Polymorphism and tissue distribution of maternally transmitted antigen defined by cytotoxic T lymphocyte lines

We have developed cytotoxic T lymphocyte (CTL) lines specific for two determinants of the maternally transmitted antigen (Mta) and have used these CTL lines to study the tissue distribution of Mta. In previous reports, we characterized CTL lines specific for the Mta.1 determinant. Here, we describe CTL lines specific for the newly defined Mta.2 determinant. Mta.2-specific CTL lines lysed target cells from F1 mice of an NZB (Mtf beta) mother but did not lyse target cells from reciprocal F1 mice of any Mtf alpha mother. Backcross mice were used as the source of target cells to demonstrate that the Mta.2-specific CTL were H-2 nonrestricted in their recognition. Mta.-1- and Mta.2-specific CTL lines were used to demonstrate Mta expression on lymphoid cells taken from spleen, thymus, lymph nodes, and bone marrow. In addition, Mta was expressed on cultured cell lines of myeloid, epithelial, and mesenchymal origin. Our results suggest that Mta is not a differentiation marker restricted to lymphocyte subpopulations.     

Vacuolar localization of wound-induced carboxypeptidase inhibitor in potato leaves

The wound-induced carboxypeptidase inhibitor in potato leaves was shown to be localized in the central vacuoles of the cells. The inhibitor was quantified by immunological assays (ELISA) in protoplasts and vacuoles isolated from upper unwounded leaves of 5- to 6-week old potato plants that had been wounded on their lower leaves 48 hours earlier to induce the accumulation of the carboxypeptidase inhibitor. The regulation of the synthesis and compartmentation of the inhibitor is similar to that of wound-induced serine proteinase Inhibitors I and II in potato and tomato leaves and appears to be part of an induced defense response against attacking pests.     

Wound-induced proteinase inhibitors from tomato leaves. II. The cDNA-deduced primary structure of pre-inhibitor II

A cDNA containing the complete amino acid-coding region of wound-induced tomato Inhibitor II was constructed in the plasmid pUC9. The open reading frame codes for 148 amino acids including a 25-amino acid signal sequence preceding the N-terminal lysine of the mature Inhibitor II. The Inhibitor II sequence exhibits two domains, one domain having a trypsin inhibitory site and the other a chymotrypsin inhibitory site, apparently evolved from a smaller gene by a process of gene duplication and elongation. The amino acid sequence of tomato leaf Inhibitor II exhibits homology with two small proteinase inhibitors isolated from potato tuber and an inhibitor from eggplant. The small potato tuber inhibitors are homologous with 33 amino acids of the N-terminal domain and 19 amino acids from the C-terminal domain. Two identical nucleotide sequences of Inhibitor II cDNA in the 3' noncoding region were present that were also found in an Inhibitor I cDNA. These include an atypical polyadenylation signal, AATAAG, and a 10-base palindromic sequence, CATTATAATG, for which no function is yet known.     

Lack of specificity of brain gangliosides in the modulation of lymphocyte activation

A potential role for glycolipid gangliosides to act as immunomodulating agents has been suggested. Most studies have employed brain gangliosides. We have systematically investigated highly purified murine brain gangliosides for their ability to modulate lymphocyte activation. All sialic acid classes of ganglioside inhibited lipopolysaccharide (LPS)-induced antibody secretion and all polysialated gangliosides inhibited LPS-induced DNA synthesis. Monosialated gangliosides had no effect on DNA synthesis induced by LPS. 8-BrcGMP-induced DNA synthesis was also inhibited, suggesting that a negative signal was delivered to B lymphocytes by co-cultivation with exogenous gangliosides. The lack of specificity with respect to sialic acid class observed in these studies suggests that further investigation of an immunomodulatory role for gangliosides focus on endogenous lymphocyte gangliosides.     

Isolation of Z-DNA binding proteins from SV40 minichromosomes: evidence for binding to the viral control region

Proteins dissociated from SV40 minichromosomes by increasing NaCl concentration were tested for their binding to Z-DNA [Br-poly(dG-dC)] and B-DNA [poly (dG-dC)]. Z-DNA binding proteins are largely released in 0.2 M NaCl whereas most B-DNA binding proteins are not released until 0.6 M NaCl. Incubation of SV40 minichromosomes with Z-DNA-Sephadex in low salt solution results in proteins with Z-DNA binding activity (PZ proteins). These proteins bind to negatively supercoiled DNAs containing left-handed Z-DNA but not to relaxed DNAs. They compete with anti-Z-DNA antibodies in binding to negatively supercoiled DNAs. The binding is tighter to negatively supercoiled SV40 DNA than to other plasmids, suggesting sequence-specific Z-DNA binding. PZ proteins binding to negatively supercoiled SV40 DNA interfere with cleavage at the Sph I sites, within the 72 bp repeat sequences of the viral control region, but not with cleavage at the Bgl I site, at the origin of replication. Removal of PZ proteins also exposes the Sph I sites in the SV40 minichromosomes while addition of PZ proteins makes the sites inaccessible.     

