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J L Greenstein

Publications and source records attributed to J L Greenstein.

At least 55 records · Page 3Linked to original sources
PubMed1986

Recognition of the alpha-1 and alpha-2 domains of H-2 molecules by allospecific cloned T cells.

Previously we had shown that allospecific bulk cultures of cytolytic T lymphocytes lysed the products of cloned class I major histocompatibility genes expressed after DNA-mediated gene transfer. In these experiments, performed by using cloned allospecific T cell effectors, a T cell hybridoma, and recombinant DNA technology, we have been able to map determinants recognized by these T cell clones to the alpha-1 domain of H-2Dd and the alpha-2 domain of H-2Ld (four of eight clones). Target cells used were L cells (H-2k), expressing wild type or hybrid H-2 antigens of H-2d origin. Thus, for the first time determinants recognized by cloned T cells are found in the recombined alpha-1 and alpha-2 domains.

Amino Acid Sequence↗
PubMed1986

The mechanism of antigen presentation by dendritic cells and splenic adherent cells in the induction of an allogeneic cytotoxic T-lymphocyte response to H-2Kk liposomes.

Induction of an allogeneic cytotoxic T-lymphocyte (CTL) response to purified alloantigen is partially dependent on uptake and processing of the class I alloantigen by antigen-presenting cells (APC) followed by recognition of the alloantigen and self Ia by helper T cells (TH). The activated TH provides the helper signal(s) to the alloantigen-specific CTL for proliferation and differentiation into an active effector CTL. The role of antigen processing and presentation of major histocompatibility complex alloantigens was examined and the ability of different types of APC to present purified H-2Kk liposomes was investigated. Splenic adherent cells (SAC), splenic dendritic cells (DC), and B-cell lymphoblastoid lines were all shown to be effective in the presentation of H-2Kk liposomes. The relative ability of these cells to serve as APC was determined to be DC greater than B-cell tumors greater than SAC. The role of processing of H-2Kk liposomes by SAC and DC was examined by investigating the effect of weak bases on pulsing of the APC. These experiments suggest that presentation of alloantigen by both SAC and DC involves a step which is sensitive to inhibition by weak bases. We examined whether the TH were activated by similar mechanisms when stimulated by the various APC. The functional involvement of the T-cell surface marker L3T4 was demonstrated in the induction of TH. In contrast, L3T4 was not involved in the subsequent generation of CTL since monoclonal antibody (MAb) specific for L3T4 was not effective in blocking CTL function in the presence of nonspecific T helper factor (THF). Similarly, Ia on the APC was shown to be involved in the stimulation of the TH pathway but not directly in the differentiation of the CTL. Thus, DC and B cells in addition to SAC can present H-2Kk to TH. The presentation of alloantigen by both cell types may involve an intracellular route as demonstrated by the blocking of the TH response by weak bases. Both Ia and L3T4 are required on the APC for induction of the TH response. The minimal requirements for activation of the CTL were H-2Kk liposomes and a source of THF.

Animals↗
PubMed1985

Role of L3T4 in antigen-driven activation of a class I-specific T cell hybridoma.

The expression of L3T4/Lyt-2 on murine T cells has led to the association of these surface markers with recognition of either class II or class I major histo-compatibility complex (MHC) antigens. It has been suggested that these T cell surface antigens interact with nonpolymorphic determinants on MHC antigens. We have examined the role of L3T4 in the recognition of H-2Dd by the T cell hybridoma, 3DT52.5. Mouse L cells transfected with either the H-2Dd gene, or with both the alpha and beta genes of I-Ak and the H-2Dd gene have been used to assess the role of an L3T4/la interaction at varying doses of H-2Dd. A role of L3T4 in activation of 3DT52.5 becomes evident only at limiting doses of antigen. It appears that an L3T4/la interaction can influence T cell function during suboptimal stimulation, implying that the L3T4/la interaction serves to raise the functional affinity of interaction between the T cell and the antigen-bearing cell.

Animals↗
PubMed1985

The ability of Ia and H-2Kk-bearing membranes to replace the antigen-presenting cell in an H-2Kk allogeneic cytotoxic T cell response.

