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Biomedical subjects

J A Kapp

Publications and source records attributed to J A Kapp.

At least 55 records · Page 3Linked to original sources
PubMed1990

The development and characterization of encephalitogenic cloned T cells specific for myelin proteolipid protein.

T-cell clones have been isolated from SJL/J mice after immunization with myelin proteolipid protein (PLP). The cloned cells responded strongly to PLP stimulation in vitro as well as to the synthetic PLP-related peptide 139-151. The response to PLP is Ia mediated, since it was inhibited by monoclonal antibodies to the matched I-As haplotype, but not with antibodies to other I-A haplotypes. Phenotypic analysis using immunofluorescence demonstrated the following characteristics of the clones: Thy-1+, CD4+, CD5+ and CD8-. Injection of 10-30 million PLP-activated cells from one clone induced severe experimental allergic encephalomyelitis in five mice, both clinically and histologically. This represents to our knowledge the first report of PLP-specific encephalitogenic cloned T cells.

Animals↗
PubMed1989

The adoptive transfer of chronic relapsing experimental allergic encephalomyelitis with lymph node cells sensitized to myelin proteolipid protein.

In this report we describe the transfer of chronic relapsing experimental allergic encephalomyelitis (EAE) with in vitro-stimulated lymph node cells (LNC) from SJL/J mice immunized with human myelin proteolipid protein (PLP). No additional immune enhancing procedures were applied in the transfer recipients. Clinical and histological EAE was transferred with 10-30 X 10(6) LNC to 27/28 mice. The LNC proliferated in vitro to PLP, but not to myelin basic protein (MBP), and induced delayed-type hypersensitivity. Enrichment for lymphoblasts by Ficoll centrifugation was essential for the disease development. The clinical course usually showed an early episode of acute paralytic illness, followed by chronic relapsing disease, and resembled the transfer of EAE using MBP-specific cells, both clinically and histologically.

Animals↗
PubMed1989

Tolerance induced by physiological levels of secreted proteins in transgenic mice expressing human insulin.

We have used transgenic mice to study immune tolerance to autologous, non-MHC encoded proteins that are expressed at physiological levels in the circulation. The transgenic mice used in these studies express the human preproinsulin gene and synthesize human proinsulin. Human and mouse insulin are secreted from the pancreatic islets of transgenic mice in response to normal physiological stimuli, such as glucose. Our data demonstrate that the transgenic mice have acquired tolerance to human insulin. The repertoire of T cells specific for exogenous antigens is shaped by the acquired tolerance to autologous proteins since pork but not beef or sheep insulin is also nonimmunogenic in the transgenic mice. We also found that the transgenic mice were tolerant to human proinsulin, the intracellular precursor of insulin. Unresponsiveness to human proinsulin most likely results from tolerance of insulin-specific and proinsulin-specific T cells that recognize the secreted enzymatic cleavage products of proinsulin, insulin and C-peptide.

Animals↗
PubMed1989

Effect of IL-2 on suppressor factor production.

Suppressor T-cell hybridomas specific for the synthetic polypeptide antigen L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) release TsF spontaneously and are not dependent on exogenous sources of lymphokines for their growth. IL-2 has no effect on the cell growth of these hybridomas and little overall effect is observed on protein biosynthesis. Nevertheless, the addition of IL-2 to one of these hybridomas (762 B3.7), leads to a substantial increase in suppressor factor (TsF2) production as measured by both bioactivity and direct analysis of 35S-methionine incorporation into TsF2. Treatment of the TsF2 producing hybridoma with phorbol myristate acetate (PMA) causes an increase in the level of IL-2 receptor expression in this hybridoma and enhances the effects of IL-2 on the biosynthesis of TsF2. These data suggest that in addition to its growth promoting properties, IL-2 may provide a signal that triggers suppressor cells to produce antigen specific suppressor factors.

Autoradiography↗
PubMed1989

Structures on T cells and macrophages involved in interleukin 1 (Il-1) secretion by macrophages upon contact with syngeneic thymocytes.

