Generation of H-2-restricted cytotoxic T cells by ultraviolet light-treated trinitrophenyl-modified syngeneic cells: increased requirement for adherent cells

Metabolically inactive (ultraviolet light- [UV] irradiated) cells are incapable of serving as allogeneic stimulators in a mixed lymphocyte reaction (MLR). The reason for the requirement of metabolic activity is not known. Now we have used UV-irradiated, trinitrophenyl- (TNP) coupled syngeneic spleen cells as stimulators in vitro to generate TNP-specific cytotoxic T cells (CTL). It was found that UV-irradiated cells were stimulatory only if adherent cells (nylon wool [NW] and carbonyl iron-adherent Thy-1-) were present in the responder cell population. Nonadherent allogeneic cells were also able to augment the CTL response to UV-irradiated stimulators, suggesting that the requirement for adherent cells can be replaced by the nonspecific stimulatory effects of a MLR. When spleen cells from mice primed in vivo with TNP-coupled syngeneic cells were used in vitro, it was noticed that UV-irradiated stimulators were able to induce as strong a secondary CTL response as metabolically active stimulators but this response was also entirely dependent on the presence of adherent cells in the responder cell population. As a summary, these results suggest that metabolically inactive haptenated stimulators do not present the necessary proliferative (?) stimulus to the CTL precursor cells, but this 'signal' can be mediated via the adherent cell population, thus offering an explanation for the significance of this cell type in CTL responses in vitro.

Major histocompatibility complex-restricted self recognition. A monoclonal anti-I-Ak reagent blocks helper T cell recognition of self major histocompatibility complex determinants

The functional role of cell surface Ia antigens has been studied for in vitro antibody responses, using as a probe the ability of anti-Ia reagents to inhibit these responses. A hybridoma monoclonal anti-Ia reagent specific for a product of I-Ak (Ia.17) profoundly inhibited in vitro antibody responses to TNP-KLH by spleen cells of the I-Ak but not I-Ab haplotype. This inhibition by anti-I-Ak product, but not by interaction with T or B cell product, in spite of the fact that functional B cells as well as accessory cells could be shown to express the determinant detected by this hybridoma reagent. These results suggest that the Ia expressed by accessory cells in of unique functional importance in these responses. To further characterize the function of Ia antigens in this response system, the mechanism of anti-I-Ak inhibition was determined. The inhibition resulting from interaction of anti-I-Ak with accessory cell Ia was not mediated by nonspecific suppressor cells, nor was there nonspecific interference with accessory cell function as a result of the binding of anti-Ia antibody. The relationship between anti-Ia inhibition and T helper cell recognition of self determinations on accessory cells was analyzed using T cells from radiation bone marrow chimeras. It was demonstrated that (B10 X B10.A)F1 leads to B10 (F1 leads to B10) chimera T cells were able to cooperate with B10 (H-2b and I-Ab) but not B10.A (H-2a and I-Ak) accessory cells for responses to TNP-KLH; F1 leads to B10.A T cells were able to cooperate with B10.A but not B10 accessory cells; and both chimera populations were able to cooperate with (B10 X B10.A)F1 (F1) accessory cells. Monoclonal anti-I-Ak inhibited the cooperation of F1 leads to B10.A T cells with the same F1 accessory cells. Thus, inhibition by anti-I-Ak is dependent upon active helper T cell recognition of I-Ak-encoded determinants expressed on accessory cells. These findings demonstrate that T cells recognize self Ia determinants expressed on accessory cells, and that such recognition is required for the generation of T cell-dependent antibody responses.

