bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface antigens of melanoma and melanocytes. Specificity of induction of Ia antigens by human gamma-interferon.
Authors: Houghton A N , Thomson T M , Gross D , Oettgen H F , Old L J
Published: June 2004

IFN-gamma is known to induce expression of Ia antigens on a variety of cell types. In the present study, this activity of IFN-gamma has been analyzed with a panel of 36 melanoma cell lines, normal melanocytes, and 97 cell lines representing a range of other differentiation lineages. 55% of the melanoma cell lines express Ia antigens in a constitutive manner without IFN-gamma induction. Of the 16 Ia-melanoma lines, 13 could be induced to express Ia antigens by IFN-gamma, whereas three were noninducible. Melanocytes, which do not normally express Ia antigens, are converted to Ia expression by IFN-gamma. Ia antigens expressed constitutively or after IFN-gamma induction were identified with antibodies detecting monomorphic and allomorphic products of DR and DC loci. IFN-gamma appeared to be unique in its ability to induce Ia expression on melanoma and melanocytes; 14 other agents (including IFN-alpha and IFN-beta) known to influence growth or differentiation did not have Ia-inducing activity. Equally striking is the restriction of antigenic changes following IFN-gamma induction to HLA-associated products; of the 38 systems of cell surface antigens examined, only HLA-A,B,C, beta 2m, and Ia antigens were affected. A variety of other Ia- cell types were shown to be Ia-inducible by IFN-gamma; these included established lines of breast, colon, pancreas, bladder, kidney, ovary, and brain cancers, and cultures of normal fibroblasts, kidney epithelia, and epidermal keratinocytes. In contrast, three tumor types, teratocarcinoma, choriocarcinoma, and neuroblastoma, were not inducible for Ia expression, even though IFN-gamma could induce expression of HLA-A,B,C products. The broad representation of Ia antigens on most somatic cell types expressed either constitutively or after IFN-gamma can be viewed in an immunological context (antigen presentation/immune regulatory signals) or could indicate that Ia products have functions other than those related to immune reactions.
Linkage analysis of the murine interferon-alpha locus on chromosome 4.
Authors: Dandoy F , Kelley K A , DeMaeyer-Guignard J , DeMaeyer E , Pitha P M
Published: June 2004

Southern blot analysis with a murine interferon-alpha2 (MuIFN-alpha2) cDNA probe revealed restriction fragment polymorphism of EcoRI- and HindIII-digested C57BL/6 and BALB/cDNA. The inheritance pattern of this polymorphism was examined using DNA from each of the seven recombinant inbred strains derived from C57BL/6 and BALB/c; the strain distribution pattern suggests linkage of INF-alpha genes to two histocompatibility loci on chromosome 4. Southern blot analysis of DNA from six bilinear congenic strains carrying different fragments of the BALB/c chromosome 4 on a C57BL/6 background showed linkage of IFN-alpha genes to the histocompatibility locus H-15. It can therefore be concluded that the IFN-alpha gene cluster is situated on chromosome 4 near the H-15 locus, between loci Mup-1 and b.
Interaction of helper T cells and Lyb5+ B cells responding to phosphorylcholine is MHC-restricted.
Authors: Mosier D E , Feeney A J
Published: June 2004

The requirements for T cell/B cell interaction for the induction of primary in vitro antibody responses to phosphorylcholine (PC)-keyhole limpet hemocyanin (KLH) were examined. Long-term helper T cell lines derived from KLH-primed (CBA/N X BALB/c) F1 female mice (H-2k/d) were able to support a T15-idiotype dominant, IgM anti-PC response of BALB/c (H-2d) B cells and macrophages, but could not activate PC-specific responses by BALB.B (H-2b) B cells, even in the presence of irradiated H-2k/d antigen-presenting cells. Polyclonal IgM secretion in the same cultures did not appear to depend upon a major histocompatibility complex (MHC)-restricted T-B interaction. Since IgM anti-PC responses seem to be entirely derived from the Lyb5+ B cell subpopulation, we conclude that at least some Lyb5+ B cells can only be activated by MHC-restricted T-B interactions. We also found that xid B cells from (CBA/N X BALB/c) F1 male mice could be polyclonally activated by helper T cell lines by an apparently MHC-unrestricted interaction. Our data thus suggests that residence in the Lyb5- or Lyb5+ B cell subset does not determine the T:B interaction requirements for antibody synthesis.
Physiology of B cells in mice with X-linked immunodeficiency. II. Influence of the thymus and mature T cells on B cell differentiation.
Authors: Sprent J , Bruce J
Published: June 2004

Evidence is presented that the in vivo differentiation of B cells expressing X-linked immunodeficiency (xid) is controlled by mature T cells. Normal (C57BL/6 X CBA/J)F1 mice were thymectomized (ATx), heavily irradiated, and reconstituted with CBA/N (xid) or CBA/Ca (nondefective) marrow. In contrast to sham-operated mice, ATx recipients of xid marrow showed an almost total absence of Ig+ B cells in lymph nodes (LN) and thoracic duct lymph at 2 mo post-reconstitution ; B cells were markedly reduced in the spleen in some mice but only moderately in others. Addition of mature T cells soon after marrow reconstitution substantially abrogated the B cell depletion. In control experiments with nondefective B cells, the number of B cells developing in ATx irradiated recipients of normal (xid-) marrow cells was not detectably lower than in sham-operated recipients. These data imply that a subset of T-dependent B cells is either missing in normal mice or present in only very small numbers.
Cytotoxicity of a cell-reactive immunotoxin containing ricin A chain is potentiated by an anti-immunotoxin containing ricin B chain.
Authors: Vitetta E S , Fulton R J , Uhr J W
Published: June 2004

