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J Forman

Publications and source records attributed to J Forman.

At least 37 records · Page 2Linked to original sources
PubMed1990

Peripheral tolerance in mice expressing a liver-specific class I molecule: inactivation/deletion of a T-cell subpopulation.

We previously demonstrated that C3H/HeJ transgenic (TG) mice that express a laboratory-engineered class I molecule, Q10/L, exclusively on liver parenchymal cells show no evidence of hepatic disease even after deliberate immunization. Nevertheless, these animals demonstrate cytotoxic T-lymphocyte (CTL) activity specific for Q10/L, although it is less than that obtained from non-TG littermates. We now show that this decrease in CTL activity is not a reflection of a decrease in precursors, since both TG and normal animals have similar numbers. When non-TG C3H mice are primed with H-2Ld and H-2Kbm1 antigens, which extensively crossreact with Q10/L, their specific in vitro CTL activity directed against H-2Ld, H-2Kbm1, and Q10/L is increased 10- to 20-fold, as expected. Although primed TG mice show similar increases in in vitro CTL activity directed against H-2Ld and H-2Kbm1, they display no increase in anti-Q10/L activity. Whereas anti-H-2Ld spleen cells from non-TG mice readily generate CTL lines and clones specific for H-2Ld and Q10/L, TG cells give rise to anti-H-2Ld lines or clones only. These data indicate that the tolerance in TG mice is accounted for by the inactivation or deletion of an important CTL subpopulation having the capability of recognizing the peripheral antigen in situ. To determine whether tolerance would persist in the absence of Q10/L, TG cells were transferred into non-TG recipients. Three weeks later Q10/L-specific lytic activity generated in in vitro bulk cultures remained reduced compared to non-TG cells, indicating that the tolerant phenotype was stable during this interval.

Animals↗
PubMed1990

D2d, a D-End class I gene: tissue expression and alternative processing of the pre-mRNA.

The H-2D region in the major histocompatibility complex (MHC) of the BALB/c mouse includes at least five class I genes: Dd, D2d, D3d, D4d, and Ld. The pattern of expression and functions of the D2d, D3d, and D4d genes are not known. To examine the expression of D2d we obtained mouse L cells transfected with a wildtype D2d gene or an exon shufled D2d/D2d/Dd gene that contained exons encoding the alpha 1 and alpha 2 domains of D2d and the alpha 3 domain of H-2Dd. Analysis of the mRNA in transfected cells suggested that two forms of the message were generated at approximately equal abundance by alternative splicing. Several tissues were analyzed and shown to express both forms of the D2d mRNA although the highest levels were found in lymphoid organs. Tumor lines also expressed D2d mRNA but exhibited differing ratios of alternative versus normally spliced message. This ratio was also affected by treatment of cells with Con A supernatants that contain interferon or infection with vesicular stomatitis virus (VSV).

Amino Acid Sequence↗
PubMed1990

[Percutaneous valvuloplasty of congenital pulmonary stenosis in adults over 50 years of age].

The authors report three cases of congenital pulmonary stenosis in adults over 50 years of age treated by percutaneous balloon valvuloplasty. Three symptomatic women aged 74, 80 and 51, had systolic pressure gradients ranging from 107 to 113 mmHg between the right ventricle and pulmonary artery. After valvuloplasty with two balloons or one trefoil balloon, the transvalvular pressure gradient fell to 25 to 30 mmHg. It was only 14 mmHg in one patient controlled after one year's follow-up. The cardiac index was initially decreased and did not change very much immediately after the procedure, increasing from 1.68 1/m2/mn to 1.77 1/m2/mn. The pulmonary valve surface area increased from 0.22 to 0.43 cm2. There were no complications and in one patient, reviewed two years later, the clinical improvement was maintained. Percutaneous valvuloplasty is indicated in severe and/or poorly tolerated pulmonary stenosis. With the 10 other previously reported cases of patients over 50 years of age, the procedure was successful in 12 out of 13 patients (92%). In these patients of 51 to 80 years of age, the systolic pressure gradient between the right ventricle and pulmonary artery was reduced from 112 +/- 46 mmHg to 43 +/- 26 mmHg (-62%). Slight pulmonary regurgitation appeared in 5 out of 9 cases. Valvuloplasty was usually well tolerated and there were no fatalities. There were no signs of restenosis in 5 cases controlled 10 days to 1 year after dilatation. In the future, systematic Doppler echocardiographic examinations should help comparison of cardiac haemodynamics before, immediately after valvuloplasty and at long-term.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Non-ruptured calcified aneurysm of the Valsalva's sinus with angina pectoris and aortic insufficiency. Surgical treatment].