Study of the effect of β-1,3-glucanase fromBasidiomycete QM 806 on yeast extract production

Summary Cell free supernatants, containing -1,3-glucanase fromBasidiomycete QM 806, dramatically augmented the effect of papain on yeast autolysis. This enables the process time to be significantly reduced and/or the yield of extract to be substantially increased.     

Isolation and characterization of the proteinase inhibitor-inducing factor from tomato leaves. Identity and activity of poly- and oligogalacturonide fragments

Mild acid hydrolysis of a small (Mr = 6 kDa) pectic polysaccharide isolated from tomato leaves, an inducer of the synthesis and accumulation of two proteinase inhibitors in excised tomato plants, yielded a alpha-D-polygalacturonic acid polymer with degree of polymerization = 20 that retained proteinase inhibitor-inducing activity. Enzymic and acid hydrolysis of this polygalacturonan yielded a series of alpha-1,4-D-galacturonic acid oligomers with degrees of polymerization from 2 to 6 which were purified to homogeneity and assayed for proteinase inhibitor-inducing activity in young excised tomato plants. All of the oligomers exhibited activity. The hexagalacturonide possessed the highest activity and the trimer the lowest. The evidence supports a possible role for plant cell wall fragments as systemic messengers that regulate the expression of proteinase inhibitor genes in plant leaves in response to pest attacks.     

Recognition and response to alloantigens in vivo. I. Negative and positive selection of MLR reactivity in murine peripheral blood lymphocytes to major histocompatibility complex and Mls antigens

Specific mixed lymphocyte reaction (MLR) responsiveness to allogeneic major histocompatibility complex (MHC), or minor lymphocyte-stimulating (Mls) determinants, was depleted in the peripheral blood lymphocytes (PBL) obtained from mice 24 to 48 hr after i.v. injection of 5 to 7.5 X 10(7) MHC or Mlsa-incompatible spleen cells, respectively. Results of cell mixture experiments suggest that the generation of suppressor cells was not the explanation for this specific reduction in MLR proliferation occurring with these PBL responder cells. To gain additional insight into parameters involved in the recognition of allodeterminants in vivo, experimental manipulations of the host environment and donor cell inoculum utilized in the negative selection procedure were employed. For example, removal of the spleen in the recipient animal, an anatomic site in which injected allogeneic cells and corresponding host antigen-reactive cells (ARC) are trapped, still permitted the specific depletion in murine PBL of host ARC for donor foreign MHC antigens. This finding may implicate other sites such as the liver where unprimed host alloreactive clones are trapped. In addition, irradiation of allogeneic donor cells significantly reduced their capacity to trap alloreactive T cell clones in vivo, whereas heat treatment of the donor cells completely eliminated this ability, even though the Ia determinants were still expressed, measured by flow cytometry. After the negative selection period, kinetic analysis of proliferation showed that 3, 4, or 5 days after injection of MHC-incompatible allogeneic spleen cells, the PBL of the recipient showed specific hyperresponsiveness to the MHC-haplotype of the donor cells. Interestingly, these primed PBL responder cells had the volume distribution of small resting cells; thoracic duct lymphocytes (TDL), positively selected by adoptive transfer of T cells to irradiated semiallogeneic recipients, are reported to be mainly blast cells. In contrast to the MLR hyperresponsiveness that results from priming with MHC-incompatible splenocytes, PBL, obtained at these later time points from mice primed with Mlsa-incompatible, H-2-compatible splenocytes, showed complete unresponsiveness in MLR to these Mlsa-bearing stimulator cells, as well as some nonspecific reduction in proliferation to MHC-incompatible stimulator cells regardless of their Mls genotype.(ABSTRACT TRUNCATED AT 400 WORDS)     

Cellular requirements for induction of human primary proliferative responses to trinitrophenyl-modified cells

Cellular requirements for induction of primary proliferative responses by human T cells to trinitrophenylated autologous stimulators have been characterized. Substantial proliferative responses were observed with each of the Ia+ stimulator populations tested. Nevertheless, major differences in the hapten specificity of such responses were observed. Thus purified macrophages/monocytes (M phi) when TNP-modified induced responses that were relatively modest in absolute magnitude, but were highly hapten specific. This reflected the very limited capacity of purified M phi to induce proliferation when unmodified, i.e., an autologous mixed leukocyte response (AMLR). In contrast, unmodified M phi-depleted B plus null cells were potent stimulators of AMLR, but hapten modification did not significantly enhance the responses induced by these cells. Moreover, when M phi were added to B plus null cell stimulators AMLR responses were reduced and, with TNP-modified stimulators, hapten-specific responses were restored. The data thus suggest that M phi may have important roles in induction of primary T cell responses to conventional antigens but function largely as regulators rather than stimulators of AMLR. Finally, we have introduced a novel antigen-presenting cell population, the irradiated Ia+ TNP-specific cloned T cell. The possibility that such cells may utilize autostimulatory positive feedback circuits for activation of naive T cells and in interactions between subpopulations of hapten-reactive T cells is discussed.