We demonstrate, using a new rosette method of determination of interleukin 1 activity that macrophages secrete Il-1 upon contact with syngeneic thymocytes or with thymocytes homologous in the Ia region of MHC complex. The phenomenon takes place in the absence of foreign antigen. Blocking of class II MHC antigens on macrophages with monoclonal antibodies against structures of the T-cell receptor complex (alpha/beta T-cell receptor-TCR, CD3 and L3T4) inhibits production of Il-1 to the background level. We conclude that secretion of Il-1 from macrophages, upon contact with syngeneic thymocytes, is triggered by a T-cell signal following interaction: TCR-Ia molecules.

Animals↗
PubMed1988

Identification of suppressor T cells in virgin non-responder spleen cells responsible for primary unresponsiveness to L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT).

T cell subsets that regulate antibody responses to L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) in mice that are Ir gene non-responders have been further characterized. We previously defined several T cell subsets in GAT-primed non-responder mice. The Lyt-2+ suppressor-effector T cells suppress responses to GAT and GAT complexed to methylated BSA (GAT-MBSA). The Lyt-1+ cell population is complex and can be separated into I-J- Th cells, which support responses to GAT and GAT-MBSA. After priming, the Lyt-1+, I-J+ cell population contains suppressor-inducer cells that activate precursors of suppressor-effector cells to suppress responses to GAT and GAT-MBSA as well as Ts cells that directly inhibit responses to GAT but not GAT-MBSA. By contrast, the Lyt-1+ cells from virgin mice contain only cells that directly suppress responses to GAT but not GAT-MBSA. The major question addressed in the present studies was whether the Lyt-1+, I-J+ Ts cells in virgin and primed mice and the suppressor-inducer cells in GAT-primed mice were functionally and serologically distinct subsets. The studies used mAb and panning procedures to separate cell populations and inhibition of PFC cell responses to functionally define the activity of the cell populations. We used the following two mAb that were raised by immunizing rats with GAT-specific suppressor factors: 1248A4.10 (known to react with suppressor-inducer cells) and 1248A4.3, another reagent from the same fusion. Lyt-1+ cells from virgin spleens contained Ts cells that were A4.10-, A4.3+ and no suppressor-inducer T cells, whereas Lyt-1+ cells from GAT-primed spleens contained Ts cells that were A4.10-, A4.3+ as well as A4.10+, A4.3- suppressor-inducer cells. Thus, the Lyt1+, I-J+ cell subset can be divided into two functionally and serologically distinct subsets, direct Ts cells (1248A4.3+), which suppress responses to GAT but not GAT-MBSA, and GAT-primed suppressor-inducer T cells (1248A4.10+).

Animals↗
PubMed1988

Characterization of L-glutamic acid60-L-alanine30-L-tyrosine10-specific suppressor T cells in responder mice restricted by Igh-C-linked genes.

A Ts cell subset has been identified in the spleens of responder mice 3 to 6 wk after immunization with an optimally immunogenic dose of L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT). These Ts were positively selected by panning procedures by using a mAb (1248 A4.10) produced by immunization of rats with semipurified mouse GAT-specific, single polypeptide chain suppressor factor. These Ts cells inhibited the activity of virgin Th cells but not memory Th cells and this activity was genetically restricted by genes which are linked to the Ig H chain (Igh) locus on chromosome 12. Use of the Igh recombination strain, BAB.14, which has a crossover near the VHCH region junction, demonstrated that the genes regulating the Igh restriction map telomeric to the VH genes. The Igh-linked restriction regulated the interaction of A4.10+ Ts cells with virgin T cells and not B cells. However, A4.10+ Ts did not act directly on Lyt-2-Th cells, but required the presence of Lyt-2+ cells for suppression. Suppression by GAT-primed A4.10+-Ts cells also required syngenicity at Igh-linked genes by both Lyt-2- and Lyt-2+ T cells. These results indicated that A4.10+-Ts cells were inducer Ts cells which activated Lyt-2+ effector Ts cells which prevented primary GAT specific Th cell activity. The interaction between A4.10+-Ts inducer and effector Ts cells and/or the interaction of the effector Ts and its target cell were restricted by genes linked to the Igh constant region.

