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P Marrack

Publications and source records attributed to P Marrack.

At least 181 records · Page 10Linked to original sources
PubMed1985

Rearrangement of T-cell receptor beta-chain genes during T-cell development.

The kinetics and order of rearrangements in the gene complex encoding T-cell-receptor beta chains were studied by Southern blot hybridization in a collection of hybridomas derived from fetal thymocytes at various stages of ontogeny (day 14 to day 17). Our results show a steady increase in the frequency of rearranged beta complexes during this period and suggest that these rearrangements occur within the thymus. beta-chain diversity region (D beta) to beta-chain joining region (J beta) joining preceded other types of rearrangements. More complex hybridization patterns consistent with fully rearranged functional beta-chain genes did not begin to accumulate until day 16, 1 day prior to significant surface expression of the receptor protein.

Age Factors↗
PubMed1985

The major histocompatibility complex-restricted antigen receptor on T cells: the genetics of expression of an allotype.

The monoclonal antibody KJ16-133 binds an allelic determinant expressed on the antigen-specific, major histocompatibility complex (MHC)-restricted receptors on approximately 20% of T cells in most mouse strains. The locus controlling the presence or absence of the determinant mapped 9.8 +/- 2.2 centimorgans from the Igk/Ly-2 locus on chromosome 6 in mice, and may be the beta-chain locus. Other genetic loci were identified that controlled the frequency of cells that expressed the allele in positive mice. One of these was the MHC itself, which may control expression of the beta-chain allele by controlling T cell repertoire. The identity of the other, as yet unmapped locus is unknown. KJ16-133 was used to show that T cell receptor gene products are expressed in a manner consistent with allelic exclusion.

Animals↗
PubMed1985

The function of antigen-presenting cells in mice with severe combined immunodeficiency.

We have examined the antigen-presenting function of spleen cells in the C.B-17 scid mouse, a mutation that severely impairs the development of T and B lymphocytes. We show that antigen-presenting cells (APC) of SCID mice function normally in antigen-specific proliferative responses of primed T cells and in the antigen-specific activation of IL 2-producing T cell hybridomas. In both quantitative and qualitative terms, APC of SCID mice are equivalent to those of normal mice. These results indicate that the development and differentiation of APC function in vivo is independent of signals from mature, functional T or B lymphocytes.

Animals↗
PubMed1984

Interleukin-induced increase in Ia expression by normal mouse B cells.

The constitutive culture supernatant (SN) of the macrophage tumor line P388D1 (P388 SN) and the concanavalin A (Con A)-induced culture supernatant of the T cell hybridoma FS6-14.13 (FS6 Con A SN) were shown to contain nonspecific factors capable of inducing increased Ia expression by normal resting B cells in a dose-dependent manner. In six consecutive experiments the relative increase in Ia expression induced by P388 SN was 4.9 +/- 0.9, with FS6 Con A SN 10.7 +/- 1.5, and with a combination of both preparations 13.0 +/- 1.7. This increase in Ia expression was observed to occur in virtually all the B cells, reaching maximum levels within 24 h of culture. The interleukin-induced increase in B cell Ia expression occurred in the absence of ancillary signals provided by ligand-receptor Ig cross-linking and despite the fact that virtually all the control B cells, cultured in the absence of factors, remained in G0. These results suggest that functional receptors for at least some interleukins are expressed on normal resting B cells and their effects can be manifest in the absence of additional activating signals. The increased Ia expression induced by the nonspecific factor preparations was shown to be correlated with enhanced antigen-presenting capacity by the B cells to T cell hybridomas. The nature of the interleukins responsible for these effects remains to be definitively determined, however, the activity of FS6 Con A SN was shown to correlate with B cell growth factor activity and increased B cell Ia expression was not observed using interleukin 2 (IL-2) or interferon-gamma, prepared by recombinant DNA technology.

Animals↗
PubMed1984

The antigen-specific, major histocompatibility complex-restricted receptor on T cells. VI. An antibody to a receptor allotype.

