SEARCH · PubMed Health

Results for “Functional characterization”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources

PubMed1991

Functional characterization of tumor-infiltrating lymphocytes, lymph-node lymphocytes and peripheral-blood lymphocytes from patients with breast cancer.

Mononuclear cell infiltration is frequently seen within human solid tumors. Effector cells within the tumor site usually fail to exhibit cytotoxic or natural killer activity when freshly isolated; however, they develop potent and sometimes specific cytotoxicity after expansion in IL2. Thus, local tumor environment may influence lymphocyte function. In our study, we disaggregated human breast-cancer and lymph-node tissue to obtain lymphocyte-enriched cell fractions. Besides phenotypic analysis, functional characterization with regard to proliferation and cytokine production of tumor-infiltrating lymphocytes (TIL), peripheral-blood lymphocytes (PBL) and lymph-node lymphocytes (LNL) was the aim of our study. TIL showed an enrichment of CD8+ cells with a corresponding decrease in CD4+ cells in comparison with PBL and LNL. In response to PHA, TIL showed decreased 3H-thymidine uptake, but TIL were significantly stimulated by rhIL2. TIL produced low levels of IL2, TNF and IFN gamma upon mitogen/phorbol ester stimulation, while PBL produce high levels of TNF and IFN gamma but low levels of IL2. Under the same experimental conditions, LNL produce high levels of TNF and IL2 but low levels of IFN gamma. Mitogen-mediated TNF secretion was increased after addition of autologous tumor cells in TIL and LNL, whereas IFN gamma secretion tended to be suppressed. Our results indicate different patterns of activities of TIL, LNL and PBL from breast-cancer patients.

Breast Neoplasms↗

PubMed1987

The combined use of immunohistochemistry and intracellular staining with horseradish peroxidase for light and electron microscopic studies of transmitter-identified inputs to functionally characterized neurons.

Physiologically identified triceps surae alpha motoneurons in the cat were stained intracellularly with horseradish peroxidase (HRP). After fixation with 2% glutaraldehyde and treatment with sodium borohydride, spinal cord sections were incubated with rabbit antiserum against thyrotropin-releasing hormone (TRH) and rabbit peroxidase-antiperoxidase complex. Light microscopically detected close contacts between immunoreactive nerve terminals and intracellularly HRP-stained profiles were studied under the electron microscope. In this way, synaptic contacts between TRH-immunoreactive boutons and functionally characterized alpha motoneurons could be demonstrated.

Animals↗

PubMed1990

Isolation and functional characterization of TIF-IB, a factor that confers promoter specificity to mouse RNA polymerase I.

The murine ribosomal gene promoter contains two cis-acting control elements which operate in concert to promote efficient and accurate transcription initiation by RNA polymerase I. The start site proximal core element which is indispensable for promoter recognition by RNA polymerase I (pol I) encompasses sequences from position -39 to -1. An upstream control element (UCE) which is located between nucleotides -142 and -112 stimulates the efficiency of transcription initiation both in vivo and in vitro. Here we report the isolation and functional characterization of a specific rDNA binding protein, the transcription initiation factor TIF-IB, which specifically interacts with the core region of the mouse ribosomal RNA gene promoter. Highly purified TIF-IB complements transcriptional activity in the presence of two other essential initiation factors TIF-IA and TIF-IC. We demonstrate that the binding efficiency of purified TIF-IB to the core promoter is strongly enhanced by the presence in cis of the UCE. This positive effect of upstream sequences on TIF-IB binding is observed throughout the purification procedure suggesting that the synergistic action of the two distant promoter elements is not mediated by a protein different from TIF-IB. Increasing the distance between both control elements still facilitates stable factor binding but eliminates transcriptional activation. The results demonstrate that TIF-IB binding to the rDNA promoter is an essential early step in the assembly of a functional transcription initiation complex. The subsequent interaction of TIF-IB with other auxiliary transcription initiation factors, however, requires the correct spacing between the UCE and the core promoter element.

