T cell replacing factor substitutes for an I-J+ idiotype-specific T helper cell

Augmentation of the antibody response by lipoic acid in mice. I. Analysis of the mode of action in an in vitro cultures system

Lipoic acid (Lip), a naturally occurring disulfide compound, was found to augment markedly in vitro antibody responses to sheep erythrocytes (SRBC), dinitrophenyl-Ficoll and trinitrophenyl-lipopolysaccharide (TNP-LPS) as effectively as 2-mercaptoethanol (2-ME) in murine lymphocytes. The mitogenic response to LPS or concanavalin A (Con A) was augmented by Lip only slightly. 2-ME has been reported to facilitate cystine utilization by the lymphocytes, but Lip did not, indicating that the mode of action of Lip is different from that of 2-ME. Lip-augmentation of anti-SRBC response was markedly abrogated when murine lymphocytes were depleted of T cells and cultured in the presence of Con A-conditioned medium containing T cell-replacing factor. The effect of Lip was also diminished in the response to TNP-LPS when the spleen cells were depleted of T cells. These observations suggest that Lip could augment the antibody response by stimulating a T cell subpopulation. This idea was confirmed by the experiment that Lip could enhance helper T cell activity which was induced by culturing murine lymphocytes with the antigen.

TMA-specific first-order T-suppressor hybridoma. I. Characterization of the hybridoma-derived single-chain inducer suppressor factor, TsF1

Experiments described in this report will characterize a monoclonal phenyltrimethylammonium (TMA) specific, first-order T-suppressor factor (TsF1) produced by a T-cell hybridoma, 8A.3. The hybridoma expressed the Thy-1, Lyt-1, Lyt-2 antigens as well as cross-reactive idiotypic (CRI) determinants but did not express I-J encoded epitopes. It was also found to bear determinants recognized by a monoclonal antibody raised against single-chain GAT-specific TsF1. The hybridoma-derived factor was capable of suppressing primary in vitro trinitrophenol (TNP)-specific responses induced with the Brucella abortus antigen, conjugated with TMA and TNP haptens (TMA-BA-TNP). In addition, in vivo administration of 8A.3 culture supernatant resulted in the specific suppression of TMA-specific delayed-type hypersensitivity (DTH) responses. Analysis of this factor revealed it to be an induction-phase, antigen-binding, CRI+, and I-J+ single chain polypeptide. Our results represent only the second such described single chain, antigen binding, I-J+ suppressor factor derived from a monoclonal T-cell hybridoma.

Direct interactions between B and T lymphocytes bearing complementary receptors

A murine cloned Th cell line specific for the antigen conalbumin in the context of self I-A molecules can be activated by low concentrations of soluble antireceptor mAb. By using an antireceptor mAb to shared antigenic determinants on T cell receptors, we have shown that the ability to be activated by soluble antireceptor mAb is an unusual, although not unique, feature of this cloned T cell line. This activation does not involve occult APC, FcR, or interaction between individual cloned T cells, as limiting-dilution analysis shows that individual cells of this clone will grow in the presence of the antireceptor antibody and IL-1 as stimulus. This cloned T cell line is highly immunogenic in vivo, giving rise to antireceptor antibodies that stimulate its growth in both mice and rats. This response is not dependent upon exogenous T cells. Rather, the clone directly interacts with complementary B cells, as shown by the production of mAb in nude mice, and by production of stimulating antireceptor antibodies by purified B cells cultured with cloned Th cells in vitro. Several features of this cloned Th cell line, most especially its ability to be activated, rather than inhibited, by antireceptor antibodies, may account for its striking ability to directly activate B cells bearing complementary receptors. The direct interaction of the cloned Th cell with B cells bearing complementary receptors may serve as a model for receptor-receptor interactions in the generation of both T and B cell repertoires.

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.

