bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulation of natural killer and cytotoxic T large granular lymphocytes in the liver during virus infection.
Authors: McIntyre K W , Welsh R M
Published: June 2004

The immunologic mechanisms involved in virus-induced hepatitis were examined by measuring the cytotoxic capabilities and the morphologic and antigenic phenotypes of leukocytes isolated from livers of virus-infected mice. Large granular lymphocytes (LGL) of both natural killer (NK) cell and cytotoxic T lymphocyte (CTL) phenotypes were found to accumulate in livers of mice infected with either the nonhepatotropic Armstrong strain of lymphocytic choriomeningitis virus (LCMV-ARM) or the hepatotropic WE strain (LCMV-WE). Between days 1 and 5 postinfection (p.i.), both viruses induced a three- to fourfold increase in NK cell lytic activity in the livers of C3H/St mice and a three- to fourfold increase in the number of LGL in the organ. These LGL were characterized as NK cells on the basis of cell surface antigens, kinetics of appearance, target cell range, and morphology. By day 7 p.i., virus-specific, H-2-restricted, Thy-1+, Lyt-2+, CTL activity was present in the liver, and its appearance correlated with a second wave of LGL accumulation. CTL activity, total leukocyte number, and CTL/LGL number were at least fivefold higher in the livers of mice infected with LCMV-WE than with LCMV-ARM. The dramatic LCMV-WE-induced day 7 increases in total leukocytes and LGL were absent in athymic nude (nu/nu) mice, suggesting that the increases were T cell-dependent. LCMV-ARM infection of C57BL/6 mice induced significant spleen CTL activity but little liver CTL activity, whereas LCMV-WE infection resulted in significant liver CTL activity but minimal spleen CTL activity. Mice infected with the cytopathic hepatotropic viruses, mouse hepatitis virus (MHV) and murine cytomegalovirus (MCMV), experienced much greater increases in liver NK/LGL by day 3 p.i. than did mice infected with LCMV or injected with the interferon-inducer poly(I-C). MHV-infected mice homozygous for the beige (bg/bg) mutation also exhibited significant increases in liver NK/LGL cell number and activity, although the activity was less than heterozygote controls, and the morphology of the LGL granules was aberrant. These data show that the LGL accumulate in virus-infected organs, in this case, the liver. An early NK/LGL influx is most pronounced during infection with cytopathic hepatotropic viruses. This initial influx of NK/LGL is followed later by an influx of CTL also possessing LGL morphology. The CTL/LGL response in the liver is significantly greater during hepatotropic virus infections, even when a strong CTL response in the spleen is lacking.
Class II histocompatibility antigen expression in human melanocytes transformed by Harvey murine sarcoma virus (Ha-MSV) and Kirsten MSV retroviruses.
Authors: Albino A P , Houghton A N , Eisinger M , Lee J S , Kantor R R , Oliff A I , Old L J
Published: June 2004

Human melanocytes infected with Ki-MSV or Ha-MSV, but not amphotropic MuLV, undergo a series of transformation-related changes that are characteristic of malignant melanoma. These are (a) expression of Ia antigens, in particular DP, DQ, and DR class II histocompatibility gene products, (b) a transformed morphology and ability to grow in soft agar, and (c) a 5-10-fold increase in the cell surface expression of GD3 ganglioside. However, other characteristics of melanoma, such as independence from specific growth factors and loss of adenosine deaminase binding protein were not observed. We conclude that viral ras oncogenes initiate early transformation events in melanocytes, and that Ia antigen expression is a transformation marker in this system.
Isolation and partial characterization of the reduction-modifiable protein of Neisseria gonorrhoeae.
Authors: Lytton E J , Blake M S
Published: June 2004

We have isolated and purified the reduction-modifiable protein (protein III) from several strains of Neisseria gonorrhoeae. We have found them to be basic proteins (pI 8.6) and virtually identical. A similar but not identical protein was isolated from a meningococcal strain. Antibodies raised against this purified protein would absorb to whole bacteria, confirming that the protein is exposed on the surface of the organism.
Inhibition of acute experimental allergic encephalomyelitis in mice by colchicine.
Authors: Lyons M J , Amador R , Petito C , Nagashima K , Weinreb H , Zabriskie J B
Published: June 2004

Colchicine was found to inhibit the clinical and histopathological manifestations of monophasic experimental allergic encephalomyelitis in mice. For inhibition of actively induced disease, inoculation of colchicine at the time of encephalitogenic challenge was found to be most effective. In adoptive transfer experiments, lymph node cells (LNC) from colchicine treated donors failed to transfer the disease. Additionally, colchicine treatment of recipients receiving an otherwise disease-inducing level of sensitized LNC prevented the development of disease. Experiments involving delayed-type hypersensitivity expression support an inhibitory role for the drug on event(s) of the efferent pathway of the cellular immune response.
Different structural constraints for recognition of mouse H-2Kd and -Kk antigens by alloimmune cytolytic T lymphocytes.
Authors: Schøller J , Shimonkevitz R , MacDonald H R , Kvist S
Published: June 2004

