Stimulating effect of MDP and its adjuvant-active analogues on guinea pig fibroblasts for the production of thymocyte-activating factor.

Synthetic muramyl dipeptide (MDP) could stimulate skin fibroblasts of the guinea pig to produce thymocyte-activating factor, which augments the proliferative response of thymocytes to phytohemagglutinin (PHA). Adjuvant-active analogues of MDP also stimulated fibroblasts to produce the factor, whereas adjuvant-inactive analogues failed to do so. Thus a marked parallelism was found between adjuvant activity of these compounds and the stimulating effect on fibroblasts. Thymocyte-activating factor derived from MDP-stimulated fibroblasts was found in the fraction of mol wt 30,000-60,000 by gel filtration on a Sephacryl S-200 column. Furthermore, this factor did not exhibit T cell growth factor activity.

Clonal variation in tumorigenicity of L1210 lymphoma cells: nontumorigenic variants with an enhanced expression of tumor-associated antigen and Ia antigens.

Clonal variations in the tumorigenicity and in the expressions of tumor-associated antigens (TAA) as well as normal cell surface antigens were studied using clones of a highly tumorigenic DBA/2 lymphoma, L1210, which were isolated by limiting dilution in vitro. The majority of the clones were highly tumorigenic (tum+) in normal syngeneic mice, as was the parent L1210. The rest were nontumorigenic (tum-) in such mice; these clones, however, were tumorigenic in host mice that had been immunosuppressed by irradiation with 450 rads. Moreover, these tum- variants were shown to have an ability to elicit, in syngeneic mice, strong host resistance specifically directed against challenge with the parent L1210 and tum+ cloned cells and an ability to generate an in vitro primary syngeneic cytotoxic T-cell response against L1210 clones, indicating an enhanced immunogenicity in tum- variants. The expression of TAA by tumor clones was defined by determining the reactivity of monoclonal antibody, raised in syngeneic mice against an immunogenic L1210 subline, L1210/GZL. Marked clonal variation in the expression of monoclonal antibody-defined TAA was demonstrated, while no significant variation was seen in the H-2Dd expression. There was an inverse relationship between the TAA expression and the tumorigenicity. Furthermore, the enhanced expression of the TAA and the increased immunogenicity was associated with the I-Ad expression on the tum- variants. The unique characteristics of the tumor variants were very stable and heritable although occasional revertant phenotypes were detected on some clones. The results suggest that the tumor variants bearing distinct immunological properties exist in the parent L1210 line and carry a potential to modulate host immune responses directed against tumor cells.

Superoxide assay-leukocyte adherence inhibition test and a soluble factor which stimulates the adherence of macrophages.

A modified method for the leukocyte adherence inhibition test is described. Peritoneal cells from immune guinea pigs or peripheral mononuclear cells from cancer patients were incubated with immunizing antigen or tumor extract in a 4-mm-wide glass microcell for spectrophotometer analysis. Instead of visual cell counting, the cells adherent to the bottom of the microcell were stimulated with cytochalasin E and wheat germ agglutinin, and the amount of the superoxide (O2.-) generated from the adherent macrophages or monocytes was assayed. Antigen-specific adherence inhibition of peritoneal cells of the immunized guinea pigs was detected 2 weeks after immunization. In contrast, cell adherence was stimulated after 3 weeks. It was shown that a soluble factor was responsible for the adherence stimulation and that nonadherent cells were necessary for its production. Peripheral mononuclear cells of 70% of the tumor-bearing lung cancer patients reacted to the lung tumor extract (9 adherence inhibitions and 7 adherence stimulations per 23 patients). Twenty-five % (3 of 12) of tumor-free patients showed positive reactions, all with adherence stimulation. Of the 12 healthy donors, 3 cases of pneumonia, one case of angiosarcoma of the left flank, one case of hemangiopericytoma of the mediastinum, and 8 cases of breast cancer, non reacted with the lung tumor extract, and only one of 7 lung tuberculosis patients showed positive adherence stimulation.