We have prepared a monoclonal antibody, KJ16-133, from the cells of a rat immunized with the purified receptor for antigen plus I-A of a BALB/c T cell hybridoma, DO-11.10. Unlike most other monoclonal anti-receptor antibodies that have been described before, KJ16-133 is not clone specific. It reacts with approximately 20% of the receptors on T cells of normal BALB/c mice. It also reacts with about the same percentage of antigen-specific, major histocompatibility complex (MHC)-restricted or allogeneic I-region specific T cell hybridomas. Reaction of KJ16-133 with a given T cell hybridoma does not seem to depend on the antigen specificity or MHC-restricting element of the T cell in question. The determinant recognized by KJ16-133 has some unexpected properties. It is absent in several strains of mice including SJL/J and SJA/20, but present on the T cells of most other commonly used strains. The determinant recognized therefore does not map to Igh. Our experiments suggest that a clone-specific "antiidiotypic" antibody and KJ16-133 recognize determinants on different parts of the receptor. For example, the binding of a clone-specific antibody to target T cells is relatively temperature insensitive, whereas KJ16-133 binds well to cells at 37 degrees C but poorly to cells at 4 degrees C. The determinant recognized by a clone-specific antibody is sensitive to reduction and alkylation of the receptor, whereas KJ16-133 reactivity is not. Finally, binding of KJ16-133 at saturating concentrations to target T cells does not block the binding of a clone-specific antibody. Similarly, binding of a clone-specific antibody only marginally inhibits binding of KJ16-133. Taken together, these results suggest that KJ16-133 is directed against an allelic determinant on T cells that may be close to the membrane, and not in the receptor binding site for antigen plus MHC. The antibody may recognize an allele of a constant region isotype, or an allele of a J region.

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

Gene transfer of H-2 class II genes: antigen presentation by mouse fibroblast and hamster B-cell lines.

We have transferred the mouse Ak alpha and Ak beta genes, which encode the class II I-Ak molecule, into mouse L-cell fibroblasts and hamster B cells. I-Ak molecules are expressed on the surface of both cell types. The L-cell and hamster B-cell I-Ak molecules appear normal by serological analyses and two-dimensional gel electrophoresis. Furthermore, the I-Ak molecules on L cells can act as targets for the allogenic T-cell killing of the transformed L cells. The I-Ak molecules in both mouse fibroblasts and hamster B cells can present certain antigens to T-cell helper hybridomas. Thus only class II molecules are required to convert the nonantigen-presenting cell. Accordingly, it will be possible to dissect the structure-function relationships existing between Ia molecules, foreign antigen, and T-cell receptor molecules by in vitro site-directed mutagenesis and gene transfer.

Animals↗
PubMed1984

The major histocompatibility complex-restricted antigen receptor on T cells: distribution on thymus and peripheral T cells.

A monoclonal antibody, KJ16-133, which binds to antigen-specific, major histocompatibility complex-restricted (Ag/MHC) receptors on about 20% of BALB/c peripheral T cells has been used to examine the expression of these receptors on thymocytes and different subpopulations of peripheral T cells. Although KJ16-133-reactive receptors were found on mature thymocytes at similar frequencies and levels as on peripheral T cells, these molecules were absent from the first cells to enter the thymus, and in less mature thymocyte populations KJ16-133-reactive cells were less frequent than in the periphery and bore lower quantities of receptor. These results showed that Ag/MHC receptors are present on the surfaces of immature thymocytes, albeit at variable levels, during the time that the repertoire of these cells for Ag/MHC is thought to be selected. Additional experiments showed that KJ16-133 could not be used to distinguish T-cell receptors with different restriction specificities, i.e., for Class I or Class II products of the MHC.

Age Factors↗
PubMed1984

Antigen presentation by supported planar membranes containing affinity-purified I-Ad.

