bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of T cell populations that induce and mediate specific resistance to graft-versus-host disease in rats.
Authors: Kimura H , Pickard A , Wilson D B
Published: June 2004

F1 hybrid (A X B) rats immunized with parental strain (A) T cells, or which recover from graft-versus-host (GVH) reactions caused by parental T cells, develop strong T cell-mediated immune responses against anti-major histocompatibility complex (MHC) receptor structures on donor T cells specific for host (MHCb) alloantigens. This immune response provides the basis for a profound and specific resistance to the subsequent induction in these animals of local or systemic GVH disease. Using subset-specific monoclonal antibodies and negative selection rosetting procedures, we attempted to determine which donor T cell subset possesses the immunogenic idiotypic markers, and which host T cell subpopulation mediates GVH resistance. We show here that the immunizing donor cell population belongs to the W3/25+ helper T cell (Th) subset, the same one that causes local GVH reactions, and that both the W3/25+ Th and the OX8+ killer/suppressor (Tk/s) subsets of host T cells are able to transfer GVH resistance to secondary F1 recipients.
Sequence similarities among kappa IIIb chains of monoclonal human IgM kappa autoantibodies.
Authors: Pons-Estel B , Goñi F , Solomon A , Frangione B
Published: June 2004

Light chains of the serologically and chemically defined V region sub-subgroup kappa IIIb are preferentially associated with several types of human IgM kappa (monoclonal) autoantibodies and are remarkably homologous in primary structure, as evidenced by partial amino acid sequence data. To establish the extent of homology among such proteins, we have determined the complete variable region (V) sequence of the light chains of four monoclonal IgM kappa autoantibodies, of which two (GAR and GOT) are rheumatoid factors (RFs), the third (SON) has anti-apo beta lipoprotein specificity, and the fourth (PIE) binds specifically to intermediate filaments. The region encoded by the V kappa segment gene (positions 1-95) in all four light (L) chains is virtually identical in sequence, differing by only one residue in the FR3 of protein SON and in the first CDR of protein GOT. Further, the CDR3 of kappa chain SON contains an additional residue (prolyl) located at the carboxyl-terminus of the V segment. The region encoded by the J gene (positions 96-108) is identical after position 96 for the two RFs GAR and GOT (J kappa 2), but different in proteins SON (J kappa 4) and PIE (J kappa 1). The amino acid residue at position 96, located in CDR3 at the site of combinatoriaL joining of the V kappa and J kappa gene segments and involved as a contacting residue in the hapten binding site, is different in all four light chains. These results demonstrate the extensive homology in sequence among light chains of IgM kappa autoantibodies and indicate that a particular V kappa germ line gene, kappa IIIb, is expressed as a phylogenetic response to certain self antigens or as part of a selection process by which these autoimmune responses are regulated.
Degradation of the epidermal-dermal junction by proteolytic enzymes from human skin and human polymorphonuclear leukocytes.
Authors: Briggaman R A , Schechter N M , Fraki J , Lazarus G S
Published: June 2004

The degradation of normal human skin by the human polymorphonuclear leukocyte proteinases cathepsin G and elastase, and by a human skin chymotrypsin-like proteinase that appears to be a mast cell constituent, was examined. Enzymes were incubated with fresh, split-thickness skin for up to 8 h; the tissue was examined ultrastructurally and immunohistochemically using antibodies to known basement membrane constituents. In all cases, the primary damage observed was at the epidermal-dermal junction. Elastase degraded the lamina densa leaving scattered and disorganized anchoring fibrils, dermal microfibril bundles, and normal-appearing collagen fibers. Immunohistochemically, type IV collagen, laminin, KF1 antigen, and EBA antigen were absent. The bullous pemphigoid antigen was present and localized on the basal cells. Epidermal-dermal separation produced by the chymotrypsin-like proteinases, cathepsin G, and the human skin proteinase, was confined to the lamina lucida. The lamina densa and sub-lamina densa fibrillar network remained intact. The human skin chymotrypsin-like proteinase produced extensive epidermal-dermal separation, while cathepsin G, at comparable concentrations, produced only focal separations. Immunohistochemically, all antigens were present after incubation with enzyme. The bullous pemphigoid antigen, however, was found on the epidermal side of the split, while laminin was found on the dermal side. These results show that the epidermal-dermal junction is highly susceptible to neutral serine proteinases located in mast cells and polymorphonuclear leukocytes. Although all the proteinases produce epidermal-dermal separation, the patterns and extent of degradation are different. The distinctive patterns of degradation may provide a clue to the involvement of these proteinases in skin diseases.
Glycolipids of the mouse peritoneal macrophage. Alterations in amount and surface exposure of specific glycolipid species occur in response to inflammation and tumoricidal activation.
Authors: Mercurio A M , Schwarting G A , Robbins P W
Published: June 2004

We have characterized the major glycolipid constituents of the mouse peritoneal macrophage, and have demonstrated that alterations in the amount and in the accessibility of specific glycolipid species to galactose oxidase/NaB3H4 labeling, an indicator of glycolipid surface exposure, occur in response to inflammation and as a consequence of activation to a tumoricidal state. The key findings are: (a) Asialo GM1, a major neutral glycolipid constituent of all macrophage populations examined, is accessible to galactose oxidase/NaB3H4 labeling on the surface of TG-elicited and BCG-activated macrophages but not on resident macrophages; (b) GM1 is the predominant ganglioside constituent of the mouse macrophage. Resident macrophages contain two distinct GM1 species, as determined by cholera toxin binding, while TG-elicited and BCG-activated macrophages contain an additional GM1 species. Differences in the relative amounts of these GM1 species, as well as in their accessibility to galactose oxidase/NaB3H4 labeling, exist among the macrophage populations. These observations suggest that both a chemical and spatial reorganization of surface glycolipids occurs in response to inflammation and tumoricidal activation.
Carboxylic ionophores enhance the cytotoxic potency of ligand- and antibody-delivered ricin A chain.
Authors: Raso V , Lawrence J
Published: June 2004

