bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased plasma membrane permeability to Ca2+ in anti-Ig-stimulated B lymphocytes is dependent on activation of phosphoinositide hydrolysis.
Authors: Ransom J T , Chen M , Sandoval V M , Pasternak J A , Digiusto D , Cambier J C
Published: December 2022

The biochemical basis of Ca2+ mobilization after anti-Ig binding to B cell Ag-R has been further characterized by flow cytometric analysis of indo-1-loaded B cells. The ability to distinguish intracellular Ca2+ release from extracellular Ca2+ influx by using an extracellular calcium depletion-repletion approach has allowed us to study the relationship between the mobilization of Ca2+ from these sources. Studies involving manipulation of the Ca2+ gradient across the plasma membrane indicate that a significant portion of the Ca2+ mobilization response is preserved even when the normal inwardly directed Ca2+ gradient is reversed. In the presence of an extracellular calcium concentration ([Ca2+]o) of 10 microM, the response to anti-Ig is not blocked by the organic Ca2+ channel blockers. This response is not reduced by further depletion of [Ca2+]o by EGTA Ca2+-binding buffers. Thus, the Ca2+ response that occurs when [Ca2+]o less than or equal to 10 microM represents intracellular calcium release. Analysis of B cells stimulated with anti-Ig in low Ca2+ medium ([Ca2+]o = less than 10 microM) followed by repletion of [Ca2+]o to 1 to 5 mM reveals that a significant increase in permeability of the plasma membrane to Ca2+ develops in the stimulated cells. The resultant Ca2+ influx is nimodipine (20 microM) sensitive. Both intracellular Ca2+ release and Ca2+ influx are reduced in parallel as the concentration of anti-Ig stimulus is decreased, suggesting that Ca2+ influx may be coupled to the release of intracellular stores. Neomycin blocks anti-Ig-stimulated formation of inositol trisphosphate, which mediates release of Ca2+ from the endoplasmic reticulum. It also blocks the anti-Ig-induced release of intracellular Ca2+ stores as well as Ca2+ influx, indicating that both responses may be dependent upon phosphatidylinositol 4,5-bisphosphate hydrolysis.
Idiotype stimulation of T lymphocytes from Trypanosoma cruzi-infected patients.
Authors: Gazzinelli R T , Morato M J , Nunes R M , Cançado J R , Brener Z , Gazzinelli G
Published: December 2022

Anti-Trypanosoma cruzi epimastigote antibodies (anti-epi) from pooled and individual sera from patients with chronic Chagas' disease were purified on immunoaffinity columns of epimastigotes antigens (epi) coupled to activated Sepharose 4B. SDS-PAGE analysis of purified anti-epi preparations showed only the presence of human IgG H and L chains. These antibodies preparations showed similar Western blotting profiles as the sera pools from which they originated. The main polypeptides recognized by anti-epi had apparent molecular masses 31, 46, 51, 75 and 85 kDa. No difference in these patterns were detected between anti-epi from pooled sera of cardiac (anti-epiC) and indeterminate (anti-epiI) clinical forms. Anti-epi preparations (20 to 60 micrograms/ml) of pooled and individual sera stimulated proliferation of homologous and autologous PBMN or T-lymphocyte-enriched population. The stimulatory ability was dependent upon the PBMN-anti-epi combinations. There is no direct correlation between the level of PBMN response to epi and anti-epi stimuli. Comparison of the stimulatory activities of anti-epiC vs anti-epiI on PBMN of either cardiac or indeterminate group of patients indicate that anti-epiC is significantly more active than anti-epiI (p less than 0.025). These data demonstrate the presence of auto-anti-idiotypic-T cells in chagasic patients and lead to the possibility that idiotype/anti-idiotype interactions may play a role in determining the pathogenesis of chagasic cardiopathy.
Failure or success in the restoration of virus-specific cytotoxic T lymphocyte response defects by dendritic cells.
Authors: Kast W M , Boog C J , Roep B O , Voordouw A C , Melief C J
Published: December 2022

C57BL/6 (B6, H-2b) mice are CTL responders to both Sendai virus and Moloney leukemia virus. In the former response the H-2Kb class I MHC molecule is used as CTL restriction element, in the latter response the H-2Db molecule. B6 dendritic cells (DC) are superior in the presentation of Sendai virus Ag to CTL in comparison with B6 normal spleen cells. Con A blasts have even less capacity to present viral Ag than NSC, and LPS blasts show an intermediate capacity to present viral Ag. H-2Kb mutant bm1 mice do not generate a CTL response to Sendai virus, but respond to Moloney leukemia virus, as demonstrated by undetectable CTL precursors to Sendai virus and a normal CTL precursor frequency to Moloney virus. Compared to B6 mice, other H-2Kb mutant mice show decreased Sendai virus-specific CTL precursor frequencies in a hierarchy reflecting the response in bulk culture. The Sendai virus-specific CTL response defect of bm1 mice was not restored by highly potent Sendai virus-infected DC as APC for in vivo priming and/or in vitro restimulation. In mirror image to H-2Kb mutant bm1 mice, H-2Db mutant bm14 mice do not generate a CTL response to Moloney virus, but respond normally to Sendai virus. This specific CTL response defect was restored by syngeneic Moloney virus-infected DC for in vitro restimulation. This response was Kb restricted indicating that the Dbm14 molecule remained largely defective and that a dormant Kb repertoire was aroused after optimal Ag presentation by DC. In conclusion, DC very effectively present viral Ag to CTL. However, their capacity to restore MHC class I determined specific CTL response defects probably requires at least some ability of a particular MHC class I/virus combination to associate and thus form an immunogenic complex.
The role of L3T4+ and Lyt-2+ T cells in the IgE response and immunity to Nippostrongylus brasiliensis.
Authors: Katona I M , Urban J F , Finkelman F D
Published: December 2022

