bluuebunny/crossref_metadata_2025 huggingface dataset:
Somatic hypermutation of the JC intron is markedly reduced in unrearranged kappa and H alleles and is unevenly distributed in rearranged alleles.
Authors: Weber J S , Berry J , Litwin S , Claflin J L
Published: December 2022

Somatic hypermutation of the Ig genes occurs in rearranged V(D)J and its flanking sequences after Ag stimulation. Even though C regions and unrearranged V segments have been found to lack mutations, it is not known whether the mutational mechanism can be active in unrearranged J segments and their flanking regions. By polymerase chain reaction and direct sequencing of the 500 bp at the 5' end of the JC intron of hybridoma DNA derived from splenic B cells, we show that the frequency of mutations in unrearranged J regions of kappa and H chain genes is 0/7849 bp (upper 95% confidence interval, less than 0.00038) and 1/3209 bp (upper 95% confidence interval, less than 0.0015), respectively. The frequency (f) for the same region of rearranged kappa and H chain genes was 29/9380 bp (95% confidence, 0.0021 less than f less than 0.0044) and 16/2750 bp (95% confidence, 0.0033 less than f less than 0.0094), respectively. The significantly higher frequency of mutations in the rearranged alleles indicates that rearrangement is needed to effect full activation of the mutational mechanism. The data also show that mutations occur predominantly in the 5'-most 250 bp of the JC kappa intron. Statistical analysis of the distribution of mutations within the 5'-most 521 bp of the JC kappa intron reveals significant deviation (p = 0.000085) from a theoretically determined uniform distribution, indicating that mutations are not evenly distributed within this region.
Expression and functional characterization of a soluble form of endothelial-leukocyte adhesion molecule 1.
Authors: Lobb R R , Chi-Rosso G , Leone D R , Rosa M D , Bixler S , Newman B M , Luhowskyj S , Benjamin C D , Dougas I G , Goelz S E
Published: December 2022

Endothelial leukocyte adhesion molecule 1 (ELAM1) is a leukocyte adhesion molecule induced on human venular endothelium in vitro and in vivo by inflammatory stimuli. A truncated cDNA for ELAM1 has been constructed, stably expressed in Chinese hamster ovary cells, and the secreted recombinant soluble form of ELAM1 (rsELAM1) purified to homogeneity by immunoaffinity chromatography. rsELAM1, when immobilized on plastic, is fully functional as an adhesion protein, and selectively binds only cells known to bind cell-surface ELAM1 expressed on human endothelial cells, including the myelomonocytic cell line HL60 and the colon carcinoma cell line HT29. Immobilized rsELAM1 also binds human PMN, monocytes, NK cells, and T cells. T cell subset analyses indicate preferential binding of CD4+ T memory cells. However, rsELAM1 is only a weak inhibitor of ELAM1-mediated adhesion. rsELAM1 should prove valuable for the further study of the role of ELAM1 expressed on the vascular wall during the inflammatory response.
Retinoic acid enhances IL-1 beta expression in myeloid leukemia cells and in human monocytes.
Authors: Matikainen S , Serkkola E , Hurme M
Published: December 2022

We have examined the role of retinoic acid (RA), the biologically active metabolite of vitamin A, in expression of the IL-1 beta gene in the human myeloid leukemia cell line THP-1 and in human monocytes. Both protein kinase C-activating phorbol esters, e.g., PMA, and LPS induce IL-1 beta expression in these cells. Physiologic RA concentrations alone were not able to induce any IL-1 beta production, but they strongly enhanced the PMA-induced IL-1 beta protein production and mRNA accumulation in both human monocytes and in THP-1 cells. Nuclear run-off analysis revealed that the enhancing effect was at the transcriptional level. RA also slightly potentiated LPS-induced IL-1 beta expression in THP-1 cells but not in human monocytes. These data suggest that RA can be a strong up-regulator of IL-1 production, but its strength varies depending on the nature of the activating signal.
Characterization of secretory component in amniotic fluid. Identification of new forms of secretory IgA.
Authors: Cleveland M G , Bakos M A , Pyron D L , Rajaraman S , Goldblum R M
Published: December 2022

Amniotic fluid (AmF) contains low levels of IgA of fetal origin. Western blot analysis revealed that the major forms of IgA in human AmF contain secretory component (SC), but ranged in size between 170 and 200 kDa, unlike the 380-kDa size typical of previously described secretory (s)IgA. Preliminary characterization of these novel forms of sIgA suggests they may arise by reduction of selected disulfide bonds, rather than proteolytic cleavage, of 380-kDa sIgA. This study also shows that AmF contains SC in its free form. Free SC measured by ELISA in 30 AmF samples increased with gestational age of the fetus from 26 to 40 wk postconception. Late in gestation, the concentrations of free SC levels reached those of other external secretions. Both the fetal urogenital system and the amniotic membrane appear to contribute to both the free SC and sIgA in AmF. This report presents the initial description of a new form of sIgA and provides evidence that the AmF may be an early expression of the mucosal immune system in the developing fetus.
Arachidonic acid as a second messenger. Interactions with a GTP-binding protein of human neutrophils.
Authors: Abramson S B , Leszczynska-Piziak J , Weissmann G
Published: December 2022