We have constructed a new series of hybrid genes among the H-2Kd,-Kk, and -Kb. The site of recombination occurs in the third exon, encoding the alpha 2 domain, and divides this domain into two parts, alpha 2A and alpha 2B. The novel genes differ only in the COOH-terminal half of the alpha 2 domain, i.e., the alpha 2B region. This region, comprising residues 142-182, contains a limited number of amino acid differences between the three alleles. The hybrid genes have been introduced into 1T 22-6 cells (H-2q), and cell surface expression of hybrid antigens was verified. Cells expressing different types of hybrid antigens have been examined for their susceptibility to lysis by cytotoxic T lymphocytes directed either against the H-2Kd antigen or the H-2Kk antigen. Our results show that the alpha 1 and alpha 2A domains of the H-2Kk antigen can constitute target molecules for alloimmune anti-Kk T cells, whereas the alpha 2B region, when exchanged for Kd or Kb sequences, plays only a limited role. In contrast, the alpha 1 and alpha 2A domains of Kd are not sufficient to be recognized by alloimmune anti-Kd T cells. In this instance, the alpha 2B domain seems to play an essential role. This region has undergone several amino acid substitutions involving charged residues.
Properties and distribution of a lectin-like hemagglutinin differentially expressed by murine stromal tissue macrophages.
Authors: Crocker P R , Gordon S
Published: June 2004

We describe a novel hemagglutinin which is differentially expressed on murine stromal tissue macrophages. Resident bone marrow macrophages (RBMM), which are physically associated with immature, proliferating hematopoietic cells in vivo, formed striking rosettes with unopsonized sheep erythrocytes (E) in vitro, unlike resident peritoneal macrophages (RPM). Binding of E was macrophage (M phi) specific, not accompanied by ingestion and independent of temperature (0-37 degrees C), divalent cations, and the metabolic inhibitors azide and iodoacetate. Pretreatment of RBMM with trypsin prevented rosette formation, but neuraminidase enhanced it. Conversely, binding was virtually abrogated if E were pretreated with neuraminidase, whereas trypsin pretreatment of the ligand resulted in a slight enhancement. The lectin-like nature of the E receptor (SER), with specificity for sialylated glycoconjugates, was consistent with the inhibition of binding we saw with neuraminyllactose or the ganglioside GD1a (50% inhibition at 5-10 mM and 11 microM, respectively). Expression of SER on freshly isolated RBMM was heterogeneous and exhibited a striking inverse correlation with expression of Ia antigens. During cultivation in 10% FCS, levels of SER on RBMM declined with a half-life of approximately 24 h. Other cell surface changes induced by cultivation included a transient increase in expression of Ia antigen and acquisition of Mac-1. To determine whether SER was expressed on other stromal M phi populations, adherent cells were isolated from various tissues by collagenase digestion or lavage. Binding of E was highest on RBMM and lymph node stromal M phi, at intermediate levels on Kupffer cells and splenic stromal M phi, but was low or undetectable on blood monocytes and thymic, peritoneal, pleural, and bronchoalveolar M phi. SER therefore appeared to be expressed on certain M phi populations embedded in solid tissues but was largely absent from M phi recoverable by lavage. Its absence from monocytes implies that SER is acquired by M phi after entering tissues where it may perform adhesive functions. In bone marrow, SER on RBMM could interact with an appropriate sialylated ligand on murine hematopoietic cells, and could influence their rate of growth and differentiation.
Two monokines, interleukin 1 and tumor necrosis factor, render cultured vascular endothelial cells susceptible to lysis by antibodies circulating during Kawasaki syndrome.
Authors: Leung D Y , Geha R S , Newburger J W , Burns J C , Fiers W , Lapierre L A , Pober J S
Published: June 2004

Kawasaki syndrome (KS) is an acute febrile illness of early childhood characterized by diffuse vasculitis and marked immune activation. The present study was undertaken to determine whether the acute phase of KS is associated with circulating cytotoxic antibodies directed to target antigens induced on vascular endothelium by the monokines, IL-1, or tumor necrosis factor (TNF). Sera from 20 patients with acute KS, 11 patients in the convalescent phase of KS, and 17 age-matched controls were assessed for complement-dependent cytotoxic activity against 111In-labeled human endothelial cells (HEC), dermal fibroblasts, and vascular smooth muscle cells. Sera from patients with acute KS but not the other subject groups caused significant (p less than 0.01) complement-mediated killing of IL-1- or TNF-stimulated HEC. None of the sera tested had cytotoxicity against control HEC cultures or the other target cell types, with or without IL-1 or TNF pretreatment. Expression of the IL-1- or TNF-inducible target antigens on endothelial cells was rapid and transient, peaking at 4 h and disappearing after 24 h despite continued incubation with monokine. In contrast, we have previously shown that IFN-gamma requires 72 h to render HEC susceptible to lysis with acute KS sera. Serum adsorption studies demonstrated that IL-1- and TNF-inducible endothelial target antigens are distinct from IFN-gamma-inducible antigens. These observations suggest that mediator secretion by activated monocyte/macrophages could be a predisposing factor to the development of vascular injury in acute KS. Although our present observations have been restricted to KS, the development of cytotoxic antibodies directed to monokine-inducible endothelial cell antigens may also be found in other vasculitides accompanied by immune activation.
Inhibition of an IgE response by secondary B cells of a different isotype.
Authors: Haba S , Gurish M F , Nisonoff A
Published: June 2004

We found that the synthesis of IgE anti-Ars antibodies is strongly inhibited by the presence of secondary non-IgE-producing cells that are specific for the Ars hapten. Such B cells can be induced by inoculation of a protein-Ars conjugate in CFA. The effect is seen after inoculation of OVA-Ars in CFA followed by KLH-Ars in alum, or, more convincingly, after adoptive transfer of B cells induced by antigen in CFA. Dose-response data indicated that inhibition can be effected by B cells containing noninhibitory numbers of contaminating T cells. Possible synergistic effects of carrier-specific regulatory T cells were ruled out by using a different protein carrier for immunization of donor and recipient mice. The effect was shown to be specific for the hapten used for immunization of donor mice.
Identification and characterization of a pore-forming protein of human peripheral blood natural killer cells.
Authors: Liu C C , Perussia B , Cohn Z A , Young J D
Published: June 2004

