Mechanisms of idiotype suppression. I. In vitro generation of idiotype-specific suppressor T cells by anti-idiotype antibodies and specific antigen

Demonstration of anti-idiotypic antibodies directed against IgM rheumatoid factor in the serum of rheumatoid arthritis patients

We have identified the presence of anti-idiotypic activity against IgMRF in the sera of RA patients. Only patients seropositive for IgMRF had significant levels of anti-idiotypic activity, while seronegative patients and normal volunteers did not. When this anti-idiotypic activity was affinity-purified from a single RA patient, two separate binding activities were identified. IgG antibodies were pepsin-digested to F(ab')2 fragments before affinity-purification to remove the Fc portion capable of binding to IgMRF. Anti-idiotypic F(ab')2 fragments of IgG were eluted from an IgMRF-Sepharose 4B column. These F(ab')2 bound preferentially to IgMRF bearing an idiotype recognized by the anti-idiotypic murine monoclonal 17.109. A second anti-idiotypic F(ab')2 was affinity purified using rabbit anti-human Fc antibody bound to Sepharose 4B. These eluted antibodies behaved as the internal image of IgG, binding five out of seven IgMRF's tested. The binding of both anti-idiotypic F(ab')2 was inhibited with human IgG. The presence of both IgMRF and anti-idiotypic antibodies directed against it in the sera of RA patients suggests that anti-idiotypic antibodies alone are not capable of inhibiting the production of rheumatoid factor.

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.

Components of immune function studied with lymphoid tumors

Lymphoid tumors have proven to be productive models for investigating genetic, biochemical, physiological and developmental mechanisms of lymphoid cells. Lymphoid tumors of a given lineage exhibit a spectrum of phenotypes from clones whose features overlap extensively with their normal counterparts to clones whose features are not obviously represented in normal lymphoid populations. In addition to the phenotypic continuum represented in a library of related tumors, many clones exhibit phenotypic diversity spontaneously or in response to various stimuli. As laboratory technology has advanced many interesting biological features of lymphoid tumors have become amenable to precise analysis. Progress made in understanding the mechanisms that underly the phenotypic diversity and plasticity of lymphoid tumor cells has the dual impact of improving our knowledge of malignant and normal lymphoid cells.

RISH V. Application to monoclonal antibody production

RISH considers that cell surface components involved in like cell identification are not involved in the structure of the plasma membrane per se and are attached to a part of their mRNA. The mRNA then acts as a template for the synthesis of DNA. Thus the component at the cell surface is attached to an RNA/DNA receptor. If there is a conformational change in the component (antigen) this will cause a distortion in its RNA/DNA receptor. This distortion is then detected by a tissue specific T lymphocyte which removes all or part of the RNA/DNA receptor from the aberrant cell and the lymphocyte then undergoes replication. During this process receptor RNA/DNA is incorporated into the daughter lymphocyte which becomes a B lymphocyte/plasma cell producing immunoglobulin. The initial tissue specific T lymphocyte becomes a dual functional helper/suppressor cell. The plasma cell after the initial immune response becomes a circulating memory B cell displaying IgM or IgD. If this cell complexes an antigen with its surface IgM or IgD a humoral immune response will be developed as previously described, but in this case the antibodies produced will be anti-idiotypic antibodies. The anti-idiotypic antibodies will regulate the production of the antibody directed against the antigen per se. The anti-idiotypic antibodies will in turn be regulated by a second anti-idiotypic antibody. In RISH five such anti-idiotypic systems may be involved in regulating the immune response to the initial non-immunoglobulin antigen. Based on the RISH anti-idiotypic mechanism a system is briefly described whereby human memory B cells, to a particular antigen, may be isolated. These B cells may then be activated to secrete immunoglobulin with autologous isolated anti-idiotypic antibodies. These activated cells may then be infected with E.B. virus to establish an immortal cell line of B cells secreting the immunoglobulin of interest.