The role of L3T4+ and Lyt-2+ T cells in protective immunity to Nippostrongylus brasiliensis (Nb) was studied in BALB/c mice that were depleted of either the L3T4+ or Lyt-2+ T cell population by injection with rat mAb specific for the appropriate determinant. Host responses to Nb infection including spontaneous elimination of adult worms, development of intestinal mucosal mast cell hyperplasia and the generation of a polyclonal IgE response were all completely blocked by 0.5 mg anti-L3T4 antibody administered simultaneously with Nb inoculation. However, administration of 0.5 mg of anti-Lyt-2 antibody at the same time and 7 days after inoculation with Nb had no effect on any of these responses. Injection of anti-L3T4 antibody as late as 9 days after Nb inoculation interfered with spontaneous cure of Nb infection and anti-L3T4 antibody injection 11 days after Nb inoculation inhibited serum IgE levels measured on day 13 by 50%. In addition, administration of anti-L3T4 antibody at the time of the peak serum IgE response, 13 days after Nb inoculation, accelerated the decline in serum IgE levels. Injection of previously Nb-infected mice with anti-L3T4 antibody at the time of a second Nb inoculation prevented the development of a secondary IgE response but did not affect immunity to Nb infection based on finding no adult worms in the intestines of these mice. These data indicate that 1) L3T4+ T cells are required for spontaneous cure of Nb infection, development of intestinal mucosal mast cell hyperplasia, and the generation and persistence of an IgE response during primary infection with Nb and 2) L3T4+ T cells are required for a considerable time after inoculation for optimal development of these responses. However, L3T4+ T cells are not required for all protective responses in immune mice. In contrast, our data indicate that considerable depletion of the Lyt-2+ T cell population has no significant effect on either worm expulsion or the generation of serum IgE responses.
Characteristics and epitope mapping of a cloned human autoantigen La.
Authors: Sturgess A D , Peterson M G , McNeilage L J , Whittingham S , Coppel R L
Published: December 2022

The La (SS-B) polypeptide is a ribonucleoprotein against which high titer antinuclear antibodies (ANA) react in the human autoimmune disease primary Sjögren's syndrome. To identify the autoepitopes with which the ANA anti-La (anti-SS-B) reacts, we isolated a 1.4-kb cDNA clone for La from a lambda gt10 library made from a human Burkitt's cell line. This clone contained an open reading frame of 1065 bp, encoding a 40.1-kDa polypeptide that corresponded to the carboxyl-terminal end of the La protein. The predicted polypeptide sequence of the recombinant protein was highly charged and unrelated to any previously published sequence. We also compared this clone to a previously published cDNA sequence for La and demonstrated significant differences, particularly that the open reading frame in our cDNA continued for 926 additional bases 3' to a putative termination codon in the previously reported sequence. The recombinant La protein was expressed in Escherichia coli and tested for reactivity with 200 sera containing ANA of various specificities. Only the sera containing anti-La antibodies reacted with the cloned La. By expressing subclones of the La cDNA as fusion proteins with beta-galactosidase, we have localized at least one epitope for the binding of anti-La antibodies to the carboxyl-terminal 103 amino acids of the La protein. No anti-La binding could be demonstrated to the region of the La protein that had previously been predicted to contain an autoepitope for the binding of anti-La (SS-B) antibodies. Studies of cloned autoepitopes could provide important clues to the role ANA play in disease and lead to targeted intervention in the treatment of primary Sjögren's syndrome.
Sites of switch recombination in IgG2b- and IgG2a-producing hybridomas.
Authors: Katzenberg D R , Birshtein B K
Published: December 2022

The technique of genomic Southern blot analysis was employed to map the sites of class switch rearrangement in five hybridoma cell lines, four of which produce gamma 2b, whereas the fifth secretes gamma 2a. Two of the class switch recombinations we have mapped represent secondary switches to gamma 2b with a gamma 1 intermediate. We also observe isotype specificity in class switch recombination, with both allele rearranging to the same isotype in the three lines where an unexpressed chromosome is retained. Every 5' break occurred outside of and immediately 5' to the tandem repeats associated with Cmu, a result consistent with earlier studies on myelomas but in contrast to the pattern seen in lymphomas. Seven of the eight 3' switch sites, however, were within tandem repeats. This disparity in the distribution of 5' and 3' break points may reflect a unique role for the mu-associated tandem repeats in the switch process.
Analysis of the anti-Schistosoma mansoni surface antibody response during murine infection and its potential contribution to protective immunity.
Authors: Omer Ali P , Smithers S R , Bickle Q , Phillips S M , Harn D , Simpson A J
Published: December 2022

Absorption of serum from chronically infected mice with homogenized schistosome eggs reduced antibody binding to the schistosomulum surface by 94%, indicating that almost all schistosomulum surface recognition during chronic infection is due to epitopes shared with the egg. Absorption of the serum with egg homogenate from which protein antigens had been removed by boiling and digestion with proteinase K resulted in a similar reduction of antisurface antibody demonstrating that all the shared epitopes that are recognized are carbohydrate in nature. Analysis of the time course of anticarbohydrate antibody production and the levels of antibody in mice infected with a single sex of schistosome indicated that eggs directly stimulated this response. Mouse mAb were identified that bound at very high levels to the schistosomulum surface and that recognized carbohydrate epitopes shared with the egg. Three of these had previously been demonstrated to passively transfer resistance, indicating that these surface carbohydrates are potential targets of protective immunity in the mouse. All the anticarbohydrate mAb also bound to the surface of schistosomula of other schistosome species. Thus, the strong immune response against these epitopes in chronic infection could account for the cross-specific immunity observed. Mice vaccinated with irradiated cercariae lacked high levels of anticarbohydrate antibodies and their recognition of the surface was largely due to antibody to species-specific polypeptide epitopes. With respect to the Mr greater than 200,000 and 38,000 antigens, it was demonstrated that these epitopes were present on the same antigens that bear the carbohydrate moieties recognized by antibodies from chronically infected mice. This specific polypeptide recognition is also reflected in the immunity generated by exposure to irradiated cercariae.
Activation of human T lymphocytes by bryostatin.
Authors: Hess A D , Silanskis M K , Esa A H , Pettit G R , May W S
Published: December 2022