In vitro killing of the human Daudi cell line by either univalent [F(ab')] or divalent (IgG) forms of rabbit anti-human Ig (RAHIg) coupled to ricin A chain can be specifically potentiated by a "piggyback" treatment with ricin B chain coupled to goat anti-rabbit Ig (GARIg). When cells are treated with univalent immunotoxin (IT) [F(ab') RAHIg-A] and then cultured, IT can be detected on the cell surface for at least 5 h, since GARIg-B can still enhance killing at this time. These results provide a strategy for in vivo use of A chain- and B chain-containing IT.
Effect of MuLV-related genes on plasmacytomagenesis in BALB/c mice.
Authors: Potter M , Hartley J W , Wax J S , Gallahan D
Published: June 2004

The role of spreading somatic cell infections with ecotropic MuLV viruses in the induction of plasmacytomas in BALB/cAN pi mice was determined by constructing congenic mice that lacked the gene locus Cv that codes for ecotropic virus. DBA/2 mice that lack Cv on chromosome (chr) 5 carry a closely linked gene Rmcfr that determines resistance to infection with mink cell focus-forming viruses (MCF). Rmcfr was retrogressively back-crossed onto BALB/c for six successive generations to produce N6 mice. N6 mice were mated to each other to produce BALB/c.DBA/2 Rmvfr/Rmcfr homozygotes. This stock of mice lacked Cv, as demonstrated by DNA hybridization and were as fully susceptible to developing plasmacytomas as the parental BALB/c. A second congenic stock BALB/c.DBA/2 Rmcfr/Rmcfr Fv-1n/Fv-1n was also developed, but the mice of this stock showed a reduced incidence of plasmacytomas, as did BALB/c.DBA/2 Fv-1n/Fv-1n mice. These findings indicated Fv-1 or a gene closely linked to it conferred partial resistance to plasmacytomagenesis. In constructing the BALB/c.DBA/2 Fv-1n/Fv-1n stock, a "control" congenic BALB/c.DBA/2 Fv-1b/Fv-1b was also developed at N6. Surprisingly, this stock carried the Qa2+ trait. These mice were also partially resistant to plasmacytomagenesis, suggesting a gene on chromosome 17 (the location of Qa2) or a gene located elsewhere that regulates Qa2 expression is linked to a gene controlling partial resistance to plasmacytoma development.
The antigen-specific, major histocompatibility complex-restricted receptor on T cells. VI. An antibody to a receptor allotype.
Authors: Haskins K , Hannum C , White J , Roehm N , Kubo R , Kappler J , Marrack P
Published: June 2004

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.
Transcriptional regulation of the mu-delta heavy chain locus in normal murine B lymphocytes.
Authors: Yuan D , Tucker P W
Published: June 2004

The heavy chain genes for IgM (C mu) and IgD (C delta) are expressed differentially during B cell maturation and activation. We have determined the role that transcription plays in the regulation of these changes by using the method of in vitro nascent RNA chain elongation. In neonatal cells that express much lower densities of IgD than IgM on their surface, transcription of C delta is observed at half the level of C mu. This 3:1 transcriptional ratio of mu to delta is preserved in mature resting cells, which express higher densities of IgD on the surface than IgM. When activated by the mitogen, lipopolysaccharide (LPS), transcription of C mu is preferentially enhanced. However, C delta transcription is not shut off even though the expression of IgD in the stimulated cells is greatly decreased. In all three differentiative stages, polymerase unloading occurs in the vicinity of a large inverted repeat sequence, 5' to C delta and 3' to the mu membrane exons. This suggests that the developmental selection of secreted vs. membrane-bound carboxyl-terminal exons is controlled by RNA cleavage. The data presented here, together with our previous analysis of mRNA and protein synthesis, show that the differential expression of IgM and IgD in normal B lymphocytes is regulated at the transcriptional, translational, and posttranslation levels.
Cytolytic T cell granules. Isolation, structural, biochemical, and functional characterization.
Authors: Podack E R , Konigsberg P J
Published: June 2004

The cytoplasmic, dense granules of cloned T cell lines were isolated and analyzed for their functional and biochemical properties. Isolated granules of approximately 90% homogeneity, in the presence of Ca, effect strong tumoricidal and hemolytic activity. Tumor cell lysis is complete in less than 30 min, with less than 2 micrograms granule protein corresponding to a killer/target ratio of 3-6:1 by assuming 50% yield for granule isolation. The granules contain a set of unique proteins, responsible for cytolytic activity and designated K1 to K6, in the molecular weight range of 14,000 to 75,000, as defined by sodium dodecyl sulfate (SDS) polyacrylamide slab gel analysis under reducing and nonreducing conditions. Cytolysis mediated by isolated granules is accompanied by the assembly of tubular complexes of 160 A (poly P1) and of approximately 70 A width (poly P2) that are inserted into membranes and form ultrastructural membrane lesions. As shown by immunofluorescence and by Percoll gradient fractionation, cytolytic granules are detected in cells of cytolytic T cell lineage and not in the T cell lymphomas E14 and S194. Poly perforin 1 assembled by CTLL-2 upon stimulation with concanavalin A (Con A) and phorbol myristate acetate (PMA) was isolated by detergent extraction and gel filtration. Poly P1 is composed of disulfide-linked subunits that, after reduction, co-migrate with certain granule proteins. The results are compatible with the hypothesis that the dense granules of cytolytic T cells contain cytolytic proteins that polymerize to disulfide-linked tubular poly perforins in a Ca-dependent reaction and may cause cytolysis by membrane insertion and transmembrane channel formation.
Physiology of B cells in mice with X-linked immunodeficiency (xid). III. Disappearance of xid B cells in double bone marrow chimeras.
Authors: Sprent J , Bruce J
Published: June 2004