The highly selective cytotoxicity of site-directed ricin A chain conjugates can be potentiated by membrane-active carboxylic ionophores. The combined use of the two agents results in much faster inactivation of ribosomes and subsequent cell death and lysis. The potency of A chain cytotoxins is correspondingly increased by several orders of magnitude and cells that sparsely express the target antigen or receptor can be killed.
The deoxyribonucleoside phosphotransferase of Trichomonas vaginalis. A potential target for anti-trichomonial chemotherapy.
Authors: Wang C C , Cheng H W
Published: June 2004

Trichomonas vaginalis, a human protozoan parasite known to lack the capability of synthesizing purine and pyrimidine nucleotides de novo, was found also incapable of converting its ribonucleotides to deoxyribonucleotides. The only apparent means of providing deoxyribonucleotides for DNA synthesis relies on salvaging exogenous deoxyribonucleosides by a deoxyribonucleoside phosphotransferase activity in the T. vaginalis 10(5) g pelletable fraction. The activity, constituted by at least two isozymes I and II, can be solubilized by Triton X-100, has a pH optimum of 5.0-6.0, and recognizes only thymidine, deoxyadenosine, deoxyguanosine, and deoxycytidine as the phosphate acceptor. TMP, dAMP, dGMP, dCMP, dUMP, FdUMP, and p-nitrophenylphosphate can serve as phosphate donors. Enzyme I has been purified 10-fold by DEAE-Sepharose chromatography and Sephacryl 200 filtration, and is totally freed of the acid phosphatase of T. vaginalis. It has an estimated molecular weight of 200,000 and Km values of 2-3 mM for the four deoxyribonucleosides, which act on each other as competitive inhibitors. It also possesses phosphatase activity capable of hydrolyzing p-nitrophenylphosphate with a Michaelis constant of 0.74 mM. The rates of hydrolysis are enhanced by thymidine, which suggests that the latter may be the preferred phosphate acceptor, and Enzyme I may be, thus, more a transferase than a phosphatase. This enzyme could be a potential target for antitrichomonial chemotherapy.
Functional properties of T cell clones with a double specificity for alloantigens and foreign antigens.
Authors: Waters S J , Luzzatti P R , Bona C A
Published: June 2004

Four keyhole limpet hemocyanin (KLH)-specific clones prepared from the lymph node of CB6F1 mice immunized with KLH had a proliferative response restricted to parental major histocompatibility complex (MHC)-encoded antigens. These clones provided help for CB6F1 trinitrophenyl-ovalbumin (TNP-OVA)-primed B cells to mount IgM and IgG plaque-forming cell (PFC) responses in the presence of KLH-TNP conjugate. In addition, two of these clones (A12.11 and F6) proliferated in response to allogeneic cells from mice strains bearing H-2k or H-2q haplotypes, respectively. However, they did not provide help for C3H/He or B10.Q primed B cells. The clonal nature of A12.11 and F6 was demonstrated by subcloning and in BUdR-suicide experiments. The proliferative response to KLH was ablated by anti-Iad antibodies, whereas the proliferation induced by C3H/HeJ stimulating cells was ablated by anti-Iak antibodies. Furthermore, both responses were inhibited by a monoclonal anti-clonotype (idiotype) antibody. Taken together, these results strongly support the hypothesis that the same receptor recognizes alloantigens and KLH associated with self-antigens.
Identification of two cis-encoded HLA-DQ molecules that carry distinct alloantigenic specificities.
Authors: Johnson J P , Wank R
Published: June 2004

The monoclonal antibodies Genox 3.53, S1, and R1 define polymorphic epitopes localized to DQ molecules. All three antibodies showed a strong association with the HLA-DR antigens 1, 2, and w6 when tested on a panel of 68 unrelated individuals, suggesting that they all recognized the DQw1 allospecificity. However, segregation analysis and binding studies with a panel of HLA-D/DR homozygous cells indicated that these monoclonal antibodies defined two different alloantigens. Cells homozygous for DR 1, 2, or w6 expressed the epitopes defined by all three antibodies (i.e., S1, R1, and Ge) while cells homozygous for DR4 and DRw8 expressed only the S1 and R1 epitopes. Sequential immunoprecipitation analyses in S1+/R1+/Ge+ individuals, in which the three epitopes were shown by segregation analysis to be encoded by the same chromosome, revealed two distinct DQ-like molecules. While R1 and S1 appeared to reside on the same molecule, the epitope defined by Genox 3.53 was on a different molecule. Identical results were obtained with DR1-, DR2-, or DRw6-bearing cells. Thus it appears that DQw1-bearing individuals express two cis-encoded DQ-like molecules that carry distinct alloantigenic specificities.
Acquisition of high metastatic capacity after in vitro fusion of a nonmetastatic tumor line with a bone marrow-derived macrophage.
Authors: Larizza L , Schirrmacher V , Pflüger E
Published: June 2004