Arachidonic acid (20:4) and other cis-unsaturated fatty acids exert direct effects on a variety of cells, effects that do not depend on the metabolism of fatty acids via cyclooxygenase or lipoxygenase pathways. In these studies arachidonic acid and other cis-unsaturated fatty acids (but not trans-unsaturated or saturated fatty acids) increased the specific binding of the nonhydrolyzable analog of GTP, [35S]GTP gamma S, to purified neutrophil membrane preparations and elicited superoxide anion generation from intact neutrophils. There was a positive correlation (r = 0.70) between the capacity of fatty acids to increase nucleotide binding and to elicit the respiratory burst. Scatchard plot analysis of binding at equilibrium demonstrated an increase in the number of available GTP binding sites in the presence of 50 microM arachidonic acid. Nonsteroidal antiinflammatory agents interfered with the arachidonic acid effect on [35S]GTP gamma S binding. ADP-ribosylation of the pertussis toxin substrate Gi alpha within the plasmalemma-reduced specific [35S]GTP gamma S binding and blocked arachidonate-dependent enhancement of binding. Moreover, pertussis toxin treatment of intact neutrophils inhibited arachidonic acid-induced superoxide anion generation. The data indicate that arachidonic acid directly activates a GTP binding protein in the neutrophil plasma membrane and may thereby act as a second messenger in signal transduction.
Monokines released during short-term Fc gamma receptor phagocytosis up-regulate polymorphonuclear leukocytes and monocyte-phagocytic function.
Authors: Simms H H , Gaither T A , Fries L F , Frank M M
Published: December 2022

Freshly explanted monocytes phagocytosing IgG antibody-coated erythrocyte targets (EIgG) release a factor(s) that stimulates phagocytosis by neighboring monocytes and polymorphonuclear leukocytes (PMN). Culture supernatants obtained after 30-min incubation of adherent monocytes with EIgG, but not unopsonized sheep erythrocytes, markedly up-regulated the extent of PMN phagocytosis and enhanced the rate at which monocytes ingested EIgG. The presence of this factor(s) was first evident in phagocytic studies in which monocytes were prepared by a colloidal silica-based continuous gradient technique (Sepracell-Mn). After introduction of erythrocyte targets, there was a 20- to 30-min delay before initiation of phagocytosis that was not observed with monocytes prepared by the standard Percoll-gradient technique. Experiments suggest that, when compared with monocytes prepared by the Percoll-gradient method, Sepracell-Mn monocytes are closer to a base line state of activation with regard to the expression of Fc gamma RI and the ability to ingest EIgG. The mechanism of PMN upregulation by the monocyte factor(s) was explored. Monocyte supernatants did not induce an increase in the surface expression of PMN Fc gamma RI, II, or III. Neither anti-TNF, anti-IL-2, nor anti-GM-CSF had any significant effect on monocyte supernatant activity. Neutrophil activating protein-1 was not detected by ELISA. In contrast, anti-IL-1 completely blocked the effect of the supernatant on subsequent monocyte phagocytosis, and partially inhibited its effect on PMN phagocytosis. Furthermore, it was shown that RIL-1 as well as TNF markedly enhanced monocyte and PMN ingestion of EIgG. These results suggest that monocytes, after Fc gamma R-mediated phagocytosis, release monokines, including at least IL-1, which enhance the phagocytic function of neighboring PMN and monocytes to augment the host defense process.
Immune response to Schistosoma mansoni infections in inbred rats. VII. Resistance is contingent on OX-8(+)-regulated high affinity IL-2 receptor-bearing W3/25+ lymphocytes but not on IL-4-dependent cells.
Authors: Phillips S M , Perrin P J , Tung A S , Lin J J , Diamantstein T , Galal N
Published: December 2022

These studies assess the roles of subpopulations of T lymphocytes in resistance to Schistosoma mansoni. CDF rats were depleted of the T cell subpopulation bearing the high affinity IL-2R by in vivo treatment with ART18+ mAb or of soluble IL-4 by treatment with 11B11 mAb. The development of parasites, the expression of resistance after sensitization, and the intensity of delayed type hypersensitivity (DTH), Ag-mediated blast transformation (AMBT), IgG2a, passive cutaneous anaphylaxis, and IgE-mediated antibody-dependent cell-mediated cytotoxicity responses against S. mansoni or control Ag were ascertained. Isolated T cell subpopulations were assessed in vivo and in vitro for effects upon the protective Ir. Depletion with ART18 mAb suppressed the development of W3/25+ helper-inducer cells and resulted in the initial survival of more worms, decreased resistance to challenge after initial sensitization, decreased IgG2a and IgE antibody, AMBT, and DTH reactivity against schistosome Ag. Depletion with ART18 did not prevent the development of OX8+ (T suppressor) cells. Depletion with 11B11 mAb led to insignificant changes in initial parasite survival and resistance to challenge; had no effect on IgG2a antibody, AMBT, or DTH; but profoundly suppressed the IgE responses against the parasite. Protective immunity to S. mansoni in rats is dependent upon IL-2R-bearing T lymphocytes and regulated by OX8+ cells but not absolutely contingent upon IL-4 or the IgE response.
Recurrent utilization of genetic elements in V regions of antinucleic acid antibodies from autoimmune mice.
Authors: Eilat D , Fischel R
Published: December 2022

Two IgG anti-DNA and two IgG anti-RNA autoantibodies derived from lupus prone NZB/NZW F1 mice have been analyzed for their Ag fine specificities and for their H and L chain V-region sequences. A remarkable similarity of VH gene sequences with previously sequenced antinucleic acid autoantibodies (Eilat, D., D. M. Webster and A. R. Rees. J. Immunol. 141:1745, 1988) was noted. This finding indicates that a small number of unique VH genes is involved in this autoimmune response and that the sequences of these genes are correlated with the different specificities for the autoantigen. The VK sequences appeared, by computer search, to be selected nonrandomly, but their use was not restricted to autoantibodies. An additional striking feature was evident in the construction of the D region elements, giving rise to CDR3 peptides that can interact with DNA and RNA. These constructs probably include D-D fusion products, which are relatively rare in Ig rearrangements.
Inhibition by brefeldin A of the specific B cell antigen presentation to MHC class II-restricted T cells.
Authors: Kakiuchi T , Takatsuki A , Watanabe M , Nariuchi H
Published: December 2022