We report a case of aneurysm of the straight frontal, and not coronary, aortic sinus, non ruptured and calcified, responsible for a refractory angina pectoris and a massive aortic failure in a 71 year old woman. The surgical treatment consisted in the exclusion of the aneurysm of the aortic sinus by a tubular prosthesis in which only two thirds of the circumference have been used, associated with the replacement of an aortic valve by a bioprosthesis, without associated coronary by-pass.

Aged↗
PubMed1989

Expression of mutant H-2d proteins encoded by class I genes which alternatively process the 5' end of their transcripts.

Mutation of the 3' splice sites bordering exon 2 of the H-2Dd and H-2Kd genes generated alternatively spliced transcripts when the constructs were transfected into L cells (J. Immunol. 143:1018). The H-2Dd transcripts contained an additional 84 nucleotides derived from the first intervening sequence, whereas 60 extra bases were included in the H-2Kd mRNA. Proteins derived from these transcripts were recognized by mAb. Moreover, both Ag served as recognition elements for CTL, and the mutant H-2Kd molecule functioned as a restricting element for an Ag peptide. As a result of alternative splicing, the mutant proteins should have additional residues at their NH2 termini to increase their lengths by 28 (Dd) or 20 (Kd) amino acids. Immunoprecipitation and analysis on SDS-PAGE demonstrated that the mutant H-2Kd molecule was indeed larger than the normal H-2Kd protein, but the mutant and wild-type H-2Dd Ag were the same size. In addition, treatment of H-2Dd mutant and normal Ag with N-glycanase produced molecules of equal size, demonstrating that the mutant protein was completely glycosylated. Limited amino acid sequencing of this Ag indicated that it was normal H-2Dd. Therefore, before its transfer to the cell surface, post-translational modifications remove the additional NH2-terminal residues of the mutant Dd but not Kd protein.

Amino Acid Sequence↗
PubMed1989

Mutation of 3' splice sites in two different class I genes results in different usage of cryptic splice sites.

To determine the pattern of alternative splicing at the 5' end of class I genes, the 3' splice sites bordering exon 2 of the H-2Dd and H-2Kd genes were mutated from AG to GG (H-2Dd) or CG (H-2Kd). The mutant genes were transfected into L cells, and RNA from clones expressing these Ag was used for analysis by RNase and S1 nuclease mapping techniques. The first intervening sequence of both class I genes contains several potential 3' splice acceptor sites. However, a clear preference for only one site was detected in each of the H-2Dd and H-2Kd mRNA. Examination of the endogenous H-Dd and H-2Kd class I transcripts in normal murine tissues and in tumors demonstrated that the alternatively spliced mRNAs were produced, but at a low frequency. Infection of transfected L cells or tumor lines with vesicular stomatitis virus altered the level of differentially spliced message in these cells.

Animals↗
PubMed1989

Differential expression of the class I MHC genes in the embryo and placenta during midgestational development in the mouse.

