Human MCL forms a heteromeric receptor complex with Mincle but not Dectin-2

MCL, Mincle and Dectin-2 are C-type lectin receptors expressed by subsets of myeloid cells, and their genes cluster together in the APLEC/Dectin-2 gene complex. We have previously shown that MCL and Mincle form a heterodimer in the rat, and others have shown that MCL and Dectin-2 form a heterodimer in the mouse. In the rat, Dectin-2 is a pseudogene, but here we examine the association of the three receptors in human. In co-transfection experiments analyzed with flow cytometry and immunoprecipitation, we here show that human MCL and Mincle form a disulfide-linked heterodimer that associates with the signaling adaptor molecule FcεRIγ, in accordance with our previous findings in the rat. In contrast to previous findings in the rat, data in this paper indicate a direct association of MCL with FcεRIγ, as previously shown for mouse MCL. We were unable to demonstrate the formation of a heterodimer between human MCL and Dectin-2. Thus, despite similarities, there may be important differences in the conformation of these receptors between rat, mouse and human, and this may have functional consequences.

Dendritic Cell Activating Receptor 1 (DCAR1) Associates With FcεRIγ and Is Expressed by Myeloid Cell Subsets in the Rat

Dendritic cell activating receptor-1 (DCAR1) is a cell-surface receptor encoded by the Antigen Presenting Lectin-like gene Complex (APLEC). We generated a mouse monoclonal antibody against rat DCAR1, and used this to characterize receptor expression and function. Rat DCAR1 was expressed on minor subsets of myeloid cells in lymphoid tissue, but was uniformly expressed at a high level by eosinophils, and at a low level by neutrophils. It was expressed by eosinophils in the peritoneal cavity and the lamina propria of the gut, and by subsets of macrophages or dendritic cells at these sites. Polarization of peritoneal macrophages showed that DCAR1 expression was absent on M1 macrophages, and increased on M2 macrophages. DCAR1 could be expressed as a homodimer and its associated with the activating adaptor protein FcεRIγ. This association allowed efficient phagocytosis of antibody-coated beads. Additionally, cross-linking of DCAR1 on the surface of rat eosinophils lead to production of reactive oxygen species. These data show that DCAR1 is an activating receptor. Its expression on M2 macrophages and eosinophils suggests that it may play a role in the immune response to parasites.

Hyperemesis gravidarum and long-term mortality: a population-based cohort study

OBJECTIVE

To investigate whether exposure to hyperemesis gravidarum (HG) is associated with increased maternal long-term mortality.

DESIGN

Population-based cohort study.

SETTING

Medical Birth Registry of Norway (1967-2002) linked to the Cause of Death Registry.

POPULATION

Women in Norway with singleton births in the period 1967-2002, with and without HG. Women were followed until 2009 or death.

METHODS

Cox proportional hazard regression model was applied to estimate hazard ratios (HRs) with 95% confidence interval (CI).

MAIN OUTCOME MEASURES

The primary outcome was all-cause mortality during follow up. Secondary outcomes were cause-specific mortality (cardiovascular mortality, deaths due to cancer, external causes or mental and behavioural disorders).

RESULTS

Of 999 161 women with singleton births, 13 397 (1.3%) experienced HG. During a median follow up of 26 years (25 902 036 person-years), 43 470 women died (4.4%). Women exposed to HG had a lower risk of long-term all-cause mortality compared with women without HG (crude HR 0.82; 95% CI 0.75-0.90). When adjusting for confounders, this reduction was no longer significant (adjusted HR 0.92; 95% CI 0.84-1.01). Women exposed to HG had a similar risk of cardiovascular death as women not exposed (adjusted HR 1.04; 95% CI 0.83-1.29), but a lower long-term risk of death from cancer (adjusted HR 0.86; 95% CI 0.75-0.98).

CONCLUSION

In this large population-based cohort study, HG was not associated with an increased risk of long-term all-cause mortality. Women exposed to HG had no increase in mortality due to cardiovascular disease, but had a reduced risk of death from cancer.

TWEETABLE ABSTRACT

Population-based cohort study: Hyperemesis was not associated with an increased risk of long-term mortality.

The Activating Human NK Cell Receptor KIR2DS2 Recognizes a β2-Microglobulin-Independent Ligand on Cancer Cells

The functions of activating members of the killer cell Ig-like receptor (KIR) family are not fully understood, as the ligands for these receptors are largely unidentified. In this study, we report that KIR2DS2 reporter cells recognize a ligand expressed by cancer cell lines. All cancer targets recognized by KIR2DS2 were also recognized by KIR2DL2 and KIR2DL3 reporters. Trogocytosis of membrane proteins from the cancer targets was observed with responding reporter cells, indicating the formation of KIR2DS2 ligand-specific immunological synapses. HLA-C typing of target cells showed that KIR2DS2 recognition was independent of the HLA C1 or C2 group, whereas targets cells that were only recognized by KIR2DL3 expressed C1 group alleles. Anti-HLA class I Abs blocked KIR2DL3 responses toward C1-expressing targets, but they did not block KIR2DS2 recognition of cancer cells. Small interfering RNA knockdown of β₂-microglobulin reduced the expression of class I H chain on the cancer targets by >97%, but it did not reduce the KIR2DS2 reporter responses, indicating a β₂-microglobulin-independent ligand for KIR2DS2. Importantly, KIR2DL3 responses toward some KIR2DS2 ligand-expressing cells were also undiminished after β₂-microglobulin knockdown, and they were not blocked by anti-HLA class I Abs, suggesting that KIR2DL3, in addition to the traditional HLA-C ligands, can bind to the same β₂-microglobulin-independent ligand as KIR2DS2. These observations indicate the existence of a novel, presently uncharacterized ligand for the activating NK cell receptor KIR2DS2. Molecular identification of this ligand may lead to improved KIR-HLA mismatching in hematopoietic stem cell transplantation therapy for leukemia and new, more specific NK cell-based cancer therapies.

