bluuebunny/crossref_metadata_2025 huggingface dataset:
Gorilla class I major histocompatibility complex alleles: comparison to human and chimpanzee class I.
Authors: Lawlor D A , Warren E , Taylor P , Parham P
Published: June 2004

14 gorilla class I major histocompatibility complex (MHC) alleles have been isolated, sequenced, and compared to their counterparts in humans and chimpanzees. Gorilla homologues of HLA-A, -B, and -C were readily identified, and four Gogo-A, four Gogo-B, and five Gogo-C alleles were defined. In addition, an unusual Gogo class I gene with features in common with HLA-A and its related pseudogene, HLA-H, is described. None of the gorilla alleles is identical or even closely related to known class I alleles and each encodes a unique antigen recognition site. However, the majority of polymorphic substitutions and sequence motifs of gorilla class I alleles are shared with the human or chimpanzee systems. In particular, elements shared with HLA-A2 and HLA-B27 are found in Gogo-A and -B alleles. Diversity at the Gogo-B locus is less than at the Gogo-A locus, a trend the opposite of that seen for HLA-A and -B. The Gogo-C locus also appears to have limited polymorphism compared to Gogo-A. Two basic Gogo-C motifs were found and they segregate with distinctive sets of HLA-C alleles. HLA-A allels are divided into five families derived from two ancient lineages. All chimpanzee A alleles derived from one of these lineages and all gorilla alleles derive from the other. Unlike chimpanzee Patr-A alleles, the Gogo-A alleles do not clearly partition with one of the HLA-A families but have similarities with two. Overall, gorilla class I diversity appears from this sampling to show more distinctions from class I HLA than found for chimpanzee class I.
Interleukin 7 generates antitumor cytotoxic T lymphocytes against murine sarcomas with efficacy in cellular adoptive immunotherapy.
Authors: Jicha D L , Mulé J J , Rosenberg S A
Published: June 2004

Interleukin 7 (IL-7) is a 25-kD cytokine that was initially described as a pre-B cell growth factor. This cytokine has also been shown to have T cell proliferative and differentiation effects. In this report, we demonstrate that antitumor cytotoxic T lymphocytes (CTL) generated by secondary in vitro sensitization of draining lymph node cells in IL-7 are effective in treating 3-day syngeneic methylcholanthrene (MCA) sarcoma pulmonary metastases in mice. In vivo titrations comparing IL-7 to IL-2 antitumor CTL show that they have equivalent potency in adoptive immunotherapy. IL-7 antitumor CTL generated against MCA sarcomas of weak immunogeneity are also tumor specific in their in vivo efficacy. This study represents the first successful use of a cytokine other than IL-2 for the generation of cells with in vivo efficacy in cellular adoptive transfer.
Cytotoxic T lymphocytes recognize an HLA-A2-restricted epitope within the hepatitis B virus nucleocapsid antigen.
Authors: Penna A , Chisari F V , Bertoletti A , Missale G , Fowler P , Giuberti T , Fiaccadori F , Ferrari C
Published: June 2004

The absence of readily manipulable experimental systems to study the cytotoxic T lymphocyte (CTL) response against hepatitis B virus (HBV) antigens has thus far precluded a definitive demonstration of the role played by this response in the pathogenesis of liver cell injury and viral clearance during HBV infection. To circumvent the problem that HBV infection of human cells in vitro for production of stimulator/target systems for CTL analysis is not feasible, a panel of 22 overlapping synthetic peptides covering the entire amino acid sequence of the HBV core (HBcAg) and e (HBeAg) antigens were used to induce and to analyze the HBV nucleocapsid-specific CTL response in nine patients with acute hepatitis B, six patients with chronic active hepatitis B, and eight normal controls. By using this approach, we have identified an HLA-A2-restricted CTL epitope, located within the NH2-terminal region of the HBV core molecule, which is shared with the e antigen and is readily recognized by peripheral blood mononuclear cells from patients with self-limited acute hepatitis B but less efficiently in chronic HBV infection. Our study provides the first direct evidence of HLA class I-restricted T cell cytotoxicity against HBV in humans. Furthermore, the different response in HBV-infected subjects who successfully clear the virus (acute patients) in comparison with patients who do not succeed (chronic patients) suggests a pathogenetic role for this CTL activity in the clearance of HBV infection.
Limiting dilution analysis of cytotoxic T lymphocytes to human immunodeficiency virus gag antigens in infected persons: in vitro quantitation of effector cell populations with p17 and p24 specificities.
Authors: Koup R A , Pikora C A , Luzuriaga K , Brettler D B , Day E S , Mazzara G P , Sullivan J L
Published: June 2004

The presence of cytotoxic T lymphocytes (CTL) to the gag antigens of human immunodeficiency virus (HIV) has been described in infected populations. We found that the majority of this immune response as measured in bulk CTL assays of unstimulated peripheral blood mononuclear cells (PBMC) is directed against the p24 component of the p55 gag precursor protein. Using limiting dilution analysis of this effector cell population we confirm that the majority of activated gag-specific CTL circulating in the PBMC of infected hemophilic patients are directed at p24 determinants and are present at frequencies of 1/36,000 to 1/86,000 lymphocytes. By performing in vitro stimulation after limiting dilution, the precursor population of gag-specific CTL are characterized and quantitated. HIV gag-specific CTL precursors are identified at frequencies of 1/1700 to 1/17,000 lymphocytes and are made up of cells with both p17 and p24 specificities. No HIV gag-specific CTL precursor cells are identified in the PBMC of HIV-uninfected individuals. These studies demonstrate that CTL directed at both p17 and p24 determinants make up the cellular immune repertoire in HIV-infected individuals but that only the p24-specific CTL are routinely found in an activated state in the circulation.
A gene required for class II-restricted antigen presentation maps to the major histocompatibility complex.
Authors: Mellins E , Kempin S , Smith L , Monji T , Pious D
Published: June 2004