Helper T cell requirements for T15 idiotype expression on phosphorylcholine-specific antibodies

The requirement for idiotype-specific T cells was investigated in the T15 idiotype-dominant T cell-dependent response of unprimed BALB/c and (BALB/c X C57BL/6)F1 B cells to phosphorylcholine (PC). It was first demonstrated that cloned keyhole limpet hemocyanin (KLH)-specific, major histocompatibility complex (MHC)-restricted T helper (Th) cells as well as heterogeneous KLH-primed Th populations were capable of generating PC-specific antibody responses in T-depleted unprimed B cell populations cultured in the presence of PC-KLH. The PC-binding antibody responses generated under these conditions were indistinguishable when assayed for carrier-hapten linkage requirements, immunoglobulin isotype (predominantly IgM) or PC affinity. Further, it was observed that the PC-binding antibodies which were generated in the presence of these two T cell populations expressed equivalently high levels of T15 idiotype. Assaying antibody and idiotype by either enzyme-linked immunosorbent assay or plaque-forming cell assay yielded similar results. Since monoclonal MHC-restricted, KLH-specific Th cells presumably lack any additional T cell populations, these results argue against an absolute requirement for anti-idiotypic Th cells in the generation of T15-dominant antibody responses.

Idiotype-specific T-helper cells

In the present study we investigated the induction and fine specificity of T-helper cells that recognize idiotypes. The data presented show that both low-dose priming with anti-T15 antiserum and priming with PC-Hy are effective in stimulating T15-specific T help. Phosphorylcholine-hemocyanin priming can generate these T cells in either PC-responding or nonresponding strains of mice. Furthermore, the PC-primed T-helper cells can also recognize another anti-PC myeloma, M167, that is idiotypically different from T15. The fine specificity of the anti-PC-idiotype recognizing T-helper cells was examined by studying the effect of in vitro inhibitors on the T-cell help. Both PC and PC-BSA as well as T15 and M167 had an inhibitory effect on the T help. Free T15 and M167 heavy chains also blocked the helper activity for T15; T15 and M167 light chains had no effect, however. Viewed collectively, these results show that PC-Hy priming induces T-helper cells that recognize idiotypic determinants common to both T15 and M167, and that the proteins' H chain is the major structural component of the determinant. Finally, the generation of these idiotype-recognizing T cells was found to occur by way of a T-T interaction loop, based on the finding that T-helper cells are induced by PC-Hy priming in animals that lack PC-responding B cells.

Suppression of in vitro monoclonal human rheumatoid factor synthesis by antiidiotypic antibody. Target cells and molecular requirements

Previous studies have indicated that antiidiotypic antibody can modulate expression of idiotype both in vivo and in vitro. Although the precise mechanisms underlying modulation of idiotype expression by antiidiotype remains unclear, a requirement for intact IgG antiidiotypic antibody has been suggested and T cells appear to play a role in some systems. We have studied peripheral blood mononuclear leukocytes (MNL) from a patient with a B cell lymphoma and a circulating IgMK rheumatoid factor (RF) paraprotein in an effort to delineate mechanisms involved in regulation of idiotype expression by antiidiotypic antibody. 1-10% of MNL from this patient could be cytoplasmically stained with specific F(ab')2 antiidiotypic antibody. MNL from the patient spontaneously synthesized IgM RF in culture that possessed the same idiotype as the circulating IgM RF paraprotein. Production of RF by MNL was suppressed by pretreatment with either intact IgG or the F(ab')2 fragments of antiidiotypic antibody (50% inhibitory concentration was 0.2 and 1.1 micrograms/culture, respectively). In contrast, the Fab' fragment of antiidiotypic antibody was not inhibitory (up to 57 micrograms/culture) despite retaining demonstrable antiidiotype activity. Suppression of RF production was not observed over the same concentration range with the IgG or F(ab')2 fractions of a non-cross-reactive antiidiotypic antibody prepared against another monoclonal IgMK RF paraprotein or with IgG or F(ab')2 fractions prepared from normal rabbit serum. Inhibition of RF production by antiidiotypic antibody did not require T cells. Antiidiotypic antibody decreased intracellular and extracellular levels of idiotype indicating diminished synthesis of idiotype by the patient's B cells. Synthesis of IgM RF by MNL obtained from unrelated donors was not suppressed by the antiidiotypic antibody specific for the patient's paraprotein. The results indicate that (a) antiidiotypic antibody is capable of directly suppressing human B cell release of idiotype, (b) the bivalent antigen-binding fragment (F[ab']2) of antiidiotypic antibody is sufficient for mediating such suppression, (c) an intact Fc portion of antiidiotypic antibody enhances suppression of idiotype, and (d) antiidiotypic antibody inhibits idiotype expression by suppressing synthesis of idiotype.