The immunologic effects of bryostatin (Bryo), a PKC activator with antineoplastic activity, were assessed and compared to PMA. Bryo induced IL-2R expression on CD4+ and CD8+ human T lymphocytes with a dose response comparable to PMA. However, Bryo induced only a marginal proliferative response as compared with the vigorous response induced by PMA. Bryo mediated functional receptor expression because the proliferative response was enhanced by addition of rIL-2. Furthermore, the proliferative response was inhibited by the relatively specific Ca+, phospholipid-dependent protein kinase (PKC) inhibitor, H-7, indicating a role of PKC in Bryo-induced activation. Addition of the calcium ionophore, ionomycin, to Bryo-stimulated lymphocytes resulted in the production and secretion of IL-2 with a concomitant proliferative response. This effect of the calcium ionophore could be inhibited by cyclosporine with identical results obtained in PMA-stimulated cultures. A most intriguing finding was that Bryo could effectively antagonize PMA-induced T cell proliferation. Although this mechanism of inhibition is unclear, a discussion with respect to differential effects on potential intracellular PKC isoforms is provided. These studies indicated that Bryo has potent immunopotentiating properties that share some similar effects of the phorbol ester, PMA, but offers the additional property of modulating other phorbol ester effects on proliferation.
Molecular analysis of the dissociation between IL-2 production and proliferation in a response of a T cell clone to the antigen presented by B cells.
Authors: Kakiuchi T , Mizuguchi J , Nariuchi H
Published: December 2022

Using B cells as APC, antigen specific responses of two murine T cell clones, 34-7F and 35-8H, were analyzed. 34-7F cells produced IL-2 but failed to proliferate, whereas 35-8H cells both produced IL-2 and proliferate. The antigenic stimulation increased intracellular free Ca2+ concentration in both clones, but enhanced inositol phospholipid metabolism only in 35-8H cells. The treatment of 34-7F cells with PMA, an activator of protein kinase C, synergized with the antigenic stimulation to induce the proliferation of the T cells. Thus, the failure of 34-7F cells to proliferate in the Ag response appears to result from the absence of an increase in inositol phospholipid metabolism. The absence is likely due to the defect in B cells as APC, inasmuch as the antigenic stimulation of 34-7F cells with whole spleen cells induced increases in inositol phospholipid metabolism and proliferation. The PMA treatment synergized with the Ag on B cells to enhance IL-2R expression, which was not inhibited by the addition of nifedipine, a calcium channel blocker. The agent inhibited the IL-2 production. Taken together, the results in the present experiments suggest the association of IL-2 production with increases in intracellular free Ca2+ concentration but not in inositol phospholipid metabolism, and that of IL-2R expression with increases in the metabolism but not in intracellular free Ca2+ concentration.
Specific inhibition of hybrid resistance in F1 hybrid mice pretreated with parent-strain spleen cells. II. Evidence for an Hh-1 antigen-specific tolerization.
Authors: Kosmatopoulos K , Scott-Algara D , Halle-Pannenko O
Published: December 2022

Lethally irradiated F1 mice reject bone marrow graft from H-2b parents. In a previous paper we showed that pretreatment of F1 hybrid with H-2b parental spleen cells abrogates this hybrid resistance (HR) to parental bone marrow growth by inducing a Thy-1+Lyt-1+2- nylon-adherent suppressor cell. We studied the mechanism of induction of this suppressor cell. Two hypotheses were tested; both were based on the observation that parental spleen cells when injected into a F1 hybrid, recognize the alloantigens of the opposite parent and proliferate; the proliferation of these Hh-1+ cells may result in an overload of the pretreated F1 hybrids with Hh-1 Ag, and in the development of a graft-vs-host reaction that is followed by a non-specific immunodeficiency (GVHID). Thus abrogation of HR could be due to either a tolerization with high doses of Hh-1 Ag or the GVHID. Our results show that abrogation of HR does not correlate with the GVHID because 1) it is induced after pre-treatment with H-2b parental cells only, whereas GVHID is observed after injection with cells from either of the two parents; and 2) it is induced in several conditions where GVHID does not occur; after pre-treatment with 1000-rad-irradiated or T-cell depleted or only class I incompatible spleen cells or with spleen cells from nude parents as well as after pre-treatment with H-2b bone marrow cells. HR is overcome by the injection of H-2Db homozygous or of cross-reactive H-2Ds homozygous cells only. However, although pretreatment with H-2Db homozygous spleen cells is necessary, it is not sufficient for an efficient overcoming of HR. Indeed enhancement of H-2b bone marrow growth after pre-treatment with 1000-rad-irradiated, T-cell depleted or nude parent spleen cells is very short-lasting and never reaches the level observed after pre-treatment with normal spleen cells. We conclude that inhibition of HR in F1 hybrids pretreated with parental spleen cells is not a consequence of a GVHID but of a specific tolerization with Hh-1 Ag; however, the HR is inhibited more consistently when inoculum used for the pretreatment contains fully immunocompetent T cells. The role of the immunocompetent parental T cells in abrogation of HR is discussed.
Class I MHC-restricted recognition of cells expressing a gene encoding a 41 amino acid product of the influenza hemagglutinin.
Authors: Sweetser M T , Braciale V L , Braciale T J
Published: December 2022