We show here that human peripheral blood NK cells contain a pore-forming protein (PFP) with an Mr of 70,000-72,000 that assembles structural lesions (with an average internal diameter of 150-170 A) and forms functional channels. The PFP was isolated by affinity chromatography from human NK cells, using a specific anti-C9 antiserum as the immunoadsorbent. The NK cells were isolated from PBL by positive or negative selection by indirect rosetting using a panel of monoclonal antibodies directed against different NK and T cell surface antigens. PFP was identified in NK cells freshly isolated and isolated from cultured PBL, both stimulated with interleukin 2, but not in NK cell-depleted lymphocytes. In planar bilayers, the channels formed by the NK cell-derived PFP are highly voltage resistant, with most channels persisting in the open state once they have inserted into the bilayer. The unit conductances of these channels range 0.3-1 nS in 0.1 M NaCl. The channels show poor selectivity for monovalent and divalent ions. The PFP is also released from human NK cells stimulated with the calcium ionophore A23187, suggesting that this protein, like the one produced by murine CTL lines, may be similarly secreted during cell-mediated killing. Its identification in primary human NK cell cultures indicates that this protein may play an active role in NK cell-mediated killing.
The pore-forming protein (perforin) of cytolytic T lymphocytes is immunologically related to the components of membrane attack complex of complement through cysteine-rich domains.
Authors: Young J D , Liu C C , Leong L G , Cohn Z A
Published: June 2004

Structural, functional and immunological similarities between the ninth component of complement (C9) and the lymphocyte pore-forming protein (PFP, perforin) have recently been described (8-10). PFP is shown here to be immunologically related to all other components of the membrane attack complex (MAC) of human complement, namely, C5b-6, C7, C8, and C9. Polyclonal antibodies raised against purified human C5b-6, C7, C8, or C9 react with other components of the MAC and with mouse lymphocyte PFP. The antigenic epitopes shared by human complement proteins and mouse lymphocyte PFP are limited to cysteine-rich domains. Only complement proteins that have been reduced and alkylated elicit the production of crossreactive antibodies when used as immunogens. The nonreduced forms of complement components or lymphocyte PFP neither react with these antibodies nor give rise to crossreactive antibodies. The homologous domains of complement proteins and lymphocyte PFP may play related functions in their attachment to lipid membranes and assembly of membrane lesions.
Cell growth cycle block of T cell hybridomas upon activation with antigen.
Authors: Ashwell J D , Cunningham R E , Noguchi P D , Hernandez D
Published: June 2004

Stimulation of antigen-specific T cell hybridomas with the appropriate antigen/MHC combination, at concentrations that resulted in the secretion of the lymphokine interleukin 2, resulted in a dose-dependent decrease in both [3H]thymidine incorporation and cell growth. Flow cytometric studies demonstrated that stimulation with antigen resulted in a cell cycle block that was most evident at the G1/S border, and mixing studies revealed that bystander T cells of different antigen specificities were not affected. For at least the large majority of T cells, the G1/S cell cycle block appeared to be irreversible after 24 h of exposure to antigen. This cell cycle block may be useful as a rapid and quantitative measure of T cell hybridoma activation, as a means of selecting T cell hybridomas that have functional alterations in the reception of stimulatory signals, and may serve as a model of the induction of tolerance in immature T cells.
Phenolic glycolipid-I of Mycobacterium leprae induces general suppression of in vitro concanavalin A responses unrelated to leprosy type.
Authors: Prasad H K , Mishra R S , Nath I
Published: June 2004

Using a costimulant assay, in vitro Con A responses of patients across the leprosy spectrum were found to be markedly suppressed by phenolic glycolipid-I (PGL-I), a unique antigen of M. leprae. The degree of inducible suppression as well as the number of leprosy patients showing suppression of mitogenic responses was higher with PGL-I as compared with integral M. leprae (p less than 0.05 to less than 0.01). Both untreated lepromatous (60%) as well as tuberculoid leprosy (67%) patients showed significant suppression ranging from 13 to 64% and 12 to 79%, respectively. Thus, PGL-I appears to have a universal suppressive effect on Con A responses and is unlikely to play a central role in determining the leprosy spectrum.
Expression of a murine polyclonal T cell receptor marker correlates with the use of specific members of the V beta 8 gene segment subfamily.
Authors: Behlke M A , Henkel T J , Anderson S J , Lan N C , Hood L , Braciale V L , Braciale T J , Loh D Y
Published: June 2004

A series of murine T lymphocyte clones were examined for reactivity with the KJ16-133 and F23.1 mAbs. Clones that were KJ16-133+,F23.1+ and KJ16-133-,F23.1+ were identified, but no KJ16-133+,F23.1- clones were observed. Within our panel of clones, therefore, the KJ16-133 antibody identifies a subset of F23.1+ cells. All F23.1+ clones examined express members of the V beta 8 subfamily of beta chain variable region genes; clones expressing V beta 8.1 or V beta 8.2 reacted with both KJ16-133 and F23.1, while clones expressing V beta 8.3 reacted only with F23.1. Thus, the differential reactivity of the KJ16-133 and F23.1 antibodies with cloned T cells correlates with the V beta gene expression of each clone. Reactivity with these antibodies should therefore be of utility for predicting the V beta gene expression in some T cell clones.
Antibody-defective, genetically susceptible CBA/N mice have an altered Salmonella typhimurium-specific B cell repertoire.
Authors: Duran L W , Metcalf E S
Published: June 2004