A sensitive RNase mapping technique was used to investigate the expression of individual class I mRNA in the embryo and placenta of the mouse from day 7.5 through day 13 of gestation. Transcripts of the H-2Kd and -Dd genes appeared in both placental and embryonic tissues as early as day 7.5 post coitum and continued to be expressed thereafter. In contrast, H-2Ld mRNA was barely detectable in embryonic RNA until day 18 of pregnancy, although it was present in placental RNA samples on days 10 to 13 of gestation. Qa-region genes demonstrated a different pattern of expression than H-2Dd, -Kd, and -Ld. Transcripts of Q7, one of the genes encoding Qa-2 surface Ag, were detected in the developing embryo on days 9 to 11 post coitum but decreased thereafter. However, Q7d transcripts were not detected in placental tissues at any stage. Q6 mRNA was not detected in any of the tissues, and Q10 mRNA was detected only in day 12 to 13 embryos, where expression is known to be restricted to the fetal liver. Transcripts from T13, a Tla-region gene, and D2d, a D-region gene, were not detected in any of the samples tested. This study has revealed a complex pattern of class I gene regulation both within the genes of the MHC and between the embryo and placental lineages during the midgestational stages of development.

Animals↗
PubMed1989

An H-2Ld hybrid molecule with a Qa-2 alpha-3 domain and phosphatidyl-inositol anchor is not recognized by H-2Ld-specific cytotoxic T lymphocytes.

Ld/Q7d, a hybrid molecule consisting of alpha-1 and alpha-2 domains from H-2Ld and alpha-3 and carboxy-end components from Q7d, was expressed on the surface of CRL-3A rat liver cells. This molecule retained serologic H-2Ld epitopes. The Ag is attached to the cell membrane through a phosphatidyl-inositol linkage, characteristic of Qa-2 molecules. Both bulk cultured and cloned H-2Ld alloreactive CTL as well as H-2Ld restricted vesicular stomatitis virus-specific CTL lyse CRL-3A cells which express H-2Ld but show little or no lytic activity on cells which express the Ld/Q7d hybrid. These cells also fail to act as cold target competitors for alloreactive anti-H-2Ld CTL. However, cells expressing Ld/Q7d are not resistant to CTL mediated lysis because they can be killed in the presence of lectin. These data indicate that recognition of polymorphic class I CTL epitopes in the alpha-1 and alpha-2 domains are influenced by the structure of the carboxy-end of the molecule.

Animals↗
PubMed1989

Analysis of D2d: a D-region class I gene.

The mouse major histocompatibility complex is composed of several genes arranged into the K, D, Qa, and Tla regions. The D region of the BALB/c mouse includes genes D2d, D3d, and D4d, in addition to H-2Dd and H-2Ld. We have determined the DNA sequence of the D2d gene and compared it with the known sequences of several class I genes. The exon/intron structure of the D2d gene is similar to other class I genes. It also contains similar 5' regulatory elements. A frameshift occurs in exon seven, resulting in a gene product with a truncated cytoplasmic tail. To examine the surface expression of the D2d molecule, we generated an exon-shuffled construct containing the promoter and exons 1-3, encoding the signal peptide, alpha 1, and alpha 2 external domains of the D2d gene linked to exons 4-8, encoding the alpha 3, transmembrane and cytoplasmic domains, of the H-2Dd gene. The construct was transfected into mouse L cells, and a protein was detected at the cell surface by a monoclonal antibody (mAb) specific for the alpha 3 domain of H-2Dd, as well as by other class I-specific mAbs. Although D2d is expressed at low levels, it may be a functional class I gene that most probably evolved from a Qa region gene.

Amino Acid Sequence↗
PubMed1989

Effect of indomethacin, cycloheximide, and aminoglutethimide on ovarian steroid and prostanoid levels during ovulation in the gonadotropin-primed immature rat.

It has become popular to use the gonadotropin-primed immature rat to study ovulation. The ovarian content of progesterone, estradiol, PGE2, PGF2 alpha, and 6-keto-PGF1 alpha during the ovulatory process was determined in this model. Also, the effect of three anti-ovulatory agents on the ovarian levels of the above substances was determined. At 23 days of age, Wistar rats were primed with pregnant mares serum gonadotropin (PMSG) sc, and two days later the ovulatory process was initiated with human chorionic gonadotropin (hCG) sc. The ovarian follicles began rupturing 12 h later. Ovaries were assayed for the two steroids and prostanoids at 2-h intervals before and several 4-h intervals after ovulation. The ovarian estradiol level increased slightly between 0 and 2 h after hCG, while the progesterone level increased sharply between 2 and 4 h after hCG--at a time when the estradiol declined markedly. All three prostanoids increased concomitantly with progesterone. When the PG synthesis was blocked by indomethacin treatment at 1 h before hCG, ovarian progesterone levels still increased. In contrast, when steroidogenic activity was inhibited by aminoglutethimide, the ovarian prostanoid levels also decreased. Cycloheximide had little effect on the steroids and prostanoids. It is concluded that ovarian prostanoid synthesis might be influenced by ovarian steroid output.

