Antigen-specific suppressor factors produced by T cell hybridomas for delayed-type hypersensitivity

MHC- and Igh-unrestricted interaction between L3T4+, Lyt-2- Ts inducer cells and L3T4-, Lyt-2+ Ts effector cells is required for T cell-dependent suppression of DTH to histocompatibility antigens

This paper describes the characteristics of T suppressor inducer (Ts ind) cells which can interact with T suppressor effector (Ts eff) cells and thereby can account for suppression of delayed-type hypersensitivity (DTH) to alloantigens. Adoptive transfer of spleen cells from mice intravenously (i.v.) injected with allogeneic spleen cells one day earlier induced an antigen-specific state of suppression in the recipients. This became apparent when DTH was induced by subcutaneous (s.c.) immunization of the recipients three days after transfer. The induction of suppression after adoptive transfer of spleen cells required Thy-1+, L3T4+, Lyt-1+2- cells. These cells that by themselves did not exert a suppressive effect induced a state of suppression in recipient mice by activation of recipient-type Ts eff cells. Therefore, the former cell type was classified as Ts ind cell. When athymic nude mice were used as recipients, Lyt-2+ precursors of Ts eff cells had to be transferred together with the Ts ind cells to induce a state of suppression in these mice. The Ts ind cells could activate Ts eff cells in MHC- and Igh-incompatible recipients. The results are discussed in relation to previously described immunoregulatory T cell pathways.

Mode of action of monoclonal-nonspecific suppressor factor (MNSF) produced by murine hybridoma

Monoclonal-nonspecific suppressor factor (MNSF), a product of murine T cell hybridoma, suppresses antibody response to lipopolysaccharide. In an attempt to clarify the functional mechanisms in vitro, we investigated the mode of action of MNSF. This factor inhibited the antibody response by B cells (depleting T cells and Mø), thereby indicating that the lymphokine acts directly on B cells, without interaction between B and T cells or Mø. MNSF activity was absorbed by mitogen-stimulated T or B cells, but not by resting lymphocytes. Proliferative responses to T cell and B cell mitogens were inhibited dose dependently by the addition of MNSF. Kinetic studies showed that MNSF suppressed the antibody response, in all culture periods, thereby indicating that immunoglobulin secretion and proliferation were inhibited. The effect of growth factor on MNSF-mediated suppression was investigated to search for a possible suppression of MNSF action. Interleukin 2 (IL-2) remarkably inhibited MNSF activity, and the effect of IL-1 or IL-4 was less. IL-2 was most effective when added on the fourth day of culture. MNSF also inhibits division in the plasmacytoma line MOPC-31C or in thymoma EL4, but not in L929 fibroblasts. Tumor necrosis factor (TNF) inhibits cell division of various tumor cells and suppresses the pokeweed mitogen-induced antibody response, without cytotoxic action, as does MNSF. While MNSF and TNF have similar biochemical and physiochemical properties, the cross-reaction tests showed that both are antigenically discrete lymphokines. Although MNSF lacks TNF activity, the concomitant addition of both factors to L929 increases the cytotoxic action, a finding indicative of a synergistic effect.

Comparison between the in vitro activities of in vivo-induced hapten-specific suppressor cells and supernatants of a hapten-specific suppressor hybridoma

A trinitrophenyl (TNP)-specific suppressor hybridoma was obtained by fusing hapten-binding spleen cells (SC) of BALB/c mice 1 week after intravenous (iv) injection of TNP-modified syngeneic lymphocytes with the AKR lymphoma BW5147. The suppressive activity of supernatants from one clone (TNP-44) was compared with that of in vivo-induced TNP-specific suppressor cells. Both the TNP-specific suppressor cells (TsTNP) and the TNP-44 were hapten binding and hapten specific. They suppressed the functional activity of TNP-haptenized T as well as B cells. TNP-44 supernatant also inhibited the proliferation of TNP-modified cells. Using native target cells, both TNP-44 supernatant and the in vivo-induced suppressor cells suppressed the anti-TNP B-cell response to TNP-bound T-dependent soluble or cellular antigens, but not to TNP-lipopolysaccharide (LPS). Furthermore, the function of TNP-specific helper T cells (THTNP) was impaired in the presence of TSTNP or supernatant from TNP-44. From these observations it was concluded that both the TSTNP and a TNP-specific factor derived from a suppressor hybridoma function via an antigen bridge at the TH or at the TH-dependent B-cell subset.