CBA/N mice, which express the X-linked immunodeficiency gene xid, are susceptible to Salmonella typhimurium. The basis for this susceptibility is currently unknown. However, previous studies (10) from this laboratory have provided evidence that susceptibility may be due to a defective anti-S. typhimurium antibody response. In that report we hypothesized that the defective antibody response may be a reflection of an altered S. typhimurium-specific B cell repertoire. In the studies described here, we have investigated this hypothesis using a modification of the in vitro splenic focus system. The frequency and characteristics of salmonella-specific B cells in normal, innately resistant, CBA/Ca mice have been compared with those of salmonella-susceptible, anti-S. typhimurium antibody-defective CBA/N mice. The results show that CBA/N mice express no primary or secondary S. typhimurium-specific B cell precursors after stimulation with an acetone-killed and dried (AKD) preparation of S. typhimurium strain TML. However, after three immunizations, the CBA/N tertiary frequency of 15.4 per 10(6) splenic B cells was similar to the primary precursor frequency in immunologically normal CBA/Ca mice, but 23-fold lower than the tertiary precursor frequency in CBA/Ca control mice. Moreover, CBA/N mice had an altered isotype distribution pattern after stimulation with AKD-TML. Greater than 70% of the tertiary CBA/N TML-specific B cells secreted IgG2, in contrast to either nonimmune or primed control mice. In addition, 80% of the CBA/N TML-specific B cells secreted only a single isotype, whereas the majority of B cells from primed normal mice secreted multiple isotypes. Fine specificity analysis of the TML-specific B cells indicated that the array of antigenic determinants to which CBA/N B cells could respond was restricted. Although the majority of primed CBA/Ca and primed CBA/N B cells were specific for LPS, the fine specificity pattern exhibited by CBA/N B cells was similar to that observed in unprimed normal mice, i.e., the vast majority were specific for the O antigen region of the LPS molecule. In contrast, a major portion of the LPS-specific B cells in primed CBA/Ca mice were directed against the KDO/lipid A region of the LPS molecule. Therefore, it appears that CBA/N mice lack or are unable to stimulate the B cell subset that predominates in primed, normal mice. Taken together, these studies indicate that the basis for susceptibility of CBA/N mice to S. typhimurium is multifactorial and suggests that the inability of some animals to respond to some infectious agents may be related to holes in their B cell repertoire.
IgG2a restriction of murine antibodies elicited by viral infections.
Authors: Coutelier J P , van der Logt J T , Heessen F W , Warnier G , Van Snick J
Published: June 2004

The isotypic distribution of IgG antibodies was determined in the serum of mice after infection with a panel of RNA and DNA viruses representative of 11 different genera. The antiviral response induced by all these viruses showed a striking preponderance of the IgG2a subclass whatever the strain of mice tested or the time elapsed after infection. Together with the predominance of IgG1 in antiprotein and of IgG3 in anticarbohydrate response, this IgG2a restriction of antiviral antibodies strongly suggests the existence of highly specific mechanisms for the regulation of individual subclasses in the mouse.
Generation of diversity in T cell receptor repertoire specific for pigeon cytochrome c.
Authors: Sorger S B , Hedrick S M , Fink P J , Bookman M A , Matis L A
Published: June 2004

17 T cell clones and 3 T cell lines, specific for pigeon cytochrome c, were analyzed for fine specificity and rearranged T cell receptor (TCR) gene elements. Clones of similar fine specificities were grouped into one of four phenotypes, and correlations between phenotype differences and gene usage could be made. All the lines and clones rearranged a member of the V alpha 2B4 gene family to a limited number of J alpha regions. The beta chain was made up of one of three non-cross-hybridizing V beta regions, each rearranging to only one or two J beta s. The use of alternate V beta regions could be correlated with phenotype differences, which were manifested either as MHC- or MHC and antigen-specificity changes. In addition, the presence of alloreactivity, which defined a phenotype difference, could be correlated solely with the use of an alternate J alpha region. These observations were substantiated by prospective analyses of pigeon cytochrome c-specific T cell lines that were selected for alternate MHC specificity or alloreactivity and were found to express the correlated alpha and beta chain rearrangements. Previously, the TCR DNA sequences from two clones, each representing a variant of one phenotype, showed sequence differences only in the N regions of their TCR genes. Since only these two variants, using identical V alpha-J alpha and V beta-J beta gene elements, were repeatedly observed in this study, we would predict that the junctional diversity differences are selectable. In this T cell response, all the gene elements involved in the generation of diversity appear to be selected, and may therefore be important in the determination of TCR specificity. This high degree of receptor gene selection represents a fundamental difference from the diversity seen in several extensively analyzed antibody responses.
Use of insertional inactivation to facilitate studies of biological properties of pneumococcal surface protein A (PspA).
Authors: McDaniel L S , Yother J , Vijayakumar M , McGarry L , Guild W R , Briles D E
Published: June 2004