Evidence is presented that B cells from mice with X-linked immunodeficiency (xid) differentiate at a slower rate than normal B cells. This conclusion stems from studies in which (B6 X CBA/J)F1 mice were heavily irradiated (1,000 rads) and reconstituted with a mixture of T-depleted marrow cells taken from (a) nondefective B6 mice (H-2b) and (b) xid CBA/N or nondefective CBA/Ca mice (both H-2k). With transfer of CBA/Ca plus B6 marrow cells, the irradiated recipients become repopulated with B cells derived from both parental marrow sources; except for an early imbalance (probably reflecting Hh resistance), the degree of chimerism remained relatively stable over a period of more than 6 months. Very different results occurred with transfer of a mixture of xid CBA/N and normal B6 marrow. Within the first 2 months after marrow reconstitution, a low but significant proportion of the B cells in both spleen and lymph nodes were of CBA/N origin. Thereafter the proportion of these cells fell progressively, and by 6-9 months virtually all of the B cells were of B6 origin. This gradual decline in CBA/N-derived cells did not apply to other cell types, i.e., T cells or pluripotential stem cells. Analogous results were obtained with transfer of CBA/N vs. CBA/Ca marrow cells into sublethally irradiated (750 rads) (CBA/N X DBA/2)F1 male vs. female mice. For example, CBA/N-marrow derived B cells differentiated effectively and survived for long periods in F1 male mice (xid----xid) but not in F1 female mice (xid----normal). The finding that xid B cells eventually disappear in the presence of normal B cells strengthens the view that xid B cells are an abnormal population not represented in normal mice.
Endocytosis in Entamoeba histolytica. Evidence for a unique non-acidified compartment.
Authors: Aley S B , Cohn Z A , Scott W A
Published: June 2004

Our studies on endocytosis in Entamoeba histolytica trophozoites suggest that there are two vacuolar compartments in this organism. The first compartment consists of large vacuoles (greater than 2 microns diameter). As measured by the fluid phase markers, fluorescein isothiocyanate (FITC)-dextran and horseradish peroxidase (HRP), this compartment is a rapid equilibrium with the external milieu and is constantly exchanging (1-2 h) its contents with the external medium. The contents of these vacuoles are not acidified. This together with the absence of degradation of fluid phase markers clearly differentiates these vacuoles from lysosomes of eucaryotes. By labeling externally disposed peptides on the surface membrane of trophozoites with 125I, we could show that the surface membrane was rapidly internalized over a 2-h period and then reached a plateau. All major 125I surface proteins, with the exception of a set of peptides in the 40,000 molecular weight range, were interiorized and approximately 60% of the total radiolabel were found to be in the internal membrane fraction at any given time. The kinetics of this process were similar to those for the uptake of fluid phase markers and are best explained by cycling of the surface membrane into the vacuolar compartment(s) and then back to the cell surface. The second vacuolar compartment consisted of small vesicles (less than 2 microns diameter) with acidified contents as indicated by acridine orange uptake. The endocytic nature of these vesicles was shown by their slow (days) labeling with FITC-dextran, and spectral analysis of internalized FITC-dextran confirmed that this second compartment is acidified (pH 5.2).
Two-dimensional gel electrophoretic analysis of the MT3 and DR4 molecules from the different D-typed cells.
Authors: Suzuki M , Yabe T , Satake M , Juji T , Hamaguchi H
Published: June 2004

This report demonstrates directly, using two-dimensional gel electrophoresis and alloantisera, the following: (a) The DR4 light chains show a structural polymorphism among the Dw4, DKT2, and DYT cells. (b) Most of the class II light chains consist of the DR light chain. (c) The MT3 molecule is distinct from the DR4 molecule in the Dw4, DKT2, and DYT cells. (d) The MT3 molecule does not show any structural heterogeneity among the Dw4, DKT2, and DYT cells. These results suggest that the dissection of the D specificity among Dw4, DKT2, and DYT is mainly caused by the differences of the DR4 molecules.
Purification and partial biochemical characterization of normal human interleukin 1.
Authors: Schmidt J A
Published: June 2004

A protocol for the rapid, efficient purification of the major charged species of human interleukin 1 (IL-1) has been developed using high performance anion exchange and size exclusion chromatography. The isolated material is pure as determined by sodium dodecyl sulfate (SDS) gradient polyacrylamide gel electrophoresis (PAGE) and analytical isoelectric focusing (IEF). The molecular weight of the purified material is 15,000 and the isoelectric point (pI) is 6.8, values that are in good agreement with those previously reported for human IL-1. 10(-10) M concentrations of the purified material give half-maximal stimulation in the thymocyte proliferation assay. Amounts of IL-1 sufficient for receptor studies and detailed biochemical analysis can now be produced on a regular basis.
Clustering of dendritic cells, helper T lymphocytes, and histocompatible B cells during primary antibody responses in vitro.
Authors: Inaba K , Witmer M D , Steinman R M
Published: June 2004