Auto-delayed-type hypersensitivity induced in immunodeficient mice with modified self-antigens. IV. Characterization of the suppressive T-cell factor that controls the autoreactivity against self-antigens

Suppressor cells obtained from spleens of normal A mice, or factor extracted from these suppressor cells, abolished the syngeneic delayed-type hypersensitivity (syn-DTH) response of X-irradiated A mice injected with trinitrophenylated spleen cells and challenged with syngeneic lymphoblasts. Some of the physical, chemical and biological properties of the suppressive factor (SF) were characterized. The SF was relatively temperature-stable and its activity was destroyed by pronase (but not with RNase or DNase). The activity of the SF was absorbed on concanavalin A and anti-I-Jk Sepharose columns, suggesting that the factor is a glycoprotein-bearing I-Jk product. The approximate molecular weight of the factor is 50,000-60,000. The SF was absorbed on plastic adherent cells (but not on non-adherent cells). Adherent cells that absorbed the SF abrogated the ability of primed T cells to transfer the syn-DTH to naive X-irradiated recipients. In contrast, SF that was presented directly to the primed T cells failed to abolish their ability to transfer DTH. These findings suggest that the adherent cells serve as mediators, transferring the SF from factor-producing cells (Lyt-1+2+3+, I-Jk+ T cells) to target cells (Lyt-1+ primed T cells).

Detection of helper and suppressor T cell lines to soluble antigens using a modified ELISA system

Helper and suppressor activity of T cell lines were investigated using an assay system which is based on measurement by the enzyme-linked immunosorbent assay (ELISA) of the antibody produced in vitro. T cell lines were established from spleens of BALB/c mice immunized with ovalbumin and human serum albumin. The T cells were expanded in culture with irradiated spleen cells and antigen or concanavalin A supernatant. The culture system used for assay of T cell activities contained antigen (Ag)-primed unfractionated spleen cells or Ag-primed B cells. Ag-primed cells and cultured T cells were incubated together with Ag (0.05 ng/ml-100 micrograms/ml) for various times, washed at varying intervals, and supernatants assayed for specific antibody activity by an ELISA adapted for this purpose. A total incubation time of 9 days was required for significant antibody production. Complete reconstitution of the antibody response was observed with Ag-primed B cells and Ag-primed T cells were combined. In one experiment, a helper cell line was shown to restore specific antibody production to approximately 50% of the normal response while a suppressor cell line suppressed antibody production by 90%. A linear response of between 0.2 and 1.4 OD units was observed in the ELISA allowing easy detection of help or suppression. As little as 80 ng of specific antibody could be detected. This technique allows quantitative determination of antibody production for a large number of individual microcultures.

Activation of beta-galactosidase by monoclonal antibodies

Four monoclonal cell lines secreting antibodies that activate the beta-galactosidase protein from lac-aba strains of Escherichia coli have been isolated. One of the antibodies, BG 79, inhibits the normal beta-galactosidase from E. coli in addition to its activation of the protein from mutants. Moreover, when in combination with any of the other activating antibodies, BG 79 exhibits synergistic activation of the beta-galactosidase protein, and the synergistically activated enzyme is stimulated by methanol, although most of the proteins activated by single antibodies are inhibited by methanol. The equilibrium of binding of BG 79 to the beta-galactosidase protein is not affected by the presence of a second antibody, and the half-time for activation by BG 79 is only slightly, though significantly, increased by preincubation of the protein with the second antibody. Our results imply that activation of beta-galactosidase proteins is not a simple correction of a conformational defect, and that many distinct active conformations are available to the enzyme.

Analysis of T cell hybridomas. II. Comparisons among three distinct types of monoclonal suppressor factors

Five hybridoma T cell lines were prepared by fusion of Ts3 cells with the BW 5147 thymoma. The culture supernatants from these T cell hybrids contained a factor, TsF3, which specifically suppressed 4-hydroxy-3-nitrophenyl acetyl hapten (NP(-hapten cutaneous sensitivity responses. The properties of this new series of hybridoma factors was compared with those of two previously characterized types of NP-specific suppressor factors (TsF1 and TsF2). TsF3 activity was only observed if the factor was administered during the effector phases of the immune response. TsF3 bears I-J and C57BL anti-NP antibody idiotypic determinants and has binding specificity for the NP hapten. Furthermore, TsF3 does not suppress H-2 (I-J)-incompatible mice. In addition to this H-2 restriction, the monoclonal TsF3 factors also demonstrated an Igh genetic restriction. Finally, the TsF3 factors could be distinguished by their ability to suppress cyclophosphamide-treated recipients.