We have shown previously that specific Ag presentation is prevented by the inhibition of protein synthesis but nonspecific presentation is not. In the present paper, Ag presentation by Ag-specific B cells was examined for sensitivity to brefeldin A (BFA), which blocks protein export from the endoplasmic reticulum. A20-HL B lymphoma expressing surface receptors specific for TNP was used as a B cell, and TNP-OVA was used as a specific Ag. The presence of BFA during pulsing of A20-HL cells with TNP-OVA inhibited the ability of the pulsed cells to stimulate 42-6A T cell clone, specific for OVA323-339 and Iad. The inhibition was not due to nonspecific toxicity of BFA, because the presence of BFA during pulsing of A20-HL cells with OVA323-339 did not affect their APC function. Ag binding to the receptor on A20-HL cells and internalization by the cells were observed in the presence of BFA. Thus, BFA might inhibit intracellular processing of specific Ag or intracellular complex formation of antigenic peptide from specific Ag with MHC class II molecules. Nonspecific Ag presentation by A20-HL cells, however, was resistant to BFA. A20-HL cells pulsed with OVA in the presence of BFA, even after fixation, could stimulate 42-6A cells to produce IL-2, although the IL-2 production was lower than that induced by A20-HL cells pulsed in the absence of BFA. These results suggest that the processing pathways for specific Ag and nonspecific Ag are different from each other, at least partly, in A20-HL cells.
Mouse T lymphocyte response to acetylcholine receptor determined by T cell receptor for antigen V beta gene products recognizing Mls-1a.
Authors: Krco C J , David C S , Lennon V A
Published: December 2022

Mice of strain B6, but not AKR/J, respond to immunization with Torpedo acetylcholine receptor (AChR) by manifesting in vitro an Ag-specific T lymphocyte proliferative response. Our analysis of (AKR x B6)F1 mice reveals that the T cell unresponsiveness of AKR/J is inherited as a dominant trait, possibly associated with expression of the Mls-1a allele. Mice derived from backcrossing (AKR x B6)F1 x B6 were selected for H-2b homozygosity and were classified as Mls-1a or Mls-1b according to the relative numbers of peripheral blood T cells that expressed the TCR V beta 6 gene product. After challenge by injection with AChR in CFA, lymph node cells from mice classified as having less than 2% of V beta 6+ peripheral T cells had low responsiveness to AChR, whereas mice with greater than 7% V beta 6+ peripheral T cells had high T cell responsiveness to AChR. These results are consistent with the notion that regulation of the T cell repertoire by Mls loci may be a determinant of susceptibility to autoimmunity.
Murine cryoglobulinemia: pathogenic and protective IgG3 self-associating antibodies.
Authors: Berney T , Shibata T , Izui S
Published: December 2022

A murine IgG3 mAb, 6-19, derived from autoimmune MRL-lpr/lpr mice, is a rheumatoid factor (RF) specific for IgG2a and is able to generate cryoglobulins via nonspecific IgG3 Fc-Fc interaction. Intra-peritoneal passive transfer of ascites containing the 6-19 mAb into BALB/c mice induces skin leukocytoclastic vasculitis and acute glomerulonephritis associated with cryoglobulinemia. Because IgG3 interact with each other, we have determined whether noncryoprecipitating IgG3 mAb were able to inhibit the cryoprecipitation of 6-19 mAb and the development of related tissue lesions. In vitro, the cryoprecipitation of 6-19 mAb was almost completely inhibited by a fourfold excess of a noncryoprecipitating non-RF IgG3 (9-106) mAb derived from MRL-lpr/lpr mice. Cryoprecipitation of five other IgG3 mAb was similarly inhibited by the 9-106 mAb, and two other noncryoprecipitating IgG3 mAb, including the 2-6D antinuclear autoantibody, inhibited the cryoprecipitation of 6-19 mAb. In vivo, pretreatment of BALB/c mice with 9-106 or 2-6D mAb prevented the development of skin vasculitis and glomerulonephritis induced by the 6-19 mAb. The cryoglobulin formation was greatly diminished in 9-106 or 2-6D mAb-treated mice, although their serum levels of 6-19 mAb and RF activity were comparable to those of control mice. This indicated that pretreatment with non-cryoglobulin IgG3 inhibited the cryoglobulin generation and cryoglobulin-associated tissue lesions induced by an IgG3 RF cryoglobulin-generating mAb. These results suggest that the balance of formation of IgG3 autoantibodies with or without the cryoglobulin activity may be critical for the development of IgG3 cryoglobulin-mediated tissue lesions in murine lupus, particularly in MRL-lpr/lpr mice.
A predominance of the T cell receptor V gamma 2/V delta 2 subset in human mycobacteria-responsive T cells suggests germline gene encoded recognition.
Authors: Panchamoorthy G , McLean J , Modlin R L , Morita C T , Ishikawa S , Brenner M B , Band H
Published: December 2022

Little is known about the nature of Ag recognition by the TCR-gamma delta. The recent observation that gamma delta T cells preferentially recognize mycobacterial Ag provides a model to examine the molecular basis of gamma delta-TCR recognition. Here, examination of the Mycobacteria-stimulated peripheral blood T cells with TCR-specific mAb revealed a predominance of T cells bearing V gamma 2/V delta 2 gene products. PCR cloning and sequence analysis of the TCR chains demonstrated extensive junctional diversity indicating that the response was polyclonal. The marked in vitro gamma delta T cell response to Mycobacteria was also detected in newborns before encounters with foreign Ag and exclusively involved the same V-gene usage observed in adults. Together, these results suggest that a major mechanism of gamma delta T cell reactivity involves recognition mediated by germline-encoded segments of the TCR.
Identification of a cytoplasmic protein kinase regulated by IL-1 that phosphorylates the small heat shock protein, hsp27.
Authors: Guesdon F , Saklatvala J
Published: December 2022

