effect of suppressor T cells on the development of memory T cells involved in accelerated generation of DTH-effector cells in vitro

The effect of suppressor T cells (Ts) on the induction and the subsequent development of memory T cells for delayed-type hypersensitivity (DTH) was examined. The memory cells were induced in the spleens of mice primed previously with a low dose of reduced and alkylated ovalbumin (Ra-OA), and they generated DTH-effector T cells (DTH-Te) in a significantly accelerated fashion when cultured with OA in vitro. Ts were obtained from the spleens of mice which received OA-coupled spleen cells i.v. 4 days previously, and they inhibited antigen-specifically the induction of DTH responses in the recipient mice sensitized with alum-absorbed OA only when transferred with 5 weeks before sensitization. The spleen cells from mice given Ts together with the priming antigen 7 weeks before culture failed to generate DTH-Te in an accelerated manner on restimulation with OA in vitro. The memory cells from primed mice also did not cause accelerated generation of DTH-Te, when cultured with Ts in the presence of OA in vitro. These results indicate that both the induction of the memory cells by priming with antigen in vivo and the subsequent development of memory cells to DTH-Te by restimulation in vitro are inhibited independently by Ts. This corresponded well with the effect of Ts on the development of DTH-memory in vivo.     

Pathogenic idiotypes of autoantibodies in autoimmunity: lessons from new experimental models of SLE

Systemic lupus erythematosus (SLE) is considered a classical autoimmune disease that involves many biological systems. Similar to other autoimmune conditions, its etiology is multifactorial entailing genetic, environmental, hormonal, and immunologic factors. In this review we demonstrate that by using a pathogenic idiotype of anti-DNA autoantibodies, it is possible to explain some of the pathogenesis and diversity of clinical and serological manifestations reported by SLE patients. The 16/6 idiotype (Id) is a representative pathogenic idiotype of anti-DNA autoantibodies. The serum titers of 16/6 Id in SLE patients correlate with clinical activity of the disease, and are deposited in afflicted tissues in SLE patients. SLE was experimentally induced in naive mice after immunization with 1 microgram of the Id. The disease is characterized clinically (proteinuria), serologically (e.g., anti-dsDNA, anti-Sm antibodies), and by pathological findings (e.g., deposition of 16/6 Id in the kidneys). The condition can be induced by other human and mouse antibodies carrying the 16/6 Id, as well as by mouse antimonoclonal-16/6 Id and by T cell lines and clones specifically reactive with 16/6 Id. There are strain-dependent differences in susceptibility to the induction of systemic lupus erythematosus (SLE). Induction of SLE is directly correlated with the ability to respond to the 16/6 idiotype (or 16/6 Id)2 by anti-Id antibody production. It is easier to induce the disease in females, and it can be modulated by manipulation of sex hormones. Being able to identify the pathogenic idiotype allowed us to generate T suppressor (Ts) cells specific for the 16/6 Id. Treatment of mice with these T cells abrogated the disease. Our studies point to the importance of pathogenic idiotypes of autoantibodies in autoimmunity, which suggests that SLE may represent a dysregulation of a functional network of idiotypes-anti-idiotypes interactions among autoreactive B cells, T helper cells, and T suppressor cells.     

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.     

Characterization of anti-idiotypic suppressor T cells (Tsid) induced after antigen priming

The induction and fine specificity of idiotype-specific suppressor T cells (Tsid) were studied. Spleen cells from C57BL/6 mice, immunized 4 wk previously with NP-KLH, failed to express NPb3 idiotype-bearing PFC when challenged in vitro with NP-Ficoll or NP-Brucella abortus. After treatment of NP-primed responder cultures with anti-Thy-1.2 anti-serum + C, NPb idiotype-bearing B cells could be detected. This B cell subset was preferentially suppressed by the addition of T cells from NP-primed mice. With this reconstitution protocol, it was determined that suppression of the NPb idiotype-bearing portion of the B cell response was mediated by a specifically induced T cell population (Tsid) that directly suppressed NPb-bearing B cells. As with a previously described suppressor population induced with hapten-modified syngeneic spleen cells (Ts2), the Tsid population bound and was lysed by NPb idiotype-bearing serum antibodies. However, the Tsid could be distinguished from the Ts2 population because it lacked I-J determinants and functioned as an effector T cell, not an intermediary suppressor cell. Furthermore, fine specificity studies with monoclonal NP-specific antibodies expressing various levels of serologically detectable NPb idiotypic determinants indicated that unlike the Ts2, the Tsid population reacts with conventional, serologically detected members of the NPb family. The combined idiotype binding studies for the Tsid and Ts2 populations demonstrate that the fine specificity of suppressor T cell populations reflects their independent mechanisms of regulation.     