Class I H-2Kd-restricted influenza hemagglutinin (HA)-specific CTL recognize two immuno-dominant sites as represented by synthetic peptides spanning epitopes located in the HA1 and hydrophobic transmembrane domains of the influenza HA. Using a vaccinia virus recombinant expression system, we have examined CTL recognition of HA deletion mutants expressed in target cells. We have demonstrated that a truncated influenza HA gene encoding only the transmembrane anchor region containing a class I recognition site and a short segment of the cytoplasmic tail of the HA can be efficiently presented to class I CTL. These results set the stage for detailed analyses of the intracellular events associated with Ag presentation to class I CTL and offer novel possibilities for future vaccine design.
Subtypes of helper cells. Non-inflammatory type 1 helper T cells.
Authors: Wong R L , Ruddle N H , Padula S J , Lingenheld E G , Bergman C M , Rugen R V , Epstein D I , Clark R B
Published: December 2022

Class II MHC-restricted T cells recently have been characterized as being either type 1 (Th1) or type 2 (Th2) based on their ability to both secrete different lymphokines and perform different functions. Characterization of these subtypes to date have indicated that Th1 cells secrete IL-2, IFN-gamma, lymphotoxin, and IL-3, whereas Th2 cells secrete IL-4, IL-5, and IL-3. Functionally, Th1 cells mediated cytotoxicity and delayed-type hypersensitivity, and have been termed "inflammatory cells," whereas Th2 cells mediate helper function for Ig secretion and have been termed, "regulatory cells." We now present evidence that not all Th1 clones are inflammatory and capable of mediating cutaneous delayed-type hypersensitivity. We have generated a number of myelin basic protein-specific Th1 clones that do not mediate swelling when injected together with myelin basic protein directly into the footpads of syngeneic mice. These results suggest that Th1 cells can be further subdivided based on their ability to mediate delayed-type hypersensitivity, and that the Th1/Th2 characterization of Th cells may be insufficient to adequately characterize all functional subtypes of class II MHC-restricted T cells.
Characterization of human peripheral lymphocytes expressing the CD3-gamma/delta complex with anti-receptor monoclonal antibodies.
Authors: Faure F , Jitsukawa S , Triebel F , Hercend T
Published: December 2022

Three mAb, anti-Ti gamma A, anti-TCR delta 1, and anti-delta TCS1, have been developed against the CD3-associated gamma/delta molecular complex. One of this antibody anti-Ti gamma A is specific for an epitope encoded by the V9 gamma-gene. The two others react with the delta-chain but their fine epitopic specificity has not been characterized previously. In the present study, we have compared the surface expression of these three antigenic determinants on 27 cloned and 5 polyclonal CD3+ TCR gamma/delta + cell lines derived from human peripheral blood of 13 distinct individuals. It was found that all CD3+ TCR alpha/beta- clones and polyclonal cell lines tested were recognized by anti-TCR delta 1. In contrast, only a fraction of both clones and cell lines reacted with either anti-Ti gamma A or anti-delta TCS1 mAb. In fact reactivity of the latter reagents was found to be mutually exclusive on the cell panel. Northern blot analysis of RNA extracted from a series representative clones showed a positive correlation between the surface expression of the delta TCS1 epitope and the transcription of the V-delta gene isolated from the IDP2 cell line. These data support the view that anti-TCR delta 1 can be used to positively define the entire TCR gamma/delta+ fraction. Moreover, the reciprocal reactivity of anti-delta TCS1 and anti-Ti gamma A on cultured cell lines suggests that these reagents should delineate in human peripheral blood distinct, essentially non-overlapping, subsets. Taken together, the present results indicate that the complementary use of these three antibodies will be helpful to further characterize the TCR gamma/delta + peripheral lymphocyte fraction.
Pre-exposure of human B cells to recombinant IL-1 enhances subsequent proliferation.
Authors: Freedman A S , Freeman G , Whitman J , Segil J , Daley J , Nadler L M
Published: December 2022

The reported effects of the monocyte-derived cytokine IL-1 on human B lymphocytes are both varied and controversial. IL-1 has been reported to augment both proliferation and Ig secretion of previously activated human B cells. In the present study highly purified splenic B cells were cultured with rIL-1 before, simultaneously with, and after the addition of the polyclonal B cell mitogen, anti-Ig. rIL-1 had no significant effect on B cell proliferation when added simultaneously with or after B cell activation with anti-Ig. However, incubation of splenic B cells with rIL-1 for 24 h before stimulation with anti-Ig appeared to enhance mitogenesis. With the observation that rIL-1 exerted effects on resting B cells, the effect of rIL-1 on several events which accompany B cell activation was examined. rIL-1 failed to stimulate RNA synthesis, effect increases in cell size or intracellular Ca2+ levels, or lead to the hyperexpression of MHC class II or B cell activation Ag. These studies suggest that rIL-1 does not activate B cells but primes them to respond to subsequent activation.
Cholera toxin discriminates between murine T lymphocyte proliferation stimulated by activators of protein kinase C and proliferation stimulated by IL-2. Possible role for intracellular cAMP.
Authors: Kim D K , Nau G J , Lancki D W , Dawson G , Fitch F W
Published: December 2022