IL-1 increases phosphorylation of the small heat shock protein (hsp27) in intact cells. This change was also shown both by introducing [gamma-32P]ATP and Mg2+ into MRC-5 fibroblasts permeabilized by LPC after stimulation by IL-1, and by adding the labeled ATP and Mg2+ to cell extracts. Hsp27 phosphorylated in permeabilized cells or cell extracts was shown by 2D electrophoresis to comprise the three forms seen in metabolically labeled cells, suggesting that the physiologically relevant kinase was acting on the substrate in vitro. Mixing of extracts of resting and IL-1-stimulated cells revealed that stimulated cells contained increased levels of kinase activity that phosphorylated substrate hsp27 in the extracts of resting cells. Existence of the activated kinase was confirmed by showing that extracts of IL-1-stimulated cells phosphorylated purified homogeneous hsp27 at a greater rate than those of resting cells. The kinase activity was maximal in cells stimulated with IL-1 for 5 to 10 min, but had declined to the resting level after stimulation for 40 min. Membrane and cytosolic fractions prepared from cell homogenates both contained hsp27 kinase, but the IL-1-dependent increase was associated with the cytosolic fraction. TNF-stimulated cells also contained increased hsp27 kinase activity in the cytosol. The evidence suggests that the cytosolic hsp27 kinase is responsible for the changes in hsp27 phosphorylation induced by the cytokines in intact cells.
C-reactive protein receptors on the human monocytic cell line U-937. Evidence for additional binding to Fc gamma RI.
Authors: Crowell R E , Du Clos T W , Montoya G , Heaphy E , Mold C
Published: December 2022

C-reactive protein (CRP) is an acute-phase protein that binds to components of damage tissue, activates C, and stimulates phagocytic cells. CRP binding to receptors on monocytic and polymorphonuclear phagocytes has been shown. Recently, CRP-binding proteins of 38 to 40 kDa and 57 to 60 kDa have been identified on the human promonocyte cell line U-937 and the mouse macrophage cell line PU5 1.8, respectively. However, analysis of CRP binding to these cells and to peripheral blood leukocytes suggests that additional CRP receptor sites may be present. Because many studies have shown interactions between CRP binding and IgG binding to leukocytes, we have examined further the CRP binding sites on U-937 cells and determined their relationship to the FcR for IgG (Fc gamma R) expressed on these cells. Our results demonstrate specific saturable binding of CRP to peripheral blood monocytes and U-937 cells, which is readily inhibited by aggregated IgG. Monomeric IgG, which binds specifically to Fc gamma RI, inhibited a maximum of 20% of CRP binding to these cells. mAb 197 and mAb IV.3, which block IgG binding to Fc gamma RI and Fc gamma RII, respectively, failed to inhibit CRP binding to U-937 cells. Two CRP-binding molecules were identified by precipitation of lysates from surface-labeled U-937 cells and cross-linking experiments. One of these had a molecular mass of 43 to 45 kDa, similar to the molecule previously described as the CRPR on U-937 cells. The other had the same mobility by SDS-PAGE as Fc gamma RI. The identity of this protein with Fc gamma RI was confirmed by the ability of both IgG-Sepharose and CRP-Sepharose to preclear the protein from cell lysates and by inhibition of binding to both IgG-Sepharose and CRP-Sepharose by anti-Fc gamma RI mAb 197.
Response of Jurkat T cells to phorbol ester and bryostatin. Development of sublines with distinct functional responses and changes in protein kinase C activity.
Authors: Levine B L , May W S , Tyler P G , Hess A D
Published: December 2022

T lymphocyte activation is initiated as a result of the interaction between the TCR complex and Ag as seen in the framework of a membrane-bound MHC molecule. Receptor stimulation results in a rise in free intracellular Ca2+ and the activation of protein kinase C (PKC). Bryostatin (Bryo) and phorbol esters (e.g., 12-O-tetradecanoylphorbol 13-acetate (TPA] are PKC activators with somewhat different immunologic effects. We compared the effect of Bryo and TPA on the T cell tumor line Jurkat and derivatives of Jurkat cells grown in media supplemented with 100 nM Bryo ("BR100" cells) or 100 nM TPA ("TP100" cells). In untreated Jurkat cells, there is a dose- and time-dependent decrease in proliferation, compared to media controls, after the administration of as little as 10 nM TPA. This can be reversed in a dose- and time-dependent manner by Bryo. Interestingly, the expression of the transferrin receptor parallelled this effect on proliferation. Furthermore, Jurkat cells grown continuously in 100 nM TPA regained full proliferative capacity after several weeks in culture and transferrin receptor expression returned to near the level seen in untreated Jurkat cells. The chromatographic separation of PKC activity in these three cell lines showed that total PKC activity was dramatically decreased in both the TP100 and BR100 cells when compared to untreated Jurkat cells. However, in the TP100 cells there exists a peak of activity that is activated by Bryo, but not TPA. Western blots of whole cell lysates of the three cell lines showed that PKC-alpha and PKC-beta II were both down-regulated in BR100 and TP100 cells compared to untreated Jurkat cells. PKC-gamma was not detected in any of the cell lines. Therefore, the Bryo-specific peak seen in TP100 cells may be PKC-delta, -epsilon, -zeta, -eta, or a novel PKC isoform. This could provide the basis for a molecular characterization of the differences in PKC activation between phorbol esters and Bryo.
Dynamics of lymphocytes and inflammatory cells recruited in liver during murine listeriosis. A cytofluorimetric study.
Authors: Goossens P L , Jouin H , Milon G
Published: December 2022