Mouse spleen suspensions generate discrete cell clusters within 1-2 d of culture. We have isolated these clusters by velocity sedimentation to study their contribution to primary antibody responses. Clusters represent approximately 5% of the starting spleen cells and consist of 20-50% B cells, 20-50% T cells, and 10-20% dendritic cells (DC). When the cultures are stimulated with thymus-dependent antigens, like heterologous red cells or dinitrophenyl-keyhole limpet hemocyanin (DNP-KLH), the clusters are the principal site for the development of plaque-forming cells (PFC). Noncluster fractions form few PFC and only when supplemented with fresh DC. PFC responses in all cases are antigen specific. B cells cluster only in the presence of T cells and DC (1 DC/200 B-T cell mixtures) and only after encountering specific antigen. The elimination of either DC or Lyt-1+2- T cells, with monoclonal antibody and complement, ablates B cell development into PFC. PFC responses are restored with antigen-nonspecific helper factors formed in the syngeneic mixed leukocyte reaction between DC and T cells. Since PFC to DNP-KLH do not develop de novo when B cells are exposed to antigen and helper factors, anti-DNP PFC precursors must be stimulated within clusters to become responsive to helper factors. PFC development within clusters is restricted by the major histocompatibility complex (MHC). When DC and T cells are from strain P1, then P1 but not P2 B cells develop into PFC; when DC are from strain P2 and T cells from strain P1, strain P2 B cells are selected to become PFC in clusters. The entry of B cells into clusters is itself MHC restricted, since P1 DC/T cells aggregate six times as many B cells from strain P1 as strain P2. Thus, clusters are the site in which DC, B, and T cells interact to generate PFC. One can use clusters to retrieve B cells that have been selected in an antigen-dependent, MHC-restricted fashion and to show that clustering B cells become responsive to soluble, polyclonal helper factors.
Complete amino acid sequence of heavy chain variable regions derived from two monoclonal anti-p-azophenylarsonate antibodies of BALB/c mice expressing the major cross-reactive idiotype of the A/J strain.
Authors: Meek K , Jeske D , Slaoui M , Leo O , Urbain J , Capra J D
Published: June 2004

The primary structure of A/J anti-p-azophenylarsonate (anti-Ars) antibodies expressing the major A-strain cross-reactive idiotype (CRIA) has provided important insights into issues of antibody diversity and the molecular basis of idiotypy in this important model system. Until recently, this idiotype was thought to be rarely, if ever, expressed in BALB/c mice. Indeed, it has been reported that BALB/c mice lack the heavy chain variable segment (VH) gene that is utilized by the entire family of anti-Ars antibodies expressing the A/J CRI. Recently, however, it has been possible to elicit CRIA+, Ars binding antibodies in the BALB/c strain by immunizing first with anti-CRI and then with antigen. Such BALB/c, CRIA+ anti-Ars antibodies can be induced occasionally with antigen alone. VH region amino acid sequences are described for two CRIA+ hybridoma products derived from BALB/c mice. While remarkably similar to each other, their VH segments (1-98) differ from the VH segments of A/J CRIA+, anti-Ars antibodies in over 40 positions. Rather than the usual JH2 gene segment used by most A/J CRIA+ anti-Ars antibodies, one BALB/c CRIA+ hybridoma utilizes a JH1 gene segment, while the other uses a JH4. However, the D segments of both of the BALB/c antibodies are remarkably homologous to the D segments of several A/J CRIA+ antibodies sequenced previously, as are the amino terminal amino acid sequences of their light chains. These data imply that BALB/c mice express the A/J CRIA by producing antibodies with very similar, if not identical, light chain and heavy chain D segments, but in the context of different VH and JH gene segments than their A/J counterparts. The results document that molecules that share serologic specificities can have vastly different primary structures.
Response of resting human peripheral blood natural killer cells to interleukin 2.
Authors: Trinchieri G , Matsumoto-Kobayashi M , Clark S C , Seehra J , London L , Perussia B
Published: June 2004

The present study shows that recombinant interleukin 2 (IL-2) purified to homogeneity induces a rapid and potent enhancement of spontaneous cytotoxicity of human peripheral blood lymphocytes. The cells mediating cytotoxicity after 18-h treatment with IL-2 have surface markers of natural killer (NK) cells and are generated from the peripheral blood subset containing spontaneous cytotoxic cells. A parallel production of gamma interferon (IFN-gamma) is induced by recombinant IL-2 (rIL-2), and NK cells appear to be the major producer cells, whereas T cells are unable to produce IFN-gamma under these experimental conditions. However, the kinetics of the enhancement of cytotoxicity are faster than those of IFN-gamma production, and monoclonal anti-IFN-gamma antibodies do not suppress this effect, making it unlikely that the IFN-gamma produced is responsible for the enhancement. The enhancement of NK cell activity induced by rIL-2 precedes any proliferative response of the lymphocytes, which is instead observed in longer-term cultures of both NK and T cells.
Augmentation of macrophage complement receptor function in vitro. IV. The lymphokine that activates macrophage C3 receptors for phagocytosis binds to a fucose-bearing glycoprotein on the macrophage plasma membrane.
Authors: Griffin F M , Mullinax P J
Published: June 2004