We have previously described a set of mutants (16.23-selected mutants) of a B lymphoblastoid cell line that are defective in the presentation of intact proteins to class II-restricted T cells, but effectively present immunogenic peptides. The mutations in these mutants are recessive in somatic cell hybrids and are not in Class II structural genes. Here, we report on a unique mutant, 5.2.4, in which a similar defect in class II-restricted antigen presentation has occurred in association with a one-megabase homozygous deletion in the class II region of the major histocompatibility complex (MHC). The defects in class II presentation among three of the 16.23-selected mutants, and between these mutants and 5.2.4, are noncomplementary in somatic cell hybrids. This suggests that the class II presentation-defective phenotype in all four mutants results from lesions in a single MHC-linked gene, a conclusion strengthened by the finding that in a hybrid made with a second, unrelated MHC deletion mutant, T2, the class II presentation defect in a 16.23-selected mutant is also not complemented. Mutant 5.2.4, in addition to its class II presentation defect, is also defective in surface expression of MHC class I molecules, most likely because its deletion encompasses the peptide supply factor 1 gene, whose function is known to be required for normal abundance of cell surface class I molecules. However, the surface abundance of class I molecules is normal in the 16.23-selected mutants, suggesting that the lesions affecting class I surface abundance and class II presentation result from mutations in different genes.
Developmental potential of the earliest precursor cells from the adult mouse thymus.
Authors: Wu L , Antica M , Johnson G R , Scollay R , Shortman K
Published: June 2004

A new, numerically minute population of cells representing the earliest T precursor cells in the adult mouse thymus has recently been isolated. This population has been shown to be similar to bone marrow hemopoietic stem cells in surface antigenic phenotype and to express moderate levels of CD4. We now show, by fluorescence-activated cell sorting and intrathymic transfer to irradiated mice, that this apparently homogeneous population differs from multipotent stem cells in expressing the surface stem cell antigen 2 (Sca-2), that it differs from most early B lineage cells in lacking B220 and class II major histocompatibility complex expression, and that it binds rhodamine 123 like an activated rather than a quiescent cell. Irradiated recipient mice differing at the Ly 5 locus were used to compare the developmental potential of these early intrathymic precursors with bone marrow stem cells. Only T lineage product cells were detected when the intrathymic precursor population was transferred back into an irradiated thymus. However, when the intrathymic precursor population was transferred intravenously, it displayed the capacity to develop into both B and T lymphoid cells in recipient bone marrow, spleen, and lymph nodes, but no donor-derived myeloid cells were detected. The absence of myeloid and erythroid precursor activity was confirmed by showing that the intrathymic precursor population was unable to develop into myeloid or erythroid spleen colonies on intravenous transfer or to form colonies in an agar culture. These findings indicate that this earliest intrathymic precursor population has become restricted (or strongly biased) to lymphoid lineage development, but not exclusively to T lymphocytes.
Retention of adenovirus E19 glycoprotein in the endoplasmic reticulum is essential to its ability to block antigen presentation.
Authors: Cox J H , Bennink J R , Yewdell J W
Published: June 2004

The E3/19K glycoprotein of adenovirus functions to diminish recognition of adenovirus-infected cells by major histocompatibility complex class I-restricted cytotoxic T lymphocytes (CTLs) by binding intracellular class I molecules and preventing them from reaching the plasma membrane. In the present study we have characterized the nature of the interaction between E3/19K and the H-2Kd (Kd) molecule. An E3/19K molecule genetically engineered to terminate six residues from its normal COOH terminus (delta E19), was found to associate with Kd in a manner indistinguishable from wild-type E3/19K. Unlike E3/19K, however, delta E19 was transported through the Golgi complex to the plasma membrane, where it could be detected biochemically and immunocytochemically using a monoclonal antibody specific for the lumenal domain of E3/19K. Importantly, delta E19 also differed from E3/19K in being unable to prevent the presentation of Kd-restricted viral proteins to CTLs. This is unlikely to be due to delta E19 having a lower avidity for Kd than E3/19K, since delta E19 was able to compete with E3/19K for Kd binding, both physically, and functionally in nullifying the E3/19K blockade of antigen presentation. These findings indicate that the ability of E3/19K to block antigen presentation is due solely to its ability to retain newly synthesized class I molecules in the endoplasmic reticulum.
Molecular characteristics of antibodies bearing an anti-DNA-associated idiotype.
Authors: Manheimer-Lory A , Katz J B , Pillinger M , Ghossein C , Smith A , Diamond B
Published: June 2004

