The genetic and cellular basis of antigen and receptor stimulated regulation

Regulation of immune responses by I-J gene products. VI. Recognition of I-E molecules by I-J-bearing suppressor factors

Poly(Glu50Tyr50) (GT) is not immunogenic in most inbred mouse strains. GT injection produces an I-J--bearing, GT-specific T-cell--derived suppressor factor (GT-TsF1) in H-2b,d,k haplotype mice. GT-TsF1 generates second-order suppressor T cells (Ts2) in H-2a,d,k haplotype mice. Here, we show that in order for GT-TsF1 to act, the recipient strain must express I-E molecules. This suggests that T cells are not the primary target of GT-TsF1. GT-TsF1 can be presented by Ia+ A20-2J B lymphoma cells. GT-TsF1 presentation is blocked by anti-I-E, but not by anti--I-A, mAb, whereas GAT presentation is blocked by anti-I-A, but not by anti--I-E, mAbs. These data suggest that I-J recognizes (or is recognized by) I-E. The existence and role of I-J molecules in immune regulation are discussed in light of these data.

Studies of monoclonal antibodies specific for major histocompatibility complex products of the rat. IV. Production and characterization of polyclonal and monoclonal anti-anti-idiotypic antibodies

Polyclonal syngeneic, allogeneic, and xenogeneic and monoclonal syngeneic anti-anti-idiotypic antibodies have been produced against previously described monoclonal anti-idiotypic antibodies with specificity for monoclonal RT1 alloantigen-specific antibodies. The anti-anti-idiotypes could again be shown to be highly specific for the monoclonal anti-idiotype used for the induction of the anti-anti-idiotypic antibodies and to carry the same, or a very similar, idiotype as the original monoclonal idiotypic antibody used to induce the monoclonal anti-idiotypic. Among the 30 syngeneic and allogeneic and the five xenogeneic polyclonal anti-anti-idiotypic antisera and the three monoclonal anti-anti-idiotypes, only one polyclonal antiserum showed binding capacity to the corresponding RT1-encoded antigenic determinants on spleen cells. All the other antibodies were idiotypic but not antigen binding.

Induction of immunodeficiency in mice by injection with syngeneic splenocytes immune to semi-allogeneic hybrid cells

Intravenous transfer of BALB/c spleen cells (1-10 X 10(6] immunized against semi-allogeneic hybrid cells bearing H-2k antigens into BALB/c mice resulted in splenomegaly (2- to 6-fold). As few as 2 X 10(4) spleen cells could transfer splenomegaly. A significant spleen enlargement was seen from 2 weeks after cell transfer and reached the peak level at 3 weeks. Those mice with splenomegaly displayed markedly reduced levels of proliferative responses to concanavalin A and lipopolysaccharide. However, the levels of the major Ig classes (i.e., IgG, IgM, and IgA) in the immunodeficient mice were significantly elevated. Such induction of immunodeficiency in mice may help further to understand the acquired immunodeficiency syndrome of humans.

Suppressor mechanisms in tumor immunity

There are many parallels between T cell-mediated suppression of tumor immunity and suppression of immune responses to haptens and polypeptides. We propose a cell interaction model which takes this into account and outlines a regulatory pathway for suppression of immunity to tumor antigens. Free antigen or antigen/antibody complexes trigger an inducer T cell subset, Tsi, which is tumor-specific. This cell activates a non-immune T cell population, pre Tse, to generate effector suppressor cells, Tse. The Tse are specific for either the idiotype of Tsi or for antigen complexed with a soluble factor made by the Tsi, but the suppression they mediate is antigenically nonspecific. Tumor antigen-specific suppressor factors, TsF, play a major role in the communication between different suppressor cells. Characterization of polyclonal and monoclonal factors produced by Tsi, called TsFi, indicates that they both bind to tumor antigen and contain tumor-specific (idiotypic?) determinants.

A study of CSF idiotypes in multiple sclerosis

Six anti-idiotypic antisera have been raised against isolated cerebrospinal fluid (CSF) bands from five patients with multiple sclerosis and against a serum band from an additional patient. Preparative isoelectric focusing in agarose was useful for isolating highly purified bands. Individual antigenic specificities defined by these antisera were not detected on other bands from the same patients or in IgG isolated from the CSF of other patients. The CSF to serum ratios of the idiotypic determinants ranged from 1:2 to 1:8, consistent with substantial local synthesis in the central nervous system; the higher concentration in serum suggests that initial clonal expansion of antibody-making cells may have occurred outside the nervous system. An anti-idiotypic antiserum raised against the dominant band from postmortem CSF was used to compare the levels of idiotypic IgG eluted from four plaque areas. Although the amount of IgG eluted from each differed, the concentration of idiotype was similar for all plaques tested. The interaction of anti-idiotype with idiotype could not be inhibited by saline extracts of normal or multiple sclerosis brain.

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.

The expression and functional involvement of nuclease- specific idiotype on nuclease-primed helper T cells

The expression and functional significance of idiotypic determinants on antigen-specific helper T (Th) cell populations for responses to Staphylococcal nuclease (Nase) were evaluated in an in vitro antibody response system. Trinitrophenyl (TNP)- specific plaque-forming cell responses to TNP-conjugates of Nase (TNP-Nase) were shown to require the cooperation of Nase-primed Th cells as well as unprimed B and accessory cells. The expression on these antigen-primed Th cells of idiotypic determinants cross-reactive with those on anti-Nase antibodies was demonstrated by the specific elimination of Th cells for TNP-Nase by treatment with affinity-purified anti-idiotypic antibodies plus complement. The susceptibility of Nase-primed Th cells to elimination by such treatment was specific in that anti-idiotypic antibodies affected Th cells only from strains normally expressing the same (or a cross-reactive) idiotype on anti-Nase antibodies. A functional role of the idiotypes expressed on Nase-primed Th cells was suggested by the fact that anti-idiotypic antibody present throughout the period of culture, in the absence of complement, suppressed responses to TNP-Nase in an antigen- and strain-specific manner. It was further shown, by cell mixing experiments, that this inhibition appeared to occur at the level of the Th cells and was not dependent on the strain of origin of the B cells. Thus, antigen-specific Nase-primed Th cells express strain-specific idiotypic determinants cross-reactive with, or identical to, those of anti-Nase antibodies. These cell surface idiotypic determinants appear to be functionally involved in the activity of Th cells for the induction of antibody responses to TNP-Nase in vitro.

Tthyd, a new thymocyte alloantigen linked to Igh-1. Implications for a switch mechanism for T cell antigen receptors

Tthyd is an alloantigen coded for by a gene(s) near the immunoglobulin locus on chromosome 12 in the mouse. This T cell-specific antigen may be the third member of a family of antigen receptors on T cells encoded by a cluster of genes in the IgT-C region. This antigen is preferentially expressed on thymocytes in contrast to Tindd or Tsud that are expressed on peripheral T cells. The hypothesis that T cell receptors undergo a switch in surface isotype upon maturation is discussed.

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.

The genetic and cellular basis of regulation of the immune response to tumor antigens

In this chapter I have dealt with the cellular and genetic basis of regulation of the immune response to tumor antigen. I have knowingly omitted discussion of effectors such as ADCC, NK, and B cells, since my own experience with such effectors relates primarily to early events associated with small-tumor inocula (Greenberg and Greene, 1976). In that model, NK and ADCC mechanisms, in which natural antibody and macrophages participate, are of importance and T cells are not. In the studies I have dealt with herein, more advanced tumor models have been evaluated. It is clear, I hope, from this chapter that understanding the pathways to immune-cell or Ts activation will provide the basis for applied immunotherapy techniques in the future.