PspA is a cell surface protein of Streptococcus pneumoniae that is present on a number of clinical isolates as well as the nonencapsulated laboratory strain Rx1. In a previous report we have shown that mAbs directed against PspA can protect mice from at least some of the pneumococcal strains bearing this protein. In our present report we have produced insertional inactivation mutants that lack PspA and have used these mutants to demonstrate that PspA can play a role in pneumococcal virulence and that anti-PspA immunity can lead to protection against pneumococcal infection. PspA- mutants were obtained using derivatives of plasmid pVA891 carrying chromosomal fragments from Rx1. From one of the mutants, we cloned a 550 bp fragment of the pneumococcal gene into pVA891 and transferred this chimeric plasmid, designated pKSD300, into Escherichia coli. After transformation of pKSD300 into Rx1, PspA production is not detected. In colony hybridization experiments, the 550 bp fragment hybridizes specifically to pneumococcal isolates in a pattern consistent with the hypothesis that the fragment is a portion of the pspA structural gene that is different from the portions coding for the antigenic determinants detected by mAbs Xi64 or Xi126. When X-linked immunodeficient (xid) CBA/N mice were immunized with wild-type Rx1, they were resistant to challenge with type 3 strain WU2. However, when these mice were immunized with a PspA- mutant of Rx1, they failed to survive the subsequent challenge, indicating that immunity to PspA can contribute to the resistance to pneumococcal infection. Using pKSD300 we insertionally inactivated pspA in D39, a virulent strain of S. pneumoniae. When injected intravenously there was a 10-fold greater reduction of the mutant pneumococci in the blood, as compared to the wild-type D39.
Phenotype and proliferation of early B lymphocyte precursor cells in mouse bone marrow.
Authors: Park Y H , Osmond D G
Published: June 2004

Bone marrow cells were examined by double immunofluorescent labeling techniques to detect determinants for the B lineage monoclonal antibody, 14.8, the nuclear enzyme, terminal deoxynucleotidyl transferase (TdT), cytoplasmic mu chains (c mu), and surface mu (s mu). In 8-9-wk-old C3H/HeJ mice, 14.8+ cells totalled 22.2% of all marrow cells (35 X 10(5) cells/femur). While many 14.8+ cells were c mu+ s mu- pre-B cells and s mu+ B lymphocytes (17.0%), the remainder (5.2%) were large cells lacking mu chains. After injecting vincristine sulfate, these 14.8+ mu- cells accumulated in mitosis at a rate of 13.5%/h (turnover time, 7.4 h). Their calculated total production rate (41 X 10(6) cells/whole marrow/d) exceeded that previously determined for large pre-B cells, suggesting some cell loss from the B lineage. TdT+ cells made up 1.8% of marrow cells and were mainly medium-sized cells. They all lacked mu chains, but half (0.9%) bound 14.8 antibody at low to medium intensity. Three discrete cell populations were thus defined, differing in mean cell diameter TdT+ 14.8- mu-, 9.5 micron; TdT+ 14.8+ mu-, 10 microns; and TdT- 14.8+ mu-, 11.5 micron, presumptively representing a sequence of cell stages preceding the expression of mu chains in large pre-B cells (TdT- 14.8+ c mu+ s mu-, 11.5 microns). This work provides a tentative model of early progenitor cells and their proliferation in normal marrow as a basis for studies of perturbations and the control of B lymphocytopoiesis.
Parallel sets of autoantibodies in MRL-lpr/lpr mice. An anti-DNA, anti-SmRNP, anti-gp70 network.
Authors: Migliorini P , Ardman B , Kaburaki J , Schwartz R S
Published: June 2004

The public idiotype Id-H130 occurs in MRL-lpr/lpr serum both on a high proportion of anti-DNA autoantibodies as well as on antibodies that do not bind to DNA. To define members of the latter population, we prepared hybridomas and selected Id-H130+ mAbs that did not bind to DNA. One such antibody, mAb 28/12, was found to be an anti-SmRNP antibody. To determine whether mAb 28/12 had rheumatoid factor activity, we tested its ability to bind, in a solid-phase assay, to 16 mouse IgM mAbs. mAb 28/12 bound to only four of the panel, two anti-DNA antibodies (mAbs 512 and 319) and two anti-gp70 antibodies (mAbs 514 and 1417). In a liquid-phase competition assay with a panel of 32 monoclonal IgM and IgG antibodies, including allotype-matched Igs, mAb 28/12 reacted only with mAbs 512, 319, 514, and 1417. The binding of mAb 28/12 to mAbs 512 and 319 was displaced by DNA, but not by RNA, indicating that the idiotype it defines (Id-28/12) is in the antigen-binding region of the two anti-DNA antibodies. In the two anti-gp70 antibodies (mAbs 514 and 1417), Id-28/12 seems to occur in the framework region. To determine if all four Id-28/12+ antibodies shared a common antigen-binding property, they were tested for their ability to react with DNA and gp70. The two anti-gp70 antibodies did not bind to DNA. However, the two anti-DNA antibodies were found to immunoprecipitate viral proteins from retrovirus-infected cells. mAb 512 reacted with gp70, both in cell membrane lysates and in purified form; mAb 319 reacted with gp85, which contains both gp70 and the retroviral protein p15. Antibodies with properties similar to those of mAb 28/12 were found in MRL-lpr/lpr serum. It was possible, by affinity chromatography on an anti-gp70 antibody column, to isolate from serum those anti-(anti-gp70) antibodies with anti-SmRNP activity. These results show that parallel sets of autoantibodies, which share a common idiotype, but which bind to different autoantigens, occur in MRL-lpr/lpr mice. Some populations of anti-DNA, anti-SmRNP, and anti-gp70 antibodies appear to constitute a network of autoantibodies in that strain. We speculate that part of the anti-SmRNP population of autoantibodies can arise by mutation of germline-encoded anti-DNA antibodies.
Interleukin 1 enhances T-dependent immune responses by amplifying the function of dendritic cells.
Authors: Koide S L , Inaba K , Steinman R M
Published: June 2004