The regulation of the activation of T lymphocyte proliferation is not well understood. It is known that the tumor promoter, PMA, which activates protein kinase C (PKC), can induce the proliferation of several murine CTL clones; in combination with calcium ionophores, which raise the level of intracellular Ca2+, PMA can also stimulate the proliferation of several HTL clones. Activation of the TCR is believed to result in the liberation of diacylglycerol, which is an activator of PKC, and inositol 1,4,5-trisphosphate, which stimulates an increase in intracellular levels of calcium. We now report that pretreatment with cholera toxin (CT) inhibits the proliferation of murine T cell clones stimulated through the TCR/CD3 complex. In addition, CT-pretreatment blocks the proliferation of CTL clones activated with PMA or of HTL clones activated with PMA + calcium ionophore. In contrast, CT-pre-treatment inhibits much less effectively (100- to 1000-fold) the proliferation of these T cell clones stimulated with IL-2. Furthermore, activators of PKC, but not IL-2, potentiate the CT-induced cAMP elevation in T cell clones. The ability of CT to inhibit much more effectively the proliferation triggered by putative activators of PKC than that induced by IL-2 may be mediated by cAMP-dependent mechanisms.
Expression of CD5 regulates responsiveness to IL-1.
Authors: Nishimura Y , Bierer B E , Burakoff S J
Published: December 2022

The role of the CD5 surface molecule in T cell responsiveness to IL-1 was examined. A CD5-mutant Jurkat cell line was generated from a CD5+ parent cell line. This CD5- mutant subclone was infected with a defective retrovirus containing the CD5 cDNA and/or the neo gene encoding G418 resistance. The CD5+ wild type Jurkat produced IL-2 in response to anti-CD3 mAb, OKT3, cross-linked to a solid surface. IL-2 production was enhanced by co-culture with IL-1 or anti-CD5 Mab. Neither the CD5- mutant nor the CD5- G418-resistant infectant responded to anti-CD5 mAb or to IL-1. Responsiveness to IL-1 was restored by cell surface expression of CD5 in the CD5+ infectant. Both the CD5+ wild type Jurkat and the CD5+ infectant responded equivalently to purified IL-1, IL-1 alpha and rIL-1 beta. Optimal concentrations of IL-1 and anti-CD5 mAb had an additive effect on the enhancement of IL-2 production stimulated with cross-linked anti-CD3 mAb suggesting that IL-1 and CD5 act through distinct, complementary pathways to augment T cell activation. The correlation of CD5 expression and specific binding of rIL-1 beta was examined in these cell lines. Both the specific binding (at 4 degrees C) and subsequent internalization (at 37 degrees C) of 125I labeled rIL-1 beta was equivalent in the CD5+ infectant and the CD5+ wild type Jurkat cell, whereas specific binding of 125I-labeled rIL-1 beta was markedly decreased in the CD5-G418-resistant infectant. These observations strongly suggest that cell surface expression of CD5 regulates binding of and responsiveness to IL-1.
Characterization of protein kinase C and its isoforms in human T lymphocytes.
Authors: Beyers A D , Hanekom C , Rheeder A , Strachan A F , Wooten M W , Nel A E
Published: December 2022

Protein kinase C (PKC) regulates numerous T cell functions and is present in abundance in normal human T cells and certain T cell lines. Although crude Triton X-100 soluble material obtained from T cell pellets contains minimal PKC activity, DEAE chromatography revealed that 12 to 37% of cellular PKC was membrane associated, probably due to removal of an inhibitor through column chromatography. As in other tissues, PKC from lymphoid tissue was phospholipid and Ca2+ dependent and diolein reduced the Ca2+ requirements for enzyme activity. Hydroxylapatite chromatography revealed that T cells possess two major peaks of PKC activity. Although, the enzyme in these peaks had similar m.w. and identical iso-electric mobility, the proteins differed with respect to their autophosphorylation sites and immunoreactivity toward an isoform specific antibody. Furthermore, differences in their activities in the presence of phospholipid, diolein, and limiting amounts of Ca2+ imply that these isoforms may be differentially activated. We discuss optimal conditions for activation of PKC and its isoforms for study of T lymphocyte cellular function.
Neutrophils and mast cells. Comparison of neutrophil-derived histamine-releasing activity with other histamine-releasing factors.
Authors: White M V , Kaplan A P , Haak-Frendscho M , Kaliner M
Published: December 2022

Human neutrophil-derived histamine-releasing activity (HRA-N) was partially purified and found to contain a heat-stable 1400 to 2300-Da fraction which caused human basophils and rat basophil leukemia cells (RBL) to degranulate. The capacity of HRA-N to activate basophils was not related to the gender or atopic status of the basophil donor, but was related to anti-IgE responsiveness. Several lines of evidence suggest that HRA-N and anti-IgE induce histamine release through distinctly different mechanisms: 1) the time course of HRA-N- and anti-IgE-induced RBL histamine release are different; 2) HRA-N causes histamine release from RBL with and without surface-bound IgE; 3) lactic acid stripping of IgE from human basophils reduces anti-IgE-induced histamine release, but has no consistent effect on HRA-N-induced histamine release; and 4) passive sensitization of lactic acid-stripped basophils with IgE restores anti-IgE-induced histamine release but not HRA-N-induced histamine release. Several histamine-releasing factors (HRF) were compared with HRA-N. Human nasal HRF (HRF-NW, crude and partially purified fractions of 15 to 30, 3.5 to 9, and less than 3.5 kDa), like HRA-N, caused equal histamine release from both native and IgE-sensitized RBL. However, only the 15- to 30-kDa fraction caused histamine release from human basophils in the doses tested. Mononuclear cell HRF (HRF-M, crude and a partially purified 25 kDa Mr fraction) and platelet HRF (HRF-P, crude preparation) failed to cause histamine release from either native or IgE-sensitized RBL but caused 30 +/- 5.5% and 20 +/- 10% net histamine release from human basophils, respectively. HRA-N and HRF-NW were both stable to boiling. These data, taken together, suggest that the capacity of HRA-N to induce RBL and human basophil histamine release and of HRF-NW to stimulate RBL histamine release is independent of IgE. The data further suggest that HRA-N and HRF-NW can be distinguished by size, and that they both differ from mononuclear cell HRF and platelet HRF. Thus, it appears that inflammatory cells generate a family of distinct HRF.
Lineage and stage specificity of isotype switching in humans.
Authors: Borzillo G V , Cooper M D , Bertoli L F , Landay A , Castleberry R , Burrows P D
Published: December 2022