Macrophage receptors for the third component of complement (C3) are normally immobilized and unable to diffuse within the cell's plasma membrane and, even though they promote avid particle binding, are unable to promote phagocytosis of C3-coated particles. We have previously identified a lymphokine that activates macrophage C3 receptors for phagocytosis and have found that it acts by freeing the receptors so that they can diffuse within the macrophage plasma membrane. It seemed likely to us that the initial lymphokine-macrophage interaction would occur at the macrophage surface, perhaps via a specific lymphokine receptor. Since the binding of many ligands to cells is mediated by cell surface glycoproteins, we examined the protein and sugar requirements for murine peritoneal macrophages to respond to the lymphokine. Macrophages treated with the neutral protease Dispase lost the ability to respond to the lymphokine, and inclusion of L-fucose in the incubation medium containing lymphokine and macrophages inhibited markedly the macrophages' response to the lymphokine, suggesting that the lymphokine exerts its effects by first binding to fucose residues on a glycoprotein receptor on the macrophage surface. Further evidence for the essential role of macrophage surface fucose was obtained by demonstrating that pretreatment of macrophages with either fucosidase or gorse lectin, a fucose-binding lectin, strikingly disabled the cells from responding to the lymphokine. All treatments that prevented lymphokine activation of macrophage C3 receptors for phagocytosis also prevented lymphokine-induced C3 receptor mobility. These results strongly suggest that the lymphokine binds to a fucose-bearing macrophage surface glycoprotein, perhaps a specific lymphokine receptor. They also strengthen our hypothesis that, for a receptor to be able to promote phagocytosis, it must be able to diffuse within the macrophage plasma membrane.
Class 1 (unique) tumor antigens of human melanoma. Identification of a 90,000 dalton cell surface glycoprotein by autologous antibody.
Authors: Real F X , Mattes M J , Houghton A N , Oettgen H F , Lloyd K O , Old L J
Published: June 2004

Analysis of the humoral immune response of patients with melanoma has identified a small group of individuals with antibody to cell surface antigens that are restricted to autologous melanoma cells. These antigens, referred to as Class I or unique tumor antigens, are demonstrated by reactions between serum and cultured melanoma cells from the same patient and absorption tests with autologous and allogeneic normal and malignant cells to determine antibody specificity. Five Class 1 melanoma antigens have been defined to date, but insight into the nature of these antigens has been limited because antibodies identifying these antigens lacked detectable immunoprecipitating activity. We have now defined a Class 1 melanoma antigen (designated FD) that is immunoprecipitated by autologous antibody. FD antigen is identified by an IgG antibody present in the sera of patient FD, and peak titers of this antibody in tests with cultured autologous melanoma cells are in the range of 1:2048. By absorption tests, FD antigen could not be detected on any other cell type, including 33 allogeneic melanomas. Prolonged culture of FD melanoma cells resulted in decreased expression of FD antigen, but sublines could be obtained with stable antigen expression. FD antigen is trypsin and heat sensitive, neuraminidase resistant, and is shed in the culture medium. Immunoprecipitation of 125I-labeled cell membrane preparations revealed a 90,000 dalton component of pI 5.5. Serum immunoprecipitating activity could be absorbed by autologous melanoma cells but not by autologous B cells or allogeneic cell lines. A component of the same molecular mass could be precipitated from lysates of cells metabolically labeled with [3H]mannose. The membrane form of the FD antigen binds strongly to Con A-Sepharose and can be eluted with methyl-alpha-D-mannoside. The identification of a precipitating Class I antigenic system of melanoma facilitates efforts to generate monoclonal antibodies to this tumor antigen and to clone its coding sequence.
A common antigenic determinant found in two functionally unrelated toxins.
Authors: Gariepy J , O'Hanley P , Waldman S A , Murad F , Schoolnik G K
Published: June 2004

The heat-stable enterotoxin ST Ib produced by enterotoxigenic E. coli strains shares a sequence homology with the sea snail neurotoxin, conotoxin GI. Rabbit antisera were raised against synthetic analogs of these toxins and to a six-residue peptide representing the region common to both toxins. Results from enzyme-linked immunosorbent assays indicate that the homologous region of both toxins represents part of their antigenic site. The lack of cross-reactivity exhibited by the six-residue common domain with serum directed against either toxin suggests that this region probably retains a similar conformation in the intact toxins but not in the isolated fragment.
Trichomonas vaginalis is dependent on uptake and degradation of human low density lipoproteins.
Authors: Peterson K M , Alderete J F
Published: June 2004

Human plasma low density lipoprotein uptake by the urogenital pathogen, Trichomonas vaginalis, was examined. Rapid binding and internalization of 125I-labeled low density lipoproteins by live T. vaginalis was observed at 37 degrees C. Data showing parasite degradation of the internalized apoproteins and lipid accumulation following low density lipoprotein uptake was obtained. Acquisition of low density lipoproteins was by a trichomonad surface protein that possessed a molecular weight of greater than 250,000. The receptor is specific for apolipoprotein CIII, a component of high, low, and very low density lipoprotein subfractions. Low density lipoproteins in a semi-defined medium of trypticase, nucleic acid precursors, vitamins, and maltose promoted T. vaginalis growth and multiplication at rates and levels equal to the yeast extract-trypticase-serum complex medium routinely used for culture of trichomonads. HeLa cell membranes as a source of lipids were unable to sustain T. vaginalis organisms. These data demonstrate host lipoprotein internalization by T. vaginalis via a specific uptake mechanism.
Identification of the principal T lymphocyte-stimulating antigens of Pseudomonas aeruginosa.
Authors: Parmely M J , Iglewski B H , Horvat R T
Published: June 2004