The function of exogenous murine recombinant IL-1 alpha as a T lymphocyte-activating molecule was examined. IL-1 did not induce IL-2 release or responsiveness in purified T cells regardless of their state of activation: unprimed lymphocytes, freshly sensitized lymphocytes, or memory cells derived from the blasts. Nor did IL-1 synergize with mitogens, or with antigens, to stimulate proliferation. For example the combinations of IL-1 plus Ia+ peritoneal macrophages, or IL-1 plus Con A, were less than 5% as effective in triggering T cell growth as a low dose (1%) of dendritic cells. However, when IL-1 was added at the onset of culture, the response to limiting doses of dendritic cells was increased 3- to 10-fold in several systems: the syngeneic and allogeneic MLR, Con A- and periodate-induced polyclonal mitogenesis, and T-dependent antibody formation against foreign red cells. The amplifying effect of IL-1 could be obtained if the dendritic cells but not the responding lymphocytes were exposed to IL-1 before use as accessory cells. Optimal activation of dendritic cells required a dose of 5 U/ml (50 pM) and 18 h of exposure, and was not due to carryover of IL-1 into the lymphocyte culture. IL-2, IL-3, and cachectin/TNF did not amplify dendritic cell function, while IFN-gamma diminished it. The enhanced function of IL-1-treated dendritic cells was due to an enhanced clustering with helper T lymphocytes in the first day of the MLR response. Therefore IL-1 does not seem to act as an activating factor for most peripheral T lymphocytes. Instead, IL-1 enhances the function of accessory dendritic cells and represents the first molecule that has been shown to enhance the immune response at this critical level.
Cutaneous leishmaniasis. The defect in T cell influx in BALB/c mice.
Authors: McElrath M J , Kaplan G , Nusrat A , Cohn Z A
Published: June 2004

Local cellular responses to cutaneous infection with Leishmania mexicana amazonensis were examined in susceptible (BALB/c) and resistant (C57BL/6) mouse strains by immunocytochemical and electron microscopic studies. Infection during the first 8 wk in both animal strains was characterized by progressively enlarging lesions, epidermal thickening and ulceration, and accumulation of eosinophils and Ia+ infected macrophages. Healing of C57BL/6 mouse lesions began after 12 wk of infection and was associated with local influx of both Th (L3T4+) and T cytotoxic/suppressor (Lyt-2+) cells into the dermis, and Ia antigen expression on epidermal keratinocytes. T lymphocyte infiltration was marked and intracellular parasites were scarce by 21 wk of C57BL/6 infection. Similarly, granulomas in C57BL/6 livers contained L3T4+ and Lyt-2+ T lymphocytes and no visible intracellular parasites by 21 wk of infection. In contrast, BALB/c mouse lesions continued to enlarge and never healed. Throughout the entire course of infection, T lymphocyte influx into the heavily infected dermis was minimal. Keratinocyte Ia expression was absent in BALB/c lesions. BALB/c livers were heavily infected by 18 wk of cutaneous infection, with few demonstrable T lymphocytes. A systemic absence of T cells could not be demonstrated in BALB/c mice. Both L3T4+ and Lyt-2+ T cells were found in the peripheral blood in normal numbers in both mouse strains. Our results support the role of T cells as important local effector cells in the healing response of murine cutaneous leishmaniasis. We suggest that local T lymphocyte infiltration may provide lymphokines, particularly IFN-gamma, that can activate infected macrophages to destroy the intracellular parasites. Alternatively, T cells may play a cytotoxic role, killing infected macrophages and allowing local humoral factors to destroy released extracellular parasites.
Deficiency of the homologous restriction factor in paroxysmal nocturnal hemoglobinuria.
Authors: Zalman L S , Wood L M , Frank M M , Müller-Eberhard H J
Published: June 2004

The affected E of two patients with paroxysmal nocturnal hemoglobinuria (PNH) were enriched by lysing the unaffected, normal E with anti-human decay-accelerating factor (DAF) and guinea pig serum. The membranes of the unlysed, DAF-deficient cells (PNH-E) were dissolved and examined by SDS-PAGE and immunoblotting using an antiserum to homologous restriction factor (HRF). Whereas the 65 kD complement regulatory protein was readily detectable in the normal controls, it was completely lacking in both samples of PNH-E membranes. Functional studies likewise indicated the absence of HRF activity from PNH-E. When radiolabeled, isolated HRF protein was offered to PNH-E, it became firmly attached to the cell. Approximately 1,000 molecules of HRF per cell reduced the characteristic susceptibility of these cells to reactive lysis by C5b-9 to nearly normal levels. The results suggest that HRF, which is known to control the action of C8 and C9 on normal human E membranes, is deficient in PNH, as well as acetylcholinesterase and DAF.
Downregulation of T cell responses by antibodies to the T cell receptor.
Authors: Webb S , Sprent J
Published: June 2004