Anti-double-stranded DNA antibodies are the hallmark of the disease systemic lupus erythematosus and are believed to contribute to pathogenesis. While a large number of anti-DNA antibodies from mice with lupus-like syndromes have been characterized and their variable region genes sequenced, few human anti-DNA antibodies have been reported. We describe here the variable region gene sequences of eight antibodies produced by Epstein-Barr virus (EBV)-transformed B cells that bear the 3I idiotype, an idiotype expressed on anti-DNA antibodies and present in high titer in patients with systemic lupus. The comparison of these antibodies to the light chains of 3I+ myeloma proteins and serum antibodies reveals that EBV transformation yields B cells producing antibodies representative of the expressed antibody repertoire. The analysis of nucleotide and amino acid sequences of these antibodies suggests the first complementarity determining region of the light chain may be important in DNA binding and that paradigms previously generated to account for DNA binding require modification. The understanding of the molecular genetics of the anti-DNA response requires a more complete description of the immunoglobulin germ line repertoire, but data reported here suggest that somatic diversification is a characteristic of the anti-DNA response.
Conversion of a self peptide sequence into a Kd-restricted neo-antigen by a Tyr substitution.
Authors: Healy F , Drouet C , Romero P , Jaulin C , Maryanski J L
Published: June 2004

We have previously found that a Tyr residue was critical for the interaction of peptides with the Kd molecule, and therefore may be acting as an anchor residue. In the present report we show that it is possible to convert a self peptide sequence into a Kd-restricted neo-antigen by a single Tyr substitution at position 2 of the peptide. This supports the idea that Tyr is a critical element in the binding motif of Kd-restricted peptides and is a finding that could also prove useful for vaccine development.
Human immunodeficiency virus infection of eosinophils in human bone marrow cultures.
Authors: Freedman A R , Gibson F M , Fleming S C , Spry C J , Griffin G E
Published: June 2004

Normal human bone marrow, cultured in vitro with interleukin 5 to promote eosinophil production and maturation, was inoculated with cell-free isolates of human immunodeficiency virus type 1 (HIV-1). CD4 expression by eosinophil precursors, determined by immunocytochemistry, was found to be greatest early in their maturation with a rapid decline after 28 d in culture. Productive HIV infection of eosinophil precursors was detected 14 d after inoculation, by a combination of immunostaining for HIV-1 p24 and gp41/160 and in situ hybridization for viral RNA, together with assay of culture supernatants for p24 antigen and reverse transcriptase activity. Thus, eosinophils are susceptible to productive HIV-1 infection in vitro and may be an important reservoir for the virus in vivo.
Fine specificity of cytotoxic T lymphocytes primed in vivo either with virus or synthetic lipopeptide vaccine or primed in vitro with peptide.
Authors: Schild H , Norda M , Deres K , Falk K , Rötzschke O , Wiesmüller K H , Jung G , Rammensee H G
Published: June 2004

Standard synthetic peptide preparations contain numerous peptidic byproducts in small amounts, which may be efficiently recognized by cytotoxic T lymphocytes (CTL). Recognition patterns of such peptide mixtures by CTL may serve as a kind of fingerprint for CTL fine specificity. Three types of H-2Db-restricted CTL were compared in this way. CTL primed in vivo either with A/PR/8/34 influenza virus or with a synthetic lipopeptide vaccine prepared from influenza nucleoprotein (NP) peptide 365-380 showed identical fine specificity. Both recognize virus-infected cells. In contrast, CTL primed in vitro with NP 365-380 had a different fine specificity and they did not recognize virus-infected cells. Most significantly, the two in vivo primed CTL types efficiently recognized the natural viral nonapeptide NP 366-374 presented by virus-infected H-2b cells, whereas the in vitro primed CTL failed to do so.
Immunity to Trichinella spiralis infection in vitamin A-deficient mice.
Authors: Carman J A , Pond L , Nashold F , Wassom D L , Hayes C E
Published: June 2004

Vitamin A-deficient (A-) mice make strikingly poor IgG responses when they are immunized with purified protein antigens. Previously, we showed that A- T cells overproduce interferon gamma (IFN-gamma), which then could inhibit interleukin 4 (IL-4)-stimulated B cell IgG responses. To determine if the altered IFN-gamma regulation pattern and its immunological consequences would extend to a natural infection, we studied mice infected with the parasitic helminth Trichinella spiralis. The course of the infection was similar in A- and A-sufficient (A+) mice. These mice did not differ with respect to newborn larvae/female/hour produced in the intestine, or muscle larvae burden 5 wk postinfection. They also did not differ in the intestinal worm expulsion rate until day 15, when A- mice still harbored parasites, whereas A+ mice had cleared intestinal worms. Vitamin A deficiency reduced both the frequency of B lymphocytes secreting IgG1 antibodies to parasite antigens, and the bone marrow eosinophilia associated with helminth infection. The cytokine secretion patterns in infected mice were consistent with these observations and with previous studies. Mesenteric lymph node cells from infected A- mice secreted significantly more IFN-gamma, and significantly less IL-2, IL-4, and IL-5 than infected A+ controls. A- splenocytes secreted significantly more IFN-gamma, and equivalent amounts of IL-2, IL-4, and IL-5 compared with A+ controls. Interestingly, CD4-CD8- cells secreted the majority of the IL-4 produced in the spleen. The IL-2, IL-4, and IL-5 steady-state transcript levels correlated with secreted protein levels, but IFN-gamma transcripts did not. Although they secreted more protein, A- cells contained fewer IFN-gamma transcripts than A+ cells. These results suggest two vitamin A-mediated regulation steps in IFN-gamma gene expression: positive regulation of IFN-gamma transcript levels, and negative regulation posttranscriptionally. The essentially unaltered outcome of T. spiralis infection in vitamin A-deficient mice probably reflects a balance between cellular and humoral responses. The IFN-gamma overproduction might have a positive effect on the gut inflammatory response, but the decrease eosinophilia, cytokine production in mesenteric lymph node, and IgG1-secreting cell frequency might have a negative effect on T. spiralis immunity.
Small B cells as antigen-presenting cells in the induction of tolerance to soluble protein antigens.
Authors: Eynon E E , Parker D C
Published: June 2004