Antiidiotype stimulation of antigen-specific antigen-independent antibody responses in vitro. I. Evidence for stimulation of helper T lymphocyte function

Antibodies specific for the idiotypes of B10 anti-(T,G)-A-L antibodies (anti-Id) induced in vivo (T,G)-A-L-primed lymphocytes to secrete anti-(T,G)-A-L antibodies in vitro in the absence of antigen. Responses to anti-Id were quantitatively and qualitatively similar to responses to antigen. Responses were specific in that: (a) only lymphocytes primed in vivo with (T,G)-A-L (but not other antigens or unprimed cells) were inducible; (b) only anti-Id (but not a variety of control antibodies) induced responses; and (c) only anti-(T,G)-A-L antibodies were secreted. Antigen-primed T lymphocytes mixed with unprimed B plus accessory cells also responded to anti-Id and the phenotype of the responding T cells was Lyt-1+, Lyt-2-. Supernatants obtained from antigen-primed T cells incubated for 3 d with anti-Id (but not when incubated with controls) provided help to unprimed B plus accessory cells in the presence of anti-Id, thus providing direct evidence for induction of T lymphocyte helper function by anti-Id. In contrast to responses to (T,G)-A-L, responses to anti-Id did not appear to be regulated by H-2-linked Ir genes. The system described is a powerful tool for delineation of the mechanisms whereby antiidiotype antibodies affect lymphocyte function.

Anti-idiotype regulation of the formation of IgE antibody to timothy grass pollen. II. In vitro induction of suppressor T cells in mini-Marbrook cultures

A method is described for using mini-Marbrook chambers for culturing spleen cells together with anti-idiotype antibody (anti-Id) to induce the appearance of suppressor T cells (Ts). Spleen cells that have been cultured with affinity prepared anti-Id (IgG) but not those cultured with normal IgG, suppress a secondary IgE response to timothy grass pollen antigen B (AgB) when injected intravenously into AGB-primed and boosted syngeneic recipient mice. Suppressor T cells are not induced if the spleen cells cultured with anti-Id are depleted of B cells of if the cells are cultured with the F(ab)2 fragment of anti-Id: both of these results are compatible with Fc+ cells playing a role in the induction of Ts cells by anti-Id. Analysis of soluble suppressor factors in an ELISA test suggests that both TS1 and TS2 cells may be induced by anti-Id.

Role of blood transfusions on the induction of antibodies against recognition sites on T lymphocytes in renal transplant patients

We have tested sera from 23 renal allograft recipients to study the effects of blood transfusions on the induction of antibodies directed against recognition sites on T lymphocytes. The results demonstrate that antibodies capable of inhibiting responses in MLC could be induced by blood transfusion. This inhibition in MLC is observed by treatment of responder lymphocytes with serum plus rabbit complement and is mediated by IgG antibodies. Also, the inhibitory effect is specific for certain responder cells and is not mediated by antibodies against common surface antigens of either the responder or the stimulator lymphocytes. The antibodies inhibiting proliferative responses in MLC against antigens present on the kidney donor were demonstrable in renal transplant recipients with functional allografts, but not in patients who had rejected the graft. The data suggest that antibodies directed against recognition sites on T lymphocytes could be induced by blood transfusions and these antibodies may be associated with prolonged graft survival.

Suppression of interstitial nephritis by auto-anti-idiotypic immunity

Rats immunized with renal tubular antigens were protected from the development of interstitial nephritis by pretreatment with tubular antigen-reactive T lymphoblasts. Protected animals developed anti-idiotypic antibodies against idiotypes primarily within the antigen-binding region of monoclonal antitubular basement membrane antibodies. These studies extend the concept of auto-anti-idiotypic regulation to autoimmune disease, and they also provide an experimental basis for further efforts to develop biologically relevant mechanisms for attenuating the expression of other kidney diseases.