Animals↗
PubMed1988

Helper T-cell clones that recognize autologous insulin are stimulated in nonresponder mice by pork insulin.

Murine antibody responses to various species of insulin are under major histocompatibility complex-linked Ir gene control. Beef insulin differs from pork insulin by only two amino acids in the A-chain loop, yet strain C57BL/10 (B10) mice produce insulin-specific antibodies after immunization with beef insulin and fail to produce antibody after stimulation with pork insulin. Nevertheless, pork insulin primes helper T cells in B10 mice that can be demonstrated if insulin-specific Lyt-1-, -2+ suppressor T cells are removed. Not only do the pork insulin-primed helper and suppressor T cells cross-react with autologous insulin, but also rat insulin (the amino acid sequence of which is identical to mouse insulin) elicits functionally identical helper and suppressor T cells. In this report, we demonstrate that in B10 mice the frequency of helper T cells stimulated by pork insulin is equivalent to that stimulated by beef insulin and that helper T-cell clones induced by beef and pork insulin are major histocompatibility complex-restricted T cells that proliferate, produce lymphokines, and provide helper activity after activation. These helper T-cell clones exhibit different antigenic fine specificities: beef insulin-induced clones respond to beef insulin but not pork or autologous insulin, whereas pork insulin-induced clones cross-react with all species of insulin tested, including rat insulin. In addition, the helper activity of cloned pork insulin-specific T cells is abrogated by pork insulin-primed suppressor T cells. These data support the hypotheses that Ir gene control of antibody responses to certain antigens involves mechanisms used for maintenance of self-tolerance.

Animals↗
PubMed1988

Direct demonstration that an antigen-specific suppressor factor purified from extracts of T cell hybridomas binds antigen and bears I-J determinants.

One of the problems that has plagued the investigation of soluble suppressor T cell factors (TsF) has been the lack of sufficient material for direct assessment of their serological reactivities and biochemical characteristics. In the studies described in this communication, biosynthetically radiolabelled TsF and purified, radio-iodinated TsF were used to address these issues. We found that the cell-associated form of a factor specific for L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT-TsF1) is a 66 kDa protein which exhibits a slightly acidic isoelectric point, but no carbohydrate as determined by enzymatic analysis and lectin-affinity chromatography. The biological analysis of suppression is specific for GAT and the specific activity of GAT-TsF1 is 2 x 10(9) suppressive units/micrograms. Direct measurement of the antigen binding capacity of GAT-TsF1 by affinity chromatography demonstrated that it binds to GAT but not an irrelevant antigen, and that only GAT-binding TsF1 is biologically active. Furthermore, GAT-TsF1 can be specifically eluted from GAT-Sepharose with soluble GAT. Lastly, purified GAT-TsF1 binds to polyvalent anti-TsF1 and alloantisera produced against the I region histocompatible cells of the H-2q haplotype, the so-called anti-I-J antibodies, but does not bind to immunosorbents containing antisera to irrelevant I-region haplotypes. Thus, these data physically verify the serological characteristics of GAT-TsF1 that were originally defined solely on the basis of biological activity.

Animals↗
PubMed1988

Establishment of antigen-specific and MHC-restricted B cell hybridoma clones: a model for studying antigen presentation to T cell lines and clones.

Presentation of GAT by GAT-specific hybridoma B cell clones to GAT-specific T cell lines and clones was investigated. B cell clones expressed surface IgG2b, Ia and Fc receptors, and did not secrete immunoglobulins. The clones formed rosettes with GAT-SRBC which could be inhibited by monoclonal antibodies against GAT idiotype. Presentation of GAT by the clones was MHC-restricted and highly efficient, i.e., a few hundred B cells or very low concentration of GAT stimulated proliferation of GAT-specific T cell lines. The fusion partner, M12.4.5.2, clone presented GAT much less efficiently. Although GAT-specific B cell clones presented also heterologous antigen beef insulin to insulin-reactive T cell lines, they were not able to present insulin in the absence of soluble antigen. Presentation of GAT was inhibited by pretreatment of the clones with monoclonal antibodies against I-E, mouse Ig and GAT-idiotype, as well as related antigens GA and GT. The rate of antigen uptake was much shorter compared to resting B cells for cells pulsed with GAT for 4 hours presented the antigen well. The studies suggest that a membrane-associated Il-1 may be required in the presence of antigen presentation by B cells. The results also revealed that antigen-specific hybridomas can present specific antigen in part with association of surface immunoglobulins which may be involved in antigen uptake and focusing to T cells.