Animals↗

PubMed2026

Genetic evidence and cross-species functional characterization implicate CNN2 in age-related macular degeneration susceptibility.

Age-related macular degeneration (AMD) is a leading cause of irreversible visual impairment in the aging population globally. Although genome-wide association studies (GWAS) have identified many AMD susceptibility loci, the genes and mechanisms underlying many of these associations remain unresolved. Here, we integrated expression quantitative trait locus (eQTL) data with AMD GWAS to prioritize nine putative genes. Through in vivo screening in zebrafish, we demonstrated that the downregulation of cnn2 and sarm1 expression led to ocular structural abnormalities and visual functional impairment. Subsequent mouse model studies confirmed that Cnn2 deficiency affected photoreceptor structure and function, impaired contrast sensitivity, and caused abnormalities in cone cell immunostaining. Given that CNN2 is predominantly expressed in endothelial cells, we propose that endothelial dysfunction may cascade to impair photoreceptor function. Collectively, through in silico prioritization and cross-species functional characterization, we identify CNN2 as a candidate susceptibility gene in AMD pathogenesis, providing vital underlying mechanistic insights.

Animals↗

PubMed1977

Estrogen binding proteins of calf uterus. Molecular and functional characterization of the receptor transforming factor: A Ca2+-activated protease.

It was previously shown that calf uterus cytosol contains a Ca2+-activated receptor transforming factor (RTF) which irreversibly converts the larger molecular states of estrogen receptor (5.3 to 8.6 S, depending on ionic strength) into a smaller, salt-stable form (4.5 S, independent of ionic strength). We now describe a method for rapid and reliable separation of precursor and RTF-transformed receptor forms, which takes advantage of a difference in isoelectric point between the two: the more acidic precursor (isoelectric point, 6.2) is still retained by DEAE-cellulose under conditions (0.12 M KCl, pH 8.3) which produce release from cellulose of the less acidic transformed form (isoelectric point, 6.6 to 6.8). Based on this method of separation, RTF activity can be assayed easily and we could thus progress in the purification and physical and functional characterization of this factor, RTF has been purified about 100-fold. Molecular properties, as assayed by methods suited to partially purified preparations, are as follows: sedimentation coefficient, 6.4 S; Stokes radius, 45 A; molecular weight, 115,000; isoelectric point, 4.9. The Michaelis constant, expressed as moles/liter of estradiol binding sites, is 1.25 X 10(8), at pH 7.5 and 4 degrees, pH 8.5 is optimum for activity. RTF attacks native casein (Km, 1.25 X 10(-5) mol/liter at pH 7.5 and 22 degrees) but not hemoglobin, ovalbumin, or albumin. N-Benzoylarginine methyl ester is a competitive inhibitor of RTF-induced receptor transformation, while L-leucylglycylglycine and N-benzoyltyrosinamide are not. RTF activity is protected by -SH compounds. RTF activity is Ca2+-dependent. Ca2+ starts an activation-inactivation cycle of RTF, with permanent loss of transforming activity which proceeds at a particularly fast rate in the absence of substrate. Mg2+ is inactive, while Sr2+ and Mn2+ may in part substitute for Ca2+. RTF is present in both endometrium and myometrium. RTF is not a lysosomal hydrolase, as shown by its alkaline pH optimum (8.5) and exclusive location in cytosol, nor is it trypsin or a protease of the trypsin group. Also, it is distinct from known proteases of human uterus. The functional significance of this Ca2+-activated protease of cytosol with alkaline pH optimum and high affinity for the larger native form of receptor is still unknown.

Animals↗

PubMed1988

Granulocyte-activating mediators (GRAM): III. Further functional characterization of monocyte-derived GRAM.