Reaction null-space filter: extracting reactionless synergies for optimal postural balance from motion capture data.

This paper introduces the notion of a reactionless synergy: a postural variation for a specific motion pattern/strategy, whereby the movements of the segments do not alter the force/moment balance at the feet. Given an optimal initial posture in terms of stability, a reactionless synergy can ensure optimality throughout the entire movement. Reactionless synergies are derived via a dynamical model wherein the feet are regarded to be unfixed. Though in contrast with the conventional fixed-feet models, this approach has the advantage of exhibiting the reactions at the feet explicitly. The dynamical model also facilitates a joint-space decomposition scheme yielding two motion components: the reactionless synergy and an orthogonal complement responsible for the dynamical coupling between the feet and the support. Since the reactionless synergy provides the basis (a feedforward control component) for optimal balance control, it may play an important role when evaluating balance abnormalities or when assessing optimality in balance control. We show how to apply the proposed method for analysis of motion capture data obtained from three voluntary movement patterns in the sagittal plane: squat, sway, and forward bend.

Epitope specific antibody response against human type II collagen induced by anti-idiotypic antibody.

A species specific epitope on human type II collagen (CII) recognized with mAb, 2-60, was found to be localized on a cyanogen bromide-cleaved peptide (CB10) of human CII. To characterize the antibody response to the 2-60 epitope, we raised rabbit anti-idiotypic (Id) antibody against 2-60. The rabbit anti-2-60 Id antibody reacted not only with 2-60 mAb but also with 2-56 and 3-11 mAbs which were reactive with the epitopes related to the 2-60 epitope on CB10. The anti-Id antibody inhibited the binding of these three mAbs to human CII. Thus, rabbit anti-2-60 Id antibody recognized the cross-reactive idiotype expressed on 2-60, 2-56 and 3-11. The anti-2-60 Id antibody inhibited about thirty percent of the binding of polyclonal anti-human CII antibody derived from DBA/1J mice, thereby suggesting that the 2-60 idiotype might be expressed on a major fraction of the anti-human CII antibody. Immunization with the rabbit anti-2-60 Id antibody elicited antibody response to the 2-60 epitope, in DBA/1J (H-2q, Ighc), BALB/c (H-2d, Igha) and DBA/2 (H-2d, Ighc) mice. On the other hand, an epitope-specific antibody response induced by rabbit anti-Id antibody to 1-5 mAb reactive with a putative arthritogenic epitope on human CII was shown to be influenced by a single dominant gene, possibly the Igh gene. Our findings suggest that antibody responses against two distinct epitopes on human CII are probably regulated by different mechanisms.

Biological activities of guinea pig mitogenic factor from immune lymphocytes stimulated with antigen.

Mitogenic factor was produced by sensitized guinea pig lymph node cells stimulated with a specific antigen. Both T lymphocytes and macrophages were required for the production of this factor. The culture supernatant of lymphocytes containing the mitogenic factor exhibited a strong helping effect on the proliferative response of T lymphocytes to phytohemagglutinin (PHA). Mitogenic factor and the factor with the helping activity coeluted in the molecular weight range of 25,000-35,000 daltons in gel filtration. Furthermore the fraction containing mitogenic factor was found to support the proliferation of lymphoblasts induced by PHA or antigen, suggesting that the mitogenic factor may be the guinea pig equivalent of T cell growth factor (TCGF) reported in the mouse, rat, and human. On the other hand, the T cell-activating monokine of the guinea pig, possessing the helping activity for the proliferative response of T lymphocytes to PHA, never exhibited TCGF-like activity.

Partial characterization of thymocyte-activating factor derived from MDP-stimulated guinea pig fibroblasts.