We have investigated the ability of resting B cells, acting as antigen-presenting cells, to induce tolerance to soluble protein antigens in mice, using an antigen targeted specifically to B cells. We inject mice intravenously with ultracentrifuged Fab fragments of rabbit anti-mouse immunoglobulin D (IgD) (Fab anti-delta). Treatment with Fab anti-delta results in profound tolerance to challenge with 100 micrograms Fab nonimmune rabbit Ig (Fab NRG), precipitated in alum, as measured by antibody production. Tolerance to rabbit Fab is antigen specific, since the treated mice make normal antibody responses to a control antigen, chicken Ig. Tolerance is dependent on antigen presentation by B cells, since intravenous injection of soluble Fab NRG, which is not targeted to B cells, results in a much lower frequency and degree of tolerance, especially at lower doses. T cell help in this system is affected, since T cells from Fab anti-delta-treated mice fail to provide help for an adoptive primary antibody response to Fab NRG when transferred together with normal B cells into severe combined immunodeficient (SCID) mice. The antigen-specific B cell compartment is also affected during tolerance induction, since B cells from treated animals make less antibody than normal B cells when transferred into SCID mice with normal T cells. Although the mechanism of nonresponsiveness in the helper T cell compartment remains to be determined, we think it is likely that the precursors of helper T cells are inactivated or deleted by encountering antigen presented by small, resting B cells, which lack accessory signals necessary to induce helper T cell proliferation and differentiation to effector function.(ABSTRACT TRUNCATED AT 250 WORDS)
Stroma is critical for preventing or permitting immunological destruction of antigenic cancer cells.
Authors: Singh S , Ross S R , Acena M , Rowley D A , Schreiber H
Published: June 2004

Inoculated immunogenic cancer cells after initial growth are potentially rejected by specific host immunity; however, the outcome of the interaction between host and inoculated cancer cells is a function of multiple factors including the route of inoculation, the number of cells, the density of antigens on the injected cancer cells, and the state of the immune system of the host. In the present study, we have examined a different kind of variable: the stroma that inoculated tumor cells initially reside in. The impetus to examine this factor arises from observations that cancer cells from several lines inoculated as fragments of solid tumors often grow progressively, whereas the same number or more than 10-fold larger numbers of identical type cells injected as a suspension are rejected, even though fragments or suspended cells are both tumorigenic at the same doses in nude mice. In the present studies, we found that: (a) indeed, cancer cells inoculated as fragments were more tumorigenic than cancer cells in suspension; (b) the tumorigenicity of suspended cancer cells was increased by injection of the cells into polyurethane sponge implants; (c) cancer cells were more tumorigenic embedded in syngeneic stroma than in transgenic antigenic stroma expressing the K216 major histocompatibility complex class I antigen; and (d) antigenic, bone marrow-derived, stromal components (presumably passenger leukocytes) were sufficient to cause rejection of immunogenic but antigenically unrelated cancer.(ABSTRACT TRUNCATED AT 250 WORDS)
Cross-species transplantation tolerance: rat bone marrow-derived cells can contribute to the ligand for negative selection of mouse T cell receptor V beta in chimeras tolerant to xenogeneic antigens (mouse + rat----mouse).
Authors: Ildstad S T , Vacchio M S , Markus P M , Hronakes M L , Wren S M , Hodes R J
Published: June 2004

Mixed xenogeneic bone marrow reconstitution (mouse + rat----mouse) results in stable mixed lymphopoietic chimerism (1-48% rat), long-term survival, and the induction of stable functional donor-specific transplantation tolerance to xenoantigens in vivo. To examine the role of negative selection of potentially xenoreactive T lymphocytes during tolerance induction across a species barrier, mixed xenogeneic chimeras (mouse + rat----mouse) were prepared and analyzed using a mixture of mouse and rat bone marrow cells for relative T cell receptor (TCR)-V beta expression on mouse T cells. In mixed xenogeneic chimeras (B10 mouse + rat----B10 mouse), T cell maturation proceeded normally in the presence of rat bone marrow-derived elements, and functional donor-specific tolerance to rat xenoantigens was present when assessed by mixed lymphocyte reactivity in vitro. V beta 5, which is expressed at high (undeleted) levels in normal B10 mice, was consistently deleted in B10 recipients of Wistar Furth (WF), but not F344 rat bone marrow, whereas the coadministration of either F344 rat or WF rat bone marrow with B10 mouse bone marrow cells resulted in a significant decrease in expression of TCR-V beta 11. Taken together, these data demonstrate for the first time that rat bone marrow-derived cells can contribute in a strain-specific manner to the ligand for negative selection of specific mouse TCR-V beta during tolerance induction across a species barrier.
Presentation of antigen by mixed isotype class II molecules in normal H-2d mice.
Authors: Ruberti G , Sellins K S , Hill C M , Germain R N , Fathman C G , Livingstone A
Published: June 2004