The lineage and stage specificity of human isotype switch recombination was investigated by examining the IgH gene configuration in 61 hemopoietic malignancies representing different stages of B and T cell development. An unexpectedly high frequency (20%) of IgM-producing B cell leukemias and lymphomas had undergone CH gene rearrangements and deletions consistent with attempted switch recombination. These CH gene alterations were found on productive, non-productive, and 14q+ chromosomes. These data support the concept of a non-specific (common) switch recombinase activity that is often ineffective. No evidence of such switch recombination was found in 25 mu- or mu+ pre-B cell leukemias with the single exception of a mu- pre-B leukemia in which subsets of the cells were producing gamma- or alpha-H chains. The switch recombinase activity gamma- or alpha-H chains. The switch recombinase activity may be restricted to the B cell lineage, inasmuch as CH gene deletions were not observed in T lineage malignancies.
Defective E beta expression in three mouse H-2 haplotypes results from aberrant RNA splicing.
Authors: Tacchini-Cottier F M , Jones P P
Published: December 2022

The molecular basis for the defective expression of the mouse class II E beta genes in the H-2w17, H-2q, and H-2f haplotypes has been examined. The results of nuclear run-on transcription and S1 nuclease digestion assays demonstrate that E beta transcription is normal in these haplotypes. Northern blot analyses reveal reduced amounts of E beta RNA of both normal and aberrant size in the w17 and q haplotypes; an even more reduced level of E beta RNA of normal size was detected in the f haplotype. In the preceding study, we reported that the only defect detected in the E beta w17 gene is a single nucleotide insertion in the 5' RNA splice site of the first intervening sequence. S1 nuclease analysis of E beta w17 RNA indicates that splicing at this site is aberrant. One major cryptic RNA splice site is used, leading to reduced amounts of aberrantly processed RNA. Limited use of the mutated splice site and of a second cryptic site also is detected. In all three cases, stop codons in the resulting RNA would prevent their translation. The molecular defect in E beta q appears identical to that of E beta w17. In the f haplotype, even more reduced levels of E beta RNA of both normal and aberrant sizes are found. We thus show that in the three defective E beta alleles, two distinct defects are responsible for the absence of E beta protein synthesis; both of these defects affect RNA processing.
T cell activation by preformed, long-lived Ia-peptide complexes. Quantitative aspects.
Authors: Watts T H
Published: December 2022

Planar membrane-bound complexes between a fluorescent peptide, FITC-OVA(323-339), and the class II MHC Ag, I-Ad, were analyzed by fluorescence microscopy and in biological assays to determine the optimum distance between peptide-Ia complexes required for maximum activation of IL-2 production by the Th cell hybridoma DO-11.10. Optimum responses were obtained when the average distance between peptide-Ia complexes was of the order of 200 A. This implies that T cell activation by Ag-MHC requires cross-linking of the TCR via closely packed Ag-MHC complexes. The same dose response curve to the preformed complexes was obtained whether one used a fixed concentration of Ia and varied the peptide concentration or a fixed concentration of peptide and varied the Ia concentration. In both cases there was a linear relationship between the number of peptide-Ia complexes and the response of the T cells. The association between Ia and peptide in vitro is an inefficient process, requiring prolonged incubation and a large excess of peptide over Ia. Once formed, however, the complex is extremely stable with no detectable dissociation at neutral pH after days at 4 degrees C. With several different preparations of Ia it was found that only about 10 to 20% of the purified Ia is capable of forming the long-lived complex with peptide.
Avidity dictates the lytic capacity of human cytolytic T lymphocyte clones with similar fine specificity against murine cells expressing HLA-B27 antigen.
Authors: Calvo V , Rojo S , Aparicio P , Galocha B , López de Castro J A
Published: December 2022

The role of the avidity of human CTL in the recognition and lysis of murine P815 cells expressing HLA-B27.1 Ag has been examined. Seven B27-specific alloreactive CTL clones were tested for their ability to lyse a B27.1+-P815 transfectant clone 1-7E, obtained after cotransfection of P815-HTR cells with HLA-B27.1 and human beta 2-microglobulin genes. The expression level of HLA-B27.1 on 1-7E cells was comparable to that on a human lymphoblastoid cell line, as determined by flow cytometry. Of the seven CTL clones used, CTL 1, 26, and 29 displayed the same fine specificity as established with a panel of target cells expressing six structurally different HLA-B27 variants. However, CTL 1 and 29 were of higher avidity than CTL 26, in that the lysis of human target cells by only this latter clone was inhibited by an anti-CD8 mAb. Based on the same criteria, CTL 2, 15, and 48 possessed the same or very similar fine specificity, but CTL 48 was of higher avidity than CTL 2 or 15. The seventh clone, CTL 40, was of a different fine specificity and its lysis of human target cells was also inhibited by the same anti-CD8 mAb. Only those clones whose lysis of human targets could not be inhibited by anti-CD8 antibody were able to lyse the 1-7E murine transfectants. These results indicate that, for human CTL clones with identical or very similar fine specificity, only those of higher avidity are able to lyse P815 murine cells expressing the HLA-B27 antigen. The lysis of HLA-B27.1+-murine transfectants by relevant clones was inhibited by anti-CD8 antibody. This result strongly suggests that the relative contribution of CD8 in stabilizing the interaction between human CTL and HLA-B27+-murine target cells is more significant than with human target cells.
Synergistic effects of purified recombinant human and murine B cell growth factor-1/IL-4 on colony formation in vitro by hematopoietic progenitor cells. Multiple actions.
Authors: Broxmeyer H E , Lu L , Cooper S , Tushinski R , Mochizuki D , Rubin B Y , Gillis S , Williams D E
Published: December 2022