Major anti-paternal alloantibody induced by murine pregnancy is non-complement-fixing IgG1

Maternal humoral responses against antigens of the genetically alien embryo have been reported in several mammalian species, including man, although little is known of the biological relevance of this phenomenon. In the mouse, only females of certain inbred strains mated repeatedly with an allogeneic male produce antibody directed against paternally inherited fetal histocompatibility antigens, as assessed by haemagglutination techniques. It has been suggested that this characteristic of the female is associated with the H-2 haplotype, although some reports indicate that it also extends to other H-2 types. Potentially deleterious complement-dependent cytotoxicity, albeit at low levels, has been claimed to be associated with this alloantibody, but we have been unable to detect any such activity in a large number of maternal sera. Four IgG isotypes (IgG1, IgG2a, IgG2b and IgG3) have been identified and shown to occur in the serum of normal animals. Despite their similar physicochemical properties, which complicate purification procedures, the availability of immunoglobulin-secreting plasmacytomas has made possible the preparation of isotype-specific antisera. Using these antisera in modified haemadsorption assay, we have now demonstrated that the major alloantibody response induced by murine pregnancy involves the non-complement-fixing IgG1 subclass. This is a noncytotoxic antibody with potentially protective (enhancing) properties.

Cross-reactivity for different type A influenza viruses of a cloned T-killer cell line

Spleen cytotoxic T cells killing influenza virus-infected target cells are cross-reactive for the different type A influenza viruses, in contrast to the circulating antibodies, which show fine specificity for each A virus subtype variant. This finding has raised the question of whether a single T cell can recognize cells infected with all type A viruses. T-killer cell lines with specificity for alloantigens and the male Y antigen can be selected by means of growth factors present in the supernatant of T cells stimulated with concanavalin A (refs 3-7). We report here that we have been able to establish clones of mouse T cells killing target cells infected with influenza virus. Our cell line maintains the same specificity as the heterogeneous spleen cell population from infected mice, in as far as the T-killer cells are specific for A influenza virus, but do not discriminate between the different type A viruses. The cell line maintains H-2 restriction and does not kill cells infected with B influenza virus. The cells grow in the presence of T-cell growth factor and do not require antigen for growth although they maintain their receptors for type A virus. They can also be stimulated by irradiated T-helper cells from mice primed by type A influenza infection in the presence of type A virus-infected cells.

Characterization of in vivo suppression of syngenic tumor by allogenic effector cells

The purpose of this study was to characterize the effects of allogenic splenocytes transferred with tumor cells, subcutaneously, to a host syngenic for tumor cells. Cytotoxic effector cells usually resulted in tumors less than half the size of controls at E:T of 10:1. Primary immune splenocytes were more effective than hyperimmune splenocytes in delaying tumor growth. Actively cytotoxic splenocytes by in vitro 51Cr release assay were required for delayed tumor growth; memory cell populations were not effective. Delayed tumor growth correlated with in vitro cytotoxicity of primary immune splenocytes; however, hyperimmune splenocytes, even though they possessed greater in vitro cytotoxic responses, showed lesser tumor suppression in vivo. T cells were necessary for tumor suppression, as treatment of B6AF1 effector cells with anti-Thy 1.2 serum abrogated suppression; T cell enrichment by nylon-wool treatment of effector cells increased tumor suppression. Delay in tumor growth was an in vivo phenomenon, for anti-Thy 1.2 serum in AKR hosts abrogated the effect of Thy 1.2 effector cells.

Monoclonal and allospecific H-2Kk antisera precipitate a high molecular weight protein

A protein with an apparent m.w. of 68,000 has been observed in immunoprecipitations of NP-40 solubilized BW5147 thymoma cells by using monoclonal or polyclonal allospecific H-2Kk antisera. By contrast, H-2Dk alloantisera precipitated a 45,000 m.w. protein from the same membrane preparations. The 68,000 m.w. protein is expressed on the plasma membrane as determined by vectoral labeling. Extensive clearing experiments and the use of monoclonal antibody demonstrate that the protein does not bear group-specific C-type viral determinants.