A low metastatic, thioguanine-resistant murine T lymphoma line (EbTGR) was hybridized in vitro, with the help of polyethylene glycol, with syngeneic bone marrow-derived macrophages. Two HAT-resistant hybrid lines (Eb-F1 and Eb-F2) were obtained from independent fusion cultures. A cytogenetic analysis revealed that most of the macrophage chromosomes except No. 12 had segregated or become rearranged 60 d after fusion, a time at which the cell lines had become stabilized in culture. Syngeneic mice inoculated subcutaneously with the tumor macrophage hybrid lines developed, very quickly, visceral metastases and died after less than 2 wk, while those inoculated with the parental line lived for greater than 6 wk and developed only localized, large primary tumors. The metastatic hybridomas expressed a similar tumor antigen as a spontaneous, in vivo derived, high metastatic variant (ESb) of the same tumor. This suggests that ESb cells might have arisen from a spontaneous fusion with a host macrophage.
Detection and functional studies of p60-65 (Tac antigen) on activated human B cells.
Authors: Jung L K , Hara T , Fu S M
Published: June 2004

A monoclonal antibody, AT-1, is shown to precipitate a p60-65 molecule identical to the Tac antigen. With AT-1, the expression of IL-2 receptors by normal activated human B cells from peripheral blood and tonsils is documented by biosynthetic and immunofluorescence studies. AT-1 precipitated a p60-65 protein from [35S]methionine-labeled activated B cells, similar to that from activated T cells. The interleukin 2 (IL-2) receptor appeared shortly after activation with anti-IgM and B cell-stimulatory factor(s). Its expression reached its peak at 60-72 h with approximately 50% of the B blasts stained by AT-1. Other modes of activation of B cells, by T cell-independent, formalin-treated staphylococci and Epstein-Barr virus, and by T cell-dependent pokeweed mitogen, also induced IL-2 receptor expression. The functional significance of this finding was investigated using recombinant IL-2 (rIL-2). While rIL-2 did not induce resting B cells to proliferate in the presence of anti-IgM, it induced activated B cells to proliferate in the absence of other factors. On the other hand, rIL-2 did not induce the differentiation of these activated B lymphocytes. These data suggest that IL-2 may play a significant role in B cell activation.
C3b covalently bound to IgG demonstrates a reduced rate of inactivation by factors H and I.
Authors: Fries L F , Gaither T A , Hammer C H , Frank M M
Published: June 2004

We have prepared C3b covalently linked to IgG via a hydroxylamine-sensitive bond between the C3b alpha' chain and sites predominantly, but not exclusively, located in the IgG heavy chain. This C3b species displays relative resistance to inactivation by factors H and I when compared with free C3b. This resistance appears to be due entirely to reduced affinity of C3b-IgG for factor H. Resistance to inactivation is not conferred on C3b by binding to another serum glycoprotein of similar size, ceruloplasmin, and may be a special property of IgG. C3b-IgG demonstrates an enhanced capacity to consume serum C3 relative to C3b. These alterations of the behavior of C3b when bound to IgG may in part explain the augmentation of alternative pathway activity by IgG. In addition, IgG-induced protection of C3b might influence both complement-mediated killing and phagocytosis of bacteria, as well as modify the in vivo handling of IgG-containing soluble immune complexes.
Purification and characterization of a mannose-containing disaccharide obtained from human pregnancy urine. A new immunoregulatory saccharide.
Authors: Muchmore A V , Decker J M , Blaese R M , Nilsson B
Published: June 2004

Endogenous mammalian lectin-like sugar-binding molecules have been previously described that have immunoregulatory properties. Further, the addition of defined simple saccharides to lymphocyte cultures has been shown to inhibit a variety of in vitro lymphocyte functions, presumably because these sugars are able to compete with the binding of endogenous lectins to critical membrane receptors. In this report, we describe the isolation and characterization of a D-mannose-containing disaccharide in human pregnancy urine that inhibits the proliferative response of human T lymphocytes. The inhibitory disaccharide was purified to homogeneity by sequential steps including affinity chromatography on immobilized concanavalin A and molecular sizing on Sephadex G-75 and then Fractogel 40S columns, with final purification on high-performance thin-layer chromatography. By mass spectrometry of the purified material as its permethylated derivative, the deduced structure of this compound was alpha-D-Manp 1-6-D-Man. To confirm that this disaccharide was in fact immunosuppressive, an identical disaccharide was prepared by sequential digestion of yeast cell wall polysaccharide. The urinary and yeast disaccharides had identical immunosuppressive properties. It has been previously reported that D-mannose is inhibitory for antigen-specific proliferative assays in the range of 10-50 mM. The purified alpha-D-Manp 1-6-D-Man disaccharide was inhibitory at 100-fold-lower concentrations. Further, while D-mannose inhibits T cell proliferation when added at anytime up to 24 h before harvest of a 6-d lymphocyte culture, alpha-D-Manp 1-6-D-Man disaccharide was inhibitory only if added at the initiation of culture and had no inhibitory effect if added just 24 h later. These data support the concept that simple sugar compounds can exhibit marked immunoregulatory activity in vitro. The impact of these molecules on the regulation of immune responses in vivo is unknown, as is their precise mechanism of action, but structural and chemical identification should now permit a detailed analysis of these issues.
Inhibition of antigen-specific T lymphocyte activation by structurally related Ir gene-controlled polymers. II. Competitive inhibition of I-E-restricted, antigen-specific T cell responses.
Authors: Rock K L , Benacerraf B
Published: June 2004