To aid in understanding the role of cellular immunity in limiting Pseudomonas aeruginosa infections, we have identified some of the principal antigens of the organism that are recognized by human T cells. Clones of T cells were selected in such a manner that they would provide information not only about the identity of Pseudomonas antigens, but also the T cell repertoires of immune donors. Most clones were found to be specific for Pseudomonas alkaline protease (AP). Such clones could be physically isolated by selecting with crude Pseudomonas antigens or purified AP. In either case, their fine specificities were the same when tested against a panel of Pseudomonas antigens. The conclusion that AP is the principal immunogen for many donors was confirmed by measuring the absolute frequencies of proliferating T cells committed to AP and all other Pseudomonas antigens. Frequencies of AP-specific clones (1.5-2.7 X 10(-5] were comparable to those from the same donors that were specific for all secreted Pseudomonas antigens (1.3-6.0 X 10(-5]. These results provide a model system for studying human T cell-mediated immunity to bacteria by identifying discrete antigens and measuring the repertoire diversities of cells responding to them.
Induction of anti-tobacco mosaic virus antibodies in mice by rabbit antiidiotypic antibodies.
Authors: Francotte M , Urbain J
Published: June 2004

Conventional rabbit antiidiotypic antibodies were raised against a private rabbit anti-tobacco mosaic virus (TMV) idiotype. These rabbit antiidiotypic antibodies were covalently coupled to lipopolysaccharide and then injected into BALB/c mice. As compared with controls, these mice, which have never seen the antigen, synthesized anti-TMV antibodies that are strongly idiotypically cross-reactive with the starting rabbit idiotype. Monoclonal anti-TMV antibodies were prepared from these mice. Furthermore, xenogeneic or syngeneic antiidiotypic antibodies, raised against these monoclonal anti-TMV antibodies, recognized specifically the rabbit idiotype. Rabbit antiidiotypic antibodies alone can induce the same effects, but the concentration of anti-TMV antibodies is lower.
Ig RNA expression in normal B cells stimulated with anti-IgM antibody and T cell-derived growth and differentiation factors.
Authors: Nakanishi K , Cohen D I , Blackman M , Nielsen E , Ohara J , Hamaoka T , Koshland M E , Paul W E
Published: June 2004

An increase in mRNA encoding the secretory form of the mu heavy (H) chain (mus) and in the ratio of mus mRNA to the mRNA encoding the membrane form of the microH chain (micron) occurs in normal B cells stimulated with anti-IgM and BSF-p1 together with the two B cell differentiation factors B15-TRF and EL-TRF. Stimulation of cells with anti-IgM and BSF-p1 with either B15- or EL-TRF causes no change in mus levels or mus/micron ratios. The requirements for induction of high rate IgM synthesis in normal B cells stimulated with anti-IgM were precisely the same as those required for elevation of mus, mRNA levels and for increase in mus/micron mRNA ratios. A very close correlation also exists between induction of mRNA for J chain and increase in mus mRNA levels. Similarly, the increase in J chain protein concentration and percent of cells with cytoplasmic IgM were correlated to each other and to levels of mus and J chain mRNA. These results indicate that elevation of mus mRNA and mus/micron mRNA ratios occur in normal B cells only upon commitment to IgM synthesis, and reaffirm the close relation between IgM synthesis and the presence of J chain.
Pathogenesis of Shigella diarrhea. IX. Simplified high yield purification of Shigella toxin and characterization of subunit composition and function by the use of subunit-specific monoclonal and polyclonal antibodies.
Authors: Donohue-Rolfe A , Keusch G T , Edson C , Thorley-Lawson D , Jacewicz M
Published: June 2004

A simple purification scheme for shigella cytotoxin was devised, resulting in high yields (approximately 50%) and a 1,300-fold increase in specific activity compared with the initial crude bacterial cell lysate. The purified toxin was enterotoxic in ligated rabbit ileal loops and neurotoxic when injected into the peritoneal cavity of mice. Measurement of specific activity of cytotoxin and enterotoxin demonstrated that these two toxicities copurify during the fractionation procedure. On sodium dodecyl sulfate gel electrophoresis, the toxin migrated as two polypeptide subunits, an A subunit of 32,000 mol wt and a B subunit of 6,500 mol wt. Chemical cross-linking experiments demonstrate that the toxin is a complex consisting of one A and five B subunits with a molecular weight of 64,000. Polyclonal rabbit anti-toxin and anti-subunit B antisera were produced as well as subunit-specific mouse monoclonal antibodies. All antibodies preincubated with toxin neutralized cytotoxic effects in HeLa cell monolayers. In contrast, only A subunit-specific antibodies were able to neutralize toxin prebound to the HeLa cell surface. Antibody to the B subunit also inhibited binding of 125I-labeled toxin to these cells by 94% or more. These data demonstrate that the B subunit is involved in shigella toxin binding to the cell surface.
Suppression of antibody responses to topically applied antigens by ultraviolet light irradiation. Induction of phototolerance.
Authors: Spellman C W , Anderson W L , Bernhard E J , Tomasi T B
Published: June 2004