T15-specific helper T cells: analysis of idiotype specificity by competitive inhibition analysis

Optimal activation of T15 idiotype-bearing B cells has been shown previously to be influenced by two subsets of Thy-1+, Ly-1+,2-sIg- helper T cells. One of the helper T cell sets appears to be T15 specific in that its presence results in a selective augmentation of T15-bearing anti-phosphorylcholine (PC) plaque-forming cell responses. To determine the precise specificity of the idiotype-specific helper T cell (ThId), Ly-1 T cells were tested in an in vitro anti-PC response for their ability to bind directly to T15 myeloma protein-coated plastic plates. Specificity of this binding was ascertained by competitive inhibition of plate binding using idiotypically related myeloma or hybridoma proteins. These data suggest that the Ly-1 T cells which augment T15-bearing plaque-forming cell responses can bind to T15-coated plates and are T15 idiotype specific. This approach is being used currently to attempt to clone ThId cells to further analyze their activation requirements and specificities.

1,25-Dihydroxyvitamin D3 and 1,24-dihydroxyvitamin D3 suppress in vitro antibody response to T cell-dependent antigen

1,25-Dihydroxyvitamin D3 and 1,24-dihydroxyvitamin D3 suppressed an antibody response to sheep red blood cells (SRBC, T cell-dependent antigen) by murine splenocytes, in concentrations ranging from 10(-10)-10(-7)M. These suppressive effects were markedly abrogated when T cell-depleted lymphocytes were cultured in the presence of a supernatant of concanavalin A-stimulated spleen cells. On the contrary, neither of them suppressed antibody response to trinitrophenyl-lipopolysaccharide (T cell-independent antigen). These results suggest that the suppressive effect of active vitamin D3 on anti-SRBC response was mediated by the inhibition of T cells.

Lectins and substitution for helper function in anti-hapten responses in Xenopus laevis

Substitution by lectins for the carrier-priming requirement in thymus-dependent, antigen-binding responses in Xenopus laevis has been examined. Concanavalin A (Con A) was found to substitute for carrier priming in control, early-thymectomized and adult-thymectomized animals, but not in animals given a single, high dose of N-methyl-N-nitrosourea, which has a permanent effect on certain thymus-dependent functions in this species. Lipopolysaccharide and other lectins, such as peanut agglutinin and wheat germ agglutinin, were unable to substitute for carrier priming. These effects of Con A are discussed in terms of substitution via amplifier T cells or a helper T cell subset.

1984: all idiotypes are equal, but some are more equal than others

Our analysis of idiotypic dominance suggests that 3 elements play an important role. The first is the genetic material that encodes the dominant idiotype. As dominant idiotypes appear to reflect germ-line-encoded sequences, one can not express a particular idiotype unless that sequence is present in the germ line. The germ-line-encoded sequences, in turn, would, I predict, be specific for commonly encountered or former environmental pathogens. The second element is the environmental antigens themselves. These antigens will induce the production of idiotype, and will prime idiotype-bearing B cells, such that idiotypic dominance emerges. In the absence of such influences, the pattern of idiotypic expression appears to differ. The third influence is regulatory. My own studies have shown that idiotype found in normal serum plays an important role in the maturation and/or function of one such cell, an idiotype-specific helper T cell. It is my working hypothesis that such cells play several roles in idiotypic dominance, but that this is the least of their important roles. Rather, such cells, being specific for idiotopes associated with antibodies specific for environmentally encountered pathogens, would be important in the priming and rapid reactivation of B cells bearing such idiotopes. As such, they speak to the basic role of the immune system, the protection of the organism from infection.

Augmentation of in vitro antibody response by disulfide compounds. II. T cell-mediated augmentation by oxidized dithiothreitol, an intramolecular disulfide

In order to investigate the mechanism of action of disulfide compounds in the augmentation of the antibody response in vitro, we attempted to identify the target cells of the action of disulfides using oxidized dithiothreitol (DTTox; an intramolecular disulfide). DTTox markedly augmented the antibody responses not only to sheep erythrocytes, a T cell-dependent antigen, but also to T cell-independent antigens like dinitrophenyl-Ficoll and trinitrophenyl-lipopolysaccharide. The augmenting effect of DTTox in the response to SRBC was markedly abrogated when murine spleen lymphocytes were depleted of T cells and cultured in the presence of concanavalin A-conditioned medium containing the activity of T cell-replacing factor. The augmentation was restored by adding back purified T cells. On the other hand, the augmentation by 2-mercaptoethanol was not affected by these treatments. The antibody responses to dinitrophenyl-Ficoll and trinitrophenyl-lipopolysaccharide, and the polyclonal antibody response induced by lipopolysaccharide were no longer enhanced by DTTox when T cells were depleted. These results suggested that the augmenting effect of DTTox was not due to the direct activation of B cells, as with 2-mercaptoethanol, but was mediated by the stimulation of T cells. This assumption was further supported by the observation that DTTox stimulated the in vitro induction of helper T cell activity in the presence of antigens.