We have derived a T cell clone that recognizes and responds to three different types of antigen: self + X (fowl gamma globulin + H-2d), allo-H-2p,b, and minor lymphocyte-stimulating (Mlsa,d) determinants. Anti-TcR mAb and their F(ab')2 and Fab fragments were tested for their capacity to block the response of this clone. When responses were assayed on day 4 or later, addition of KJ16 or F23.1 mAb caused a marked inhibition of the response to each of the three antigens recognized by the clone. Responses measured at earlier time points however were unaffected or enhanced. This finding suggested that the inhibitory effects of anti-TcR mAb that followed the phase of enhancement might have reflected downregulation of the cells rather than simple blockade of TcR. In support of this possibility it was found that addition of anti-TcR mAb caused marked inhibition of the response of the clone to IL-2, i.e., a response that is not known to involve the TcR.
The isolation and sequence of a novel gene from a human functional T cell line.
Authors: Jongstra J , Schall T J , Dyer B J , Clayberger C , Jorgensen J , Davis M M , Krensky A M
Published: June 2004

Using a subtractive hybridization procedure we have constructed a cDNA library enriched for sequences present in functional human T cell lines, but not in human EBV-transformed B cell lines. We have isolated a cDNA clone, AH2-519, representing a novel gene, designated 519. This novel gene is expressed in functional human cytolytic and Th cell lines but not in a variety of other cell lines, including several long-term human T cell tumor lines. The expression of gene 519 is inducible in cultures of normal human PBL using antigenic or mitogenic stimulation. Neither the DNA sequence determined from a full-length cDNA clone overlapping with clone AH2-519 nor the amino acid sequence of its predicted protein product has significant homology to published sequences in the GenBank or NBRF databases. The restricted expression of gene 519 suggests that its gene product is involved in the growth and/or differentiation of normal T cells. The data also show that normal, nontransformed, functional T cells express gene products that can not be readily identified in long-term tumor lines of the same cell lineage.
Rosetting of activated human T lymphocytes with autologous erythrocytes. Definition of the receptor and ligand molecules as CD2 and lymphocyte function-associated antigen 3 (LFA-3).
Authors: Plunkett M L , Sanders M E , Selvaraj P , Dustin M L , Springer T A
Published: June 2004

CD2, also known as LFA-2, T11, and the E rosette receptor, is a T lymphocyte surface protein functionally important in adhesion to target cells and T cell triggering. LFA-3 is a widely distributed cell surface protein that functions in adhesion on target cells. We find that LFA-3 is expressed on human E, and that CD2 is a receptor for LFA-3 that mediates T cell adhesion to human E. Pretreatment of T lymphocytes with CD2 mAb or of E with LFA-3 mAb inhibits rosetting. Purified CD2 molecules bind to human E and inhibit rosetting. 125I-CD2 binding to E is inhibited by LFA-3 mAb; reciprocally, binding of LFA-3 mAb to human E is inhibited by pretreatment with purified CD2. Higher concentrations of CD2 aggregate human E; aggregation is inhibited by mAb to LFA-3.
Antiviral antibody-producing cells in parenchymatous organs during persistent virus infection.
Authors: Moskophidis D , Löhler J , Lehmann-Grube F
Published: June 2004

In mice persistently infected with lymphocytic choriomeningitis virus (LCMV), the parenchymatous organs contain infiltrates of mononuclear cells, the sizes and numbers of which vary between strains and become more numerous and extensive when the animals grow older. Histologically, these were found to possess a tissue-like structure, and by use of immunohistologic procedures they were shown to contain plasma cells secreting IgM and IgG. Cells of kidneys, livers, brains, and spleens of LCMV carrier mice were dispersed by digestion with trypsin, leukocytes were separated by density gradient centrifugation, and numbers of cells producing antibodies against LCMV were determined by use of a solid-phase immunoenzymatic technique. In all these organs, cells producing LCMV-specific IgM and IgG antibodies were demonstrated, the latter more numerous than the former. Their numbers correlated with numbers and extent of the lymphoid cell infiltrates. The blood of the same mice was essentially free of antiviral antibody-forming cell. The proportion of cells producing LCMV-specific antibodies to all cells producing Ig of any specificity varied between organs, being lowest in spleen, intermediate in liver and kidney, and highest in the brain, where in individual mice up to 90% of all active cells produced virus-specific antibodies. The LCMV carrier mouse should prove to be a useful animal model to investigate antibody production in parenchymatous organs during persistent virus infections.
Distribution and turnover of Langerhans cells during delayed immune responses in human skin.
Authors: Kaplan G , Nusrat A , Witmer M D , Nath I , Cohn Z A
Published: June 2004

The changes in distribution and turnover of T6+ Langerhans cells (LC) in the skin during delayed immune responses to tuberculin, and in the lesions of tuberculoid leprosy and cutaneous Leishmaniasis were investigated. In each situation, there was a dermal accumulation of monocytes and T cells and epidermal thickening with keratinocyte Ia expression. In the tuberculin response a dramatic change in the distribution of LC was observed. By 41 h, T6+ LC were displaced to the upper zone of the thickening epidermis followed by an almost complete loss of LC from the epidermis by approximately 72 h. After 7 d, T6+ cells started to reappear in the epidermis, which regained almost normal numbers of T6+ LC by 14 d. After antigen administration and initiation of the delayed immune response, enhanced numbers of T6+ cells appeared in association with the mononuclear cell infiltrate of the upper dermal lesions. Their numbers peaked by 72 h, were reduced at 7 d, and again enhanced by 14 d, when the epidermis was being repopulated. Similar numbers of T6+ cells were found in the chronic lesions of tuberculoid leprosy and cutaneous Leishmaniasis but not lepromatous leprosy. The cells of the dermis were identified as typical LC by the presence of Birbeck granules and surface T6 antigen at the electron microscope level. These cells were closely associated with lymphocytes. We have quantified the number of LC, evaluated their directional flux into the epidermis and dermis, determined nearest neighbors, and made predictions as to their fate.
Opsonization of bacteroides by the alternative complement pathway reconstructed from isolated plasma proteins.
Authors: Bjornson A B , Magnafichi P I , Schreiber R D , Bjornson H S
Published: June 2004