Purified recombinant human B cell growth factor-1/IL-4 was evaluated, alone and in combination, with purified preparations of recombinant human (rhu) CSF or erythropoietin (Epo) for effects on colony formation by human bone marrow CFU-GM progenitor cells (GM) and burst forming unit-E progenitor cells. rhu IL-4 synergized with rhu G-CSF to enhance granulocyte colony formation, but had no effect on CFU-GM colony formation stimulated by rhu GM-CSF, rhu IL-3, or rhu CSF-1. Rhu IL-4 synergized with Epo to enhance BFU-E colony formation equal to that of Epo plus either rhu IL-3, rhu GM-CSF, or rhu G-CSF. Removal of adherent cells and T lymphocytes did not influence the synergistic activities of rhu IL-4. Rmu IL-4, synergized with rhu G-CSF, but not with rmu GM-CSF, rmu IL-3, or natural mu CSF-1, to enhance CFU-GM (mainly granulocyte) colony numbers by a greater than 90% pure preparation of murine CFU-GM. Also, rhu IL-4 at low concentrations enhanced release of CSF and at higher concentrations the release also of suppressor molecules from human monocytes and PHA-stimulated human T lymphocytes. Use of specific CSF antibodies suggested that rhu IL-4 was enhancing the release of G-CSF and CSF-1 from monocytes and the release of GM-CSF and possibly G-CSF from PHA-stimulated T lymphocytes. Use of antibodies for TNF-alpha, IFN-gamma, or TNF-beta as well as measurement of TNF and IFN titers suggested that the suppressor molecule(s) released from monocytes were acting with TNF-alpha and those released from PHA-stimulated T lymphocytes were acting with IFN-gamma. These results implicate B cell growth factor-1/IL-4 as a synergistic activity for hematopoietic progenitors and suggest that the actions can be on both progenitor and accessory cells.
Genomic structure of the murine IL-6 gene. High degree conservation of potential regulatory sequences between mouse and human.
Authors: Tanabe O , Akira S , Kamiya T , Wong G G , Hirano T , Kishimoto T
Published: December 2022

The genomic clone of mouse IL-6 was isolated and compared with the human IL-6 gene. The comparison revealed that the mouse IL-6 consists of five exons and four introns and that the overall organization is similar to that of the human IL-6 gene although the third intron is about 2 kb longer. The sequence similarity in the coding region is about 60%, whereas the 3'-untranslated region and the first 300-bp sequence of the 5'-flanking region are highly conserved (greater than 80%). Several sequence blocks with high homology are also found in the introns. Furthermore, sequences similar to transcriptional enhancer elements such as the c-fos serum responsive element and the consensus sequences for cAMP induction, activator protein 1 binding, and the glucocorticoid receptor binding are identified within the highly conserved 5'-flanking regions of the genes from the two species. These sequences may play an important role in transcriptional activation of the IL-6 gene.
Assembly of the membrane attack complex promotes decay of the alternative pathway C3 convertase on Neisseria gonorrhoeae.
Authors: Densen P , McRill C M , Ross S C
Published: December 2022

C3, C4, factor B, properdin, and C2 binding to serum-sensitive and serum-resistant gonococci was quantitated in C8-deficient and normal human serum by using fluorescein-conjugated antibodies and 3H-labeled components. Organism and serum-specific differences were noted, the most striking of which involved factor B and properdin binding to the serum-sensitive strains in the different sera. C3 binding to these organisms was quantitatively and kinetically equivalent in C8-deficient and normal human serum. In contrast, factor B and properdin binding reached a plateau after 5 min in C8-deficient serum but peaked and fell to control values in normal human serum. Identical results were obtained with normal human serum immunochemically depleted of C8. Between 7 and 15% of the bound C3 participated in formation of the alternative pathway convertase C3bBb/P. Reconstitution of the C cascade by adding purified C8 to C8-deficient serum led to the loss of factor B previously bound to the organisms. Factor B loss occurred coincident with bacterial killing and membrane disruption as observed by electron microscopy. Prevention of membrane disruption by depleting normal human serum of lysozyme had no effect on killing and failed to prevent factor B loss. Stabilization of the C3bBb complex with Ni2+ prevented factor B loss as well as gross membrane disruption but not bacterial killing. C2 (the classical pathway analog of factor B) binding to gonococci was equivalent in C8-deficient and normal human serum peaking within 2.5 min and falling to control values in both sera thereafter. We conclude that the assembly of the membrane attack complex promotes decay of C3bBb/P with release of factor B and properdin but not C3 from the organism surface. Membrane disruption does not appear to be required for this effect. This activity may represent a mechanism to limit continued C consumption.
Membrane Ig-cytoskeletal interactions. I. Flow cytofluorometric and biochemical analysis of membrane IgM-cytoskeletal interactions.
Authors: Albrecht D L , Noelle R J
Published: December 2022