Cell-mediated immunity to herpes simplex virus: specificity of cytotoxic T cells

This communication deals with the question of which of the viral antigens constitutes the targets for cytotoxic T lymphocytes (CTL) generated against herpes simplex virus type 1 (HSV-1). The approach used was, first, to compare cytotoxicity of CTL against target cells infected with virus in the presence of tunicamycin and 2-deoxy-D-glucose, which are known to inhibit glycoprotein synthesis, and second, to compare cytotoxicity of CTL against target cells infected with wild-type HSV-1 with that against target cells infected with a temperature-sensitive mutant of HSV-1 which, at the nonpermissive temperature, exhibits diminished glycoprotein synthesis. The results show that glycoprotein expression is required for the demonstration of cytotoxic activity of CTL. The level of cytotoxicity against the temperature-sensitive HSV-1 target at the nonpermissive temperature was reduced and correlated with the level of expression of the major envelope glycoprotein region (VP123; molecular weight = 123,000) at the target cell surface as measured serologically by antibody binding studies. The results were interpreted to indicate that HSV-1-induced glycoproteins are the target antigens for anti-HSV CTL and that the principal viral antigens recognized by the CTL may be glycoproteins of the VP123 region.

H-2-dependent cell-mediated immunity in vivo: delayed-type hypersensitivity and contact sensitization induced by fluorescein isothiocyanate-conjugated cells

Fluorescein isothiocyanate (FITC) was found to be a suitable hapten to study cell-mediated immunity in vivo in mice. Delayed-type hypersensitivity (DTH) footpad swelling reactions were induced and elicited by injection of FITC-conjugated syngeneic spleen cells, and contact sensitivity (CS) was induced and elicited by skin painting with reactive FITC. Cross-reactive specificity between DTH and CS was demonstrated. Thus, DTH induction with FITC-spleen cells (FITC-SC) also led to the ability to elicit CS; and CS induction by skin painting also led to the ability to elicit DTH with FITC-SC. However, the 2 reactions differed in that the ability to elicit DTH induced by subcutaneous immunization with FITC-SC was evanescent, whereas CS induced by skin painting was long lived. Specificity of these reactions was hapten dependent and additionally required homology at the H-2 locus of the major histocompatibility complex. The H-2 specificity requirement was not evanescent.

Cytotoxic cells induced during lymphocytic choriomeningitis virus infection of mice: natural killer cell activity in cultured spleen leukocytes concomitant with T-cell-dependent immune interferon production

The characteristics and specificities of spleen and peritoneal cytotoxic cells generated during lymphocytic choriomeningitis virus (LCMV) infection of C3H/St mice were examined. Activated natural killer (NK) cell activity was identified in fresh leukocyte populations from the 2nd to 8th days postinfection, whereas virus-specific cytotoxic T-cell activity was detected from the 6th to 14th days. When leukocytes were cultured overnight at 37 degrees C before assay, T-cell activity was still observed, but nonspecific activated NK cell-like cytotoxicity was only detected on the 6th and to a lesser degree the 8th day postinfection. Overnight culture of leukocytes taken earlier in the infection eliminated their NK cell activity. Similar activities were seen with spleen cell, plastic-adherent peritoneal cell, and nonadherent peritoneal cell populations. The virus-specific cytotoxicity observed with adherent peritoneal cells was due to contamination with cytotoxic T cells, as shown by H-2-restricted cytotoxicity and sensitivity to anti-theta antibody and complement. The nonspecific cultured day 6 effector cell from either the spleen or peritoneum displayed killing specificities and other physical properties identical to those of activated NK cells, but had sensitivities to anti-theta antibody and complement intermediate between activated day 3 NK cells and cytotoxic T cells. Culture stable NK-like cells were not found in athymic nude mice, suggesting a T-cell-dependent mechanism. Whereas LCMV spleen homogenates contained 10-fold-higher levels of interferon at day 2 than at day 6 postinfection, substantially more (nearly 20-fold) interferon was made in cultures of day 6 cells than day 2 cells. Spleen interferon was predominantly type I, whereas the culture interferon was predominantly type II, as shown by acid lability studies. Significant levels of interferon were produced by nylon-wool-passed day 6 spleen cells, and virtually all interferon production was eliminated by treatment of either day 2 or day 6 cells with antibody to theta antigen and complement, suggesting that T cells produced the interferon in vitro. Furthermore, athymic nude mice had no culture-stable NK cells 6 days postinfection, and spleen cells from them failed to produce significant levels of interferon in vitro. Addition of interferon (type I, fibroblast) to cultured C3H spleen cells affect the already elevated levels of cytotoxicity in day 6 cultures, suggesting that the NK cells in the day 6 culture were already activated. Our results suggest that T cells responding to LCMV infection secrete interferon type II which causes the continued activation of NK cells in culture. The resulting population of activated NK cells therefore appears to be relatively stable in culture and to express more theta antigen because of this T-cell dependence. Although one could mistakenly or allospecific cytotoxic T cells or cytotoxic macrophages, more careful examination shows that they are most likely activated NK cells...