Mincle, the receptor for mycobacterial cord factor, forms a functional receptor complex with MCL and FcεRI-γ

Upon receptor activation, the myeloid C-type lectin receptor Mincle signals via the Syk-CARD9-Bcl10-MALT1 pathway. It does so by recruiting the ITAM-bearing FcεRI-γ. The related receptor macrophage C-type Lectin (MCL) has also been shown to be associated with Syk and to be dependent upon this signaling axis. We have previously shown that MCL co-precipitates with FcεRI-γ, but were unable to show a direct association, suggesting that MCL associates with FcεRI-γ via another molecule. Here, we have used rat primary cells and cell lines to investigate this missing link. A combination of flow cytometric and biochemical analysis showed that Mincle and MCL form heteromers on the cell surface. Furthermore, association with MCL and FcεRI-γ increased Mincle expression and enhanced phagocytosis of Ab-coated beads. The results presented in this paper suggest that the Mincle/MCL/FcεRI-γ complex is the functionally optimal form for these C-type lectin receptors on the surface of myeloid cells.

Phylogenetic and functional conservation of the NKR-P1F and NKR-P1G receptors in rat and mouse

Two clusters of rat Nkrp1 genes can be distinguished based on phylogenetic relationships and functional characteristics. The proximal (centromeric) cluster encodes the well-studied NKR-P1A and NKR-P1B receptors and the distal cluster, the largely uncharacterized, NKR-P1F and NKR-P1G receptors. The inhibitory NKR-P1G receptor is expressed only by the Ly49s3(+) NK cell subset as detected by RT-PCR, while the activating NKR-P1F receptor is detected in both Ly49s3(+) and NKR-P1B(+) NK cells. The mouse NKR-P1G ortholog is expressed by both NKR-P1D(-) and NKR-P1D(+) NK cells in C57BL/6 mice. The rat and mouse NKR-P1F and NKR-P1G receptors demonstrate a striking, cross-species conservation of specificity for Clr ligands. NKR-P1F and NKR-P1G reporter cells reacted with overlapping panels of tumour cell lines and with cells transiently transfected with rat Clr2, Clr3, Clr4, Clr6 and Clr7 and mouse Clrc, Clrf, Clrg and Clrd/x, but not with Clr11 or Clrb, which serve as ligands for NKR-P1 from the proximal cluster. These data suggest that the conserved NKR-P1F and NKR-P1G receptors function as promiscuous receptors for a rapidly evolving family of Clr ligands in rodent NK cells.

The complete inventory of receptors encoded by the rat natural killer cell gene complex

The natural killer cell gene complex (NKC) encodes receptors belonging to the C-type lectin superfamily expressed primarily by NK cells and other leukocytes. In the rat, the chromosomal region that starts with the Nkrp1a locus and ends with the Ly49i8 locus is predicted to contain 67 group V C-type lectin superfamily genes, making it one of the largest congregation of paralogous genes in vertebrates. Based on physical proximity and phylogenetic relationships between these genes, the rat NKC can be divided into four major parts. We have previously reported the cDNA cloning of the majority of the genes belonging to the centromeric Nkrp1/Clr cluster and the two telomeric groups, the Klre1–Klri2 and the Ly49 clusters. Here, we close the gap between the Nkrp1/Clr and the Klre1–Klri2 clusters by presenting the cDNA cloning and transcription patterns of eight genes spanning from Cd69 to Dectin1, including the novel Clec2m gene. The definition, organization, and evolution of the rat NKC are discussed.

NK cell receptors in rodents and cattle

Natural killer (NK) cells discriminate between normal syngeneic cells and infected, neoplastic or MHC-disparate allogeneic cells. The reactivity of NK cells appears to be regulated by a balance between activating receptors that recognize non-self or altered self, and inhibitory receptors recognizing normal, self-encoded MHC class I molecules. Subfamilies of NK receptors undergo rapid evolution, and appear to co-evolve with the MHC. We here review present views on the evolution and function of NK cell receptors, with an emphasis on knowledge gained in cattle and rodents.

KLRE/I1 and KLRE/I2: a novel pair of heterodimeric receptors that inversely regulate NK cell cytotoxicity

NK cells identify infected, neoplastic, or MHC-disparate target cells via several different receptors. The NK cell receptor KLRE1 lacks known signaling motifs but has nevertheless been shown to regulate NK cell-mediated cytotoxicity. Here we demonstrate that KLRE1 forms functional heterodimers with either KLRI1 or KLRI2. Cotransfection with KLRE1 was necessary for surface expression of the NK cell receptor chains KLRI1 and KLRI2 in 293T cells. Moreover, KLRE1 can be coimmunoprecipitated with KLRI1 or KLRI2 from transfected NK cell lines. By flow cytometry, KLRE1 and KLRI1 showed colinear expression on NK cells, suggesting surface expression as heterodimers. Unlike other killer cell lectin-like receptors, KLRE1/KLRI1 and KLRE1/KLRI2 heterodimers predominantly migrated as single chains in SDS-PAGE, indicating noncovalent association. KLRI1 was coimmunoprecipitated with the tyrosine phosphatase Src homology region 2 domain-containing phosphatase 1. In accordance with an inhibitory function, anti-HA Ab induced reduced killing of FcR-bearing targets by KLRI1-HA-transfected NK cell lines in a redirected cytotoxicity assay. Reciprocally, KLRI2-HA transfectants displayed increased killing in this assay. Finally, Ab to KLRE1 induced inhibition in KLRI1-transfected cells but increased cytotoxicity in KLRI2 transfectants, demonstrating that KLRE/I1 is a functional inhibitory heterodimer in NK cells, whereas KLRE/I2 is an activating heterodimeric receptor.