As shown previously monocytes upon stimulation with bacterial lipopolysaccharides (LPS) release granulocyte-activating mediator(s) (M-GRAM) which induced a long-lasting chemiluminescence (CL) response in human granulocytes. M-GRAM could be separated from interleukin-1 alpha and beta, interleukin-2, interferon alpha and gamma, granulocyte colony stimulating factor (G-CSF) and macrophage colony stimulating factor (M-CSF), since these cytokines are shown to be unable to induce a significant CL response. In contrast, granulocyte macrophage colony stimulating factor (GM-CSF) and particularly tumor necrosis factor (TNF) are important triggers of the oxidative burst and they are capable of inducing a CL response. TNF activity but not lymphotoxin (LT) activity could be demonstrated in M-GRAM samples. A polyclonal rabbit IgG as well as a monoclonal antibody to recombinant human TNF which neutralized the TNF activity in M-GRAM preparations did not substantially block the CL signal. Furthermore, M-GRAM-induced CL response was not significantly inhibited by a polyclonal calf antiserum to human recombinant GM-CSF. For further functional characterization of M-GRAM-induced granulocyte activation different assays were performed in order to compare GM-CSF and TNF: (a) SOD-inhibitable cytochrome C-reduction (.O2-); (b) horseradish peroxidase-mediated oxidation of phenol red (H2O2); (c) the release of peroxidase; (d) ultrastructural detection of hydrogen peroxide production; and (e) scanning and transmission electron microscopy (SEM and TEM). Significant release of .O2- was induced by M-GRAM, TNF, and GM-CSF, whereas H2O2 production was significantly stimulated only by M-GRAM and TNF, as shown by functional and ultrastructural assays.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Factors↗

PubMed2026

Genomic and functional characterization of ST11-KL64 hypervirulence-associated carbapenem-resistant Klebsiella pneumoniae co-harboring bla KPC-2 and bla NDM-13.

BACKGROUND: Hypervirulence-associated carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) is a major clinical and public health threat. However, ST11-KL64 hv-CRKP co-harboring bla KPC-2 and bla NDM-13 remains poorly characterized, particularly regarding genomic relatedness, plasmid dynamics, and attenuated virulence-associated phenotypes. METHODS: We retrospectively investigated clinical K. pneumoniae isolates collected at a tertiary hospital in Chengdu, China, between January and December 2024. Hypervirulence-associated markers were screened by PCR, followed by antimicrobial susceptibility testing and carbapenemase inhibitor enhancement assay to identify genotype-defined hv-CRKP. All isolates were subjected to molecular typing. ST11-KL64 isolates co-harboring bla KPC-2 and bla NDM-13 were subjected to Illumina sequencing, with the representative isolate K3 undergoing hybrid whole-genome sequencing and functional characterization. RESULTS: Among the 46 hvKP isolates recovered from 43 patients, 35 were identified as hv-CRKP, predominantly ST11-KL64. Three ST11-KL64 hv-CRKP isolates co-harbored bla KPC-2/bla NDM-13, and Illumina sequencing coupled with core-genome SNP (cgSNP) typing revealed minimal genetic variation. The expanded cgSNP analysis supported close relatedness between K3 and Beijing isolate K56649. K3 carried a pLVPK-like virulence plasmid, a bla KPC-2-bearing IncFII/IncR plasmid, and a bla NDM-13-bearing IncI1 plasmid. Relative to pK2044, K3 exhibited an rmpA-proximal ISKpn26-associated insertion and a complex alteration of the 5'-terminal coding region of rmpA. The bla NDM-13 plasmid was conjugatively transferred to Escherichia coli C600 with a mean conjugation frequency of 5.213 × 10-3 transconjugants per recipient cell and bla NDM-13 maintained high stability following approximately 100 generations of antibiotic-free passage, whereas bla KPC-2 was not detected under the tested conditions. Phenotypically, K3 showed a negative string test, low mucoviscosity, and attenuated virulence-associated phenotypes. CONCLUSION: Our results reveal that the three isolates formed a closely related local genomic cluster, among which K3 was closely related to the K56649 clone. In addition, K3 exhibited conjugative transfer capacity of the bla NDM-13-bearing IncI1 plasmid, and alterations at the rmpA locus accompanied by reduced rmpA transcript abundance were associated with low mucoviscosity.