Features of cells controlling H-2-restricted presentation of antigen to T helper cells in vivo

Information was sought on the nature of cells presenting antigen (sheep red blood cells) in an H-2-restricted fashion to T helper cells in vivo. The approach used was to examine the capacity of F1 hybrid T cells to collaborate with parental strain B cells after prior positive selection of the T cells to antigen in irradiated parental strain mice in the presence of various sources of Thy 1-negative cells taken from F1 or parental strain mice. The results showed that H-2-restricted presentation of antigen to T cells is controlled by radioresistant, nylon-wool adherent. Thy 1-negative cells, which are enriched in spleen and peritoneal exudates, rare in lymph node cell suspensions, and undetectable in thoracic duct lymph; pretreatment in vitro with anti-Ia reagents directed either to I-A or I-E subregion determinants abolished antigen-presenting activity. These findings correlate closely with the known characteristics of cells that present antigen in vitro. Studies in which re-irradiated parent leads to F1 chimeras were used as hosts for positive selection suggested that nonhematopoietic cells do not play a discernible role in antigen presentation.

Derivation of a monoclonal antibody that detects an Ia antigen encoded by 2 complementing I-subregions

A monoclonal antibody designated A303, which reacts with Ia antigens controlled by the complementation of 2 distinct I-subregion genes, is described. Complementation of both I-A and I-EC subregion gene products is necessary for the cytotoxic, direct and 125I-protein A-amplified indirect cell binding, and immunoprecipitation activities of A303. Positive prototype strains of independent origin include H-2k,p, whereas A303-negative haplotypes include H-2b,d,f,r,s,u. Seven recombinant strains, H-2ap5,as1,h4,i3,i5,t3,t4 representing intra I-region cross-over events between positive and negative haplotypes are A303 negative. Trans complementation occurs between the I-Ak allele and the I-EdCd, I-EkCk and I-EkCd alleles, respectively. Analysis of F1 heterozygotes suggests that A303-binding activity is also controlled by gene-dose effects. Thus, the activity of A303 is formally equivalent to a system of coupled complementation previously described for Ir and Is genes.

Structural relation of murine "third locus" (H-2L) major histocompatibility antigens to the products of H-2K and H-2D loci

The primary structures of the allelic products of H-2L, the murine "third locus" major histocompatibility antigen, were compared with the structures of the H-2K and H-2D antigens by tryptic-peptide analysis. The H-2Ld,H-2Lq, H-2Dd, H-2Dq and H-2Kd molecules were radiolabeled and isolated from spleen cell detergent lysates with specific alloantisera. Comparisons of the tryptic maps of the H-2L, H-2D, and H-2K molecules of the H-2d haplotype demonstrated that H-2Ld molecules were as different from H-2Dd molecules as H-2Dd molecules were from H-2Kd molecules. In contrast, the H-2Lq and H-2Dq molecules were found to be extremely similar and a second peptide separation method was required to discern structural differences between the 2 molecules. Comparisons of the allelic products H-2Ld and H-2Lq indicated possible structural differences despite the lack of a known serologic difference. These results, while raising questions about the genetic evolution of the H-2L locus relative to the H-2K and H-2D loci, demonstrate that the structure of the H-2L molecule is distinct from that of the H-2K and H-2D molecules. These structural analyses further substantiate the functional studies that define the H-2L molecule as the "third" major histocompatibility molecule of the mouse.