Idiotypic lymphocytes in human monoclonal gammopathies

We have studied seven human monoclonal gammopathies using anti-idiotypic sera. In benign and malignant gammopathies, we have observed a similar number of B lymphocytes bearing idiotypic specificities also found on the monoclonal protein. These observations suggest that the plasma cell population is only a phenotypic expression of a tumoral event occurring in a B lymphocytes precursor which can still completely differentiate. In four myeloma patients and one benign monoclonal gammopathy, we also observed T lymphocytes bearing receptors idiotypically cross-reactive with the monoclonal protein. The values ranged from 1.8 to 8.0% within the purified T-cell population. In a first hypothesis, these T lymphocytes can belong to the tumoral clone itself. The tumoral event must occur at the level of a common precursor not yet determined to B or T pathway of differentiation. In a second hypothesis, these T lymphocytes are not cancerous but are induced by a strong perturbation of the idiotypic network, due to the enormous amount of the idiotypic B-cell tumoral subset.

Autoregulation of immune responses via idiotype network interactions

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Regulation of the T 15 idiotype-positive, T-independent immune response to Streptococcus pneumoniae R 36 a (Pn). I. Specific suppressor T cells induced by Pn in vitro are antigen-specific and idiotype-positive

Normal BALB/c spleen cells incubated for 2 days with Streptococcus pneumoniae R 36 a (Pn) vaccine in vitro acquired the specific ability to inhibit the T-independent anti-Pn response of fresh lymphocytes. The activated suppressor cells were susceptible to cytotoxic treatment with mouse anti-theta serum plus complement, and they inhibited the anti-Pn response of B lymphocytes deprived of T cells. The suppressive effect was eliminated by adsorbtion of cells on dishes coated with the C polysaccharide from Pn, and treatment of the suppressor cells with a rabbit antibody specific for TEPC-15 myeloma protein, in the presence of complement, abolished the suppressive effect. The results indicate that stimulation of lymphocytes with a T-independent antigen in vitro activates suppressor T cells bearing a specific antigen receptor that may express the idiotype(s) characteristic of anti-Pn antibody, and that these cells inhibit the Pn-reactive B cells directly.

Hapten-specific T cell responses to 4-hydroxy-3-nitrophenyl acetyl. V. Role of idiotypes in the suppressor pathway

4-Hydroxy-3-nitrophenyl (NP) derivatized syngeneic spleen cells injected intravenously stimulate maturation of an antigen-binding, idiotype-bearing induction-phase suppressor cell population, as well as an idiotype-binding anti-idiotype-bearing effector-phase suppressor cell population. Both cell types are present simultaneously in the spleen cell population 7-d after their induction. Furthermore, the cell population with antigen-binding properties can, in the presence of NP-derivatized syngeneic cells, induce a population of effector suppressor cells. The precursors of the effector suppressor population are not sensitive to concentrations of cyclophosphamide which prevented the generation of induction phase suppressor cells. These data provide direct evidence in support of the theory of network regulation of immune suppression. X

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.

Feedback suppression of the immune response in vitro. II. IgVH-restricted antibody-dependent suppression

Feedback suppression of the primary humoral immune response to sheep erythrocytes (SRBC) in vitro was induced with cell-free supernate material derived from antigen-(SRBC) activated B (sIg+) cells. This soluble products bears Ig determinants and binds to the eliciting antigen (SRBC). The activity of this antibody in suppressing anti-SRBC plaque-forming cell responses is restricted to spleen cell cultures containing B cells sharing VH genes with the B cells producing the suppressive antibody. The anti-hapten (trinitrophenyl) response to derivatized SRBC is not affected by antigen-primed B cells or their products. These data are compatible with suppression being mediated by anti-antigen antibody, either (a) via blockade of different SRBC epitopes recognized by a limited set of B cell clones in each mouse strain, (b) via triggering of an anti-idiotypic response, either antibody or suppressor T cell in nature, restricted to activity in cultures containing B cells sharing VH structures with the original antibody, or (c) via interference by preformed antibody with T cell help directed at idiotype bearing B cells.