Molecular cloning of LILRC1 and LILRC2 in the mouse and the rat, two novel immunoglobulin-like receptors encoded by the leukocyte receptor gene complex

We report the molecular cloning of two novel single-member receptor families with homology to LILR/CD85, PIR, and gp49: LILRC1 in the rat and the mouse, and LILRC2 in the rat. LILRC1 and LILRC2 both have two extracellular Ig-like domains and a cytoplasmic tail devoid of any known signaling motifs. The transmembrane regions of LILRC1 and LILRC2 contain an arginine residue, a common feature in receptors that associate with activating adaptor proteins. Rat and mouse LILRC1 are orthologs sharing 81.5% amino acid identity. LILRC2 represents a distinct receptor family, 47.9% identical to LILRC1. No murine LILRC2 ortholog was detected in genome or expressed sequence tag sequence databases. By radiation hybrid mapping, the rat Lilrc1 and Lilrc2 loci were localized to the leukocyte receptor gene complex (LRC) on chromosome 1, and the mouse Lilrc1 locus was mapped to the LRC on chromosome 7. Moreover, the mouse and rat Lilrc1 loci were localized to similar positions within the LRC. As shown by RT-PCR, rat LILRC1 was expressed by B cells, neutrophils, and a macrophage cell line. Transcription of LILRC2 was detected in T cells, B cells, neutrophils, and macrophages.

The rat orthologue to the inhibitory receptor gp49B is expressed by neutrophils and monocytes, but not by NK cells or mast cells

Mouse gp49B is a member of the leukocyte immunoglobulin-like receptor family. It is constitutively expressed by mast cells and certain myeloid cells, and expression can be induced on natural killer (NK) cells and T cells. We have cloned several rat cDNA, 78% identical to mouse gp49B at the amino acid level, that represent the rat orthologue to mouse gp49B. A mouse monoclonal antibody (WEN29) against rat gp49B was generated. By flow cytometry and Northern blot analysis, gp49B was found to be expressed by neutrophils and monocytes, but not NK cells (primary or IL-2-activated), T cells (resting or concanavalin A-stimulated) or peritoneal mast cells. Following pervanadate treatment, the tyrosine phosphatase SHP-1 was co-immunoprecipitated with gp49B in the macrophage cell line R2. In glutathione S-transferase pull-down experiments, the cytoplasmic tail of rat gp49B associated with the SH2 domains of both SHP-1 and SHP-2, dependent on intact and phosphorylated immunoreceptor tyrosine-based inhibition motifs (ITIM). Compared to mouse, the cytoplasmic domain of rat gp49B contains a third ITIM-like sequence (YLYASV) that was phosphorylated by several Src family tyrosine kinases, enhanced the phosphorylation of other ITIM, and bound to the SH2 domains of SHP-2, suggesting a role in the recruitment of downstream phosphatases.

The genes and gene organization of the Ly49 region of the rat natural killer cell gene complex

We here report the cDNA sequences of 11 new rat Ly49 genes with full and three with incomplete open reading frames. Although obtained from different inbred rat strains, these as well as six previously published cDNA represent non-allelic genes matching different loci in the Brown Norway (BN) rat genome, which is predicted to contain 34 Ly49 loci distributed over the distal part of the NK cell gene complex. Some of the cloned genes appear to be mutated to non-function in the BN genome, which harbors additional genes with full open reading frames, suggesting at least 26 non-allelic functional Ly49 genes in the rat. Of the encoded receptors, 13 are predicted to be inhibitory, eight to be activating, whereas five may be both ('bifunctional'). Phylogenetic analysis bears evidence of a highly dynamic genetic region, in which only the most distally localized Ly49 gene has a clear-cut mouse ortholog. In phylograms, the majority of the genes cluster into three subgroups with the genes mapping together, defining three chromosomal regions that seem to have undergone recent expansions. When comparing the lectin-like domains, the receptors form smaller subgroups, most containing at least one inhibitory and one activating or 'bifunctional' receptor, where close sequence similarities suggest recent homogenization events.

Molecular cloning of KLRI1 and KLRI2, a novel pair of lectin-like natural killer-cell receptors with opposing signalling motifs

We here report the molecular cloning of a novel family of killer-cell lectin-like (KLR) receptors in the rat and the mouse, termed KLRI. In both species, there are two members, KLRI1 and KLRI2. While the extracellular lectin-like domains of KLRI1 and KLRI2 are similar [74% (rat) and 83% (mouse) amino acid identity], they differ intracellularly. KLRI1 has two immunoreceptor tyrosine-based inhibition motifs (ITIMs) in the cytoplasmic domain, suggesting an inhibitory function. KLRI2 has no ITIM, but a positively charged lysine residue in the transmembrane region, suggesting association with activating adapter molecules. Klri1 and Klri2 are localized within the natural killer (NK) cell gene complex on rat chromosome 4 and mouse chromosome 6. By RT-PCR and Northern blot analysis KLRI1 and KLRI2 were selectively expressed by NK cells in both rat and mouse. Epitope-tagged expression constructs of rat KLRI1 and rat KLRI2 induced surface expression of a nondisulphide-linked protein of M(r) 36,000/39,000 and M(r) 34,000, respectively.

Identification of lectin-like receptors expressed by antigen presenting cells and neutrophils and their mapping to a novel gene complex

In an experimental rat model, we recently mapped an arthritis susceptibility locus to the distal part of Chromosome 4 containing genes predicted to encode C-type lectin superfamily (CLSF) receptors. Here we report the cDNA cloning and positional arrangement of these receptor genes, which represent rat orthologues to human Mincle and DCIR and to mouse MCL and Dectin-2, as well as four novel receptors DCIR2, DCIR3, DCIR4 and DCAR1, not previously reported in other species. We furthermore report the cDNA cloning of human Dectin-2 and MCL, and of the mouse orthologues to the novel rat receptors. Similar to the killer-cell lectin-like receptors (KLR) some of these receptors exhibit structural features suggesting that they regulate leukocyte reactivity; e.g., human DCIR and rodent DCIR1 and DCIR2 carry an immunoreceptor tyrosine-based inhibitory motif (ITIM), predicting inhibitory function, and conversely, in all three species Mincle has a positively charged amino acid in the transmembrane region, suggesting activating function. Sequence comparisons show that the receptors form a discrete family, more closely related to group II CLSF receptors than to the group V KLR. Their distance to the KLR is underscored by their preservation of evolutionary conserved calcium/saccharide binding residues, present in group II and lacking in group V CLSF and their cellular expression patterns, with most of the genes preferentially expressed by professional antigen-presenting cells (dendritic cells, macrophages and B cells) and neutrophils. In all three species, the genes map together, forming an evolutionary conserved gene complex, which we call the antigen presenting lectin-like receptor complex (APLEC).