Association of Ly phenotypes, T cell function and MHC recognition

Lyt molecules has been exceptionally useful in defining district subpopulations of T lymphocytes. In this paper the significance of the association of Lyt phenotypes of T cells with their specialized functions and with their recognition of different major histocompatibility complex (MHC) subregions is examined. The published data, which indicates that helper activity stimulated by allogeneic Class I (K/D) antigens is dependent on a mature Ly123 cell that does not interact with an Ly1 cell (conventional helper), is reviewed. Recent studies, which show that a long-term allospecific cell line with killer activity directed against an Ia antigen is an Ly1 cell with expression of Lyt2, are presented. It is concluded that Lyt2 molecules are not themselves required for the induction or delivery of killing. It is suggested that Lyt molecules may not be reliable markers of the functional commitment of T cells and that Lyt phenotypes may be better correlated with the subregion of the MHC that such T cells recognize.

An immunological suppressor cell inactivating cytotoxic T-lymphocyte precursor cells recognizing it

The immune system does not normally react against self components. Originally, it was postulated that self-reactive cells were somehow deleted or blocked. More recent thinking is that such cells are suppressed by regulatory networks similar to those limiting the immune response against non-self determinants. Both mechanisms may exist. I describe here a type of suppression more closely related to the first postulate. In the in vitro, one-way, mixed lymphocyte reaction (MLR), cytotoxic T-lymphocyte precursor cells (CLP) from the responder population give rise to cytotoxic T-lymphocytes (CL) capable of lysing target cells from the stimulator population. A subpopulation of cells in the spleen of athymic nude mice can, when added to such cultures, inactivate CLP capable of recognizing either the H-2 antigens or TNP modifications of the nude spleen. Regarding the nude spleen cells, activation of self-reactive cells is being prevented.

Cytolytically active murine T-cell hybrids

Following the demonstration that hybrids between normal B-lymphocytes and myeloma cell lines continue to secrete antibodies with the same specificity as those produced by the parental B-cells, many groups have tried to use this approach to obtain cell lines expressing T-lymphocyte functions by crossing thymoma lines not expressing any measurable activity with various types of T-cell populations. Although there have been reports that hybrids could be isolated which secrete T-cell products with immunological activity, efforts to produce functionally active hybrids from cytolytic T-cells have all been unsuccessful (refs 6, 7, and M. N. and H. D. Engers, unpublished). We have fused an established, T-cell growth factor (TCGF)-dependent murine cytolytic T-lymphocyte (CTL) line with a mouse thymoma line and have obtained hybrids with cytolytic activity when we selected the hybrids in TCGF-containing medium, while hybrids isolated in the absence of growth factor showed no detectable cytolytic potential.

Non-H-2 T-lymphocyte-mediated cytotoxicity after primary in vivo sensitization

A low level of T-lymphocyte-mediated cytotoxic activity was demonstrated after primary in vivo immunization in an H-2-compatible strain combination (B10.D2--DBA2). This phenomenon was demonstrated in a second responder strain (BALB/c) and was thus shown not to be restricted to the B10.D2 genetic background. Results on F1 hybrid mice indicate that the M-locus determinant might be involved in this reaction. It is possible that it is involved in the afferent, efferent, or both limbs of the reaction.

Cross-reacting xenoantibodies to the heavy chain of H-2 and HLA-A,B antigens: serologic and immunochemical characterization

H-2 cross-reactive antibodies present in HLA xenoantisera were purified by absorption on and elution from murine cells. Antibodies isolated from one of these antisera, 78-E48, were found to mediate complement-dependent lysis of both human and murine lymphoid cells but not of Daudi cells or of human lymphoid cells coated with Fab2 fragments from a cow anti-human beta 2-microglobulin (beta 2 m) antiserum. In indirect immunoprecipitation analyses 78-E48 reacted only with proteins of approximately 45,000 and 12,000 MW present in NP-40 extracts of both human and murine lymphoid cells. Sequential precipitation experiments with rabbit anti-human beta 2 m and allo-anti-H-2Kk, Iak sera established that these proteins were in fact H-2 and HLA-A,B antigens. It was also found that 78-E48 reacted only with the heavy chain of HLA-A,b and H-2 antigens, since this eluate was unreactive with beta 2 m in a radioimmunoassay, and its capacity to immunoprecipitate the 45,000 and 12,000 MW proteins from human cell extracts was unaffected by prior reaction with purified human beta 2 m. These data show for the first time that H-2 and HLA-A,B antigens share properties that probably depend upon their teritary structure.