Our previous studies have defined a highly specific competitive inhibition between a pair of structurally related antigens (GT and GAT) for antigen presentation by accessory cells. The present report investigates this phenomenon in a second antigenic system, which is controlled by a distinct Ir gene product. Two GL phi-specific, I-Ed-restricted, interleukin 2-producing T cell hybridomas were constructed. The antigenic fine specificity of these two hybrid clones was distinct. One hybrid reacted solely with GL phi while the second cross-reacted with GLleu and GLT. These latter two copolymers, as well as the antigen GL, were found to inhibit the GL phi response of the non-cross-reactive hybrid. The structurally related antigen G phi was not inhibitory for this clone's response. The cross-reactive GL phi hybrid could also be inhibited, but, in this case, G phi and not GL caused the inhibition. Reciprocal inhibitions could be demonstrated between these and other hybrids (e.g., GAT responsive), indicating a very high degree of specificity to the inhibition. The inhibition caused by the various copolymers was reversible by increasing the concentration of GL phi, This effect was localized to the antigen-presenting cell and not the T cell hybridoma. Functionally, this competition did not appear to be for antigen uptake or general antigen processing. These findings generalize the phenomenon of antigen competition to a second antigen system in the context of a second Ia molecule. The possible mechanisms accounting for the complex pattern of specificities in this system are discussed.
Importance of immunoglobulin isotype in human antibody-dependent, cell-mediated cytotoxicity directed by murine monoclonal antibodies.
Authors: Kipps T J , Parham P , Punt J , Herzenberg L A
Published: June 2004

Using the fluorescence activated cell sorter to select rare IgG2a- and IgG2b-producing variants, we developed switch variant families of hybridomas from IgG1-producing hybridomas, ME1 and MA2.1. The IgG2a and IgG2b antibodies produced by such switch variants have the same binding activities for HLA as the IgG1 antibodies produced by the parent hybridomas. Using these antibodies, we directly compared the IgG1, IgG2a, and IgG2b murine Ig isotypes for their capacities to direct human peripheral blood lymphocytes (PBL) in antibody-dependent cell-mediated cytotoxicity (ADCC) against a B lymphoblastoid cell line. We demonstrate that, for antibodies of identical binding affinity and specificity, the murine IgG2a isotype is the most effective in directing ADCC by human effector cells. The murine IgG2b directs intermediate levels of ADCC activity while IgG1 is inactive. We identified the effector cells in human PBL that mediate IgG2a or IgG2b ADCC as nonadherent killer (K) cells. These cells express the C3bi receptor and have cytolytic activity which is specifically blocked by a monoclonal antibody (anti-Leu-11a) that binds the Fc receptor (FcR) of such cells. Finally, FcR-bearing K cells bind to target cell-bound, rather than free, IgG2a or IgG2b molecules.
Multiple, heart-cross-reactive epitopes of streptococcal M proteins.
Authors: Dale J B , Beachey E H
Published: June 2004

We present evidence that a highly purified pepsin extract of type 5 streptococcal M protein (pep M5) contains at least three epitopes that are cross-reactive with sarcolemmal membrane proteins of human myocardium. The tissue-cross-reactive determinants of pep M5 are also partially shared with pep M6 and pep M19. Three rabbits immunized with a single 300 micrograms dose of pep M5 developed significant levels of heart-cross-reactive antibodies, as determined by indirect immunofluorescence tests. All three sera also contained antibodies that cross-reacted with pep M6 and pep M19. The heart tissue--specific antibodies that were eluted from sarcolemmal membranes opsonized types 5, 6, and 19 streptococci, indicating that they were directed against protective M protein epitopes on the surface of virulent organisms. Immunofluorescence inhibition tests, using purified M proteins as soluble inhibitors of heart-cross-reactive antibodies, revealed the number and M protein serotype distribution of the tissue-cross-reactive epitopes. Immunoblot analyses demonstrated the sarcolemmal membrane proteins containing the various cross-reactive antigenic determinants.
Polymorphism of a high molecular weight schizont antigen of the human malaria parasite Plasmodium falciparum.
Authors: McBride J S , Newbold C I , Anand R
Published: June 2004

Intraspecies antigenic diversity in the blood stages of the human malaria parasite Plasmodium falciparum was investigated using a collection of murine monoclonal antibodies and clones of the parasite. The results were as follows: (a) The schizont and merozoite stages of the parasite express on their surface clonally restricted antigens detectable by strain-specific antibodies in indirect immunofluorescence tests. (b) These restricted antigens are phenotypically stable characteristics of clones grown in vitro. (c) The molecules carrying the specific antigens were isolated by immunoprecipitation and were found to be parasite proteins ranging in size from Mr 190,000 to 200,000 between clones. (d) Comparative immunoprecipitation and peptide mapping of these molecules showed that each parasite clone expresses a protein that is antigenically and structurally distinct from the equivalent products of several other clones. (e) The different clonal products are, however, immunologically interrelated, since they possess determinants in common with all tested isolates of the parasite. (f) These polymorphic molecules are closely related to a previously described schizont protein of P. falciparum that is posttranslationally cleaved into fragments located on the merozoite surface. These findings show the existence of a family of related polymorphic schizont antigens (PSA) of P. falciparum, whose expression is clonally restricted, and indicate that these proteins have regions of constant and variable antigenicity. We propose that a system of immunological classification of the parasite can be developed based on the polymorphism of these proteins.
Interleukin 2 receptors on human B cells. Implications for the role of interleukin 2 in human B cell function.
Authors: Muraguchi A , Kehrl J H , Longo D L , Volkman D J , Smith K A , Fauci A S
Published: June 2004