A panel of DBA/2 T cell hybridomas specific for the sperm whale myoglobin epitope 110-121 was found to recognize antigen presented by the mixed isotype class II molecule E alpha dA beta d. The response was blocked by monoclonal antibodies specific for E alpha and A beta d chains; in addition, the hybridomas responded to antigen presented by L cells expressing E alpha A beta d molecules, and made no response with L cells expressing I-Ad or I-Ed molecules. Two more groups of hybridomas isolated from DBA/2 and B10.D2 mice immunized with myoglobin also recognized peptide 110-121 presented by E alpha d A beta d. Thus, although it is expressed at biochemically undetectable levels on spleen cells, the E alpha d A beta d molecule is an important presenting element in normal H-2d mice making a conventional immune response to a protein antigen. These results suggest that high levels of class II expression are not a prerequisite for T cell activation.
RMA/S cells present endogenously synthesized cytosolic proteins to class I-restricted cytotoxic T lymphocytes.
Authors: Esquivel F , Yewdell J , Bennink J
Published: June 2004

RMA/S is a mutant cell line with decreased cell surface expression of major histocompatibility complex class I molecules that has been reported to be deficient in presenting endogenously synthesized influenza virus nucleoprotein (NP) to cytotoxic T lymphocytes (CTL). In the present study we show that RMA/S cells can present vesicular stomatitis virus nucleocapsid protein, and, under some conditions, NP, to Kb-and Db-restricted CTL, respectively. Antigen presentation results from processing of cytosolic pools of endogenously synthesized proteins, and not the binding to cell surface class I molecules of antigenic peptides present in the virus inoculum or released from infected cells. Antigen processing of RMA/S differs, however, from processing by wild-type cells in requiring greater amounts of antigen, longer times to assemble or transport class I-peptide complexes, and in being more sensitive to blocking by anti-CD8 antibody. Thus, the antigen processing deficit in RMA/S cells is of a partial rather than absolute nature.
Searching for hematopoietic stem cells: evidence that Thy-1.1lo Lin- Sca-1+ cells are the only stem cells in C57BL/Ka-Thy-1.1 bone marrow.
Authors: Uchida N , Weissman I L
Published: June 2004

Hematopoietic stem cells (HSCs) are defined in mice by three activities: they must rescue lethally irradiated mice (radioprotection), they must self-renew, and they must restore all blood cell lineages permanently. We initially demonstrated that HSCs were contained in a rare (approximately 0.05%) subset of bone marrow cells with the following surface marker profile: Thy-1.1lo Lin- Sca-1+. These cells were capable of long-term, multi-lineage reconstitution and radioprotection of lethally irradiated mice with an enrichment that mirrors their representation in bone marrow, namely, 1,000-2,000-fold. However, the experiments reported did not exclude the possibility that stem cell activity may also reside in populations that are Thy-1.1-, Sca-1-, or Lin+. In this article stem cell activity was determined by measuring: (a) radioprotection provided by sorted cells; (b) long-term, multi-lineage reconstitution of these surviving mice; and (c) long-term, multi-lineage reconstitution by donor cells when radioprotection is provided by coinjection of congenic host bone marrow cells. Here we demonstrate that HSC activity was detected in Thy-1.1+, Sca-1+, and Lin- fractions, but not Thy-1.1-, Sca-1-, or Lin+ bone marrow cells. We conclude that Thy-1.1lo Lin- Sca-1+ cells comprise the only adult C57BL/Ka-Thy-1.1 mouse bone marrow subset that contains pluripotent HSCs.
Disparate interaction of peptide ligand with nascent versus mature class I major histocompatibility complex molecules: comparisons of peptide binding to alternative forms of Ld in cell lysates and the cell surface.
Authors: Smith J D , Lie W R , Gorka J , Kindle C S , Myers N B , Hansen T H
Published: June 2004

To determine the mechanism and structural consequences of peptide binding to class I molecules, we have studied the Ld molecule of the mouse. Previous studies have shown that a significant proportion of surface and intracellular Ld molecules can be detected in an alternative conformation designated Ldalt. Ldalt molecules are non-ligand associated and show weak if any beta 2-microglobulin (beta 2m) association. We report here that Ld molecules have a relatively rapid surface turnover compared with other class I molecules and that exogenous peptide dramatically prolongs Ld surface half-life. By contrast, Ldalt molecules are stably expressed on the surface and their half-life is unaffected by exogenous peptide. To study the surface interaction of peptide with Ld, live cells were incubated with iodinated peptides and Ld molecules were precipitated from cells precoated with monoclonal antibody before lysis. Using this assay, peptide binding to surface Ld molecules was found not to depend upon exchange with exogenous beta 2m, but did correlate with the level of beta 2m association. To study the intracellular interaction of peptide with Ld, cell lysates were used. In cell lysates, peptide was found to convert Ldalt molecules to properly folded Ld. This peptide-induced folding was almost complete at earlier but not later time points in pulse-chase analyses. Furthermore, conversion of Ldalt to Ld was found to affect almost exclusively immature (Endo Hs) class I molecules. Thus intrinsic properties of immature Ldalt molecules or their associated chaperonins are maintained in cell lysates that allow them to undergo de novo folding in vitro. These combined results demonstrate that immature Ldalt molecules are precursors awaiting constituents such as peptide and beta 2m that influence folding, whereas surface Ldalt molecules appear refractory to association with peptide, beta 2m, and consequent folding.
T cell receptor complexes containing Fc epsilon RI gamma homodimers in lieu of CD3 zeta and CD3 eta components: a novel isoform expressed on large granular lymphocytes.
Authors: Koyasu S , D'Adamio L , Arulanandam A R , Abraham S , Clayton L K , Reinherz E L
Published: June 2004