Induction of an allogeneic cytotoxic T lymphocyte (CTL) response is dependent, in part, on uptake and processing of the class I alloantigen by antigen-presenting cells and subsequent Ia-restricted recognition of the alloantigen by helper T cells, resulting in lymphokine production. The nature of the antigen-processing event has been investigated using reconstituted membranes to replace the antigen-presenting cells in the generation of a secondary allogeneic CTL response. Membranes were isolated from an Iad-positive antigen presenting B cell lymphoma (D2N), detergent solubilized and then reconstituted together with affinity-purified H-2Kk antigen in the presence of protease inhibitors. These reconstituted vesicles, containing both syngeneic Ia and alloantigen, were able to induce the helper T cell arm of the CTL response in cultures depleted of antigen-presenting cells. A variety of control experiments provided strong evidence that the helper T cells recognized the H-2Kk, probably in its native form, in an Ia-restricted manner on the vesicles, while the pre-CTL can directly recognize H-2Kk. Recognition was only effective if both the Ia and alloantigen were inserted into the same membrane bilayer. The results strongly suggest that the obligatory antigen processing event required for helper T cell recognition of alloantigen is simply the insertion of the alloantigen into the same membrane bilayer as the syngeneic Ia restricting element.

Animals↗
PubMed1984

The role of L3T4 in recognition of Ia by a cytotoxic, H-2Dd-specific T cell hybridoma.

The expression of T4/T8 surface markers on human T cells and of L3T4/Lyt-2 on murine T cells has lead to the association of these surface markers with recognition of either class II or class I major histocompatibility complex (MHC) antigens. It has been suggested that these T cell surface antigens interact with MHC antigens. We have examined the role of L3T4 in the recognition of Dd by the T cell hybridoma, 3DT52.5. This T cell hybridoma was found to be specific for the N/Cl domain of Dd. The recognition of a class I antigen by an Lyt-2-, L3T4+ T cell hybridoma allowed the separate evaluation of interactions between L3T4/Ia and the T cell antigen receptor, Dd. Recognition by this hybridoma resulted in the production of interleukin 2 (IL-2) and cytolytic activity. Antibody blocking experiments have demonstrated that L3T4 was involved in triggering the effector function of 3DT52.5 only on Ia+ stimulator or target cells. We have demonstrated that an L3T4+, Dd-specific T cell hybridoma, 3DT52.5, uses the L3T4 molecule to directly interact with nonpolymorphic Ia determinants.

Animals↗
PubMed1984

Monoclonal antibodies reactive with idiotypic and variable-region specific determinants on human immunoglobulins.

Monoclonal antibody JG-B1, specific for the human VKIIIb sub-subgroup of L chains, and JG-B4 specific for an idiotypic determinant on Glo, a monoclonal human IgM-VKIIIb anti-IgG, were produced and characterized. The VKIIIb determinant was detected on L chains alone and intact immunoglobulins with VKIIIb L chains. However, the idiotypic determinant was expressed only on IgM-Glo and required association of H and L chains. Binding of the immunogen Glo, to its antigen-IgG partially inhibited anti-idiotype and anti-VKIIIb binding. Cross-inhibition experiments demonstrated that intact pentameric IgM-Glo expressed one-half the number of idiotypic sites as VKIIIb determinants. However, Glo half-molecules expressed equal numbers of idiotypic and VKIIIb determinants. This is the first described monoclonal antibody produced by hybridoma technology which recognizes an antigenic determinant specific for a single variable region in intact immunoglobulin.

Animals↗
PubMed1984

VK IIIb expression is altered in acquired and drug-induced hypogammaglobulinaemia.

The Kappa chain variable region subgroup restriction of immunoglobulin (Ig) from patients with acquired hypogammaglobulinaemia, agammaglobulinaemia and drug-induced immunosuppression has been studied. The percent of K chain-containing Ig which expresses the VK IIIb variable region sub-subgroup was determined with a previously characterized murine monoclonal anti-VK IIIb antibody. The VK IIIb sub-subgroup percent was increased in sera from patients with idiopathic hypogammaglobulinaemia, as well as patients who became hypogammaglobulinaemic following immunosuppression. The implications of the results to the regulation of the human immune and autoimmune response are discussed.

Agammaglobulinemia↗
PubMed1983

A DC-specific cytolytic T lymphocyte line is OKT8+1.

A human cytotoxic T lymphocyte (CTL) line, A9, was generated by limiting dilution and was selected because of its apparent DC specificity. A9 is 100% OKT3+, 90% OKT4+, and 10% OKT8+, but by negative selection the CTL present are entirely OKT8+. These OKT8+ CTL are totally inhibitable by Genox 3.53, an anti-DC1 monoclonal antibody (mAb), and Leu-10, an anti-DC subgroup mAb, but are not inhibitable by a panel of anti-HLA-DR mAb. These CTL are also inhibitable by anti-OKT3 and anti-LFA-2 but not by OKT4 or OKT8 mAb. These findings extend previous studies that showed that OKT8+ CTL recognize HLA-A,B antigens, whereas OKT4+ CTL recognize HLA-DR and SB antigens. It is possible that an as yet undefined T cell surface molecule is involved in DC recognition.