C3Hf/HeN or BALB/c mice, exposed to acute ultraviolet (UV) irradiation and skin-sensitized through the irradiated skin site with soluble protein antigens, exhibit humoral tolerance to subsequent systemic challenge with antigen. We have termed this phenomenon "phototolerance" (PT). With the doses of UV radiation used, PT induction is restricted to the irradiated skin site and is observed only if sensitization is performed via the cutaneous route. PT is antigen specific and operates at the afferent level of the immune response. While single PT induction regimens result in transient humoral suppression, multiple inductions before each systemic challenge can maintain the response at low levels. The capacity to induce PT to a variety of soluble protein antigens may have potentially important clinical applications.
Inherited deficiency of the Mac-1, LFA-1, p150,95 glycoprotein family and its molecular basis.
Authors: Springer T A , Thompson W S , Miller L J , Schmalstieg F C , Anderson D C
Published: June 2004

Leukocyte surface glycoproteins that share a common beta subunit have been found to be congenitally deficient in three unrelated patients with recurring bacterial infection. The glycoproteins, Mac-1, LFA-1, and p150,95, have the subunit compositions alpha M beta, alpha L beta, and alpha X beta, respectively. Using subunit-specific monoclonal antibodies, both the alpha M and beta subunits of Mac-1, the alpha L and beta subunits of LFA-1, and at the least the beta subunit of p150,95, were found to be deficient at the cell surface by the techniques of immunofluorescence flow cytometry, radioimmunoassay, and immunoprecipitation. A latent pool of Mac-1 that can be expressed on granulocyte surfaces in response to secretory stimuli, such as f-Met-Leu-Phe, was also lacking in patients. Deficiency was found on all leukocytes tested, including granulocytes, monocytes, and T and B lymphocytes. Quantitation by immunofluorescence cytometry of subunits on granulocytes from parents of these patients and of a fourth deceased patient showed approximately half-normal surface expression, and, together with data on other siblings and a family with an affected father and children, demonstrate autosomal recessive inheritance. Deficiency appears to be quantitative rather than qualitative, with two patients expressing approximately 0.5% and one patient approximately 5% of normal amounts. The latter patient had alpha beta complexes on the cell surface detectable by immunoprecipitation. Biosynthesis experiments showed the presence of normal amounts of alpha'L intracellular precursor in lymphoid lines of all three patients. Together with surface deficiency of three molecules that share a common beta subunit but have differing alpha subunits, this suggests the primary deficiency is of the beta subunit. The lack of maturation of alpha'L to alpha L and the deficiency of the alpha subunits at the cell surface and in latent pools suggests that association with the beta subunit is required for alpha subunit processing and transport to the cell surface or to latent pools. The molecular basis of this disease is discussed in light of adhesion-related functional abnormalities in patients' leukocytes and the blockade of similar functions in healthy cells by monoclonal antibodies.
A class II gene conversion event defines an antigen-specific Ir gene epitope.
Authors: Hochman P S , Huber B T
Published: June 2004

To assess the role of Ia epitopes in conferring specificity for the immune response to nominal antigen, we compared the insulin response of mice with a defined mutation in the I-Ab beta gene, the B6.C-H-2bm12 (bm12), with that of wild-type H-2b C57BL/6 (B6) mice. We report that the bm 12 mutation resulted in a selective alteration of the specificity of insulin recognition, such that bm 12 mice responded upon immunization with sheep but not beef insulin, which differ by only one amino acid at position 9 of the insulin A chain. Thus, the bm12 mutation allows for the definition of the actual nucleotide sequence coding for an Ia epitope that is responsible for controlling the specificity of immune recognition of insulin. Furthermore, we show that the sheep insulin response of H-2k mice is controlled by the E molecule and that sheep insulin can be recognized by primed bm12 and H-2k T cells in the context of either bm12, B10.A, or B10.A(5R) antigen-presenting cells. Our data suggest that the mechanism for the bm12 mutation was the intergenic transfer of a hypervariable region in the first domain that is identical in the I-Abm12 beta, I-Eb beta, and I-Ek beta genes.
Nonspecific recruitment of cytotoxic effector cells in the intestinal mucosa of antigen-primed mice.
Authors: Klein J R , Kagnoff M F
Published: June 2004

We have examined cytotoxic responses of lymphocytes derived from the gut epithelium of mice primed systemically and enterically with alloantigens. Both gut intraepithelial (IEL) and splenic lymphocytes from alloantigen-primed mice were found to contain antigen-specific cytotoxic T cell activity. However, after priming, gut IEL also developed high levels of natural killer and spontaneous cytotoxic cell activities. We suggest that this nonspecific activation of additional cytotoxic effector populations during an antigen-specific response is an important host immune defense within the intestinal mucosa.
Induction of immunoglobulin gene expression in mouse fibroblasts by cycloheximide treatment.
Authors: Ishihara T , Kudo A , Watanabe T
Published: June 2004