Animals↗
PubMed1988

Antigen presentation to T cell lines and clones by peritoneal macrophages, peritoneal B cells and antigen-specific B cell hybridomas.

The antigen presenting cell (APC) activity of uninduced, resident peritoneal macrophages and B cells was compared to that of antigen-specific B cell hybridomas by measuring proliferative responses of antigen-specific, MHC-restricted T cell clones. The results demonstrate that peritoneal macrophages and B cells are much more efficient APC than irradiated splenic filler cells, and that unirradiated B cells were as good as, if not better than, macrophages. Both B cells and macrophages can be pulsed with antigen, although pulsed B cells were always found to be more efficient than pulsed macrophages. However, the APC activity of B cells was exquisitely sensitive to irradiation. The relative contribution of macrophages and B cells to the APC activity of mixed populations was easily distinguished by complement dependent lysis with monoclonal antibodies specific for unique differentiation antigens expressed by these cells. Normal peritoneal macrophages and B cells present the synthetic terpolymer of L-glutamic acid60-L-alanine30-L-tyrosine10 (GAT) to GAT-specific T cells clones and beef insulin to insulin-specific T cell lines nonspecifically. The APC activity of antigen-specific B cells was also examined by using novel GAT-specific, nonsecretor B cell hybridomas produced by fusing GAT-primed spleen cells to the HAT sensitive Balb/c lymphoma, M12.4.5. The hybridomas selected for these studies were GAT-specific, sIg+, Ia+ cells. These hybridomas presented GAT to GAT-specific T cells more efficiently than heterogeneous B cells suggesting that interaction with surface Ig receptors facilitated the uptake and/or processing of antigen. GAT-specific B cell hybridomas, like normal B cells, presented soluble beef insulin to an insulin-specific T cell clone nonspecifically. However, after pulsing with antigen overnight, the GAT-specific B cell hybridoma could activate only GAT-specific T cells.

Animals↗
PubMed1988

A comparison of the conventional and the rosette method of determination of interleukin 1 (IL-1) activity. The advantages of the rosette method.

In this report we compare the conventional method of determination of IL-1 activity with a new rosette assay. Determination of IL-1 activity in the rosette assay is well correlated with the conventional method and equally sensitive. However, the rosette method is able to dissect the activity of IL-1 from IL-2 and to determine the immunotropic, optimal dose of IL-1 more accurately.

Animals↗
PubMed1988

Secretion of interleukin 1 (IL-1) by peritoneal macrophages upon contact with syngeneic T cells is Ia-restricted and antigen-independent process.

We deliver an evidence that secretion of interleukin 1 by macrophages upon contact with T cells is an Ia-restricted and antigen-independent event. Antigen-specific T cell lines or quiescent thymocytes induce comparable quantities of IL-1 from Ia-compatible macrophages. Addition of antigen together with antigen-specific T cells does not increase production of IL-1. Con A-activated thymocyte-derived blasts induce less IL-1 than unstimulated thymocytes. Peritoneal B cells do not secrete IL-1 although they present GAT effeciently to GAT-specific T cell clones. Lastly, the production of IL-1 can be inhibited by a treatment of macrophages with monoclonal antibodies against Ia but not H-2D antigens. The results indicate that the release of IL-1 is solely a result of an interaction between Ia molecules on macrophages and the receptor for Ia on interacting T cells. This process does not require antigen/lectin bridge between the interacting cells.

Animals↗