IncI1 plasmid↗

PubMed1992

Phenotypic and functional characterization of cytotoxic cells derived from endomyocardial biopsies in human cardiac allografts.

This study was undertaken to characterize the phenotype and function of lymphocytes derived from endomyocardial biopsies in heart transplant patients. To this aim, tissue infiltrating lymphocytes were derived from seven heart transplant patients and were analyzed for the expression of a panel of markers, including CD3, CD4, CD8, CD16, CD56, CD45RA, CD45RO, alpha/beta and gamma/delta T cell receptor, and for their ability to lyse a series of targets, including NK-sensitive K-562 targets, NK-resistant Raji targets, donor related, and unrelated normal splenocytes. Our data show that the majority of cultured lymphocytes expressed the CD3+ phenotype and the alpha/beta T cell receptor. The CD4 and CD8 molecules were heterogeneously expressed among T cell lines tested. Concerning cytotoxic related markers, a significant percentage of cells were CD56+. The evaluation of CD45 isoforms showed that both "naive" and "memory" cells were present among heart TIL. Cytotoxic in vitro studies demonstrated that all our T cell lines showed an efficient cytotoxic machinery when tested against NK-sensitive targets. A marked lysis of donor-related splenocytes was demonstrated in all patients tested. To investigate the role of CD3 and HLA class I molecules in the cytotoxic mechanisms taking place in human heart allograft rejection mechanisms, TIL were assessed for their lytic activity against different targets in the presence of anti-CD3 and anti-HLA class I monoclonal antibodies (mAbs). Although donor-specific cytotoxicity was considerably inhibited by the anti-CD3 mAb, no inhibitory effect was displayed by this antibody on TIL-mediated cytotoxicity against donor-unrelated splenocytes. Anti-HLA class I mAb was able to inhibit both allospecific and nonallospecific cytotoxicity. These data suggest that different types of cytotoxic cells may be propagated from biopsy specimens of heart transplant patients.

Adult↗

PubMed1992

Functional characterization of a variant factor XII (F XII Locarno) in a cross reacting material positive F XII deficient plasma.

The plasma of a healthy woman was found to contain half normal factor XII (FXII) antigen level (0.46 U/ml) without any FXII clotting activity (less than 0.01 U/ml). The variant FXII in this plasma, denoted as FXII Locarno, was partially characterized by immunological and functional studies on the proposita's plasma. FXII Locarno is a single chain molecule with the same size (Mr = 80 kDa) as normal FXII. Isoelectric focusing suggested an excess of negative charge in the variant FXII as compared to normal FXII. In contrast to FXII in normal plasma, FXII Locarno was not proteolytically cleaved upon prolonged incubation of proposita's plasma with dextran sulfate. Adsorption to kaolin was similar for both, abnormal and normal FXII. Incubation of the proposita's plasma with dextran sulfate and exogenous plasma kallikrein showed normal cleavage of FXII Locarno outside of the tentative disulfide loop Cys340-Cys467, but only partial cleavage within this disulfide loop. Furthermore, plasma kallikrein-cleaved abnormal FXII showed neither amidolytic activity nor proteolytic activity against factor XI and plasma prekallikrein. These results suggest a structural alteration of FXII Locarno, affecting the plasma kallikrein cleavage site Arg353-Val354 and thus formation of activated FXII (alpha-FXIIa).

Amides↗

PubMed1986

Structural and functional characterization of a canine minor glycosylated hemoglobin, Hb Can AIc.