The activity of fibroblast-derived thymocyte activating factor (FTAF) of the guinea pig was measured, and the factor was partially characterized. The FTAF activity was heat labile, and destroyed by treatment with trypsin, chymotrypsin, and Streptomyces griseus protease, suggesting the protein nature of FTAF. FTAF bound to DEAE-Sepharose CL-6B in Tris-HCl buffer at pH 8.0, and was eluted with 0.1-0.2 M NaCl. FTAF was absorbed with Blue Sepharose CL-6B. The factor bound to a hydroxylapatite column in 10 mM phosphate buffer and was eluted in two major fractions, one fraction with 40 mM phosphate buffer, the other with 70-110 mM phosphate buffer. Finally, FTAF did not have as much effect on the proliferation of lymph node T cells as T-cell-activating monokines which exhibited marked stimulating effects on both T lymphocytes and thymocytes.

Augmentation of the proliferative response of thymocytes to phytohemagglutinin by the muramyl dipeptide1.

A synthetic N-acetylmuramyl-L-alanyl-D-isoglutamine or muramyl dipeptide (MDP) and adjuvant-active analogs, but not lipopolysaccharide (LPS), exhibited the augmenting effect on the proliferative response of thymocytes to phytohemagglutinin (PHA). MDP also had a comitogenic effect on PHA-stimulated T lymphocytes. It was shown that the thymocyte-stimulating effect of MDP is not through the production of the monikines by MDP-stimulated macrophages and that MDP has a direct action on lymphocytes.

Antibody response against a possible arthritogenic epitope on human type II collagen induced by anti-idiotypic antibody.

We reported the presence of three distinct epitopes commonly present on murine and human type II collagen (CII), observed using mAb. To investigate the possible involvement of these epitopes in collagen-induced arthritis, we raised rabbit anti-idiotypic antibodies that may bear the internal image of these epitopes. Anti-idiotypic antibodies developed against three anti-CII mAb designated as 1-5, 2-14, and 2-15 were demonstrated to recognize idiotype expressed on Ag-binding site (paratope) of their related mAb. Anti-CII antibody response specific for a given epitope could be induced in DBA/1J mice upon immunization with anti-idiotypic antibodies coupled to keyhole limpet hemocyanin. Anti-idiotypic antibody to 1-5 antibody in particular could stimulate all DBA/1J mice for production of anti-CII antibody possessing Ag specificity and idiotype similar to those of 1-5 antibody. Although the mice immunized with anti-1-5 antibody alone did not develop arthritis, they did show a much more enhanced antibody response against a given epitope than did control mice non-treated with anti-idiotypic antibody upon the subsequent immunization with human CII. Some of the mice immunized with anti-1-5 antibody and challenged with human CII developed arthritis, whereas the control mice did not. These findings strongly suggest that a common epitope recognized by 1-5 antibody might be involved in the induction of arthritis.

Production of T cell-activating monokine of guinea pig macrophages induced by MDP and partial characterization of the monokine.

The production of T cell-activating factor(s) by macrophages stimulated with muramyl dipeptide (MDP) was studied. By MDP stimulation, a rapid increase in intracellular activity of the T cell-activating factor was induced, which preceded an increase of the activity in the extracellular medium. The rapid appearance of the activity in the cell and that in the medium were both inhibited by cycloheximide or puromycin. These results demonstrated that MDP stimulated rapid production of T cell-activating factors by inducing de novo synthesis of the factors, and that these newly formed factors are rapidly secreted. The activities of intracellular and extracellular secreted factors were both found in high m.w. (50,000 to 90,000) and low m.w. (10,000 to 30,000) fractions by gel filtration. The secreted high m.w. factor migrated as a single peak and did not dissociate into smaller components in SDS-PAGE analysis, indicating that the high m.w. factor is neither a complex of low m.w. factor with other proteins nor an aggregate of low m.w. factors. The properties are similar to those of our previously reported factor that helped antigenic activation of T cells for lymphokine production.

Characterization of the antibody response against the type II collagen induced by anti-idiotypic antibody.