CD3 zeta and CD3 eta form disulfide-linked homo- or heterodimers important in targeting partially assembled Ti alpha-beta/CD3 gamma delta epsilon T cell receptor (TCR) complexes to the cell surface and transducing stimulatory signals after antigen recognition. Here we identify a new TCR isoform expressed on splenic CD2+, CD3/Ti alpha-beta+, CD4-, CD8-, CD16+, NK1.1+ mouse large granular lymphocytes (LGL), which are devoid of CD3 zeta and CD3 eta proteins. The TCRs of this subset contain homodimers of the gamma subunit of the high affinity receptor for IgE (Fc epsilon RI gamma) in lieu of CD3 zeta and/or CD3 eta proteins. The LGL display natural killer-like activity and are cytotoxic for B cell hybridomas producing anti-CD3 epsilon and anti-CD16 monoclonal antibodies, demonstrating the signaling capacity of both TCR and CD16 in this cell type. These findings provide evidence for an additional level of complexity of TCR signal transduction isoforms in naturally occurring T cell subsets.
Development of humanized bispecific antibodies reactive with cytotoxic lymphocytes and tumor cells overexpressing the HER2 protooncogene.
Authors: Shalaby M R , Shepard H M , Presta L , Rodrigues M L , Beverley P C , Feldmann M , Carter P
Published: June 2004

The HER2 protooncogene encodes a 185-kD transmembrane phosphoglycoproteins, human epidermal growth factor receptor 2 (p185HER2), whose amplified expression on the cell surface can lead to malignant transformation. Overexpression of HER2/p185HER2 is strongly correlated with progression of human ovarian and breast carcinomas. Recent studies have shown that human T cells can be targeted with bispecific antibody to react against human tumor cells in vitro. We have developed a bispecific F(ab')2 antibody molecule consisting of a humanized arm with a specificity to p185HER2 linked to another arm derived from a murine anti-CD3 monoclonal antibody that we have cloned from UCHT1 hybridoma. The antigen-binding loops for the anti-CD3 were installed in the context of human variable region framework residues, thus forming a fully humanized BsF(ab')2 fragment. Additional variants were produced by replacement of amino acid residues located in light chain complementarity determining region 2 and heavy chain framework region 3 of the humanized anti-CD3 arm. Flow cytometry analysis showed that the bispecific F(ab')2 molecules can bind specifically to cells overexpressing p185HER2 and to normal human peripheral blood mononuclear cells bearing the CD3 surface marker. In additional experiments, the presence of bispecific F(ab')2 caused up to fourfold enhancement in the cytotoxic activities of human T cells against tumor cells overexpressing p185HER2 as determined by a 51Cr release assay. These bispecific molecules have a potential use as therapeutic agents for the treatment of cancer.
c-kit ligand: a unique potentiator of mediator release by human lung mast cells.
Authors: Bischoff S C , Dahinden C A
Published: June 2004

Mast cells (MC) play a central role in extrinsic allergic reactions such as asthma and may participate in other inflammatory and fibrotic processes. However, with the exception of immunoglobulin E (IgE) receptor-dependent stimulation, no secretagogues of human lung MC have yet been described. It is also unclear whether mediator release can be regulated by certain cytokines as demonstrated previously in basophils and other human inflammatory effector cells. Here, we show that the c-kit ligand (KL), a recently identified stem cell growth factor, at concentrations 10-100 times lower than that required to promote cell proliferation, enhances the release of histamine and leukotriene C4 in response to IgE receptor crosslinking of human lung MC. KL does not induce mediator release per se, but increases the sensitivity of MC to anti-IgE receptor stimulation and also enhances mediator release to maximally effective concentrations of anti-IgE receptor antibody. By contrast, a large number of cytokines examined, including the mast cell growth factors/agonists in rodents, interleukin 3 (IL-3), IL-4, IL-9, and nerve growth factor, were ineffective in this respect. These findings suggest a unique role of KL in regulating effector functions of human mucosal MC.
The rat c-kit ligand, stem cell factor, induces c-kit receptor-dependent mouse mast cell activation in vivo. Evidence that signaling through the c-kit receptor can induce expression of cellular function.
Authors: Wershil B K , Tsai M , Geissler E N , Zsebo K M , Galli S J
Published: June 2004