Aminoglutethimide↗
PubMed1989

Developmental coupling of expression of the Igh-linked minor antigen H-40 to membrane immunoglobulin expression.

C.B-20 (Ighb) but not BALB/c (Igha) mice are able to reject BCL1, a spontaneous B cell leukemia of BALB/c origin. The protective immune response is directed toward the minor histocompatibility (H) antigen, H-40, which can be detected by cytotoxic T lymphocytes and is expressed on surface (s) immunoglobulin positive tumor cells including BCL1 as well as sIg+ lymphoblasts activated by lipopolysaccharide. The fact that only sIg+ tumor cells and lymphoblasts express H-40 suggests that sIg itself may be a component involved in CTL recognition of this antigen. However, this possibility was ruled out by demonstrating that removal of sIg from target cells did not prevent H-40-specific CTL recognition. To determine whether H-40 expression was coordinately regulated with that of membrane Ig, we determined whether H-40- sIg- cells acquire H-40 when induced to express sIg. We also transfected a functional mu c and nu region gene into a sIg- lymphoma so that it acquired a sIg+ phenotype. In neither case did such sIg+ cells acquire H-40. Together, these data indicate that H-40 is expressed on B cells representing a particular stage of differentiation that is coincidental with sIg. We previously showed that H-40 and Igh loci are linked on the 12th murine chromosome. In this study we further localized H-40 to a point beyond Aat (formerly Pre-1) near Lm-1, a locus previously described to encode minor H-antigens expressed on lymphomyeloid cells. Thus, H-40 and Lm-1 may represent a gene cluster encoding antigens expressed on subsets of lymphoid and myeloid cells.

Animals↗
PubMed1988

HLA-B27 in inbred and non-inbred transgenic mice. Cell surface expression and recognition as an alloantigen in the absence of human beta 2-microglobulin.

A gene encoding the H chain of the human class I MHC Ag HLA-B27 was introduced into the germ lines of inbred C57BL/6 (B6) and non-inbred (B6 X SJL/J) F2 mice. By immunofluorescence and flow cytometry, the HLA-B27 gene product was expressed on lymphoid cells at levels comparable to the endogenous H-2b and H-2s class I MHC molecules. In both primary and secondary MLC between responder spleen cells from non-transgenic (B6 X SJL/J) F1 mice and transgenic stimulator cells, CTL were generated that specifically lysed mouse L cell (H-2k) or human B cell targets expressing HLA-B27, and this lysis thus appeared largely unrestricted by H-2. These results indicate that transgenic mice express a functional HLA-B27 gene product on cell surfaces in the absence of the human beta 2-microglobulin gene. These transgenic mice promise to be a valuable resource in the investigation of the unique role of HLA-B27 in inflammatory human disease.

Animals↗
PubMed1988

Recognition by cytotoxic T lymphocytes of Qa-2 antigens. Sensitivity of Qa-2 molecules to phosphatidylinositol-specific phospholipase C.