Structural and functional studies of minor glycosylated hemoglobins in non-human mammals have been very few. Therefore, we attempted further characterization of a canine glycosylated hemoglobin (tentatively designated as Hb Can AIc) which had been isolated by Bio-Rex 70 chromatography (Enoki, Y. et al. (1982) Hemoglobin 6, 143-151). After isolation of the constituent subunits by hybridization-mercuration technique, we found by peptide mapping that the structural modification was confined in amino-termini of the beta subunits in which glycosyl ketoamine linkage was also shown to be localized by thiobarbituric acid reaction. Compared with the major hemoglobin (Hb Can A0), Hb Can AIc was characterized by such functional properties as a slightly lower oxygen affinity and a markedly reduced response to the allosteric effects of carbon dioxide and organic phosphates. The anion and H+ Bohr effects were not different from those in Hb Can A0. All these facts support that this hemoglobin is a canine counterpart of Hb AIc.

Amino Acids↗

PubMed1992

Identification of a new congenital defect of platelet function characterized by severe impairment of platelet responses to adenosine diphosphate.

This study characterizes a congenital hemorrhagic disorder caused by a platelet function defect with the following features: (1) severely impaired platelet aggregation and fibrinogen or von Willebrand factor (vWF) binding induced by adenosine diphosphate (ADP); (2) defective aggregation, release reaction, and fibrinogen or vWF binding induced by other agonists; (3) normal aggregation and release reaction induced by high concentrations of thrombin or collagen; (4) no further inhibition by ADP scavengers of aggregation, release reaction, and fibrinogen or vWF binding, comparable with those observed for normal platelets in the presence of ADP scavengers; (5) normal membrane glycoprotein (GP) composition and normal binding of the anti-GP IIb/IIIa monoclonal antibody 10E5; (6) no acceleration by ADP of binding of the anti-GP IIb/IIIa monoclonal antibody 7E3; (7) normal platelet-fibrin clot retraction if induced by thrombin or reptilase plus epinephrine, absent if induced by reptilase plus ADP; (8) no inhibition by ADP of the prostaglandin E1-induced increase in platelet cyclic adenosine monophosphate, but normal inhibition by epinephrine; (9) defective mobilization of cytoplasmic Ca2+ by ADP; (10) normal binding of 14C-ADP to fresh platelets, but defective binding of [2-3H]-ADP to formalin-fixed platelets. This congenital platelet function defect is characterized by selective impairment of platelet responses to ADP, caused by either decreased number of platelet ADP receptors or abnormalities of the signal-transduction pathway of platelet activation by ADP.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed1988

In vitro functional characterization of SAG-3--a naturally occurring monoclonal antibody in NZB mice: specificity toward functional T cell subsets.

Natural thymocytotoxic autoantibodies (NTA) have been suggested to contribute to the T cell mediated immune dysfunction prevalent in NZB mice. However, direct studies to confirm these suggestions have been difficult to perform due to the absence of large amounts of pure NTA. To overcome this problem, we generated a naturally occurring monoclonal antibody from an NZB mouse which possesses the serological characteristics of serum-NTA. Herein, we report the in vitro functional characteristics of this monoclonal antibody designated SAG-3. In vitro treatment of spleen and lymph node cells from BALB/c mice with SAG-3 and complement eliminated most of the proliferative response to Con-A and moderately reduced the response of these cells to PHA-P and PWM. Complement mediated cytolysis of SAG-3 reactive cells significantly reduced the capacity of unprimed lymph node cells to generate primary CTL responses in vitro against allogeneic cells. However, only a partial decrease in CTL activity was observed when primed secondary CTL effector cells were treated, due primarily to the depletion of CTL's specific towards MHC class I antigens. Furthermore, a moderate reduction in antigen-specific helper T cell function was observed. Pretreatment of responder cells with SAG-3 + C' did not appear to reduce the proliferative MLR response to a wide range of stimulator cells. In addition, contrary to previous reports on serum-NTA, SAG-3 appears not to be reactive against Con-A induced suppressor T cells. Finally, by FACS analysis SAG-3+ thymocytes constitute an overlapping population of Lyt-2+ and L3T4+ thymocytes. These findings are discussed in comparison to previous reports on NTA.

Animals↗

PubMed1986

Functional characterization of human IgG, IgM, and IgA antibody directed to the capsule of Haemophilus influenzae type b.