In the present study, we examined the expression of interleukin 2 (IL-2) receptors on normal human B cells as well as established B cell lines. Anti-Tac monoclonal antibody did not bind to freshly separated normal human B cells. Unexpectedly, with the appropriate activation of the normal B cells by anti-mu antibody, phorbol myristate acetate, or Staphylococcus aureus Cowan I (SAC), Tac antigen was induced on the activated B cells. Anti-Tac antibody showed consistent reactivity with two B cell lines that were infected by human T cell leukemia virus (HTLV) and some reactivity with two out of eight Epstein-Barr virus-transformed B cell lines established from normal adult donors. Immunoprecipitation analysis revealed that antigens of similar size with a molecular weight of 50,000-60,000 can be precipitated with anti-Tac antibody from phytohemagglutinin-stimulated normal T cell blasts and normal activated B cells, as well as a cloned B cell line. Binding assays of IL-2 on normal activated B cells and on the cloned B cell (HS1) revealed that B cells have significantly fewer sites and lower-affinity IL-2 receptors compared with phytohemagglutinin-stimulated normal T cell blasts. Finally, biological properties of the IL-2 receptor on B cells were examined by incubating B cells with recombinant IL-2. It was found that moderate concentrations of IL-2 induce significant enhancement of proliferation and differentiation in SAC-activated normal B cells. These results suggest that normal B cells may express functional IL-2 receptors or closely related proteins and thus IL-2 may play a significant role in the modulation of B cell function.
Spontaneous production of fibroblast-activating factor(s) by synovial inflammatory cells. A potential mechanism for enhanced tissue destruction.
Authors: Wahl S M , Malone D G , Wilder R L
Published: June 2004

A characteristic feature of rheumatoid arthritis is hyperplasia of the synovial lining cells and fibroblasts, the source of tissue-degrading mediators, in association with the appearance and persistence of lymphocytes in affected joints. Diseased synovial tissue obtained at arthroscopy from 10 of 12 rheumatoid arthritis patients was found to release a factor(s) that could stimulate quiescent fibroblasts to proliferate in vitro. Mononuclear cells isolated from this synovial tissue and from the synovial fluid spontaneously produced fibroblast-activating factor(s) (FAF). In contrast, synovial tissue from patients with noninflammatory joint disease did not release FAF. By gel filtration, FAF was detected in two peaks (40,000 and 15,000 mol wt) that were consistent with the previously described peripheral blood T lymphocyte- and monocyte-derived factors with identical activity. The mononuclear cells were predominantly OKT3+/Leu-1+ T lymphocytes and OKM1+ cells of monocyte/macrophage lineage that expressed HLA-DR antigens, suggesting prior activation of these cells. Mononuclear cells isolated from the peripheral blood of these patients did not spontaneously secrete FAF. Lymphocytes and monocytes from the site of synovial inflammation appear to be activated in situ to produce factors that may contribute to the hyperplasia and overgrowth of the synovial membrane in rheumatoid arthritis.
Identification of a specific HLA DR2 Ia molecule as a restriction element for measles virus-specific HLA class II-restricted cytotoxic T cell clones.
Authors: Jacobson S , Nepom G T , Richert J R , Biddison W E , McFarland H F
Published: June 2004

By using a panel of HLA-D-defined subtypes of HLA-DR2 HCL with known beta chain structural variabilities, we have demonstrated that HLA-DR2, OKT4+ cytotoxic T lymphocyte (CTL) clones specific for measles virus are apparently restricted to a distinct DR beta chain. The presence of this DR beta 2 molecule correlated precisely with the susceptibility of measles virus-infected HLA-DR2 HCL to lysis by these CTL clones. These studies demonstrate that delineation of HLA-DR2 into various subgroups can have a functional significance that parallels the structural differences within the HLA-D region. These results are discussed in the context of the possible association of HLA class II-restricted, measles virus-specific CTL and multiple sclerosis.
Sera from patients with poststreptococcal glomerulonephritis contain antibodies to glomerular heparan sulfate proteoglycan.
Authors: Fillit H , Damle S P , Gregory J D , Volin C , Poon-King T , Zabriskie J
Published: June 2004

Antibodies, found in human sera from patients with poststreptococcal glomerulonephritis, against proteoglycans (PG) derived from bovine and human glomeruli were investigated. PG were isolated by 4 M guanidine-HCl extraction of whole glomeruli, followed by DEAE-Sepharose CL-6B ion exchange chromatography. The anionic fractions were further purified by chromatography on Sepharose CL-4B. Biochemical analysis of the two resulting peaks revealed the presence of high molecular weight anionic material containing protein, uronic acid, glucosamine, and galactosamine. Enzymatic and chemical susceptibilities indicated the presence of heparan sulfate PG and a galactosamine-containing PG. Immunologic studies revealed the presence of anti-PG antibodies to both PG peaks of the Sepharose CL-4B column in glomerulonephritis sera. Inhibition studies using an ELISA demonstrated that heparan sulfate was a major antigenic determinant. Cross-reactivity with both mammalian and streptococcal hyaluronate was noted. Inhibition studies also indicated the presence of a second antigenic site containing N-acetylgalactosamine, possibly representing chondroitin or dermatan sulfate PG.
Induction of immunoglobulin isotype switching in cultured I.29 B lymphoma cells. Characterization of the accompanying rearrangements of heavy chain genes.
Authors: Stavnezer J , Sirlin S , Abbott J
Published: June 2004