Contrasuppression: the second law of thymodynamics, revisited

The data discussed here touch upon several issues in the evolving story of T cell contrasuppression, the underlying theme being that of heterogeneity. First, there is the issue of function. We are considering here only those cells that affect the function of secretory differentiation. We have evidence that different contrasuppressor cells exist for clone growth, but have not yet studied them in the same depth as those for secretory differentiation. Second, there is the important issue of target cells. In this article by Green and Gershon it is pointed out that there is clear evidence that contrasuppressor effects can work by protecting helper cells from suppressor cell effects in vitro. On the other hand, direct additional inhibition of the suppressor cells themselves has not been excluded. The latter point is also true in our system. However, we must suppose for the sake of simplicity in many of our experiments that if suppressors are not the target of the contrasuppressor effects then the B cells themselves probably are. This is because the tumor cells engage in a spontaneous rate of growth and differentiation in the absence of help or suppression. When T cell-dependent, specifically triggered effects reduce this spontaneous behavior, then a suppressive effect must have been delivered directly to the B cells. This is a simplifying assumption which is attractive, but since the experiments are carried out in vivo and thus may be affected by some factors that we have not yet recognized, we are not confident on its "intuitive" appeal. A third issue revolves around triggering specificity. One of our contrasuppressors exhibits the phenomenon of carrier crossreactivity (CRCS) and is thus behaving in accord with expectations aroused by Green and Gershon in this review. The other cell is apparently quite carrier specific (SCS). The meaning of this is not at all clear, but its potential significance may somehow be related to a sort of "mirror image" relationship of the two cells. Thus, for example, in other experiments not discussed here, we have noted that the CRCS binds to 315 protein-coated plates, but as noted here counteracts a suppressive effect which is generated by cells which do not adhere to these plates. In contrast to SCS does not bind to 315 plates and yet, as noted here, appears to counteract a suppressor effect generated by cells which do adhere to 315 plates.(ABSTRACT TRUNCATED AT 400 WORDS)

Lack of a requirement for idiotype matching: T cells from mice which cannot produce idiotype support idiotype-positive antibody response

A requirement for idiotype matching was reported such that carrier-primed T helper cells from mice, which are unable to produce an idiotype (idiotype-negative) because of genetic reasons or adult anti-idiotype or neonatal anti-mu antibody treatment, did not provide helper function for an idiotype-positive antibody response. We have analyzed the requirement for idiotype matching in the response to phosphorylcholine by using mice which are idiotype-negative because they were injected with anti-idiotype antibody shortly after birth. Carrier-primed T cells from such animals supported idiotype-positive responses when mixed with normal or primed B cell populations and challenged with appropriate antigen; these responses were quantitatively and qualitatively similar to those obtained with T cells from idiotype-positive animals. These results demonstrate no requirement for idiotype matching and suggest that the procedure used to establish an idiotype-negative T cell donor may be decisive in showing a requirement for idiotype matching.

Immunotherapeutic potential of idiotype/anti-idiotype regulation of the IgE response

Studies of the induction of suppressor cells by soluble factors and anti-idiotypic antibody in mice have progressed to the point where it now seems likely that patients' allergic responses to grass pollen can be reduced by manipulation through the idiotype-anti-idiotype network.