Rat NKp46 activates natural killer cell cytotoxicity and is associated with FcepsilonRIgamma and CD3zeta

NKp46 has been identified in the human, rat, mouse, monkey, and cattle. We have generated a monoclonal antibody, WEN23, against rat NKp46. By flow cytometry, NKp46 is expressed by all natural killer (NK) cells but not by T cells, B cells, granulocytes, monocytes, dendritic cells, or macrophages. Thus, NKp46/WEN23 is the first NK cell-specific marker in the rat. In a redirected lysis assay, preincubation of the effector cells with WEN23 augmented lysis of the Fc receptor (FcR)+ murine tumor target cells, indicating that NKp46 is an activating NK cell receptor. Moreover, preincubation of the effector cells with WEN23 F(ab')2 fragments reduced killing of target cells, confirming the activating function of NKp46 and indicating that the mouse tumor target cells express a ligand for rat NKp46. Lysis of FcR- mouse and human tumor target cells was reduced after incubation of effector cells with WEN23, suggesting that rat NKp46 recognizes a ligand that is conserved between primates and rodents. By Western blot and immunoprecipitation using WEN23, NKp46 is expressed as a monomer of approximately 47 kDa in interleukin-2-activated NK cells. The immunoreceptor tyrosine-based activation motif bearing adaptor proteins CD3zeta and the gamma chain of FcRI for IgE (FcepsilonRIgamma) with NKp46 from lysates of NK cells, indicating that rat NKp46 activates NK cell cytotoxicity by similar pathways as CD16.

Cutting edge: molecular cloning of a killer cell Ig-like receptor in the mouse and rat

We report the molecular cloning of a KIR3DL1 receptor in the mouse and the rat, between 37.4 and 45.4% identical with primate killer cell Ig-like receptors (KIRs/CD158). Both mouse and rat molecules contain a pair of immunoreceptor tyrosine-based inhibition motifs in their cytoplasmic regions, suggesting an inhibitory function. Southern blot analysis indicated a single KIR gene in the rat, whereas the mouse genome contains more than one KIR-related element. The rat Kir3dl1 locus was mapped to the leukocyte receptor gene complex on chromosome 1, whereas mouse Kir3dl1 was localized to the X chromosome. RT-PCR demonstrated that KIR3DL1 was selectively expressed by NK cells in both rat and mouse. An epitope-tagged expression construct of mouse KIR3DL1 transfected into 293T cells induced expression of a approximately 55-kDa protein. Our data indicate that KIR receptors may contribute to the NK cell receptor repertoire in rodents, alongside the Ly-49 family.

A comparison study on the effects of prewarming patients in the outpatient surgery setting

Maintenance of core body temperature in surgical patients presents a challenge to perioperative nurses. Core temperatures less than 36 degrees C are associated with multiple adverse outcomes postoperatively. Internal redistribution of heat from the body core to the colder periphery results in core temperature decreases of 0.5 degrees C to 1.5 degrees C in the first 30 minutes after induction of anesthesia. The purpose of this study was to determine if there was a difference in arrival temperatures to the PACU between surgical patients who had been warmed preoperatively with a forced warm air blanket and those patients warmed with cotton blankets. One hundred patients were randomly assigned to receive prewarming by using a forced-air warm blanket (n = 50) or a cotton blanket (n = 50). Temperatures were monitored every 15 minutes throughout the preoperative and postoperative periods. Patients in the forced warm air group had significantly higher temperatures on arrival to the PACU from the OR than did patients in the warm blanket group (P =.000). Patients in the forced warm air group exhibited a change in temperature of 0.0067 degrees C (+/-.52) compared with a decrease of 0.22 degrees C (+/-.48) for patients in the control group.

The Escherichia coli SeqA protein binds specifically to two sites in fully and hemimethylated oriC and has the capacity to inhibit DNA replication and affect chromosome topology

The SeqA protein was identified as a factor that prevents reinitiation of newly replicated, hemimethylated origins. SeqA also seems to inhibit initiation of fully methylated origins, thus contributing to the regulation of chromosomal replication. The SeqA protein was found to bind to two sites in the left part of the origin, near the AT-rich region where strand separation takes place during initiation of replication. The same binding sites seemed to be preferred irrespective of whether the origin was in the newly replicated (hemimethylated) state or not. In addition to binding specifically to groups of GATC sites, the SeqA protein was capable of interacting non-specifically with negatively supercoiled DNA, restraining the supercoils in a fashion similar to that seen with histone-like protein HU. The restraint of supercoils by SeqA was, in contrast to that of HU, cooperative.