Con A splenic lymphoblasts were incubated with phosphatidyl-inositol specific phospholipase C (PIPLC) derived from Bacillus thuringiensis and subsequently analyzed for Qa-2 Ag with the Qa-2 reactive mAb Qa-m2. This treatment completely removed Qa-2 detectable Ag on lymphoblasts from H-2d animals, indicating that these molecules are likely anchored to the cell membrane through phosphatidyl inositol (PI). Although exposure of lymphoblasts from H-2b mice to PIPLC greatly reduced Qa-2 expression, a subpopulation of cells retained a limited quantity of the Ag. Bulk cultured anti-Qa-2 CTL generated against the Qa-2 region from H-2b haplotype mice lysed Qa-2+ targets from B6.K2 (H-2b) and BALB/cJ (H-2d) animals. Pretreatment of these lymphoblast targets with PIPLC completely abolished lysis of the BALB/cJ target cells, whereas lysis of B6 targets was reduced only slightly. Anti-Qa-2 CTL clones tested against PIPLC-treated B6 target cells revealed two patterns of reactivity. One group of clones was unaffected in its ability to lyse PIPLC-pretreated targets and cross-reacted on Q6d/Ld molecules expressed on transfected L cells. A second group was unable to lyse PIPLC-pretreated lymphoblasts and cross-reacted on Q7d/Ld targets. These data suggest that H-2b-derived lymphoblasts express two different types of Qa-2 molecules with respect to PIPLC sensitivity; one type is sensitive to PIPLC and cross-reactive with Q7d, the other type is resistant to PIPLC and cross-reactive with Q6d. In contrast, H-2d lymphoblasts express only the PIPLC-sensitive type of molecules. It was also noted that bulk cultured anti-Qa-2 CTL more readily lysed H-2b target cells expressing a smaller quantity of PIPLC-resistant Ag than H-2d targets expressing a larger amount of PIPLC-sensitive Ag. Further, anti-Qa-2 CTL clones readily lysed PIPLC-treated target cells expressing very low levels of serologically detectable Qa-2. This suggests that recognition of class I molecules anchored to the membrane via a PIPLC-resistant linkage may more readily activate CTL for expression of lytic activity than molecules anchored through PI.

Animals↗
PubMed1988

An immunodominant epitope present in multiple class I MHC molecules and recognized by cytotoxic T lymphocytes.

CTL derived from (C3H x B6.K1)F1 animals were sensitized against L cells that express the transfected gene product Q10d/Ld. These CTL were highly crossreactive against three other class I molecules, H-2Kbm1, H-2Ld, and H-2Kd. In an attempt to define this crossreactive epitope it was noted that between 25 and 39% of amino acids in the alpha helices and central beta strands of these three molecules vary from Q10d. These amino acids represent residues that have been proposed to potentially interact with a peptide antigen or TCR (21). However, all four molecules share the amino acid tyrosine at positions 155 and 156. Additionally, Q10d, H-2Kbm1, and H-2Ld share alanine at position 152, while H-2Kd has an aspartic acid. We showed that these residues were important in controlling this epitope by the finding that anti-Q10d CTL did not recognize H-2Kbm1 revertant molecules that had either the position 152 alanine changed back to the wild-type H-2Kb residue (glutamic acid) or position 155 and 156 tyrosines changed back to wild-type residues arginine and leucine. Further evidence that these molecules share a crossreactive epitope was noted by the failure of (C3H x H-2Kbm1)F1 animals to generate CTL that recognized H-2Ld or H-2Kd, and the inability of (C3H x BALB/c)F1 animals to generate CTL reactive against H-2Kbm1. CTL from these mice were still able to recognize Q10d/Ld indicating that other epitopes could be detected if natural tolerance prevented recognition of the crossreactive epitope. To further define the epitope, CTL clones were generated against Q10d/Ld and maintained on either H-2Kbm1 or BALB/c feeder cells. In addition to testing these clones on the target cells described above, mutant molecules derived from H-2Ld, which have amino acid substitutions in their alpha 1 domain, were analyzed. It was noted that some anti-Q10 clones that did not crossreact on H-2Ld did react against H-2Ld mutant antigens that had H-2Dd amino acid substitutions in the alpha 1 domain at positions 63, 65, 66, and 70. Other clones had differential reactivities on these H-2Ld mutants further substantiating that alpha 1 domain amino acids play a role in controlling the expression of the crossreactive epitope. Thus, four class I molecules with multiple amino acid differences in their alpha 1 and alpha 2 domains share a crossreactive epitope readily recognized by alloreactive CTL.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1988

Selective expression of the Ly-6C.2 epitope on Lyt-2+ T cells that can develop in the absence of thymic influence.