During primary infection of mice by Listeria monocytogenes, bacterial elimination is dependent on the recruitment of myelomonocytic cells in the infectious foci and the activation of their bactericidal mechanisms through cytokines secreted by Listeria-specific T lymphocytes. The immune events occurring in the liver, one of the main infected organs, have not yet been studied in detail. In the present quantitative study, we describe the dynamics of recruitment of cells belonging to the lymphoid or myelomonocytic lineages in the liver. The different cell populations mobilized into the liver were isolated each day during the course of a sublethal L. monocytogenes infection and their phenotype was characterized by flow cytometry. Three distinct phases of recruitment were observed. 1) During the first day of infection, 17 x 10(6) lymphomyeloid cells were recruited in the liver with a predominance of myelomonocytic cells; 51% of the incoming cells were M1/70+; the NK cell population (detected by the 4D11 antibody) also increased transiently at this period. 2) From day 3 to 5, a high number of myelomonocytic cells infiltrated the liver (13 x 10(6) M1/70+ cells); most of these cells were macrophages (as detected with the macrophage-restricted antibody FA/11 or observed after May-Grünwald Giemsa staining); the antigranulocytic antibodies 7/4 and RB6.8C5 were found to label these mononuclear phagocytes at this period of infection. A subpopulation of Thy-1+ cells (16%) was found to be labeled by the RB6.8C5 antibody in normal liver and, at day 5 and 6, all Thy-1+ cells also bound the RB6.8C5 mAb.3) From day 5 onward, two waves of phenotypically distinct T lymphocytes were observed; the number of CD8+ T lymphocytes (15 x 10(6) cells) increased first at day 5 and peaked on day 7; CD4+ T lymphocytes (6.2 x 10(6) cells) were then recruited with a 2-day delay (on day 7) in the liver.
Structural basis of a conserved idiotope expressed by an autoreactive human B cell lymphoma. Evidence that a VH CDR3 mutation alters idiotypy and specificity.
Authors: Reidl L S , Friedman D F , Goldman J , Hardy R R , Jefferies L C , Silberstein L E
Published: December 2022

Our laboratory has previously investigated the relationship of autoimmune disease and B cell neoplasia in a patient with a diffuse, well differentiated splenic B cell lymphoma and associated autoimmune hemolysis due to an anti-Pr2 antibody. EBV-immortalized B cell clones, established from this lymphoma, were shown to secrete the same pathologic anti-Pr2 antibody. The antiidiotypic mAb, RI.1, defined a private Id (IdRI.1) of the anti-Pr2 antibody that was related to the Ag-binding site and was expressed by both the lymphoma and derived cell lines. This unique Id was expressed by the majority of splenic tumor B cells and also was conserved over a period of 4 yr. In this report, the structural basis of IdRI.1 expression was investigated by analysis of Id- variants isolated by flow microfluorimetry using RI.1. Six Id- cell lines that secrete IgM kappa but lack Pr2 specificity were generated from an Id+ cell line, LS2. These lines were shown to be related to LS2 and the lymphoma by karyotype and by restriction fragment analysis of Ig gene rearrangements. Shared and unshared nucleotide substitutions in the VH and VL regions of the six independent clones were used to construct a genealogic tree relating the Id- clonal members to a common Id+ precursor. The tree illustrates that the base changes occurred sequentially, suggesting that they were introduced by somatic point mutation. Only one VH CDR3 bp difference from the LS2 nucleic acid sequence is common to all Id- sequences, resulting in an amino acid substitution of cysteine 108 to tyrosine. Taken together, these findings suggest that both the expression of IdRI.1 and Ag binding are affected by a single mutation localized to the D region of the anti-Pr2 antibody.
Prolactin influences autoimmune disease activity in the female B/W mouse.
Authors: McMurray R , Keisler D , Kanuckel K , Izui S , Walker S E
Published: December 2022

Prolactin, an anterior pituitary hormone, stimulates humoral and cell-mediated immunity. This study investigated effects of manipulating prolactin levels in the autoimmune B/W mouse model of SLE. A group of B/W females was treated with daily injections of the prolactin-suppressing drug, bromocriptine. These mice had delayed elevation of anti-DNA antibodies and serum IgG; longevity was increased compared to control mice. Functioning syngeneic pituitary glands, implanted under the renal capsule, produced prolonged hyperprolactinemia in a separate group of female B/W mice. Hyperprolactinemic animals were characterized by premature albuminuria, elevated circulating gp70IC and IgG, and accelerated mortality. Analyses of thymic and splenic lymphocytes revealed no differences in lymphocyte subpopulations in mice with altered prolactin levels. This is the first report to substantiate an immunomodulatory role for prolactin in B/W mice. Further evaluation of this model may identify specific means of intervening clinically with immunosuppressive hormone-modulating therapy in SLE.
A form of circulating ICAM-1 in human serum.
Authors: Rothlein R , Mainolfi E A , Czajkowski M , Marlin S D
Published: December 2022

A circulating form of the usually membrane-bound intercellular adhesion molecule-1 (ICAM-1) was identified and characterized in normal human serum, and in sera from patients with leukocyte adhesion deficiency (LAD). The molecule, designated circulating ICAM-1 (cICAM-1) was detected and quantitated by sandwich ELISA. Levels of cICAM-1 in sera from normal individuals ranged from 100 to 200 ng/ml. Sera from LAD patients had elevated cICAM-1 levels ranging from 200 to 700 ng/ml. The elevated levels of cICAM-1 in LAD sera may be due to an inability to adsorb cICAM-1 to cell-bound LFA-1 or may be an indirect result of the pathology accompanying the syndrome. cICAM-1 bound to mAb specific for four distinct ICAM-1 epitopes localized in domains D1, D2, D4, and D5, and displayed similar molecular size properties as recombinant soluble ICAM-1 on FPLC size-exclusion chromatography. When immobilized via a domain D5-specific mAb, cICAM-1 mediated function (LFA-1)-dependent lymphocyte adhesion equivalent to sICAM-1. These data indicate that cICAM-1 contains most, if not all, of the five extracellular domains of membrane ICAM-1, as well as the ability to bind specifically to LFA-1. The cellular source of cICAM-1 appeared to be from mononuclear cells; only lymphoid cell lines or primary PBMC cultures had detectable levels of cICAM-1 in cell culture supernatants. Because cICAM-1 retains the ability to bind specifically to LFA-1, it may act to regulate cell adhesion by promoting de-adhesion. Alternatively, cICAM-1 may be the indirect consequence of inflammation or tissue damage. As such, the detection of cICAM-1 could be useful as a marker of inflammatory disease.
Hyperstimulatory CD1a+CD1b+CD36+ Langerhans cells are responsible for increased autologous T lymphocyte reactivity to lesional epidermal cells of patients with atopic dermatitis.
Authors: Taylor R S , Baadsgaard O , Hammerberg C , Cooper K D
Published: December 2022