Antibody to the capsular polysaccharide (CP) of Haemophilus influenzae b (Hib) is bactericidal, opsonic, and protective. Minimum protective levels of primarily IgG antibody to Hib CP, calculated from passive immunization studies, have been found to be approximately .06-.15 microgram/ml of serum. The human response to antigenic challenge with the Hib capsule, however, includes production of antibody to Hib CP of different isotypes whose function against Hib is unclear. In order to characterize the function of antibody to Hib CP of different isotypes, we purified human IgG, IgM, and IgA from the serum of an adult donor who had been previously immunized with purified Hib CP vaccine. The globulin preparations were greater than 99% isotypically pure, contained large quantities of anticapsular antibody, and differed in function against Hib. IgG antibody to Hib CP was bactericidal and opsonic for human polymorphonuclear leukocytes (PMNLs) in the presence of complement and protective in infant rats. IgM, although more bactericidal than IgG (P less than .01) and equally protective in rats, opsonized Hib poorly for PMNLs. IgA was not bactericidal or opsonic and did not prevent bacteremia and meningitis in rats challenged with Hib. We conclude that antibody directed against the capsule of Hib differs in antibacterial function depending on class. These data may be important to acurately estimate minimum protective levels of anticapsular antibody after vaccination or natural infection and may have implications for the manner in which the host clears Hib from the circulation.

Animals↗

PubMed2026

Genomic identification and functional characterization of the nuclear receptor gene family in relation to sex determination and gonad development in the Pacific oyster (Crassostrea gigas).

Nuclear receptors (NRs) are a large superfamily of transcription factors that control a wide range of physiological processes by modulating the expression of downstream target genes. Numerous studies have confirmed that NR family members play critical and conserved roles in sex determination and gonadal development across metazoans. However, in mollusks, systematic characterization of NRs and their potential functions in gonadal regulation remain largely unexplored. In this study, 46 NR gene family members in the Pacific oyster (Crassostrea gigas) were identified and assigned to eight subfamilies. All NR family members contain at least one of the two core domains (DNA-binding domain, DBD; ligand-binding domain, LBD), and conserved exon-intron structures were observed within the same subgroup, indicating their evolutionary conservation. Furthermore, expression profiling revealed high expression of CgNR2F, CgNR5A1-1, and CgNR0B1 in undifferentiated gonads, suggesting their potential involvement in sex determination. CgNR1A and CgNR2E5 were specifically expressed in female gonads and exhibited female-biased expression patterns, indicating a putative role in ovarian development. Moreover, CgNR3A and CgNR3B showed high expression levels during the undifferentiated stage and early male development stage, implying their possible participation in male gonadal development and gametogenesis. These results expand the understanding of the NR gene family in C. gigas and help elucidate the potential functions of NR genes in sex determination and gonadal development.

Animals↗

PubMedDate not supplied

Structural and functional characterization of the OmpF and OmpC porins of the Escherichia coli outer membrane: studies involving chimeric proteins.

The roles of submolecular regions of OmpF and OmpC, major outer membrane proteins of Escherichia coli, as concerns their biogenesis, structure and function were studied using a large number of chimeric genes constructed from the ompF and ompC genes through single or double homologous in vivo recombination. When recombination between the two genes took place at certain regions of their central regions, no chimeric protein was detected, irrespective of whether the amino-terminal and carboxy-terminal regions were derived from OmpF or OmpC. Biochemical studies revealed that these proteins were synthesized and exported across the cytoplasmic membrane normally, but that they were not properly assembled into the outer membrane and hence were degraded rapidly. Characterization of these chimeric proteins, in which recombination between OmpF and OmpC took place once or twice, suggested that the central region of each of these proteins plays an important role in the respective assembly, whereas the roles of the amino-terminal and carboxy-terminal regions may be marginal. Functional characterization of these chimeric proteins revealed the regions important for the receptor functions of OmpF and OmpC for phages TuIa and TuIb, respectively.