NILR-1, a novel immunoglobulin-like receptor expressed by neutrophilic granulocytes, is encoded by a leukocyte receptor gene complex on rat chromosome 1

Several receptors expressed by subsets of leukocytes and with sequence homology to the killer cell inhibitory receptors have recently been identified both in man and mouse. Here we describe a rat cDNA that encodes a novel receptor of this group, designated neutrophil immunoglobulin-like receptor-1 (NILR-1). The predicted 58.7-kDa mature NILR-1 protein is a type I integral membrane protein, with three C2-type immunoglobulin superfamily domains, a transmembrane region devoid of charged amino acids, and a cytoplasmic tail containing four immunoreceptor tyrosine-based inhibition motif-like regions. NILR-1 shows greatest sequence homology to the mouse paired immunoglobulin-like receptor-B and members of the human leukocyte immunoglobulin-like receptor/immunoglobulin-like transcript group of receptors. As shown by Northern blot analysis, NILR-1 was transcribed by neutrophilic granulocytes. Although weaker transcription was found with a macrophage cell line, no signal was detected with peritoneal macrophage or spleen RNA. Linkage analysis localized Nilr1 to chromosome 1, closely linked to a locus encoding a rat NKp46 orthologue. The two loci define a rat leukocyte receptor gene complex, in a region syntenic to human chromosome 19q13.4 and the proximal part of mouse chromosome 7, that harbors the human and mouse leukocyte receptor gene complexes.

Contact activation factors in plasma from women on estrogen replacement therapy after ovariohysterectomy

The plasma levels of factor XII, prekallikrein, factor XI, and high molecular weight kininogen were studied in women with bilateral oophorectomy and hysterectomy who received hormone replacement therapy with a 2 mg daily dose of estradiol valerate. Also plasminogen activator activity was investigated. The observations made provide support for the assumption that the low doses of estrogen used in hormone replacement therapy do not significantly affect the levels of contact activation or fibrinolytic factors in plasma. Plasma obtained from young, healthy women was used as a standard reference material. Significantly higher levels of factor XII and prekallikrein were registered in functional tests in the ectomized women than in the reference material, an increase not observed in the immunological assays. These observations are discussed in light of recently published data from our laboratory on an increase in the measured level of factor XII obtained upon the removal of IgG before assay. Also a marked increase in urokinase activity was registered in the ectomized women. The high levels of factor XII, prekallikrein, and urokinase, as compared with the reference material, seemed to be age dependent, being also observed in a group of naturally postmenopausal women.

Constant temperature monitoring: a study of temperature patterns in the postanesthesia care unit

Patients admitted to the PACU from the operating room exhibit fluctuations in core body temperature during the course of their stay in the PACU. Some patients present with normothermia and experience temperature decreases later in their stay. PACU policy does not dictate that temperatures be measured at a predetermined frequency in the absence of hypothermia; thus, it is possible that hypothermia may not be detected at its onset. The major purpose of this study was to describe the core body temperature patterns of postsurgical patients during the PACU stay. Secondary objectives were to (1) identify at which point in time patients become hypothermic and (2) describe length of stay in patients who develop hypothermia. Hypothermia was defined as a core tympanic temperature of less than 35.5 degrees C. A descriptive design was used using a convenience sample of 150 elective surgical patients over the age of 1 month who were normothermic on admission to the PACU. Data were analyzed using descriptive statistics. Concurrent tympanic and continuous axillary temperatures were monitored for comparison and trend monitoring. Temperatures showed clinically significant decreases into the hypothermic range (< 35.5 degrees C). Fifty-seven percent of the sample (n = 86) had temperatures that dropped after PACU admission and another 13% fell below 35.5 degrees C. Hypothermia occurred within the first 15 minutes of the PACU stay. The average length of stay for those that developed hypothermia was 1.83 hours. Monitoring temperatures more frequently will result in detecting hypothermia at its onset. Nurses may use the axillary device as a trend for continuous monitoring. Length of stay may be shortened if temperature management is embraced by the PACU nurse.

Identification of a human member of the Ly-49 multigene family

Three classes of multigene family-encoded receptors enable NK cells to discriminate between polymorphic MHC class I molecules: Ly-49 homodimers, CD94/NKG2 heterodimers and the killer cell inhibitory receptors (KIR). Of these, CD94/NKG2 has been characterized in both rodents and humans. In contrast, Ly-49 family members have hitherto been found only in rodents, and KIR molecules only in the human. In this report, we describe a human cDNA, termed Ly-49L, that constitutes the first human member of the Ly-49 multi-gene family. Compared with rodent Ly-49 molecules, the Ly-49L sequence contains a premature stop codon and predicts a truncated protein that lacks the distal part of a C-terminal lectin domain. Evidence is presented that the premature stop codon results from incomplete excision of the intron between the first two lectin domain exons. Splice variants predicting a full-size Ly-49L protein were not detected. As demonstrated by Northern blot analysis, Ly-49L was transcribed by IL-2-activated NK cells, but not by freshly isolated B or T cells. PCR screening of a 22-clone yeast artificial chromosome contig localized the LY49L locus to the human NK gene complex on chromosome 12p12-p13. Southern blot analysis of genomic DNA showed a simple pattern with a full-length Ly-49L probe at low stringency hybridization conditions, suggesting that Ly-49L may be the only human member of the Ly-49 multigene family.

Molecular characterization of rat NKR-P2, a lectin-like receptor expressed by NK cells and resting T cells

The gene for a rat NK lectin-like receptor (NKLLR), named NKR-P2, has been cloned and characterized. Sequence analysis shows that it represents the orthologue of human NKG2D and that the two molecules form a distinct NKLLR family, no more related to NKG2A/B, -C or -E than to other NKLLR families. Nkrp2 is a single-copy gene containing seven introns, mapping to the rat NK gene complex. Rat NKR-P2 differs from the human orthologue in that its cytoplasmic tail contains 13 additional amino acids, encoded by a separate exon. Splice variants lacking this exon were not detected in T cells or NK cells. NKR-P2 is strongly expressed by NK cells. In contrast to other NKLLR, it is also strongly expressed by resting thoracic duct CD4+ and CD8+ T cells, but not by thymocytes or other hemopoietic cells.