I-Ad, purified from A20-1.11 cells by affinity chromatography, was incorporated into supported planar membranes by incubation of I-Ad-containing phospholipid vesicles with clean glass coverslips. Such planar membranes present a peptide digest of ovalbumin to the ovalbumin-specific, I-Ad-restricted T-cell hybridoma 3DO-54.8, resulting in the antigen-specific release of interleukin 2. However, when the same material was provided in the form of small unilamellar vesicles, no response was obtained. Antigen presentation by the I-Ad-containing planar membranes was inhibited by the monoclonal antibody MKD6 (anti-I-Ad) but not by the antibody 10-2.16 (anti-I-Ak). The antibody GK1.5, which recognizes the T-cell surface antigen L3T4, was also inhibitory. In contrast to the results with purified I-Ad, crude membrane preparations from A20-1.11 cells were effective in antigen presentation in both planar and vesicular forms.

Animals↗
PubMed1984

Functional and inducible expression of a transfected murine class II major histocompatibility complex gene.

Using the spheroplast fusion technique, we have introduced the cloned E beta b gene into two d haplotype cell lines, the B lymphoma line A20-2J and the macrophage tumor line P388D1. Analysis with a monoclonal antibody indicates that the product of the transfected E beta b gene associates with the endogenous E alpha chain to form an E alpha dE beta b complex. While expression of E alpha dE beta b is constitutive in A20-2J cells transfected with the E beta b gene, surface expression of E alpha dE beta b is detected in transfected macrophage cells only after treatment of cells with culture supernatants from concanavalin A (Con A)-stimulated T cells. Transfected B lymphoma cells and transfected Con A supernatant-treated macrophage cells have acquired the ability to present antigen to E alpha dE beta b-restricted T-cell hybridomas. The observed inducible expression of the transfected gene in the macrophage host indicates that sequences responsible for regulated expression of the E beta b gene may be associated with the transfected gene. In combination with directed mutagenesis, the system described here provides a means to study (i) E beta b sequences that are important in determining the restriction specificity of the E molecule and (ii) sequences associated with the E beta gene that may be important in the regulation of E beta chain expression.

Alleles↗
PubMed1984

Antigen recognition by H-2-restricted T cells. II. A tryptic ovalbumin peptide that substitutes for processed antigen.

A 17-amino acid tryptic peptide of chicken ovalbumin, designated P323-339, that substituted for processed antigen when presented by glutaraldehyde prefixed accessory cells to specific I-restricted T hybridomas was characterized. The peptide antigen could not be demonstrated to have any specific or stable interactions with accessory cell Ia antigens by either direct binding or functional assays for inhibition of specific T cell activation. In addition, the T cell receptor for I-restricted antigen had no affinity for free antigen alone. A rabbit antibody specific for the antigenic peptide inhibited presentation when introduced before but not after binding of the peptide to accessory cells. These results extend our earlier finding that accessory cell-mediated processing of chicken ovalbumin can be completely explained by the fragmentation of the native molecule into smaller m.w. peptides, and suggests that if an antigen/Ia complex is important in T cell activation, it forms significantly only in the presence of the T cell receptor for I-restricted antigen.

Amino Acid Sequence↗
PubMed1983

The major histocompatibility complex-restricted antigen receptor on T cells. IV. An antiidiotypic antibody predicts both antigen and I-specificity.

In order to prove that a monoclonal antibody, KJ1-26.1, reacted with the idiotypic portion of the receptor for antigen plus major histocompatibility complex product (Ag/MHC) on the T cell hybridoma D0-11.10, 397 independent T cell hybridomas prepared from BALB/c T cells primed with ovalbumin were screened by ELISA for reactivity with the antibody. Of these T cell hybridomas one, 7D0-286, and a subclone of this hybridoma, 7D0-286.2, reacted strongly and consistently with KJ1-26.1. Further analysis revealed that KJ1-26.1 blocked the reaction of 7D0-286 with Ag/MHC, and that 7D0-286 had the same fine specificity both for Ag and MHC as D0-11.10. None of 207 other BALB/c T cell hybridomas specific for ovalbumin shared these fine specificity patterns. Thus, reaction with KJ1-26.1 defined the specificity of a T cell hybridoma both for Ag and MHC, suggesting that KJ1-26.1 reacted with the receptors for Ag/MHC on the T cells in question. KJ1-26.1 precipitated an 85-kdalton molecule from 7D0-286.2 that on reduction ran as a diffuse spot of approximately 43 kdaltons. A similar molecule was precipitated from D0-11.10.