We reported that rabbit anti-idiotypic antibody (Ab2) against mAb, termed 1-5 (Ab1) and reactive with human type II collagen (CII) induced antibody response to CII in DBA/1J mice susceptible to collagen-induced arthritis. In the present study, we further characterized the anti-CII antibody response elicited by Ab2 with respect to epitope specificity, putative genetic background, and IgG subclass. Most of anti-CII antibodies (polyclonal Ab3) derived from Ab2-immunized mice were of the IgG1 subclass. We purified polyclonal Ab3, using a CII-coupled immunoadsorbent column and we developed monoclonal Ab3 from Ab2-immunized mice. Both purified polyclonal Ab3 and two monoclonal Ab3s specifically reacted with a selected epitope on CII, recognized by Ab1. The anti-CII antibody response stimulated by Ab2 was observed in DBA/1J (H-2q, Igh-1c) and DBA/2 (H-2q, Igh-1c) mice, but not in the BALB/c (H-2d, Igh-1a) and C57BL/6 (H-2b, Igh-1b) strains, thereby suggesting that the anti-CII antibody response elicited by Ab2 is controlled by the Igh gene.

Epitope specificity of antibody response against human type II collagen in the mouse susceptible to collagen-induced arthritis and patients with rheumatoid arthritis.

The presence of species-specific and species-non-specific (common) epitopes has been demonstrated on type II collagen (CII) using monoclonal antibodies. In this study, we investigated the role of antibody response to some species-specific and common epitopes in mice immunized with human CII for the induction of collagen-induced arthritis (CIA). Antibody responses to species-specific epitopes in arthritic mice appeared significantly higher than that in non-arthritic mice. However, no significant difference of antibody responses to common epitopes was found between arthritic and non-arthritic mice. Monoclonal antibody reactive with one of the common epitopes exhibited the ability to induce arthritis in mice previously given the primary injection of CII, indicating the involvement of this epitope in the induction of CIA. Finally, we investigated the epitope specificity of anti-human CII antibody present in serum samples of patients with rheumatoid arthritis and relapsing polychondritis, and found antibodies to some common epitopes.

Induction of an anti-human type II collagen response by monoclonal anti-idiotypic antibody.

Several distinct epitopes on human type II collagen were defined by using mAb. The presence of species-specific and species-nonspecific (common) epitopes was thus clarified. Anti-idiotypic mAb (Ab2) was developed against one of the antibodies (Ab1) reactive with species-specific epitopes. Thus Ab2 was demonstrated to recognize an idiotope expressed on the Ag-binding site (paratope) of Ab1, since the binding of Ab1 to human type II collagen was blocked by Ab2, and the binding of Ab2 to Ab1 was inhibited by soluble human type II collagen, but not by murine and bovine type II collagens. DBA/1 mice immunized with Ab2 coupled to keyhole limpet hemocyanin produced an antibody (Ab3) specifically reactive with human type II collagen. It was also demonstrated that Ab3 expressed an idiotype similar to that of Ab1. These findings indicate that anti-idiotypic antibody directed against mAb to human type II collagen mimics a species-specific epitope on human type II collagen. The anti-idiotypic antibody bearing internal image of type II collagen will open the way to isolation of the arthritogenic epitope on type II collagen.

An interleukin-1 inhibitor in gingival crevicular fluid of patients with chronic inflammatory periodontal disease.

The gingival crevicular fluid of a patient(s) with marginal periodontal disease contained an activity inhibitory to interleukin-1 (IL-1). The inhibitory activity could be detected after the depletion of IL-1 alpha by the use of a specific antibody (anti-human recombinant IL-1 alpha monoclonal antibody)-conjugated Sepharose column. The inhibitory activity was not due to a toxic effect on the thymocytes since IL-1 alpha-depleted gingival crevicular fluid did not affect the incorporation of [3H]thymidine in either the presence or absence of concanavalin A. The inhibitory activity was exerted against both IL-1 alpha and IL-1 beta. The inhibitory factor did not have any effect on IL-2-induced proliferation of concanavalin A-activated spleen cells. The inhibitor was heat labile. Gel filtration on a Superose 12 column revealed the IL-1 inhibitor to have two major peaks, one in the molecular size range of 12 to 14 kDa and the other below a molecular size of 10 kDa.