Antibodies, Monoclonal↗
PubMed1981

Analysis of the response of B cells from CBA/N-defective mice to nonspecific T cell help.

We have investigated the induction of antibody responses to erythrocyte (RBC)-bound antigens in the (CBA/N x B10)F1 mouse. Male B cells, which express the CBA/N defect, were shown to be unresponsive to RBC antigens when the delivered T cell helper activity was solely nonspecific. Thus we demonstrated that defective B cells did not respond to concanavalin A supernatants or bystander helper activity, in spite of the fact that CBA/N-defective mice could produce these T cell activities. The defective B cell did not respond to RBC-bound antigen in the presence of RBC-primed T cells, although the magnitude of this response was usually twofold less than normal controls. The insensitivity of CBA/N defective B cells to nonspecific T cell helper activities seemed to involve at least the inability of RBC antigens to activate defective B cells in the absence of antigen-specific T cell help.

Animals↗
PubMed1981

Functional subsets of B cells defined by quantitative differences in surface I-A.

The quantitative expression of surface I-A determinants has been used to define functional B cell heterogeneity based on responsiveness to the trinitrophenyl (TNP) hapten on various classes of carrier molecules. Unprimed, anti-Thy 1 and complement-treated B10.A (I-Ak) B cells were stained with a monoclonal anti-I-Ak reagent that had been fluorescein (FL) conjugated. By using a fluorescence-activated cell sorter these cells were then sorted into 2 populations of cells staining heavily or lightly with this reagent. These populations of cells were then assayed for anti-TNP precursor frequency, in responses to 3 TNP-antigens, by limiting dilution analysis. B cells responsive to TNP-lipopolysaccharide (LPS) and TNP-sheep red blood cells (SRBC) were found in both the B cells that expressed a low amount of surface I-A and the B cells that expressed a high amount of I-A. However, B cells with the ability to respond to TNP-Ficoll were found only in the B cells that expressed a low amount of surface I-A. These experiments suggest that the quantitative expression of surface I-A can be used to define B cell populations with different abilities to respond to hapten coupled to Ficoll.

Animals↗
PubMed1980

Flow sorting of antigen-binding B cell subsets.

Antigen binding was used as a probe in the definition of functional B cell heterogeneity. Unprimed, anti-Thy 1 and complement-treated spleen cells were stained with fluorescent trinitrophenylated bovine serum albumin (FL-TNP-BSA). These cells were sorted, fluorescence negative from fluorescence positive, by using a multiparameter cell sorter and assayed for precursor frequency in antibody responses to TNP by limiting dilution analysis. The cells that bound FL-TNP-BSA were demonstrated to be enriched for antibody-forming precursors to the antigens TNP-lipopolysaccharide (LPS), TNP-sheep red blood cells (SRBC), and TNP- or DNP-Ficoll, whereas the fluorescence negative cells were depleted for these responses. B cells that bound FL-TNP-BSA were then sorted into populations that bound a moderate or high amount of FL-TNP-BSA. The B cells responsive to TNP-LPS and TNP-SRBC were present in both the moderate and high binding populations. In contrast, the B cells responsive to TNP- or DNP-Ficoll were present only in the cells that bound a moderate amount of FL-TNP-BSA. These experiments suggest that there is a population of B cells in adult mouse spleen that binds large amounts of antigen, and that can respond to antigen carried on LPS or SRBC but not carried on Ficoll.

Animals↗
PubMedDate not supplied

Multi-scale models of local control of calcium induced calcium release.

Calcium-induced-calcium-release in cardiac myocytes is the release of Ca(2+) from the sarcoplasmic reticulum (SR) triggered by Ca(2+) entering the cell through L-type Ca(2+) channels. The Ca(2+) is released through ryanodine receptors which 'sense' local [Ca(2+)] in the small region (the diadic space) positioned between the t-tubules and the SR. The length-scale of a single diad is of the order of 10nm and the diffusion time-scale is of order of 1 micros with each cell containing approximately 10,000 diadic spaces which act independently. However, typically one is interested in Ca(2+) currents at the whole cell level and higher. This is a multi-scale problem and cannot be solved by direct computation. In this paper we develop a general framework for deriving approximate solutions of these models.

Animals↗