Interactions between products of the mouse W locus, which encodes the c-kit tyrosine kinase receptor, and the Sl locus, which encodes a ligand for c-kit receptor, which we have designated stem cell factor (SCF), have a critical role in the development of mast cells. Mice homozygous for mutations at either locus exhibit several phenotypic abnormalities including a virtual absence of mast cells. Moreover, the c-kit ligand SCF can induce the proliferation and maturation of normal mast cells in vitro or in vivo, and also can result in repair of the mast cell deficiency of Sl/Sld mice in vivo. We now report that administration of SCF intradermally in vivo results in dermal mast cell activation and a mast cell-dependent acute inflammatory response. This effect is c-kit receptor dependent, in that it is not observed when SCF is administered to mice containing dermal mast cells expressing functionally inactive c-kit receptors, is observed with both glycosylated and nonglycosylated forms of SCF, and occurs at doses of SCF at least 10-fold lower on a molar basis than the minimally effective dose of the classical dermal mast cell-activating agent substance P. These findings represent the first demonstration in vivo that a c-kit ligand can result in the functional activation of any cellular lineage expressing the c-kit receptor, and suggest that interactions between the c-kit receptor and its ligand may influence mast cell biology through complex effects on proliferation, maturation, and function.
Requirements for hyaluronic acid binding by CD44: a role for the cytoplasmic domain and activation by antibody.
Authors: Lesley J , He Q , Miyake K , Hamann A , Hyman R , Kincade P W
Published: June 2004

The CD44-negative T lymphoma AKR1 (CD44.2 genotype) was transfected with a CD44.1 cDNA. The intact cDNA conferred on the transfected cells the ability to bind hyaluronic acid (HA) both from solution and immobilized on culture plates. It also conferred a CD44-dependent and hyaluronidase-sensitive increase in adhesion to a lymph node endothelial cell line. A mutant cDNA which codes for a CD44 molecule lacking most of the cytoplasmic domain of CD44 was also transfected into AKR1, and cell sorting was used to select transfectants expressing levels of cell surface CD44 expression comparable with the line transfected with the wild-type CD44 cDNA. The cells transfected with the mutant construct bound fluoresceinated HA from solution very poorly, but did adhere to immobilized HA, though less well than cells transfected with the wild-type construct. This result indicates that the cytoplasmic domain of CD44 is necessary for binding of HA from solution but is not required for binding to immobilized HA, although it may contribute to adhesion following ligand recognition. A monoclonal antibody (mAb), IRAWB 14, which reacts with CD44 on all CD44+ cells dramatically induced HA binding by some CD44+ cell lines that did not constitutively bind HA. The transfectant expressing a CD44 molecule with a truncated cytoplasmic domain could be induced by this antibody to bind fluoresceinated-HA from solution. Splenic T cells did not bind fluoresceinated HA constitutively. In the presence of the IRAWB 14 mAb, virtually all CD44+ splenic T cells bound HA. Induction was immediate and occurred equally well at room temperature and at 4 degrees C, indicating that the new HA-binding activity was due to preexistent CD44 molecules. These results are compatible with an antibody-induced activation of CD44 by either a conformational change in the CD44 molecule or a change in the distribution of CD44 molecules on the cell surface.
Dendritic cells are potent antigen-presenting cells for microbial superantigens.
Authors: Bhardwaj N , Friedman S M , Cole B C , Nisanian A J
Published: June 2004

Dendritic cells are a small subset of human blood mononuclear cells that are potent stimulators of several T cell functions. Here we show they are 10-50-fold more potent than monocytes or B cells in inducing T cell responses to a panel of superantigens. Furthermore, dendritic cells can present femtomolar concentrations of superantigen to T cells even at numbers where other antigen-presenting cells (APCs) are inactive. Although dendritic cells express very high levels of the major histocompatibility complex products that are required to present superantigens, it is only necessary to pulse these APCs for 1 hour with picomolar levels of one superantigen, staphylococcal enterotoxin B, to maximally activate T cells. Our results suggest that very small amounts of superantigen will be immunogenic in vivo if presented on dendritic cells.
A major T cell antigen of Mycobacterium leprae is a 10-kD heat-shock cognate protein.
Authors: Mehra V , Bloom B R , Bajardi A C , Grisso C L , Sieling P A , Alland D , Convit J , Fan X D , Hunter S W , Brennan P J
Published: June 2004

Several mycobacterial antigens, identified by monoclonal antibodies and patient sera, have been found to be homologous to stress or heat-shock proteins (hsp) defined in Escherichia coli and yeast. A major antigen recognized by most Mycobacterium leprae-reactive human T cell lines and cell wall-reactive T cell clones is a 10-kD protein that has now been cloned and sequenced. The predicted amino acid sequence of this protein is 44% homologous to the hsp 10 (GroES) of E. coli. The purified native and recombinant 10-kD protein was found to be a stronger stimulator of peripheral blood T cell proliferation than other native and recombinant M. leprae proteins tested. The degree of reactivity paralleled the response to intact M. leprae throughout the spectrum of leprosy. Limiting-dilution analysis of peripheral blood lymphocytes from a patient contact and a tuberculoid patient indicated that approximately one third of M. leprae-reactive T cell precursors responded to the 10-kD antigen. T cell lines derived from lepromin skin tests were strongly responsive to the 10-kD protein. T cell clones reactive to both the purified native and recombinant 10-kD antigens recognized M. leprae-specific epitopes as well as epitopes crossreactive with the cognate antigen of M. tuberculosis. Further, the purified hsp 10 elicited strong delayed-type hypersensitivity reactions in guinea pigs sensitized to M. leprae. The strong T cell responses against the M. leprae 10-kD protein suggest a role for this heat-shock cognate protein in the protective/resistant responses to infection.
Assessment of in vivo frequency of mutated T cells in patients with systemic lupus erythematosus.
Authors: Gmelig-Meyling F , Dawisha S , Steinberg A D
Published: June 2004