Animals↗
PubMed1983

Mouse spleen dendritic cells present soluble antigens to antigen-specific T cell hybridomas.

In the presence of the soluble polypeptide antigens ovalbumin and keyhole limpet hemocyanin, purified mouse spleen dendritic cells induce the secretion of IL-2 by antigen-specific T cell hybridomas. This response is H-2 restricted and can be specifically inhibited by monoclonal anti-I-A. These data indicate that dendritic cells can present soluble antigen to H-2-compatible T cells.

Animals↗
PubMed1983

The major histocompatibility complex-restricted antigen receptor on T cells. II. Role of the L3T4 product.

We have examined the role of the murine homologue of Leu-3 T4, L3T4, in recognition of antigen in association with products of the major histocompatibility complex (Ag/MHC) by murine T cell hybridomas. A series of ovalbumin (OVA)/I-Ad-specific T cell hybridomas were ranked in their sensitivity to Ag/I by measuring their ability to respond to low doses of OVA, or their sensitivity to inhibition by anti-I-Ad antibodies. T cell hybridomas with low apparent avidity for OVA/I-Ad, i.e. that did not respond well to low concentrations of OVA and were easily inhibited by anti-I-Ad, were also easily inhibited by anti-L3T4 antibodies. The reverse was true for T cell hybridomas with apparent high avidity for Ag/MHC. We found that the presence of low doses of anti-L3T4 antibodies caused T cell hybridomas to respond less well to low doses of Ag, and to be more easily inhibited by anti-I-Ad antibodies. These results suggested that the role of the L3T4 molecule is to increase the overall avidity of the reaction between T cells and Ag-presenting cells. In support of this idea was the discovery of several L3T4- subclones of one of our L3T4+ T cell hybridomas, D0.11.10. The L3T4- subclones had the same amount of receptor for OVA/I-Ad as their L3T4+ parent, as detected by an anti-receptor monoclonal antibody. The L3T4- subclones, however, responded less well to low doses of OVA, and were more easily inhibited by anti-I-Ad antibodies than their L3T4/ parent. These results showed that the L3T4 molecule was not required for surface expression of, or functional activity of, the T cell receptor for Ag/MHC. The L3T4 molecule did, however, increase the sensitivity with which the T cell reacted with Ag/MHC on Ag-presenting cells.

Animals↗
PubMed1983

Evidence for two distinct classes of murine B cell growth factors with activities in different functional assays.

Several previously described B cell growth factor (BCGF) activities from a number of mouse monoclonal T cell sources were compared in different functional assays. The results indicate that there are two distinct classes of BCGF defined by functional activity and source. BCGF I, whose prototype is (EL4)BCGF, synergized with anti-Ig in the proliferation of normal splenic B cells but had no activity when dextran sulfate (DXS), rather than anti-Ig, was used to costimulate the same source of B cells. BCGF I also failed to directly stimulate BCL1 tumor B cells. In contrast, BCGF II, whose prototype is (DL)BCGF, showed a reciprocal pattern of activity. BCGF II failed to synergize with anti-Ig-costimulated normal B cells to give good proliferative responses. Sources of BCGF II also directly stimulated (no anti-Ig or DXS added) B cells of the BCL1 tumor-carrying mice. These results suggest that the two BCGF may have activity on two subsets of B cells that respond differentially to induction with the two polyclonal B cell activators, anti-Ig and DXS. The possibilities that these different patterns of response occur in separate lineages of B cells and/or in B cells in different states of differentiation is discussed.

Animals↗