The murine B cell lymphoma I.29 contains cells expressing surface IgM or IgA with identical heavy chain variable regions (9, 25, and D. Klein and J. Stavnezer, unpublished data). Purified IgM+ cells from the lymphoma have been adapted to culture and induced to switch to IgA, IgE, or IgG2 by treatment with lipopolysaccharide (LPS) or by treatment with a monoclonal anti-I.29 antiidiotype plus LPS. Clones of IgM+ cells have been obtained and induced to switch. Under optimal conditions, 30% of the cells in the culture expressed IgA 8 d after the inducers were added, and by 15 d 90% of the cells were IgA+. In actively switching cultures, up to 50% of the cells whose cytoplasm stained positively with anti-IgA stained simultaneously with anti-IgM, which indicates that the appearance of IgA+ cells in the cultures was due to isotype switching and not to clonal outgrowth. Examination by Southern blotting experiments of the Ig heavy chain genes in I.29 cells before and after switching revealed that isotype switching was accompanied by DNA recombinations that occurred within or immediately 5' to the tandemly repeated switch sequences. Within 3 d after the addition of inducers of switching, the nonexpressed chromosome underwent a variety of deletions or expansions within the S mu region, and a portion of the S alpha regions had undergone a 0.9-kb deletion. In cultures that contained at least 12% IgA+ cells, rearranged, expressed alpha genes, produced by recombination between the S mu region within the expressed mu gene and the S alpha region, were detected.
Abnormalities induced by the mutant gene, lpr. Patterns of disease and expression of murine leukemia viruses in SJL/J mice homozygous and heterozygous for lpr.
Authors: Morse H C , Roths J B , Davidson W F , Langdon W Y , Fredrickson T N , Hartley J W
Published: June 2004

SJL/J mice heterozygous or homozygous for the lpr mutation were compared with SJL/J-+/+ mice for longevity, histopathology, antigenic characteristics of lymphocytes and expression of murine leukemia viruses (MuLV). In comparison to +/+ mice, lpr homozygotes had a markedly shortened life span, died with infiltrative pulmonary disease, but little or no renal disease, and expressed high levels of infectious ecotropic MuLV in lymphoid tissues. SJL-lpr/+ mice had a life span intermediate between SJL-+/+ and -lpr/lpr mice, died with lymphomas that histologically resembled the neoplasms of +/+ mice, and sometimes expressed high levels of ecotropic MuLV. The lymphomas of lpr/+ could be transplanted to +/+ recipients in 78% of cases, and continuous in vitro lines were established from some of them. Similar effects on virus expression or lymphoma development were not observed in other strains homozygous or heterozygous for the lpr mutation. These results indicate that the diseases expressed by mice homozygous for the lpr mutation are highly strain-dependent, and that this gene can have an effect in the heterozygous state in SJL mice.
Hypohaptoglobinemia associated with familial epilepsy.
Authors: Panter S S , Sadrzadeh S M , Hallaway P E , Haines J L , Anderson V E , Eaton J W
Published: June 2004

In select kindreds afflicted with familial idiopathic epilepsy, most individuals suffering seizures also have low levels of the plasma hemoglobin-binding protein, haptoglobin. This hypohaptoglobinemia may be causally associated with a tendency to develop epilepsy. Our experimental results indicate that artificially-induced hypohaptoglobinemia in mice causes retarded clearance of free hemoglobin from the central nervous system, and that such free hemoglobin may engender the peroxidation of brain lipids. We hypothesize that hypohaptoglobinemia, either inherited, or acquired via traumatic processes, may prevent efficient clearance of interstitial hemoglobin from the central nervous system, thereby predisposing these people to encephalic inflammation and the appearance of seizure disorders.
Proliferation of thymic stem cells with and without receptors for interleukin 2. Implications for intrathymic antigen recognition.
Authors: Lugo J P , Krishnan S N , Sailor R D , Koen P , Malek T , Rothenberg E
Published: June 2004

We have tested the dividing cells in the mouse thymus for expression of interleukin 2 (IL-2) receptors (IL-2-R) using the rat monoclonal antibody 7D4. A discrete subpopulation of the lymphoblasts clearly expressed IL-2-R at levels comparable to those on mitogen-activated peripheral T cells. This subpopulation, however, represented a small minority of the proliferating cells. IL-2-R-bearing cells were depleted from the PNA+ (peanut agglutinin) lymphoblast population, which contains the direct precursors of most of the cells in the thymus. The majority of receptor-bearing cells were found in the PNA- lymphoblast population, where they constituted only approximately 12% of the cells. Thus, virtually all the PNA+ and most of the PNA- blast cells were in cycle without detectable IL-2-R expression. This indicates that they were not dividing in response to IL-2, and implies that they were not dividing in response to antigen, but rather to novel thymus-specific mitogenic stimuli. On the other hand, the proliferating cells that do express IL-2-R were enriched 4-5-fold in the rapidly growing neonatal thymus, suggesting that they may also play a key role in T cell development.
Inhibition of Epstein-Barr virus (EBV) release from the P3HR-1 Burkitt's lymphoma cell line by a monoclonal antibody against a 200,000 dalton EBV membrane antigen.
Authors: Sairenji T , Reisert P S , Spiro R C , Connolly T , Humphreys R E
Published: June 2004