Membrane IgM (mIgM) and mIgD are the receptors for Ag on the surface of B lymphocytes, mIg is soluble in detergent; however, when mIg is cross-linked with anti-Ig, the mIg becomes associated with the cytoskeletal matrix and is rendered detergent-insoluble. By a novel flow cytofluorometric assay and by biochemical analysis, it has been shown that anti-isotype-specific antibodies induce mIgM and mIgD to associate with the cytoskeleton of B lymphocytes in an isotype-specific fashion. The detergent solubility of other prominent B lymphocyte surface proteins, such as class I and class II MHC proteins were unaffected by cross-linking of mIg. A panel of mu-specific mAb was analyzed for their ability to induce mIgM-cytoskeletal association. Although all mAb bound mIgM, only three out of seven rendered mIgM cytoskeletally associated. Further analysis revealed a strict correlation in the capacity of mu-specific mAb to induce capping and to induce the association of mIgM with the cytoskeleton.
Cell damage by cytolysin. Spontaneous recovery and reversible inhibition by divalent cations.
Authors: Bashford C L , Menestrina G , Henkart P A , Pasternak C A
Published: December 2022

Cytolysin-induced membrane damage (which requires low Ca2+) has been studied 1) in E by assay of hemolysis, 2) in Lettre cells by measurement of transmembrane potential, intracellular content of K+ and Na+, leakage of phosphoryl[3H]choline or 51Cr from [3H]choline-labeled or 51CrO4(2-)-labeled cells and leakage of lactate dehydrogenase, and 3) in phospholipid bilayers by measurement of electrical conductivity changes. In Lettre cells, damage is restricted and reversible: little lactate dehydrogenase leaks from cells that leak substantial amounts of Na+, K+, and phosphoryl[3H]choline; at low amounts of cytolysin, membrane potential and intracellular content of Na+ and K+ recover within minutes. In E and Lettre cells, membrane damage is inhibited by Zn2+, by high Ca2+, or by low pH. Inhibition is reversible: addition of EGTA to Zn2+-protected E or Lettre cells (incubated in the presence of cytolysin, low Ca2+ and Zn2+) initiates leakage; removal of Zn2+ (and cytolysin and Ca2+) by washing also initiates leakage; such leakage is again sensitive to Zn2+, high Ca2+, or H+. In phospholipid bilayers, channels induced by cytolysin (at low Ca2+) are partially closed by negative voltage; Ca2+, Zn2+, or H+ promote channel closure. Channels are re-opened (only partially in the case of Zn2+) by positive voltage. From all these results it is concluded that the action of cytolysin on membranes is similar to that of other pore-forming agents: damage does not necessarily lead to lysis of nucleated cells, and can be prevented by Ca2+, Zn2+, or H+.
Pleiotropic effects of the Bcg gene. II. Genetic restriction of responses to mitogens and allogeneic targets.
Authors: Denis M , Buschman E , Forget A , Pelletier M , Skamene E
Published: December 2022

The response of Bcgr and Bcgs spleen cells to allogeneic Ag, mitogens, and in a system of oxidative mitogenesis using neuraminidase and galactose oxidase was investigated in two Bcg congenic systems. The Bcgr macrophages supported the MLR across H-2 barrier much better than the Bcgs macrophages. At sub-optimal or optimal doses of mitogens Bcgr mice were higher responders than their Bcgs counterparts. The superior response of Bcgr spleen cells to Con A was further investigated with the aim of identifying the population expressing this phenotype. T cells of either Bcgr or Bcgs type showed equal ability to respond to Con A in the presence of macrophages. Purified splenic macrophages from Bcgr mice contained a significantly greater percentage of Ia+-bearing macrophages compared to Bcgs mice. Splenic macrophages of the Bcgr type were more efficient than their Bcgs counterparts at restoring the Con A response of accessory cell-depleted spleen cells. Resident peritoneal macrophages as well as splenic dendritic cells from Bcgr and Bcgs mice were equally efficient at restoring this response. Glutaraldehyde-fixed Bcgr splenic macrophages were shown to be more efficient than the Bcgs cells at replenishing the response of Con A-unresponsive spleen cells when supplemented with IL-1.
Analysis of HLA-DP allelic sequence polymorphism using the in vitro enzymatic DNA amplification of DP-alpha and DP-beta loci.
Authors: Bugawan T L , Horn G T , Long C M , Mickelson E , Hansen J A , Ferrara G B , Angelini G , Erlich H A
Published: December 2022

Allelic sequence variation of the HLA DP-alpha and DP-beta genes has been analyzed in a panel of 34 DP-typed cell lines. The polymorphic second exon of these genes was specifically amplified in vitro by the polymerase chain reaction method, using the thermostable DNA polymerase of Thermus, aquaticus. The analysis of M13 clones containing the amplified DP-beta sequences revealed a total of 14 allelic variants. In general, specific allelic DP-beta sequences were associated with each of the defined DPw1-w6 types, with beta allele subtypes revealed for the DPw2 and DPw4 specificities. An additional six DP-beta alleles which did not correlate with any of the T cell-defined specificities (DP "blanks") were also identified. Only the two previously characterized alleles of DP-alpha were detected. These observations suggest that the T cell-defined DP specificities are determined by polymorphic residues on the beta-chain. The sequence polymorphisms in DP-beta are clustered in a few specific regions, and can be detected using sequence-specific oligonucleotide probes and polymerase chain reaction amplified DNA in a rapid dot-blot format. This approach provides a simple and informative method of DP typing. The DP-beta sequences derived from four DP-typed celiac disease patients were compared with the distribution of DP-beta alleles in control individuals.