Opsonization of clinical isolates of B. fragilis and B. thetaiotaomicron with the six isolated proteins of the alternative complement pathway under physiological conditions resulted in considerable C3 deposition on the bacterial surfaces. The time course of C3 deposition was similar to that observed in EGTA-serum; however, the magnitude of C3 deposition was twofold greater in EGTA-serum. Opsonization of the bacteria with the isolated alternative pathway proteins failed to promote adherence, uptake, or killing by polymorphonuclear leukocytes, whereas opsonization of the bacteria with EGTA-serum facilitated these events. The difference in opsonic capacity of isolated proteins and EGTA-serum was not related to the quantitative difference in C3 deposition, because repeated opsonization of the bacteria with isolated proteins resulting in C3 deposition comparable to that observed in EGTA-serum only minimally increased adherence of the bacteria to polymorphonuclear leukocytes. SDS-PAGE and autoradiographic analysis of C3 extracted from bacteria opsonized with isolated proteins or EGTA-serum using methylamine and SDS demonstrated that the predominant form of C3 bound by ester bonds under both sets of conditions was iC3b. A low molecular weight C3 cleavage fragment was detected in extracts from bacteria opsonized with isolated proteins, but it accounted for only a minor fraction of the bound C3. The results of our study demonstrate that the early phase of opsonization involving activation of the alternative pathway by B. fragilis and B. thetaiotaomicron and resultant C3 deposition on the bacterial surfaces does not require auxiliary serum factors, but the effector phase of opsonization of these bacteria involving recognition of bacteria-bound C3 by polymorphonuclear leukocytes and the induction of phagocytosis and intracellular killing is dependent on such factors. Natural IgM antibodies serve as auxiliary factors is opsonization of B. thetaiotaomicron by the alternative pathway, whereas additional serum factors are required for alternative pathway-mediated opsonization of B. fragilis.
Phenotypic heterogeneity of melanoma. Relation to the differentiation program of melanoma cells.
Authors: Houghton A N , Real F X , Davis L J , Cordon-Cardo C , Old L J
Published: June 2004

Phenotypic heterogeneity is a characteristic feature of tumor lesions in patients with melanoma. Variability can be observed in cell morphology, pigmentation, and antigen expression. To test whether phenotypic heterogeneity could be the result of events regulated during cell differentiation, we evaluated the expression of a panel of differentiation traits on melanoma cells. Metastatic melanoma lesions from two patients, designated FD and AP, were examined histologically and found to contain mixed populations of cells. Established melanoma cell lines derived from each of these lesions were subcloned at early passage in culture (passages 7 and 8) to create a panel of clones derived from each tumor. There was heterogeneity in the expression of differentiation-related traits in clones, corresponding to distinct phenotypes observed within the original tumors. Clones from patient FD corresponded to early to intermediate stages of melanocyte differentiation, and clones from patient AP ranged from intermediate to late stages. The influence of cholera toxin and PMA on differentiation of parental cultures and subclone was studied. Results of induction studies demonstrated a number of features of differentiation of melanoma cells: regulation of differentiation traits is coordinated as a program of traits expressed sequentially at specific stages; early traits, such as the epidermal growth factor receptor and the melanoma chondroitin sulfate proteoglycan antigen, are downregulated as melanoma cells differentiate, whereas late markers, including melanin, tyrosinase activity, and antigens expressed in mature melanosomes, are upregulated; Ia (class II major histocompatibility) antigens are characteristically expressed on melanomas corresponding to early or intermediate stages of differentiation and are regulated as part of the differentiation program; minimal changes in stage of differentiation were observed during induction of parental cultures with either cholera toxin or PMA, whereas definite shifts in differentiation could be induced in selected cloned subpopulations. We conclude that melanoma cells are not frozen at a specific stage of differentiation, but rather are capable of differentiating when exposed to appropriate signals. Diversity in the differentiation state of melanoma cells can account for much of the phenotypic heterogeneity observed in melanoma lesions.
Schistosoma mansoni shares a protective carbohydrate epitope with keyhole limpet hemocyanin.
Authors: Grzych J M , Dissous C , Capron M , Torres S , Lambert P H , Capron A
Published: June 2004

The glycanic epitope of the 38,000 Mr Schistosoma mansoni schistosomula major immunogen defined by the IPLSm1 protective mAb was identified in the hemocyanin of the marine mollusc Megathura crenulata, better known as KLH. This antigenic community was exploited to investigate further the biological properties of this epitope. KLH was shown to strongly inhibit the binding of IPLSm1 mAb to its 38,000 Mr target antigen. Immunization of naive LOU rats with KLH elicited the production of anti-S. mansoni antibodies capable of immunoprecipitating the 38,000 Mr schistosomulum antigen. Antibodies to KLH mediated a marked eosinophil-dependent cytotoxicity and passively transferred immunity towards S. mansoni infection. Finally, rats immunized with KLH were significantly protected against a challenge with S. mansoni cercariae. The deglycosylation of KLH completely abolishes its immunological and functional KLH properties, indicating the participation of an oligosaccharidic epitope of the native KLH that is also recognized by the sera of S. mansoni-infected patients. These observations provide new opportunities of access to the well-defined structure of a glycanic epitope potentially available for the immunoprophylaxis and seroepidemiology of schistosomiasis, and a new approach to the isotypic response towards a well-chemically defined epitope.