Recognition of lambda 1 and lambda 2 murine light chains by carrier-specific isologous T helper cells; effect of L-H chain assembly

Previous studies from this laboratory have revealed an antigenic site located on the variable domain of the lambda 2 light chain of BALB/c myeloma protein 315 (the V lambda 2(315) site). This site is recognized by conventional carrier-specific T helper cells (Th) of BALB/c mice and is expressed on both the free and assembled V lambda 2(315) domain. The present work defines two new antigenic sites associated with murine lambda chains. The first site was associated with free lambda 1-chain of myeloma protein J558. It was recognized by splenic Th from animals that had been primed with free lambda 1J558 in complete Freund's adjuvant; when transferred to irradiated animals the primed Th responded to a boost with (4-hydroxy-5-iodo-3-nitro-phenyl)acetate (NIP)-free lambda 1J558 in saline, but did not respond to NIP-complete J558 or NIP-free lambda 2(315). Priming with complete J558 failed to elicit Th that responded to NIP-free lambda 1J558. This determinant was therefore only expressed on the free (as opposed to the assembled) form of lambda 1J558, and it was not shared with free lambda 2(315). The second antigenic site was shared between free lambda 1J558 and free lambda 2(315). It was defined by free lambda 2(315)-primed Th which responded to a boost with NIP-free lambda 1J558. Since priming with free lambda 1J558 did not elicit Th that recognized NIP-free lambda 2(315), the cross-reaction was undirectional. The free lambda 2(315)-primed Th failed to respond to the complete J558, and M315-primed Th failed to respond to NIP-free lambda 1J558, indicating that the second (cross-reactive) antigenic site, like the first, was only expressed on free lambda chains. Completely reduced and alkylated (unfolded) free lambda 1J558 and free lambda 2(315) chains elicited Th that recognized native (folded) free chains. Thus, free lambda 1J558 bears two antigenic determinants recognized by Th, one private and a second shared with free lambda 2(315). Lambda 2(315) also bears two determinants, a cross-reactive one on free lambda 2(315) shared with free lambda 1J558, and a private one located on the V lambda 2(315) domain of the complete M315. The discussion is focused on possible explanations for the quenching of the two new lambda chain determinants upon light-heavy chain assembly and why, by contrast, the private V lambda 2(315) site is maintained in the complete M315.

Characterization of a concanavalin A-induced amplifier T cell which augments in vitro antibody responses to DNP-Ficoll

The addition of the T-cell mitogen concanavalin A (Con A) on Day 2 of a 4-day in vitro culture of murine spleen cells with the thymus-independent (TI) antigen DNP39-Ficoll resulted in significant enhancement of the direct antitrinitrophenyl (TNP) plaque-forming cell (PFC) response. This enhancement was mediated by a nylon wool- and antiimmunoglobulin-nonadherent amplifier T cell (TA). TA activity was not eliminated by in vitro treatment of T cells with anti-Thy 1.2 and complement (C). TA activity could be eliminated by pretreatment of mice with antilymphocyte serum (ALS) in vivo, followed by in vitro treatment of T cells with anti-Thy 1.2 + C. Thus, TA appear to bear a low surface density of Thy-1 antigen. These TA were relatively resistant to ALS used alone, to cyclophosphamide, and to low dose in vitro irradiation. TA were still present in the spleen 14 weeks after adult thymectomy (ATx). They were I-J positive and apparently belonged to the Lyt 1+2- T-cell subset.

Hapten-specific responses to the phenyltrimethylamino hapten. III. Mice whose delayed-type hypersensitivity responses cannot be abrogated by the presence of anti-idiotypic suppressor T cells lack a critical modulatory T cell function

A single intraperitoneal injection of the monovalent synthetic antigen, tyrosinated trimethylaminoaniline [tyr(TMA)] in Freund's complete adjuvant induces an antiidiotypic second-order T suppressor (Ts2) cell population 6 wk later. This population was able to suppress TMA-specific delayed-type hypersensitivity (DTH) responses when adoptively transferred into normal syngeneic recipients. However, they failed to function intrinsically. The inability of the Ts2 to function intrinsically was not caused by compensating idiotype-negative T cells that mediate DTH. Rather, this paradoxical observation was found to be caused by the absence or loss of function of a critical modulatory T cell population in the suppressor cell-bearing mice. This cell is functionally active in normal mice immunized for DTH responses and is sensitive to cyclophosphamide treatment. In addition, this cell type bears idiotype on its surface and is Thy-1+ and Lyt-1-,2+. It was demonstrated that by adoptively transferring the activated modulatory T cells from normal mice into tyr(TMA)-immune recipients, it was possible to observe suppressor cell function intrinsically. The potential importance of modulatory T cell function in the regulation of antibody and DTH responses is discussed.