In raising murine hybridoma antibodies against Epstein-Barr virus (EBV)-induced membrane antigens (MA), we found one antibody that blocked the release of infectious EBV from cultured P3HR-1 cells. This monoclonal antibody (mAb) recognized a 200 kD, phosphonoacetic acid-sensitive (late) MA, and did not directly neutralize virus without complement. When this mAb was added to 33 degrees C-cultured, spontaneously EBV-producing P3HR-1 cells, the intracellular expression of viral capsid antigen and infectious virus was not inhibited, but the appearance of infectious virus in the culture medium was significantly reduced. The duration of this suppression was dependent upon the concentration of the mAb, an effect being observed to a 1:4 X 10(5) titer of the ascites mAb preparation. A more acute effect of suppression of EBV release was observed in a second model of 12-o-tetradecanoyl phorbol-13-acetate and n-butyrate induction of EBV in 37 degrees C-cultured P3HR-1 cells. Again, intracellular infectious virus production was not inhibited, but the level of infectious virus in the culture medium was significantly reduced as early as 1 and 2 d of culture with antibody. This effect was reversed within 31 h after replacement of mAb-containing medium with fresh medium. This description of antibody-mediated inhibition of EBV release might lead to the characterization of another form of immune defense for the control of EBV infections.
ras Oncogene p21 expression is increased in premalignant lesions and high grade bladder carcinoma.
Authors: Viola M V , Fromowitz F , Oravez S , Deb S , Schlom J
Published: June 2004

ras Oncogene p21 antigen is present in the most superficial cells of the normal bladder urothelium, as demonstrated by immunohistochemical staining. The pattern and intensity of p21 staining of cells in epithelial hyperplasia and low grade bladder carcinoma were similar to that seen in the normal urothelium. In contrast, epithelial cells in "premalignant" (dysplastic) lesions and high grade carcinomas exhibited an intense staining reaction for p21 antigen. ras p21 may be a useful marker for the malignant potential of both premalignant lesions and carcinomas of the bladder.
Rat lymphoid cell lines producing human T cell leukemia virus. II. Constitutive expression of rat interleukin 2 receptor.
Authors: Yodoi J , Okada M , Tagaya Y , Teshigawara K , Fukui K , Ishida N , Ikuta K , Maeda M , Honjo T , Osawa H
Published: June 2004

Three rat lymphoid cell lines (TARS-1, TARL-2, and TART-1) (12) transformed by human T cell leukemia/lymphoma virus I (HTLV-I) had rearrangement of the beta chain gene of the T cell antigen receptor, and had integrated proviral DNA from HTLV-I in their genomes. As is the case with adult T cell leukemia (ATL)-derived human T cell lines transformed by HTLV-I, these rat cell lines unequivocally expressed interleukin 2 (IL-2) receptor, as determined by radiolabeled IL-2 binding. By Scatchard plot analysis, one of the cell lines, TART-1, proved to have high affinity receptors (Ka = 1.3 X 10(11)/M and 8.8 X 10(9)/M). Rat IL-2 receptor, not human IL-2 receptor, was expressed on HTLV+ rat cell lines, as demonstrated by the fact that they expressed antigens reactive with monoclonal antibodies (ART-18) against rat IL-2 receptor, but not with anti-Tac antibodies. The collective evidence indicates that the endogenous IL-2 receptor gene is activated in human and rat lymphoid cell lines with HTLV-I production. The mechanism of abnormal IL-2 receptor expression in HTLV infection is discussed.
Obligatory role of gamma interferon in T cell-replacing factor-dependent, antigen-specific murine B cell responses.
Authors: Brunswick M , Lake P
Published: June 2004

The role of gamma interferon (IFN-gamma) in T cell-replacing factor (TRF) activity for antigen-specific plaque-forming cell (PFC) responses in vitro was studied using antibodies to murine IFN-gamma (Mu IFN-gamma). TRF activity was present in supernatants (Sn) of Con A- or mixed leukocyte reaction-stimulated murine spleen cells as well as in an IL-2-rich fraction of phytohemagglutinin-stimulated human peripheral blood lymphocyte Sn and in the Sn of the Gibbon T lymphoma MLA-144. The human TRF was highly active with cells from nu/nu mice and normal mice but not with cells from animals with the xid immunologic defect, similar to the activity of murine TRF. Antibodies to IFN-gamma consisted of hyper-immune rabbit antisera, IFN-gamma affinity-purified rabbit immunoglobulin and an interspecies hybridoma specific for Mu IFN-gamma. The results show that the activities of all preparations of TRF are markedly diminished or abrogated by antibody to Mu IFN-gamma but not by antibodies to human IFN-gamma (Hu IFN-gamma), nor by normal rabbit sera or purified rabbit Ig. The degree of inhibition was dose dependent and was quantitatively reversed by the addition to the cultures of recombinant-derived Mu IFN-gamma (Mu rIFN-gamma) but not Hu rIFN-gamma. This reversal was fully antigen specific and thus not attributable to polyclonal B cell activation by IFN-gamma, which is inactive alone in the TRF assay. Kinetic analysis shows that IFN-gamma must act by 24-48 h to produce PFC responses at 4 d. Together, the data demonstrate that IFN-gamma is a necessary mediator for TRF effects and that IFN-gamma is induced by TRF from T-depleted murine spleen cells in sufficient quantity to support large antibody responses. The source of this IFN-gamma may be the potent natural killer cells that are induced in cultures stimulated with TRF.
Replication of measles virus in human lymphocytes.
Authors: Hyypiä T , Korkiamäki P , Vainionpää R
Published: June 2004