Two genes in the rat homologous to human NKG2

Two different lectin-like receptors for MHC class I molecules have so far been identified on natural killer (NK) cells, the Ly-49 homodimeric receptors in mice and the NKG2/CD94 heterodimeric receptors in humans. The recent identification of a rat CD94 orthologue implied that NK cell receptors equivalent to NKG2/CD94 also exist in rodents. Here we describe the cDNA cloning of two rat genes homologous to members of the human NKG2 multigene family. The deduced rat NKG2A protein contains a cytoplasmic immunoreceptor tyrosine-based inhibition motif (ITIM), whereas the cytoplasmic tail of rat NKG2C lacks ITIM. The genes map to the rat NK gene complex and are selectively expressed by NK cells. The expression is strain dependent, with high expression in DA and low in PVG NK cells, correlating with the expression of rat CD94. Ly-49 genes have previously been identified in the rat, and the existence of rat NKG2 genes in addition to a CD94 orthologue suggests that NK cell populations utilize different C-type lectin receptors for MHC class I molecules in parallel.

Molecular characterization of a gene in the rat homologous to human CD94

Three classes of major histocompatibility (MHC) class I binding receptors on natural killer (NK) cells have so far been described: CD94/NKG2 heterodimeric receptors and killer cell inhibitory receptors in the human, and Ly-49 homodimers in rodents. CD94, NKG2 and Ly-49 belong to the C-type lectin superfamily. As yet, CD94 and NKG2 molecules have not been detected in rodents or Ly-49 in humans. It has therefore been proposed that the two receptors represent functional equivalents in these species. The present study describes the cDNA cloning of a novel rat gene encoding a protein of 179 amino acids, 54.2% identical to human CD94. The single-copy Cd94 gene is localized to the rat NK gene complex (NKC), within 50 kb from Nkrp2, between the Nkrp1 and Ly49 gene clusters. By Northern blot analysis, we showed that rat CD94 is selectively expressed by NK cells and a small subset of T cells, similar to the human orthologue. This expression is strain dependent, with high expression in DA NK cells and low in PVG NK cells. Evidence is presented that this difference is not due to receptor repertoire shaping by MHC-encoded ligands, but is controlled by genetic elements residing within the NKC. The identification of a rat CD94 orthologue suggests that NK cell populations utilize two different C-type lectin receptors for MHC class I molecules in parallel.

Urokinase and non-urokinase fibrinolytic activity in protease-inhibitor-deprived plasma, assayed by a fibrin micro-plate method

In the classical fibrin-plate assay, fibrinolytic activity is determined by measuring the area of the lysis zone formed when sample is applied on a planar fibrin gel. However, this method is characterized by low capacity and uncertainty in the determination of the lysis zones. To overcome these limitations an assay modified for microtiter plates was developed. Fibrin clots, with a suitable dye incorporated, were formed in wells of standard high adsorbtion microtiter plates. Each plate contained a serial dilution of urokinase as standard. Citrated test plasmas were treated with acetone to remove inhibitors before applied to the wells. The lyzate formed after appropriate incubation was removed, and the remaining volume of fibrin photometrically determined after being completely dissolved by plasmin. The fibrinolytic activity was determined as the difference in absorption before and after lysis. This is an accurate and relatively simple method for the assessment of urokinase and non-urokinase fibrinolytic activity in plasma. It is further a sensitive and quantitative fibrinolytic micro-technique with a high capacity.

An autosomal dominant locus, Nka, mapping to the Ly-49 region of a rat natural killer (NK) gene complex, controls NK cell lysis of allogeneic lymphocytes

Natural Killer (NK) cells can recognize and kill MHC-incompatible normal bone marrow-derived cells. Presently characterized MHC-binding receptors on NK cells, including the Ly-49 family in the mouse, transmit inhibitory signals upon binding to cognate class I MHC ligands. Here we study in vivo NK-mediated lysis of normal allogeneic lymphocytes in crosses between alloreactivity-competent PVG rats and alloreactivity-deficient DA rats. NK cells from both strains are able to lyse standard tumor targets. We identify an autosomal dominant locus, Nka, that controls NK-mediated alloreactivity. Individuals carrying the dominant PVG allele in single dose were fully competent in eliminating allogeneic target cells, suggesting that Nka encodes or regulates a gene product inducing or activating alloreactivity. By linkage analysis and pulsed field gel electrophoresis, a natural killer gene complex (NKC) on rat chromosome 4 is described that contains the rat NKR-P1 and Ly-49 multigene families plus a rat NKG2D homologue. Nka maps within the NKC, together with the most telomeric Ly-49 family members, but separate from NKG2D and the NKR-P1 family. The Nka-encoded response, moreover, correlates with the expression of transcripts for Ly-49 receptors in NK cell populations, as Northern blot analysis demonstrated low expression of Ly-49 genes in DA NK cells, in contrast to high expression in alloreactivity-competent PVG, (DA X PVG)F1, and PVG.1AVI NK cells. The low Ly-49 expression in DA is not induced by MHC haplotype, as demonstrated by high expression of Ly-49 in the DA MHC-congenic PVG.1AVI strain. Finally, we have cloned and characterized the first four members of the rat Ly-49 gene family. Their cytoplasmic domains demonstrate substantial heterogeneity, consistent with the hypothesis that different Ly-49 family members may subserve different signaling functions.

Dendritic leucocytes pulsed with monoclonal antibody-hapten conjugates elicit vigorous primary humoral responses in vivo

Purified dendritic leucocytes (DL) were pulsed briefly in vitro with haptenated monoclonal antibodies (MoAb) to MHC class II and immediately injected i.v. into syngeneic recipients. Strong anti-hapten humoral responses were observed even though only a few picomoles of specific MoAb-hapten conjugates were injected with the DL. In contrast, DL pulsed with control conjugates, i.e. haptenated non-binding MoAbs, gave only weak responses. DL thus, can take up, process and present protein antigens even after brief exposure in vitro, and their immunogenicity is enhanced by pulsing with antigen conjugated to specific MoAbs. Furthermore, in the presence of fetal calf serum (FCS), but not normal rat serum, the control MoAb W6/32 (against human MHC class I) bound to DL. The vigorous primary humoral response achieved following this pulsing indicates that it is the binding and the corresponding increased uptake that enhances the immunogenicity of the DL.