Tumor-specific idiotype vaccines. III. Induction of T helper cells by anti-idiotype and tumor cells

In a previous report, we have demonstrated the induction of tumor-specific immunity by monoclonal anti-idiotype antibodies generated against a monoclonal anti-tumor antibody, 11C1, that also cross-reacts with mouse mammary tumor virus envelope glycoprotein gp52. Also, we showed that whereas one anti-idiotype antibody, 2F10, could induce protective immunity, another anti-idiotype antibody, 3A4, induced nonprotective immunity. Here we demonstrated the existence of T helper cells which recognize anti-idiotypes that exert differential controls on tumor growth. The qualitative nature of idiotype recognizing T cells generated in response to 2F10, 3A4, irradiated tumor, and progressively growing tumor was compared. The reactivity pattern of idiotype recognizing T cells obtained from 2F10 and irradiated tumor immunized mice were similar in nature in the sense that Lyt-2- T cells obtained from these immunized mice responded to both 2F10 and 3A4 as antigen, although T cells from tumor immunized mice responded better to 3A4 antigen. On the other hand, the idiotype-recognizing T cells obtained from 3A4-immunized mice showed a similar reactivity pattern to T cells isolated from mice during the early phase of tumor growth (within day 4 to 5 after the inoculation of 10(4) live tumor cells). Lyt-2- T cells isolated from mice immunized with 3A4 or during the early phase of tumor growth responded only to 3A4 antigen. The inability of Lyt-2- T cells, isolated from 4- to 5-day-old tumor in mice, to cooperate with 2F10-TNP is not due to the absence of 2F10 idiotype recognizing T cells as 2F10 id recognizing T cells are present when examined at the precursor level. These data on the idiotype specificity of T helper cells show a correlation with the presence of anti-tumor immunity. This information will help in the design and application of idiotype vaccine in tumor immunotherapy.     

Inhibition of specific immune responses by feeding protein antigens. V. Induction of the tolerant state in the absence of specific suppressor T cells

The effect of CY pretreatment on the ability of OVA feeding to induce both tolerance and active suppression was examined in mice. CY-pretreated, OVA fed mice were fully unresponsive in both OVA-specific DTH and antibody responses, but, in contrast to untreated OVA-fed mice, did not transfer suppression to normal recipients via splenic lymphocytes. Restoration of Ts activity in CY-pretreated mice was accomplished by reconstitution with normal T cells before antigen feeding, indicating that the CY effect was at the Ts precursor level. In addition, it was found that certain OVA-specific immune parameters (DTH and splenic PFC responses) in recipient mice were susceptible to suppression by transfer of spleen cells from OVA-fed donors, whereas other measures (antigen-induced T cell proliferation and serum antibody titers) were not. The data suggest that CY-sensitive Ts are not necessary for either induction or maintenance of specific tolerance after OVA feeding.     

Idiotype-specific T suppressor factor alternatively interacts with a nonspecific T-acceptor-like cell to mediate immune suppression

The ability of the idiotype (Id)-specific second-order T suppressor factor (TsF2) to interact with a final effector Ts cell type other than the previously reported third-order Ts (Ts3) subset was studied in the phenyltrimethylamino (TMA) hapten system. Hence, mice were primed with unrelated heterologous haptens to induce the nonspecific T acceptor (Tacc) cells following published procedures. When enriched T cell populations containing these nonspecific Ts were briefly incubated in vitro with TMA-TsF2, they produced suppression upon adoptive transfer into cyclophosphamide-treated mice which had been previously immunized for TMA-specific delayed-type hypersensitivity. Despite the fact that the effector population studied in this report also required Id-binding TsF2 for its function, it differs markedly from the Ts3 subset studied previously in the TMA system. First, the cell type studied herein could be easily generated with noncrossreacting heterologous chemically reactive haptens when applied directly to the skin of mice. Furthermore, these Ts effector cells had no detectable intrinsic receptors for homologous haptens and most importantly, unlike Ts3, this population had no affinity for the TMA hapten. Nevertheless, the nonspecifically induced Ts once activated by TsF2 suppresses TMA-directed, but not similar immune responses specific for heterologous haptens. Thus the results indicate that TsF2 can functionally interact with a final effector Ts subset (very similar to the Tacc) other than the well described Ts3 population. The ramifications of these findings are discussed with reference to a generalized view of the cellular basis of terminal phases of immune suppression.     

The immune response and the eye. II. The nature of T suppressor cell induction in anterior chamber-associated immune deviation (ACAID)

We studied the cellular basis for the induction of Ts cells in anterior chamber (AC)-associated immune deviation (ACAID) by using TNP-modified syngeneic spleen cells (TNP-Spl). We demonstrate that the cells responsible for the induction of TNP-ACAID are non adherent, IA- T cells. This is in contrast to the antigen-presenting cells which induce suppression after the i.v. injection of TNP-Spl which are IA+/I-J+ adherent cells. Furthermore, two T cells within the TNP-Spl population are required to initiate suppression in TNP-ACAID: one is Lyt-1+, and I-J+, the other is Lyt-1+ and reactive with a monoclonal antibody, 14-30, which specifically identifies Ts inducer cells. The antigen specificity of ACAID resides in the 14-30+ T cell, and not the I-J+ cell. Although both cells must be viable to induce suppression, neither they (nor their products) must be in direct contact within the eye; one population may be in the right AC, the other in the left. Our results suggest that it is Ts inducer cells placed into the AC of the eye which initiate TNP-ACAID, and that these cells exit (or secrete Ts factors which exit) the eye to induce Ts effector cells in the spleen.