The present study focused on attempts to correlate the expression of T cell differentiation antigens and development. A series of mAb was developed that recognized an Ly-6.2-linked Ag, Ly-6C.2. These mAb reacted with a subset of peripheral Lyt-2+ T lymphocytes but not Lyt-2+ thymocytes. Functional analysis of the Lyt-2+, Ly-6C.2- and Lyt-2+, Ly-6C.2+ subsets demonstrated that both cell types responded in class I and class II allogeneic MLC as well as in virus-specific cell-mediated cytolysis assay, although precursor frequency analysis suggested that the majority of precursor CTL were Ly-6C.2+. The marker did not appear to represent an activation Ag because Ly-6C.2-, Lyt-2+ precursor CTL generated Ly-6C.2-, Lyt-2+ CTL. Finally, virtually all splenic Lyt-2+ T cells from athymic (nu/nu) mice were Ly-6C.2+ whereas all thymic CTL were Ly-6C.2-. These results suggested that Ly-6C.2+, Lyt-2+ T cells may represent a distinct lineage of Lyt-2+ T cells that can develop in the absence of thymic influence.

Animals↗
PubMed1988

A third class I major histocompatibility complex antigen encoded by a gene in the D region of the H-2d haplotype recognized by cytotoxic T lymphocytes.

The D region of the H-2d haplotype contains five class I genes: H-2Dd, D2d, D3d, D4d and H-2Ld. Although previous studies have suggested the presence of D-end encoded class I molecules in addition to H-2Dd and H-2Ld, segregation of genes encoding such molecules has not been demonstrated. In this report we have used cytotoxic T lymphocytes (CTL) to examine the D region of the H-2d haplotype for the presence of additional class I molecules. CTL generated in (C3H x B6.K1)F1 (KkDk, KbDb) mice against the hybrid class I gene product Q10d/Ld expressed on L cells cross-react with H-2Ld but not H-2Dd molecules, as determined by lysis of transfected cells expressing H-2Ld but not H-2Dd. Although H-2Ld-specific monoclonal antibodies (mAb) completely inhibit H-2Ld-specific CTL from killing B10.A(3R) (KbDdLd) target cells, only partial inhibition of anti-Q10 CTL-mediated lysis was observed, suggesting the presence of an additional D-end molecule as a target for these latter CTL. To identify the region containing the gene encoding the Q10 cross-reactive molecule, we show that anti-Q10 CTL lyse target cells from a D-region recombinant strain B10.RQDB, which has H-2Dd, D2d, D3d, D4d, and H-2Db but not the H-2Ld H-2d, and H-2Ld (including D2d, D3d, and D4d), lacks this anti-Q10 CTL target molecule. Together, these data demonstrate that a class I gene mapping between H-2Dd and H-2Ld encodes an antigen recognized by anti-Q10 CTL. A likely candidate for this gene is D2d, D3d, or D4d.

Animals↗
PubMed1988

Linked recognition of helper and cytotoxic antigenic determinants for the generation of cytotoxic T lymphocytes.

These studies present a model for T-T collaboration for the generation of cytotoxic T lymphocytes. The in vitro CTL response against Qa-1 alloantigens in B6 Qa-1 congenic mice requires that animals are first primed in vivo with Qa-1 together with a second (helper) antigen. Both the antigen recognized by CTL (Qa-1) and Th (H-Y) must be presented on the same APC for successful priming. This findings is consistent with a linked recognition model whereby both molecules are presented on the same APC in order to accomplish close proximity between the two T cells. To further test this model, we demonstrated that in the absence of the helper antigen, H-Y, mice could be successfully primed against Qa-1 if coinoculated with a product of a Th, IL-2. We further showed that mice treated with anti-L3T4 antibodies could not be primed to Qa-1 even though the cells used for immunization expressed the H-Y helper antigen. Taken together, these results lend further support to a model of linked recognition between Th and CTL.P where close proximity allows for the lymphokine IL-2 to bind to its receptor on the CTL allowing for the successful induction of CTL.P.

Animals↗