Amino Acid Sequence↗

PubMed1979

Functional characterization of drug-induced experimental papillary necrosis.

The functional expression of papillary necrosis was investigated with a model of drug-induced papillary necrosis. Bromoethylamine hydrobromide (BEA) administration to rats uniformly resulted in the development of papillary necrosis. All studies were performed 24 hours after BEA administration with the exception of the electrolyte balance studies, which were performed during the 72 hours after the induction of papillary necrosis. GFR was not different between BEA-treated and sham rats. BEA-treated rats had a significantly lower maximal urine osmolality and free water reabsorption than did sham rats. Renal tissue concentrations of sodium, potassium, and water were not different between BEA-treated and sham rats. During water diuresis, free water clearance was not significantly different between the two groups. During sodium bicarbonate administration, maximal bicarbonate reabsorption and urine-blood Pco2 gradient (at comparable urine bicarbonate concentrations) were not significantly different between the two groups. During sodium sulfate infusion, there was no difference in minimum urine pH, ammonium excretion, and net acid excretion between chronically acidotic BEA-injected and sham rats. In rats on "zero" sodium intake, BEA administration resulted in a significant increase in urine flow and sodium excretion, whereas sham rats remained in sodium balance. In rats with restriction of both sodium and chloride, BEA administration resulted in a significant wastage of sodium, chloride, and calcium. There was no difference in potassium excretion between BEA-treated and sham rats during hydropenia, bicarbonate administration, sodium sulfate infusion, or ingestion of a normal potassium diet. When potassium intake was restricted to "zero," BEA-treated rats developed potassium wastage; when potassium intake was increased to 21 mEq/day, BEA-treated rats had a significantly lower potassium excretion than did sham rats. These findings may result from alterations in collecting duct transport, but damage to deep medullary structures may also contribute.

Animals↗

PubMed1979

Functional characterization of mouse T lymphocytes with IgM-Fc receptors. I. Studies on ADCC and helper cell function.

The function of mouse T lymphocytes with receptors for IgM-Fc was analyzed by using immunofluorescence and a column separation method. The cellular uptake of FITC-IgM was inhibited with unlabeled Fc5 mu. IgM-FcR+ cells were active in ADCC against IgM-sensitized target cells, but not against IgG-coated target cells. The cells mediating ADCC with IgM antibody were shown to be distinct and physically separable from those mediating ADCC with IgG antibody. Helper T lymphocytes for humoral antibody formation in a hapten-carrier system were shown to be IgM-FcR+ and Fc-IgG-.

Animals↗

PubMed1985

Antigenic profile and functional characterization of human peritoneal macrophages.

The antigenic profile and the functional properties of human peritoneal macrophages have been analyzed by using a panel of monoclonal antibodies (MoAb) and functional assays. All peritoneal macrophages were stained by the anti-class I HLA MoAb Q6/64. Between 40 and 100% of the cells were stained by the anti-HLA-DR + DP MoAb Q2/80, Q5/6, and Q5/13; approximately 80% of the cells were stained by the anti-HLA-DQ MoAb BT3.4, and about 95% were stained by the anti-macrophage MoAb OKM1. Peritoneal macrophages were not stained by the anti-dendritic cells MoAb Ki-M4 or by MoAb to T cell subsets, although all of the MoAb were reactive with the appropriate substrates. More than 60% of the cells expressed Fc receptors and C3 receptors, and displayed phagocytic activity. Peritoneal macrophages were effective in stimulating autologous and allogeneic lymphocytes and in presenting soluble antigens to T cells. These reactions were blocked by the anti-HLA-DR + DP MoAb Q5/13, but were not affected by the anti-dendritic cells MoAb Ki-M4 or by the anti-class I HLA MoAb Q6/64. These results suggest that human peritoneal macrophage preparations, without detectable contamination with dendritic cells, can induce proliferation of autologous and allogeneic T cells, and that class II HLA antigens play a significant role in these phenomena.

Antigen-Presenting Cells↗