We studied whether abnormalities in epidermal APC could be responsible for intracutaneous T cell activation in atopic dermatitis (AD). In the absence of added Ag, patients' peripheral blood T cells demonstrated significantly increased proliferation to their autologous lesional epidermal cells (mean +/- SEM = 19,726 +/- 9,754 cpm [3H]TdR uptake) relative to epidermal cells from uninvolved AD skin (2179 +/- 697 cpm) (n = 10) (p = 0.0001, log transformed data). AD T cell proliferative responses to autologous epidermal cells were dependent upon cells expressing HLA-DR, CD1a, and CD36, and not upon keratinocytes or their cytokines. Ultrastructurally, these cells ranged from typical Langerhans cells to indeterminate cells with irregular nuclear contours. Enriched populations of lesional AD Langerhans cells were highly stimulatory for autologous T cells, whereas equal numbers of Langerhans cells from non atopic epidermis were poor stimulators, even at high concentrations. The dermal perivascular dendritic cell markers CD36 and CD1b, not usually present on normal epidermal APC, were expressed by 40 and 60% of lesional AD CD1a+ epidermal Langerhans cells, respectively. Addition of anti-CD1b to cocultures of AD epidermal cells and autologous T lymphocytes augmented T cell activation, suggesting that the expression of CD1b by AD Langerhans cells may represent over expression of a molecule functionally linked to the enhanced T cell stimulatory capacity of these cells. Thus, stimulatory signals for T cells contained within AD epidermis are carried by cells in an abnormal differentiation state as indicated by expression of phenotypic characteristics of both epidermal and dermal antigen presenting cells (HLA-DR+, CD1a+, CD1b+, CD36+). We propose that activation of autologous T cells by an altered cutaneous APC population may represent a mechanism for the hyperactive and disordered cell-mediated immune response that characterizes the dermatitic lesions of AD.
Location of a new encephalitogenic epitope (residues 43 to 64) in proteolipid protein that induces relapsing experimental autoimmune encephalomyelitis in PL/J and (SJL x PL)F1 mice.
Authors: Whitham R H , Jones R E , Hashim G A , Hoy C M , Wang R Y , Vandenbark A A , Offner H
Published: December 2022

Synthetic peptides of proteolipid protein (PLP) were screened for their ability to induce experimental autoimmune encephalomyelitis (EAE) in SJL/J, PL/J, and (SJL x PL)F1 mice, and T cell lines were selected by stimulation of lymph node cells with PLP peptides. PLP 141-151 was found to be less encephalitogenic in SJL/J mice than PLP 139-151, due to deletion of two amino acids from the amino-terminal end. PLP 139-151 immunization induced relapsing EAE in SJL/J and F1 mice but not PL/J mice. In contrast, PLP 43-64 induced relapsing EAE in PL/J and F1 mice but not SJL/J mice. F1 T cell lines specific for either PLP 43-64 or PLP 139-151 adoptively transferred demyelinating EAE to naive F1 recipients. Haplotypes H-2s and H-2u appear to be immunologically co-dominant in F1 mice in the PLP EAE system, which differs from the H-2u dominance in F1 mice in the myelin basic protein EAE system. The identification of a PLP peptide that is encephalitogenic in PL/J mice, in addition to the previous demonstration of PLP peptides that are encephalitogenic for SWR mice (PLP 103-116) and SJL/J mice (PLP 139-151), lends support to a role for PLP as a target Ag in autoimmune demyelinating diseases.
IL-4 inhibits the costimulatory activity of IL-2 or picolinic acid but not of lipopolysaccharide on IFN-gamma-treated macrophages.
Authors: Cox G W , Chattopadhyay U , Oppenheim J J , Varesio L
Published: December 2022

We reported previously that IL-2 induces tumoricidal activity in IFN-gamma-treated murine macrophages. The present study was performed to investigate the regulation of IL-2-dependent tumoricidal activity in murine macrophage cell lines. The v-raf/v-myc-immortalized murine macrophage cell lines ANA-1, GG2EE, and HEN-CV did not express constitutive levels of cytotoxic activity against P815 mastocytoma cells. Moreover, these macrophage cell lines did not become tumoricidal after exposure to IL-4, IFN-gamma, IL-2 or LPS. However, these macrophages developed cytotoxic capabilities after incubation with either IFN-gamma plus IL-2 or IFN-gamma plus LPS. IL-4 inhibited IFN-gamma plus IL-2- but not IFN-gamma plus LPS-induced tumoricidal activity. This effect of IL-4 was not restricted to v-raf/v-myc-immortalized macrophage cell lines because similar results were obtained by using a macrophage cell line that was established from a spontaneous histiocytic sarcoma. The suppressive activity of IL-4 on the ANA-1 macrophage cell line was dose-dependent (approximately 12-200 U/ml) and was neutralized by the addition of anti-IL-4 mAb. IL-4 decreased the IFN-gamma-induced expression of mRNA for the p55 (alpha) subunit of the IL-2R in ANA-1 macrophages. Therefore, at least one mechanism by which IL-4 may have inhibited IFN-gamma plus IL-2-induced tumoricidal activity was by reducing macrophage IL-2R alpha mRNA expression. We have previously reported that picolinic acid, a tryptophan metabolite, is a costimulator of macrophage tumoricidal activity. We now report that IL-4 also inhibited IFN-gamma plus picolinic acid-induced cytotoxicity in ANA-1 macrophages. We propose that IL-2 and picolinic acid may have a common mechanism of action that is susceptible to IL-4 suppression.
IL-10 inhibits cytokine production by activated macrophages.
Authors: Fiorentino D F , Zlotnik A , Mosmann T R , Howard M , O'Garra A
Published: December 2022