Replication of measles virus was restricted in human peripheral blood mononuclear cells (PBMC). However, in in vitro-infected, unstimulated cells, active synthesis of viral RNA and proteins occurred, while the release of infectious virus could not be detected. Stimulation with PHA caused a productive infection cycle comparable to the lytic infection. Replication of viral RNA was demonstrated in both T and B cells, and in both OKT4+- and OKT8+-depleted T cell subsets. The presence of measles virus RNA was detected in PBMC isolated from measles patients, and the production of the immunoreactive hemagglutinin protein was defective in these cells.
Origin and specificity of autoreactive T cells in antigen-induced populations.
Authors: Faherty D A , Johnson D R , Zauderer M
Published: June 2004

We have characterized the major histocompatibility complex (MHC) specificity of autoreactive T cell clones arising from diverse donors after immunization with different antigens. The MHC fine specificity of autoreactive T cells for unique F1 hybrid determinants of BALB.K X BALB.B F1, and for the mutant I-Ab determinants of the B6.C-H-2bm12 (bm 12) strain is similar to that previously described for antigen-specific T cells. We find, furthermore, that the MHC specificity of autoreactive T cell clones selected from primed populations grown in the absence of Con A-stimulated supernatant factors reflects the predominant MHC restriction specificity of T cells specific for the immunogen. Thus, I-E subregion-specific autoreactive T cells are detected at a much higher frequency after immunization with the I-E-restricted antigen, GL (terpolymer of glutamic acid, lysine, and phenylalanine), than with the predominantly I-A-restricted antigen, keyhole limpet hemocyanin (KLH). These experiments strongly suggest that some autoreactive T cells are derived from antigen-stimulated precursors. This result contrasts with that obtained when autoreactive T cells are selected in bulk cultures, or in the presence of exogenous T cell factors. We conclude that, under optimal conditions, most autoreactive T cells are recruited from a relatively stable pool of predominantly I-A-specific precursors. Autoreactive precursors in this pool might themselves derive from previous antigenic stimulation, or be of independent origin.
Eradication of established human melanoma tumors in nude mice by antibody-directed effector cells.
Authors: Schulz G , Staffileno L K , Reisfeld R A , Dennert G
Published: June 2004

The simultaneous injection of monoclonal antibody 9.2.27, directed against a chondroitin sulfate proteoglycan preferentially expressed on human melanoma cells, and 2 X 10(7) mononuclear splenocytes, eradicated established, progressively growing human melanoma tumors in nude mice. Neither splenocytes nor antibody alone achieved significant tumor regression. The cells responsible for tumor elimination are most likely natural killer (NK) cells: they are present in splenocytes of T cell-deficient nude mice, and cloned cells with NK activity are able to suppress tumor growth. Moreover, splenocytes treated with anti-asialo GM1 and complement or harvested from NK-deficient C57BL/6 beige mice did not cause tumor rejection. Furthermore, treatment of BALB/c nude mice just before injection with anti-asialo GM1 antiserum, which is known to eliminate NK activity in vivo, resulted in better tumor growth. In addition, evidence is presented that cells with NK activity are probably the effectors responsible for melanoma target cell lysis in vitro: Antibody-dependent and -independent cell-mediated lysis of M21 melanoma cells was suppressed when splenocytes were preincubated with complement and antibodies specific for cell surface antigens of NK cells, i.e., anti-asialo GM1, anti-Qa5, and anti-NK1.1. Moreover, splenocytes of C57BL/6 beige mice were not able to lyse M21 cells in vitro. These results strongly support the conclusion that cells with NK activity are indeed responsible for the antibody-dependent destruction of M21 melanoma cells in vivo and in vitro.
A model for the differentiation of human natural killer cells. Studies on the in vitro activation of Leu-11+ granular lymphocytes with a natural killer-sensitive tumor cell, K562.
Authors: Phillips J H , Lanier L L
Published: June 2004

A subpopulation of low density granular lymphocytes that express the natural killer (NK) cell-associated Leu-11 antigen (IgG Fc receptor) were stimulated directly by coculture with an NK-sensitive tumor cell, K562. T lymphocytes (Leu-11-) responded only weakly when cocultured with K562. The response of Leu-11+ cells apparently did not require exogeneous factors or accessory cells. The K562-activated cells retained expression of Leu-11 antigen, acquired activation antigens, and were highly cytotoxic against NK-sensitive and -insensitive tumor cells. Anti-IL-2 receptor monoclonal antibody minimally inhibited the activation of Leu-11+ cells by K562, but completely inhibited the phytohemagglutinin-induced activation of the Leu-11- cells from the same individual. Leu-11+ cells can be divided into Leu-7-11+ and Leu-7+11+ subpopulations using anti-Leu-7 antibody. These subsets were separated by two-color fluorescence-activated cell sorting and cocultured with K562. Proliferation by Leu-7-11+ cells was significantly greater than by Leu-11+7+ cells. Leu-7+11- granular lymphocytes and T lymphocytes (Leu-7-11-) typically proliferated only weakly when cocultured with K562. A proportion of the Leu-7-11+ cells acquired Leu-7 antigen after stimulation with K562, whereas the phenotype of Leu-7+11+, Leu-7+11-, and Leu-7-11- subsets was unaffected. These results demonstrate a developmental relationship between the Leu-7-11+ and Leu-7+11+ lymphocytes and suggest that Leu-7 antigen may be expressed late in the differentiation pathway of NK cells. The direct activation of highly purified Leu-11+ cells by coculture with K562 provides an in vitro model with which to study the activation and maturation of human NK cells.