H-2-restricted helper factor secreted by clone hybridoma cells

Biological and serological characteristics of a helper factor secreted by cloned hybridoma cells was described. The factor is carrier specific and contains determinants shared with immunoglobulin VH bu does not react with V kappa- or V lambda-specific antibodies. Presence of four H-2I-controlled antigenic specificities, Ia.ml, Ia.m2, Ia.17, and Ia.m7, was detected. Hence, it is possible that both A beta and E alpha loci may be involved in its control. Helper effect could be obtained only toward B cell sources that shared the H-2K and I-A antigens with the hybridoma cells. Similarly, the factor was absorbed only by spleen cells syngeneic in I-A. Previous studies have demonstrated that this clone binds antigen in an H-2-restricted manner. It follows that H-2-restricted helper cells produce H-2-restricted helper factors. Hence, they support the view that specific T cell factors may represent secreted T cell receptors.

Hapten-specific T cell responses to 4-hydroxy-3-nitrophenyl acetyl. XI. Pseudogenetic restrictions of hybridoma suppressor factors

Suppressor factor derived from three different murine T cell hybridomas were characterized . They specifically inhibited 4-hydroxy-3-nitrophenyl acetyl cutaneous sensitivity responses. The factors bind antigen and bear I-J and idiotypic determinants, but lack conventional immunoglobulin constant-region determinants. The factors function during the induction phase of the immune response, by inducing a second population of suppressor cells (Ts(e)). Suppressor factor can inhibit both cellular and plaque-forming cell responses in appropriate strains of mice. These hybridoma suppressor factors directly suppress strains of mice that are Igh-V homologous with the strain producing the factor. Thus, there is an apparent Igh-V restriction in the activity of these factors. However, this is a pseudogenetic restriction because these factors generate second order suppressor cells (Ts(e)) in Igh-incompatible mice, but in order to express the suppressive activity, the cells must be adoptively transferred into recipients that are Igh compatible with the strain producing the suppressor factor. Finally, it was shown that the factor-induced Ts(e) population is under an apparent dual genetic restriction. Thus, Igh and H-2 homology is required in order for the Ts(e) population to express its suppressive activity.

Production of antigen-specific suppressive T cell factor by radiation leukemia virus-transformed suppressor T cells

Hen egg-white lysozyme (HEL)-specific suppressor T cells induced in C57BL/6 mice have been selected by sequential passage over plates coated with goat anti-mouse Ig and HEL. These suppressor T cells, 80% I-J+, were infected in vitro with radiation leukemia virus (RadLV/Nu1) and injected intravenously into sublethally irradiated syngeneic recipients. After 4-6 months, 6 out of 20 injected mice developed thymic lymphomas, which were maintained by transplantation into histocompatible hosts and subsequently established as permanent cell lines. Cells of these six thymomas were screened for the presence of Thy 1.2, Lyt 1, Lyt 2, I-Jb, and Ig cell surface antigens by direct or indirect immunofluorescence. One tumor (thymoma L4) was found to express the expected phenotype of suppressor T cells (Thy 1.2+, Lyt 2+, I-J+). High-speed supernatants of extracts obtained from L4 cells were able to induce HEL-specific suppression in a T cell proliferative assay, demonstrating the presence of an antigen-specific suppressive T cell factor.

Regulation of delayed-type hypersensitivity. V. Suppressor cell memory in antigen-specific suppression of delayed-type hypersensitivity to sheep erythrocytes

Mice printed i.v. wit 10(9) sheep red blood cells (SRBC) produce antigen-specific T suppressor (Ts) cells which inhibit both the induction and the expression of delayed-type hypersensitivity (DTH). These Ts cells are detectable in the spleen and lymph nodes 3-5 days after priming but are largely absent by 6 days. The transient detectability of the Ts cells contrasts sharply with the profound antigen-specific suppression which persists in primed donor mice for at least a year. Evidence is presented that this long-term impairment of DTH is maintained, at least in part, by memory Ts cells which are Thy-1+, cyclophosphamide-resistant and antigen-specific. Although they appear to be co-induced with the short-lived primary Ts cells and localize initially in the lymphoid organs, they are present in the long-lived circulating pool of T cells and can be adoptively transferred by celomic parabiosis. Memory Ts cells are readily reactivated by lower doses of SRBC which would induce T effector cells rather than Ts cells in naive animals. Reactivated memory Ts cells seem to generate a population of antigen-specific secondary Ts cells which again localizes in the lymphoid organs and can adoptively suppress the induction and expression of DTH to SRBC.