IL-10 inhibits the ability of macrophage but not B cell APC to stimulate cytokine synthesis by Th1 T cell clones. In this study we have examined the direct effects of IL-10 on both macrophage cell lines and normal peritoneal macrophages. LPS (or LPS and IFN-gamma)-induced production of IL-1, IL-6, and TNF-alpha proteins was significantly inhibited by IL-10 in two macrophage cell lines. Furthermore, IL-10 appears to be a more potent inhibitor of monokine synthesis than IL-4 when added at similar concentrations. LPS or LPS- and IFN-gamma-induced expression of IL-1 alpha, IL-6, or TNF-alpha mRNA was also inhibited by IL-10 as shown by semiquantitative polymerase chain reaction or Northern blot analysis. Inhibition of LPS-induced IL-6 secretion by IL-10 was less marked in FACS-purified peritoneal macrophages than in the macrophage cell lines. However, IL-6 production by peritoneal macrophages was enhanced by addition of anti-IL-10 antibodies, implying the presence in these cultures of endogenous IL-10, which results in an intrinsic reduction of monokine synthesis after LPS activation. Consistent with this proposal, LPS-stimulated peritoneal macrophages were shown to directly produce IL-10 detectable by ELISA. Furthermore, IFN-gamma was found to enhance IL-6 production by LPS-stimulated peritoneal macrophages, and this could be explained by its suppression of IL-10 production by this same population of cells. In addition to its effects on monokine synthesis, IL-10 also induces a significant change in morphology in IFN-gamma-stimulated peritoneal macrophages. The potent action of IL-10 on the macrophage, particularly at the level of monokine production, supports an important role for this cytokine not only in the regulation of T cell responses but also in acute inflammatory responses.
Random association between the peptide repertoire of A2.1 class I and several different DR class II molecules.
Authors: Sette A , Vitiello A , Farness P , Furze J , Sidney J , Claverie J M , Grey H M , Chesnut R
Published: December 2022

The interaction between synthetic peptides and A2.1 class I MHC molecules has been investigated using an inhibition of Ag presentation assay and unbiased peptide sets derived of either viral or eucaryotic origin. For the various sets, strong binding (defined as significant inhibition at the 30 micrograms/ml level) was detected in 7 to 46% of the peptides tested, with an overall frequency of 26%. A set of self-peptides derived from human beta 2 microglobulin was also included in the study. In this case, strong binding was detected in 3 of 15 peptides (20%), thus formally demonstrating a lack of self-/non-self-discrimination at the level of class I molecules. When the whole A2.1-binding database of 105 peptides thus generated was examined by sequence analysis, a significant correlation was found with a recently proposed A2.1-binding motif, whereas no particular positive or negative association was detected between the capacity to bind A2.1 and three different class II alleles (DR1, DR5, and DR7). Finally, using this approach, several peptides capable of binding both A2.1 and multiple DR alleles have been identified, suggesting possible candidates for development of peptide vaccines eliciting both class I and class II restricted responses.
Influence of adjuvants on the antibody specificity to the Plasmodium falciparum major merozoite surface protein, gp195.
Authors: Hui G S , Chang S P , Gibson H , Hashimoto A , Hashiro C , Barr P J , Kotani S
Published: December 2022

The effect of adjuvants on the specificity of immune responses to the Plasmodium falciparum gp195 protein was investigated using adjuvant formulations based on synthetic muramyl dipeptide and monophosphoryl lipid A derivatives, in parallel with CFA and alum. Although these immunomodulators were as effective as CFA in inducing an antibody response to gp195, there were distinct differences in the recognition of B cell epitopes by these antibody populations. We have also demonstrated that MHC control of antibody specificity can be related to the adjuvant used for immunization. In general, the potency of adjuvants, their ability to induce antibodies of a particular specificity, or their ability to overcome MHC control of immune responsiveness varied independently. These findings suggest a critical role of adjuvants in the determination of the specificity of the immune response to protein Ag. Thus, the influence of adjuvants should be a major consideration in studies on immunologic recognition, as well as in the design of modern subunit vaccines.
Analysis of cis-acting elements present in the CD20/B1 antigen promoter.
Authors: Rieckmann P , Wilson G L , Thevenin C , Hong J X , Kehrl J H
Published: December 2022

A genomic clone spanning a large portion of the 5' untranscribed region of the CD20 gene was isolated. Deletion analysis of subcloned fragments identified several regulatory elements. A major positive cis-acting element was localized between base pairs -290/-186. A second positive regulatory element was localized between -454/-280 and negative regulatory elements were present in the region between bp -828/-454. The sequence -280/-186 conferred B cell-specific expression on a heterologous, TATA box containing c-fos promoter. Electrophoretic mobility shift assays with overlapping oligonucleotide probes spanning -280/-186 revealed that a 25-bp probe (-225/-201) bound a nuclear protein present in B cell lines expressing the CD20/B1 antigen but not in Jurkat (T cell), U937 (promonocytic), U251 (glioma), or HeLa cells. To confirm the functional significance of this sequence, a trimer of this region was subcloned into the c-fos promoter containing CAT plasmid. Expression was observed only in BJA-B and HS-Sultan cells but not in CD20/B1- cell lines. This sequence element is also important in phorbol ester-induced CD20 expression in the pre-B cell line BP-697. These results partially characterize several regulatory elements present in the CD20 promoter that are likely important in the B cell-specific expression of the CD20 gene.
Clonal characterization of the human IgG antibody repertoire to Haemophilus influenzae type b polysaccharide. IV. The less frequently expressed VL are heterogeneous.
Authors: Scott M G , Crimmins D L , McCourt D W , Chung G , Schäble K F , Thiebe R , Quenzel E M , Zachau H G , Nahm M H
Published: December 2022