Genetic control of cytolytic T lymphocyte responses. III. The role of K and I region alleles on the specificity of the cytolytic T lymphocyte response to trinitrophenyl-modified syngeneic cells

It has previously been demonstrated that genes in the H-2K and/or I-A region control the specificity of the cytolytic T lymphocyte (CTL) response to trinitrophenyl-(TNP) modified syngeneic cells. Strains of mice bearing the k allele in the K and/or IA region do not exhibit cross-reactive lysis of TNP-modified allogeneic targets after stimulation with TNP-modified syngeneic targets. In this report we present evidence for independent roles of genes in the H-2K and I-A regions on the control of CTL specificity. One gene, mapping in the H-2K region, is expressed on the stimulator cell population, whereas the other gene maps to the I region and is expressed in the population of responding cells and need not be expressed in the stimulator cell population. Thus, we suggest that Ir genes localized to the I region may influence the response for prekiller cells to H-2K/D gene products.

Cellular interactions in the generation of cytolytic T lymphocyte responses: role of Ia-positive splenic adherent cells in presentation in H-2 antigen

Splenic adherent cells are required for generation of both primary and, at limiting antigen dose, secondary allogeneic responses of cytolytic T lymphocytes to intact stimulator cells. Secondary responses to purified allogeneic plasma membranes or purified H-2Kk antigens in liposomes are also dependent upon splenic adherent cells. Generation of these responses requires the presence of an Ia-positive. Thy 1,2-negative, radiation-resistant cell in the splenic adherent cell population that is adherent to glass, plastic, and nylon wool. Stimulation of cytolytic T lymphocyte precursors with purified H-2Kk alloantigen bound to Ia+ splenic adherent cells is 10-20 times more efficient than stimulation with antigen added directly to culture. Furthermore, a marked decrease in the response of cytolytic T lymphocytes to liposomes was observed when antiserum against Iad specific for the Ia of the responder cells was added to culture. These results demonstrate that, for purified proteins of the major histocompatibility complex, antigen presentation by Ia+ splenic adherent cells plays a role in the generation of a cytolytic T lymphocyte response.

Existence of T cells manifesting self-reactivity indistinguishable from alloreactivity

The studies reported here were designed to analyze the phenotypic characteristics of self-reactive T lymphocytes induced in culture by allogeneic effect factor (AEF), as well as the control of their functional activities by the major histocompatibility complex (MHC). Unprimed T cells cultured with AEF in the absence of exogenous stimulating target cells become activated against self-antigens, as evidenced by their ability to manifest two distinct activities. First, such cells could lyse syngeneic target cells. This cytolytic activity was directed against H-2K antigens and was mediated by Lyt-2+ T cells. Second, the AEF-activated T cells could be stimulated in a secondary culture to high levels of proliferative activity by irradiated syngeneic spleen cells. The stimulator cells in this syngeneic mixed lymphocyte reaction (MLR) were found to be Thy-1-negative, Ia-positive splenic adherent cells. Stimulation in the secondary syngeneic MLR was provided by I-region specificities, and the majority of the proliferating cells were Lyt-1+ cells. Finally, AEF-induced T cells were effective in serving as effectors of graft-vs-host reactions in vivo in syngeneic recipients. These results prove that, under appropriate conditions, murine T lymphocytes can display aggressive patterns of self-reactivity that are similar in both quantity and quality to the classical patterns of alloreactivity and may have great significance for our understanding of MHC recognition processes.