Tumor-specific idiotype vaccines. II. Analysis of the tumor-related network response induced by the tumor and by internal image antigens (Ab2 beta).

In this study the tumor-specific immuneresponse induced by irradiated tumor cells (L1210/GZL) and by anti-idiotype antibodies was analyzed. The anti-idiotype antibodies (Ab2) were made against the paratope of a monoclonal antitumor antibody (11C1) that recognizes a tumor-associated antigen which cross-reacts with the mouse mammary tumor virus-encoded envelope glycoprotein 52. Two Ab2, 2F10 and 3A4, induced idiotypes expressed by the monoclonal antitumor antibodies 11C1 and 2B2. Cytotoxic T cells, generated by immunization with irradiated tumor cells, lyse 2F10 and 3A4 hybridoma cells. Furthermore, immunization with Ab2 induces tumor-specific cytotoxic T lymphocytes. The frequency of tumor-reactive cytotoxic T lymphocyte was found to be similar in mice immunized with Ab2 or irradiated tumor cells when examined at the precursor level. However, only 2F10 induces protective immunity against the growth of L1210/GZL tumor cells. The depletion of a L3T4+ T cell population from 2F10 immune mice was found to increase the effectiveness of transferred T cells to induce inhibition of tumor growth. The inability of 3A4 to induce antitumor immunity could be correlated with the presence of a population of Lyt2+ regulatory T cells. Collectively, these results demonstrate the existence of a regulatory network controlling the expression of effective tumor immunity. Our results demonstrate that selection of binding site-related Ab2 may not be a sufficient criteria for the development of an idiotype vaccine. A better understanding of the regulatory interactions induced by anti-idiotypes is needed for the design of effective antitumor immunotherapy.

T cell line specific for bacterial peptidoglycan subunit: possible role of the COOH-terminal amino acid of the disaccharide tetrapeptide in binding to the T cell receptor.

The T cell line specific for a bacterial cell wall peptidoglycan subunit, disaccharide tetrapeptide of diaminopimelic acid type, was examined for epitope specificity in elicitation of delayed-type hypersensitivity (DTH) in X-irradiated Lewis rats, using pairs of analogs different in optical configuration of the COOH-terminal amino acid. The test cell line induced DTH against analogs with the COOH-terminal D-amino acid but not against those with the L-amino acid at the COOH terminus. A close correlation was found between the T cell line-induced DTH reaction in vivo and the proliferative response in vitro, in terms of clear discrimination of the optical configuration of COOH-terminal amino acid of disaccharide tetrapeptide. The L-isomers (non-stimulatory analogs of T cell proliferation) competitively inhibited the proliferation of the T cell line by the corresponding D-isomers. Thus the L-isomers appear to interact with Ia molecules on antigen-presenting cells. We conclude that COOH-terminal D-amino acid of the disaccharide tetrapeptide could be involved in binding to the T cell receptor, induction of T cell proliferation, and elicitation of DTH.

Catabolic effects of muramyl dipeptide on rabbit chondrocytes.

Muramyl dipeptide, an essential structure for the diverse biologic activities of bacterial cell wall peptidoglycan, inhibited the synthesis of glycosaminoglycan/proteoglycan in cultured rabbit costal chondrocytes in a dose-dependent manner. Muramyl dipeptide, as well as lipopolysaccharide and interleukin-1 alpha, also enhanced the release of 35S-sulfate-prelabeled glycosaminoglycan/proteoglycan from the cell layer, which seems to reflect, at least partially, the increasing degradation of glycosaminoglycan/proteoglycan. Five synthetic analogs of muramyl dipeptide known to be adjuvant active or adjuvant inactive were tested for their potential to inhibit synthesis of glycosaminoglycan/proteoglycan and to enhance the release of glycosaminoglycan/proteoglycan in chondrocytes. The structural dependence of these synthetic analogs on chondrocytes was found to parallel that of immunoadjuvant activity. These results suggest that muramyl dipeptide is a potent mediator of catabolism in chondrocytes.