The frequency of mutant T cells (FMC) in blood lymphocytes from patients with systemic lupus erythematosus (SLE) was measured by growing cells in the presence and in the absence of 6-thioguanine. Patients with SLE had a spectrum of FMC ranging from normal to about 100 times normal. This high FMC among cells from SLE patients appears to reflect excessive in vivo activation and proliferation during the course of the disease. This represents the first demonstration of such a T cell abnormality in SLE; it supports the hypothesis that SLE T cells demonstrate increased in vivo division and/or survival.
The open reading frames in the 3' long terminal repeats of several mouse mammary tumor virus integrants encode V beta 3-specific superantigens.
Authors: Pullen A M , Choi Y , Kushnir E , Kappler J , Marrack P
Published: June 2004

Mice expressing the minor lymphocyte stimulation antigens, Mls-1a, -2a, or -3a, singly on the B10.BR background have been generated. Mls phenotypes correlate with the integration of mouse mammary tumor viruses (MTV) in the mouse genome. The open reading frames within the 3' long terminal repeats of the integrated MTVs 1, 3, 6, and 13 encode V beta 3-specific superantigens. Sequence data for these viral superantigens is presented, indicating that it is the COOH-terminal portion of the viral superantigen that interacts with the T cell receptor V beta element.
Oligoclonality of human intestinal intraepithelial T cells.
Authors: Van Kerckhove C , Russell G J , Deusch K , Reich K , Bhan A K , DerSimonian H , Brenner M B
Published: June 2004

T cells bearing the T cell receptor alpha/beta (TCR-alpha/beta) are the predominant lymphocyte population in the human intestinal epithelium. To examine if normal intestinal intraepithelial lymphocytes (IEL) have a TCR repertoire distinct from the TCR-alpha/beta repertoire in peripheral blood lymphocytes (PBL), comparative analysis of relative V beta gene usage in IEL and PBL was performed by quantitative polymerase chain reaction. In each of the six individuals examined, one to three V beta families made up more than 40% of the total V beta transcripts detected in the IEL, whereas there was a more even distribution of V beta gene usage in the paired PBL. The predominant V beta families, especially V beta 1, V beta 2, V beta 3, and V beta 6, were frequently shared among IEL of different individuals. PCR cloning and sequence analysis of the predominant V beta 6 family in two individuals revealed an identical V-D-J-C sequence in 13 of 21 clones obtained from one donor, and a different repeated sequence in 18 of 27 clones examined in the second donor. These data suggest that the V beta skewing in IEL is due to an oligoclonal T cell expansion and may reflect the response of the intestinal mucosal immune system to a restricted set of as yet undefined antigens present in the gut.
Tumor necrosis factor production during human renal allograft rejection is associated with depression of plasma protein C and free protein S levels and decreased intragraft thrombomodulin expression.
Authors: Tsuchida A , Salem H , Thomson N , Hancock W W
Published: June 2004

Fibrin deposition is a common accompaniment of renal allograft rejection, indicating disruption of the normal physiologic balance between procoagulant and anticoagulant pathways. In vitro, tumor necrosis factor (TNF) induces endothelial expression of the procoagulant, tissue factor, and downregulation of thrombomodulin, a key component of the thrombomodulin/protein C (PC)/protein S (PS) pathway, which normally maintains an anticoagulant state by inactivating thrombin, preventing further thrombin formation by degrading factors Va and VIIIa, and decreasing plasminogen activator inhibitor activity. Raised levels of TNF were recently demonstrated within the blood of patients during episodes of renal allograft injection, and may be an early and discriminatory marker of rejection. This led us to investigate prospectively whether monitoring of serum TNF levels was of value clinically, and was associated with effects on circulating PC and PS levels, or alterations in intragraft thrombomodulin expression. Plasma samples (n = 454) were collected three times/week from all patients (n = 25) undergoing renal transplantation during a 9-month consecutive period, and assayed by ELISA and functional assays for TNF, PC, and free PS (FPS). Portions of renal biopsies, taken to evaluate episodes of acute deterioration of renal function, were evaluated by immunoperoxidase labeling for the presence and distribution of TNF, thrombomodulin, PC, PS, thrombin, fibrin, and factors V and VIII. Comparison of 78 plasma samples collected during 26 episodes of biopsy-proven acute cellular rejection with samples collected during periods of stable renal function (n = 349) showed that TNF levels rose significantly (390 +/- 242 pg/ml, p less than 0.01) above background levels 3 days before rising serum creatinine concentrations, and peaked (2,426 +/- 978 pg/ml) on the day of clinical rejection. PC-antigen (Ag) concentrations also decreased 3 days before rejection (68 +/- 13%, p less than 0.05), and were maximally depressed (49% +/- 16%, p less than 0.001) on the day of rejection. FPS levels were normal until the day before rejection (63% +/- 8%, p less than 0.01) and, like PC, were maximally depressed (43 +/- 10%) at rejection. Plasma TNF levels were significantly and inversely correlated with PC-Ag (p less than 0.001) and FPS (p less than 0.005) levels during rejection, regardless of whether such rejection episodes were steroid responsive or required OKT3 monoclonal antibody therapy. TNF, PC, and FPS levels were normal during episodes of cyclosporine toxicity and viral infection.(ABSTRACT TRUNCATED AT 400 WORDS)