Antigen-specific T-cell factors

Antigen-specific T-cell factors are mediator molecules which are produced by helper and suppressor T cells and which can perform the function of those cells in an antigen-specific manner. They probably play an important part in immunoregulation. The major histocompatibility complex has a controlling influence on their structure and activity, while their antigen-recognition properties may be conferred by immunoglobulin V regions. Interest in the factors derives from three related areas of research, namely (i) the problem of T-cell recognition of antigen; (ii) the mechanisms of cellular interactions in antibody production and cell-mediated immunity; and (iii) the genetic control of immune responses. This review discusses the literature up to June 1980 on their production, structure, genetic restriction and mechanism of action.

Construction of T cell hybridomas secreting allogeneic effect factor

T cell hybridoma lines were constructed by fusion of DBA/2 alloantigen-activated T cell blasts with the AKR thymoma line BW5147. Certain of the hybridomas prepared in this manner secreted spontaneously into their culture supernates biologically active molecules that displayed B cell- and T cell-activating properties characteristic of allogeneic effect factor (AEF). Cell surface phenotype analysis documented that the hybridomas were, indeed, somatic cell hybrids between the two respective partner cells used for fusion. The B cell-activating properties of these hybridoma supernates was demonstrated by their capacity to stimulate T cell-depleted spleen cells to respond in vitro to T-dependent antigens. The T cell-activating properties of these hybridoma supernates was verified by their capacity to stimulate autonomous development of self-specific cytotoxic T lymphocytes and by their capacity to exert mitogenic effects on unprimed T cells. The biologically active molecules secreted by these hybridomas were, like conventional AEF, inhibitable by specific anti-Ia antibodies thus indicating the presence of Ia determinants on the relevant hybridoma products. Finally, these AEF-secreting hybridomas could be stimulated to proliferate and to secrete increased quantities of AEF when exposed to the specific alloantigen-bearing target cells to which the T cell blasts had been originally sensitized.

Major histocompatibility gene complex (MHC)-coded determinants on antigen-specific suppressor factor for delayed-type hypersensitivity and surface phenotypes of cells producing the factor

Antigen-specific suppressor factor for delayed-type hypersensitivity (DTH) to sheep red blood cells (SRBC) was obtained by incubating in vitro spleen cells from CBA mice (H-2k) injected intravenously 3 days previously with 1 x 10(9) SRBC. The suppressor factor was characterized for major histocompatibility gene complex (MHC)-coded antigenic determinants by passing the factor through immunosorbents coupled with appropriate alloantisera. The suppressor factor was absorbed by anti-H-2k, anti-Iak and anti-I-Jk immunosorbents but was not retained by anti-Ias, anti-I-Js, anti-I-Ak, anti-I-E/Ck or anti-H-2Kk immunosorbents. In addition, the factor bound to an immunosorbent coupled with rabbit antibodies against carbohydrate-defined Ia antigens. Furthermore, the suppressive activity that was absorbed was quantitatively recovered in the acid eluates from the immunosorbents. Treatment of the spleen cells with anti-Lyt-1.1 antiserum and complement completely abrogated their ability to elaborate the suppressor factor in vitro. In contrast, treatment with anti-Lyt-2.1 or anti-Iak antiserum and complement had no effect. Thus, it appears that the suppressor factor for DTH to SRBC bears I-J subregion-coded determinants, and its production is dependent on cells which have the Lyt-1+,2- and Ia- phenotype.

Delayed-type hypersensitivity to influenza virus. Induction of antigen-specific suppressor T cells for delayed-type hypersensitivity to hemagglutinin during influenza virus infection in mice

Mice infected with A/England/939/69 X A/Puerto Rico/8/34 (Rec 31) influenza virus by aerosol develop significantly lower levels of delayed-type hypersensitivity (DTH) to A/Hong Kong/1/68 X A/Puerto Rico/8/34/ (X31) virus compared to uninfected mice. The suppression of DTH to the hemagglutinin appears to be mediated by suppressor T cells which carry Lyt-1 membrane antigen marker, and not by sy serum antibody. The suppressor T cells for DTH induced by Rec 31 virus (H3N1) infection suppress the DTH response to the variants of the H3 subtype of influenza viruses, but have no effect on the DTH responses to A/Puerto Rico/8/34 virus (H0N1), a B influenza virus or the matrix protein of type A influenza virus. Suppressor T cells for DTH appear 2 wk after infection and are detectable in the spleen for at least 40 d thereafter. T-helper cells for antibody response to hemagglutinin are induced concomitantly with the T-suppressor cells for DTH. Possible implications of the present findings on the regulation of the immune response to viral infection are discussed.