We previously demonstrated that the human anti-Haemophilus influenzae type b polysaccharide (Hib-PS) VL repertoire is dominated by a product of the V kappa II gene, A2, and that V kappa II-A2 anti-Hib-PS antibodies have little or no somatic mutation in VL. To further study this VL repertoire, we studied non-A2 anti-Hib-PS antibodies that were identified either serologically or by amino-terminal amino acid sequence analysis. Of 15 non-A2 anti-Hib-PS antibodies from 12 vaccinated adults, we found four V lambda, five V kappa I, one non-A2 V kappa II, four V kappa III, and one V kappa IV antibodies. As expected, all but two of these subjects also produced V kappa II-A2 antibodies. Interestingly, one of these subjects lacks the A2 gene in the germ line. However, both subjects who did not produce detectable V kappa II antibody did produce normal amounts of total anti-Hib-PS antibody after vaccination. Candidate V kappa genes for the non-A2 antibodies were identified by comparison of up to 60 VL amino acid residues, including CDR1 and CDR2, with all sequenced V kappa genes. V kappa I antibodies appear to be products of three newly sequenced V kappa I genes, O8, O18, and L11, that are reported here. The O8 and O18 genes encode identical amino acid sequences. The non-A2 V kappa II antibody is a likely product of the A1 or A17 genes, the V kappa III antibodies are likely products of the A27 gene, and the V kappa IV antibody is a product of the single V kappa IV gene, B3. Unlike V kappa II-A2 antibodies, the V kappa I, V kappa III, and V kappa IV antibodies differed by one to five CDR residues from the germ line product of the candidate genes, suggesting the presence of somatic mutations. Thus, anti-Hib-PS antibodies can be divided into two types, the most frequently observed A2 antibodies with little or no somatic mutation and non-A2 antibodies that likely contain somatic mutations.
ICAM-1-dependent pathway is critically involved in the pathogenesis of adjuvant arthritis in rats.
Authors: Iigo Y , Takashi T , Tamatani T , Miyasaka M , Higashida T , Yagita H , Okumura K , Tsukada W
Published: December 2022

Intercellular adhesion molecule 1 (ICAM-1) plays important roles in immune responses. In order to examine whether ICAM-1 is involved in pathogenesis of adjuvant arthritis (AA), we investigated the effect of anti-ICAM-1 mAb, 1A29, on AA in rats. In vivo administration of 1A29 exerted a very strong suppressive effect on the development of arthritis and induced a marked reduction of inflammatory parameters. 1A29 suppressed the Ag-specific proliferative response of lymph node cells from AA rats, suggesting that the mAb blocked the Ag recognition phase. The study using adoptive transfer of AA revealed that 1A29 completely inhibited production of arthritogenic lymphocytes in donors and partially suppressed progression of arthritis in recipients caused by these lymphocytes. These findings indicated that the inhibitory effect of 1A29 on development of arthritis was at least twofold, i.e., 1) interference with cell-cell interaction between APC and T cells, which resulted in abrogation of effector cell generation; and 2) blocking of effector cell migration to inflammatory lesions. These results indicated that ICAM-1-dependent pathway is critically involved in the pathogenesis of AA. The data support the concept that ICAM-1-dependent pathways are important in chronic inflammatory disease.
Inhibition of in vivo lymphocyte migration to inflammation and homing to lymphoid tissues by the TA-2 monoclonal antibody. A likely role for VLA-4 in vivo.
Authors: Issekutz T B
Published: December 2022

The adhesion receptors, LFA-1 and VLA-4, on lymphocytes mediate lymphocyte adherence to cytokine-activated endothelial cells (EC) in vitro. Based on our previous data, which suggested that the mAb TA-2 reacted with rat VLA-4, the effect of TA-2 on lymphocyte migration out of the blood was examined. Small peritoneal exudate lymphocytes (sPEL) preferentially migrate to cutaneous inflammatory reactions, whereas lymphocytes from peripheral lymph nodes (PLN) migrate poorly to inflammatory sites but home avidly to PLN. Treatment of sPEL with TA-2 inhibited sPEL migration to DTH, LPS, poly I:C, IFN-gamma, IFN-alpha/beta, and TNF-alpha by 35 to 65% and their accumulation in PLN by 50%. The homing of PLN lymphocytes to PLN was not inhibited by TA-2. Spleen T cell migration to cutaneous inflammatory sites was inhibited but homing to PLN was not affected. Systemic treatment with TA-2 inhibited sPEL migration to inflamed or cytokine-injected skin by up to 70%. Similarly, TA-2 strongly inhibited the migration of Ag-stimulated PLN lymphoblasts to skin and to PLN. The migration of lymphocytes from all sources, including the peritoneum, spleen, PLN, mesenteric nodes, and Peyer's patches, to mesenteric lymph nodes and Peyer's patches was inhibited by 80% and 95%, respectively. In conclusion, our results suggest that VLA-4 and possibly other alpha 4 integrins mediate the migration of the inflammation-seeking sPEL and Ag-activated lymphoblasts to cutaneous inflammatory sites and lymph nodes but do not affect the homing of PLN lymphocytes to PLN. These integrins also appear to be necessary for the migration of all types of lymphocytes to Peyer's patches and mesenteric lymph nodes.