Expression of CD43 epitopes on NK and T cells

CD43 epitope expression was studied with a panel of monoclonal antibodies (MoAbs) by immunohistochemistry on freeze sections of lymphoid tissues. The MoAb WEN3 stained most cells weakly in the T areas and scattered splenic red pulp cells strongly, whereas the other MoAbs strongly stained the majority of the cells in the T areas but gave variable staining patterns of cells in the non-T areas. Flow cytometry on CD4+ and CD8+ T cells (T4 and T8 cells), freshly isolated NK cells and LAK cells showed distinct staining profiles for each cell type, with epitope expression patterns of T8 cells lying between those of T4 cells and NK/LAK cells. T8 cells were split by one of the MoAbs, the NK cells, but not LAK cells, were split by two other MoAbs.

Contact factors in plasma from women on oral contraception--significance of factor XI for the measured activity of factor XII

The plasma levels of contact activation factors were measured in women using a low estrogen dose oral contraceptive (OC). Basic values for factor XII (FXII), factor XI (FXI), prekallikrein (PK), and high molecular weight kininogen (HK) were obtained in immunoassays by comparing with control plasma. The plasma levels of FXII and PK were significantly increased in OC plasma, to 147% and 146% respectively, whereas no significant increase could be registered for FXI (106%) or for HK (107%). Functional assays carried out with different peptide substrates (S-2222 for FXIIa, and S-2222, S-2302 and Bz-Pro-Phe-Arg-pNA for kallikrein) showed increases in OC plasma to about 150% for both proteases, in accordance with results obtained in radial immunodiffusion (RID). However, when FXIIa was measured with the high molecular weight substrate PK, no significant increase could be registered. Further experiments suggested this result to be due to the low level of FXI present in OC plasma, as compared to the levels of FXII and PK. Assays were carried out in mixtures of test plasma (OC or control plasma) and plasma deficient in FXI or FXII. The results obtained suggested that FXIa was present in some kind of association with part of FXIIa and part of kallikrein present. At low concentrations of FXI the functional activity of FXIIa was reduced, and the assay data indicated that an appropriate level of FXI was required to obtain maximum rate of hydrolysis of prekallikrein by FXIIa.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparing macrophages and dendritic leukocytes as antigen-presenting cells for humoral responses in vivo by antigen targeting

Immunotargeting is a novel technique whereby antigen is directed against antigen-presenting cells (APC) by conjugation to specific monoclonal antibodies (mAb). In this study we have employed the technique to investigate the efficiency of macrophages as APC compared with constitutively major histocompatibility complex (MHC) class II-positive cells, i.e. dendritic leukocytes and B cells, in vivo. We first studied the organ retention of the radiolabeled conjugates by gamma counting, and their distribution within the draining lymph nodes by autoradiography. We could confirm that the conjugates reached the cells at which they were aimed. We then measured primary and secondary humoral responses. The results confirmed previous findings that targeting with mAb against MHC class II, i.e. to dendritic leukocytes, strongly enhanced the primary humoral response. In contrast, anti-IgD conjugates, directed against B cells gave only weak primary responses. Although conjugates directed against macrophages were retained for a longer time than the other conjugates, the primary humoral response was virtually abolished. The secondary responses, however, were at least as strong as those obtained in animals primed with control conjugates, whereas animals primed with anti-MHC class II conjugates showed little if any amplification of the secondary response. The discrepancies between the various conjugates could not be ascribed to TH1 versus TH2 responses as IgG1, IgG2a, IgG2b and IgE titers all co-varied in single animals. A possible explanation for the observed results is that macrophages fail to induce cytokine production for terminal differentiation of B cells to plasma cells, whereas conversely, upon presentation by dendritic leukocytes most stimulated B cells mature to plasma cells, leaving less progeny for immunological memory.

Targeting antigens to antigen presenting cells

Antigen may be targeted to antigen presenting cells (APC) by conjugating the antigen to monoclonal antibodies directed against surface molecules on APC. By now several laboratories have shown that immunotargeting enhances humoral responses, depending upon the targeted ligand or cell type, with low doses of antigen and without the use of adjuvants. There is also preliminary evidence that the method may be used to bias immune responses in desired directions, possibly also to induce tolerance. In addition to its use as an experimental tool for exploring immune reactions the method could in the future also be clinically important, e.g. in vaccination. In this article we give a brief account on work so far published with this novel method and discuss possible mechanisms behind its immunopotentiating effects.

Antigen targetting with monoclonal antibodies as vectors--II. Further evidence that conjugation of antigen to specific monoclonal antibodies enhances uptake by antigen presenting cells

Immunization of rats with haptenized monoclonal antibodies (mAbs) against accessory cells enhances anti-hapten antibody responses. To see whether the mAb-conjugates really targetted the antigen (hapten) to the antigen presenting cells, we have investigated the lymph node distribution of locally injected radiolabelled conjugates. Compared with control conjugates, i.e. haptenized non-binding mAbs, a much larger proportion of the specific conjugates were retained in the draining lymph nodes. Whereas control conjugates were rapidly phagocytosed and degraded by macrophages, the specific conjugates were associated with the targetted accessory cells, which were radiolabelled for extended periods. Haptenated MRC OX6 (anti-MHC class II) gave strong labelling of interdigitating cells (IDC) in the paracortex with 70% of IDC still labelled by 4 days and 15% by 16 days following injection. By Western blots intact OX6 conjugates were still detected in the draining lymph node as long as 3 days after injections, whereas control conjugates were hardly detectable even by 24 h. The findings substantiate the idea that mAbs can be exploited for vectorial transport of antigens to accessory cells.