A complete set of a rearranged human gamma 1-heavy chain gene, HIG1, was cloned from human plasma cell leukemia line, ARH-77, and transferred into mouse cells. It was strongly expressed in mouse myeloma cells but not in mouse L cells, indicating that immunoglobulin gene expression is not species-specific but cell-specific. However, a remarkable production of human gamma 1 chain was induced in mouse L cells containing HIG1 gene when the cells were treated with cycloheximide for a short period. The role of a labile repressor molecule in the expression of the immunoglobulin gene is proposed.
Use of monoclonal antibodies for the characterization of novel DNA-binding proteins recognized by human autoimmune sera.
Authors: Reeves W H
Published: June 2004

Autoantibodies to a DNA-binding heterodimer consisting of 70,000 and 80,000 dalton subunits were identified in 30-50% of human autoimmune sera from patients with systemic lupus erythematosus (SLE), mixed connective tissue disease (MCTD), and scleroderma. Three murine monoclonal antibodies (mAb) against the heterodimer were produced in BALB/c mice by immunizing with isolated human B cell nuclei. By immunofluorescence, the mAb and autoimmune sera demonstrated both speckled nucleoplasmic staining and diffuse nucleolar staining in all human cell types examined. The nucleoplasmic staining was sensitive to DNase but not RNase pretreatment, while the nucleolar staining was sensitive to RNase but not DNase pretreatment. Biochemical characterization of the 70,000 and 80,000 dalton proteins using the mAb indicated that two forms of the antigen, with different mobilities on sucrose gradients, are present in human B cells. A 10 S form consists of the physically associated 70,000 and 80,000 dalton proteins, while a larger, 10-20 S form probably represents the same two proteins bound to DNA. Binding of the proteins to nucleolar RNA could not be confirmed in biochemical studies. These studies indicate that non-histone, DNA-binding proteins may be more frequently recognized by autoantibodies in SLE, MCTD, and scleroderma than has been previously recognized. Along with previous studies on RNA-binding proteins such as Sm, RNP, Ro, and La, the present findings suggest that nucleic acid-binding proteins, as a class, may be particularly frequent targets of autoimmunity in SLE and related disorders.
Immune complexes can trigger specific, T cell-dependent, autoanti-IgG antibody production in mice.
Authors: Nemazee D A
Published: June 2004

Immunization of mice with a combination of passively administered syngeneic IgG (anti-p-azophenylarsonate [anti-Ars]) antibody and a soluble, multivalent form of the antibody's corresponding antigen (Limulus polyphemus hemocyanin conjugated with Ars [Lph-Ars]) resulted in specific autoanti-IgG Fc (rheumatoid factor) production. The response was rapid and only anti-IgG of the IgM isotype is found. Because immunization with either the IgG antibody or the antigen alone did not result in rheumatoid antibody production, immune complexes appear to be the active form of the immunogens. Antibody/antigen ratios that resulted in maximal anti-IgG antibody responses were the same as those required for peak in vitro immunoprecipitation, i.e., equivalence. Previous exposure of the mice to the exogenously supplied antigen was not required for the response. The response to immune complexes is specific because mice immunized with IgG2a-containing complexes produced autoanti-IgG2a, while mice immunized with IgG1-containing complexes produced anti-IgG1 with little reactivity to other IgG isotypes. IgG2a blocked in its complement-fixing capacity was more effective in eliciting the anti-IgG2a response than native IgG2a, suggesting a possible role for the complement system in modulating the anti-IgG2a response. Induction of rheumatoid factor production by immune complexes could be induced in xid mice but not in nu/nu mice, indicating T lymphocyte dependence of the response. In contrast, the B lymphocyte activator lipopolysaccharide was able to elicit vigorous rheumatoid factor production in both nu/nu and normal mice, demonstrating that nu/nu mice contain B cells capable of making the response. Rheumatoid antibody produced in the immune complex- or LPS-induced responses is Fc specific and has relatively low affinity for IgG that is not bound to antigen.
Idiotype connectance in the immune system. II. A heavy chain variable region idiotope that dominates the antibody response to the p-azobenzenearsonate group is a minor idiotope in the response to trinitrophenyl group.
Authors: Hornbeck P V , Lewis G K
Published: June 2004

We describe the recurrence of a cross-reactive idiotope (CRIAD8) in antibody responses to different epitopes, and explore factors leading to its dominance in some responses, but not others. Serological and genomic DNA analyses showed that CRIAD8 is a marker of the CRIa heavy chain variable region (VH) that encodes the majority of anti-p-azobenzenearsonate (anti-ABA) antibodies. The independence of CRIAD8 from any particular light chain or antigen specificity was underscored by the fact that we could isolate hybridomas that secrete antitrinitrophenyl (TNP) antibodies expressing CRIAD8, with lambda 1 light chains. CRIAD8 is dominant in anti-ABA responses, recurrent but nondominant in anti-TNP and anti-chicken gammaglobulin responses, and is virtually absent in other antihapten responses, including that to p-azobenzenephosphonate (ABP), which contains an ABA-cross-reactive component (approximately 5-40%). Dominance in the anti-TNP response could not be achieved by immunization with doubly haptenated TNP-ABA-KLH (keyhole limpet hemocyanin), where the anti-ABA response was dominated by CRIAD8. These observations suggest that, while the CRIAD8 VH region is necessary for idiotypic dominance, it is not sufficient. Apparently, an additional specificity is required. Since immunization with ABA calls up anti-ABP antibodies that express CRIAD8, but not vice versa, it is possible that the additional specificity is ABA itself. This possibility imposes a new constraint on the specificity of the putative idiotype-specific regulation that may establish dominance in the CRIa system.