Allospecific recognition of hemic cells in vitro by natural killer cells from athymic rats: evidence that allodeterminants coded for by single major histocompatibility complex haplotypes are recognized

We have previously shown that large granular lymphocyte (LGL)-enriched cell populations have the capacity to spontaneously recognize and kill allogeneic small lymphocytes and bone marrow cells (BMC) in vitro in certain strain combinations of rats. Here, we have studied the alloreactivity of natural killer (NK) cells from PVG nude (RT1c) rats against a panel of major histocompatibility complex (MHC) incompatible hemic cells. Both lymphocytes and BMC from the AO (RT1u), DA (RT1a), BN (RT1n) as well as the MHC-congenic PVG-RT1u (RT1u) rat strains were efficiently killed in vitro, whereas cells from syngeneic PVG rats were spared. The structures recognized on lymphocytes and BMC were probably similar since the two cell populations inhibited each other in cross-competition experiments. A number of features aligned the alloreactive effector cells with NK cells and not T cells. (a) Only about 5% of the effector cells from nude spleens expressed the T cell antigens CD3, CD5 or T cell receptor (TcR) alpha/beta whereas greater than 50% of the cells expressed markers present on NK cells (CD2, CD8, OX52 and the rat NK cell-specific marker NKR-P1 recognized by the monoclonal antibody 3.2.3). (b) The alloreactive cells were granular since pretreatment of nude spleen cells with the lysosomotropic agent L-leucine methyl ester which eliminated LGL, simultaneously abolished the cytolysis of both allogeneic lymphocytes and YAC-1 tumor cells. (c) Nude spleen cells stimulated with human recombinant interleukin 2 for 1 week in vitro generated large granular proliferating cells which were CD3-, CD5-, TcR alpha/beta-, but greater than 95% 3.2.3+. These cells efficiently killed allogeneic hemic cells from the same rat strains as did freshly isolated effector cells. (d) The cytolysis of allogeneic hemic cells could effectively be inhibited with unlabelled NK-sensitive (YAC-1 and K-562), but not NK-resistant (Roser leukemia) tumor cells. Cross-competition studies showed that PVG nude NK cells discriminated between AO, BN and DA BMC, suggesting that different alloantigens were positively recognized by subsets of NK cells. The mode of inheritance of the allodeterminant specifically recognized on AO BMC was investigated in crosses and backcrosses between AO and BN or DA rats. A gene dosage effect was observed in that this determinant was expressed at a slightly reduced level in F1 hybrids.(ABSTRACT TRUNCATED AT 250 WORDS)

Anaemia in elderly patients. Incidence and causes of low haemoglobin concentration in a city general practice

Haemoglobin concentration was determined in all patients (530) over 70 years of age in a general practice in Oslo during an eight month period. 72 had anaemia and were investigated further. Iron deficiency was found in 13 patients and was most often caused by gastrointestinal blood loss. Chronic diseases, particularly chronic infections and rheumatoid arthritis, were responsible for anaemia in 34 patients. Renal failure caused anaemia in 14 patients. In 10 patients we found no explanation for the anaemia. Nine patients with a previously undiscovered disease were found, six of whom could be offered some kind of treatment. We conclude that anaemia in elderly patients in general practice is often caused by chronic diseases. The main cause of iron deficiency is blood loss, and routine prescription of iron is not justified in this age group. The therapeutic benefit from routine measurement of haemoglobin concentration is small and the test should be used selectively.

The MRC OX-47 antigen is a member of the immunoglobulin superfamily with an unusual transmembrane sequence

The MRC OX-47 monoclonal antibody recognizes a membrane antigen present at low levels on many lymphocytes but whose expression is markedly increased on activation with mitogens. cDNA clones for the OX-47 antigen were isolated from an expression library and the protein sequence deduced. It contains a leader sequence giving a mature protein of 251 amino acids with a single putative transmembrane region, a cytoplasmic domain of 40 amino acids and an extracellular domain of 187 amino acids that contained two immunoglobulin-like domains. The putative transmembrane sequence includes a glutamic acid residue within the hydrophobic sequence. The presence of acidic residues within the hydrophobic sequence of transmembrane sequences usually indicates association with other polypeptides and this is predicted for the OX-47 antigen. A sequence of 37 amino acids that included all the transmembrane region was identical to that of the chicken HT7 antigen present on endothelium in brain and erythroblasts. The level of protein sequence identity in the Ig-like domains was lower but HT7 is almost certainly the chicken homologue of the rat OX-47 antigen. The ligand and function of the molecule are unknown. In addition to lymphoblasts the OX-47 antigen was localized on a variety of other cell types including various immature cells, endothelia and cells with excitable membranes.

Contact activation factors in plasma from pregnant women--increased level of an association between factor XII and kallikrein

The plasma levels of FXII, prekallikrein (PK), and high- and low molecular weight kininogens (HK and LK) were studied in pregnant women in the last trimester and in non-pregnant controls. FXIIa and plasma kallikrein were assayed in acetone-treated citrated plasma (CPLa) with the tetrapeptide S-2222 as substrate, using soybean trypsin inhibitor and corn inhibitor to exclude kallikrein and FXIIa respectively. No difference in PK-level could be registered for the two kinds of plasma, but the level of FXII had increased to about 150% in the pregnancy plasma. No difference in HK-level was observed, whereas the LK-level was significantly higher in pregnancy plasma, about 250% and 160% in rocket immunoassay and bioassay respectively. In fractions from gel filtration of plasma acetone-activated in the presence of benzamidine (BPLa), kallikrein was assayed as S-2302 amidase, HK and LK were measured in rocket immunoassay, and HK and FXII were studied in PAGE immunoblot experiments. In contrast to previous results obtained upon gel filtration of CPLa, not only kallikrein and HK, but in addition also FXII now appeared together in the same fractions and as two separate peaks. One peak eluting in early fractions (gel mol. wt. 300-400 KD), and one late eluting peak of proteins adsorbed to the gel material. The first peak was notably marked in pregnancy plasma. The results provide support for the assumption of an association in plasma between the three contact activation factors studied.