Interaction among hepatocyte-stimulating factors, interleukin 1, and glucocorticoids for regulation of acute phase plasma proteins in human hepatoma (HepG2) cells

Human hepatoma (HepG2) cells respond to unfractionated conditioned media of human squamous carcinoma (COLO-16) cells and lipopolysaccharide-stimulated human peripheral blood monocytes by increasing the synthesis of alpha 1-acid glycoprotein, haptoglobin, complement C3, alpha 1-antichymotrypsin, alpha 1-antitrypsin, and fibrinogen, while decreasing the synthesis of albumin. The regulation of the acute phase proteins is mediated by hepatocyte-stimulating factors (HSF) and interleukin 1 (IL-1) present in the conditioned medium. Purified HSF-I from COLO-16 cells stimulates preferentially alpha 1-acid glycoprotein synthesis, whereas COLO-HSF-II stimulates preferentially the synthesis of haptoglobin, fibrinogen, and alpha 1-antitrypsin. HSF from monocytes, which has been identified as interferon-beta 2 (B cell stimulating factor-2), displayed the same activity as COLO-HSF-II. Dexamethasone alone had no effect on acute phase plasma protein synthesis but enhanced the response to various HSF severalfold. IL-1 had a relatively low stimulatory activity on the synthesis of alpha 1-acid glycoprotein, haptoglobin, and alpha 1-antichymotrypsin but strongly reduced the basal expression of fibrinogen. The only synergistic action between IL-1 and HSF (or interferon-beta 2) was noted for the synthesis of alpha 1-acid glycoprotein. Tumor necrosis factor active on other hepatic cells failed to modulate significantly the expression of any plasma proteins in HepG2 cells. These studies showed that for an optimal HepG2-cell response a combination of HSF (or interferon-beta 2), IL-1, and dexamethasone is needed. This finding might indicate the identity of some of those hormones involved in regulation of the hepatic acute phase response in vivo.     

Plasma levels of immunoreactive ceruloplasmin and other acute phase proteins during lactation

Lactation elevates plasma copper as well as oxidase activity levels of the copper-containing, acute phase protein ceruloplasmin (Cp). The present study provides an initial inquiry into the mechanisms behind these changes. Plasma obtained from 12 lactating women, 1 month postpartum, displayed a greater percentage increase in immunoreactive Cp levels (mean increase = 89%) than in plasma copper (mean = 66%) or Cp oxidase activity (mean = 42%). Lactation did not increase plasma content of C-reactive protein or alpha 1-antitrypsin but significantly elevated haptoglobin concentrations. Plasma alpha 2-macroglobulin contents correlated with immunoreactive Cp levels in lactating women but not in controls. These results strengthen the hypothesis that plasma content of individual acute phase proteins is regulated by both overlapping and individualized processes. In addition, the present findings raise the possibility that lactation increases both Cp synthesis and plasma turnover time of Cp-bound copper.     

Effect of source of supplemental selenium on uterine health and embryo quality in high-producing dairy cows

Lactating Holstein cows (n = 135) were randomly assigned to one of the two sources of supplemental selenium (Se), sodium selenite (SS) or Se yeast (SY), fed at 0.3 mg/kg diet dry matter from 25 d before calving to 70 d in milk (DIM), in diets not suboptimal in basal Se concentrations. Cows were evaluated for health daily in the first 10 DIM, and uterine cytology of the previously gravid uterine horn was assessed at 30 DIM. The Ovsynch protocol was initiated at 42 DIM; ovarian responses to hormonal treatments were evaluated by ultrasonography. The uteri of cows were flushed 6 d after timed AI for collection of embryos and oocytes. Plasma concentrations of Se and progesterone were measured throughout the postpartum period and during the reproductive protocol, respectively, and plasma glutathione peroxidase activity was determined 6 d after AI. Concentrations of Se in pre- and postpartum diets ranged from 0.43 to 0.56 mg/kg of dry matter. Incidence of retained placenta, fever, ketosis, mastitis, acute puerperal metritis, clinical endometritis, and subclinical endometritis were not significantly different between treatments. There were no differences between groups in concentrations of Se and progesterone or glutathione peroxidase activity in plasma. Treatment did not influence ovarian responses to the synchronization protocol, fertilization rate, number of blastomeres and live blastomeres, or proportions of grades 1 and 2, degenerated, and degenerated-unfertilized embryos/oocytes. Odds of subclinical endometritis on Day 30 postpartum more than doubled in cows with fever of unknown origin or acute puerperal metritis in the first 10 DIM. Fertilization rate tended to be reduced in cows with subclinical endometritis. In summary, replacing SS with an organic source of Se in diets not suboptimal in basal Se concentrations did not improve Se status, uterine health, fertilization, or embryo quality in early lactation dairy cows.     

Distinct sets of acute phase plasma proteins are stimulated by separate human hepatocyte-stimulating factors and monokines in rat hepatoma cells

A subline of the rat hepatoma (H-35) cells has been identified which responds to hepatocyte-stimulating factors (HSFs) of human squamous carcinoma cells by increased synthesis of all major rat acute phase plasma proteins. The regulation occurs at the level of mRNA. Two HSFs (HSF-I and HSF-II) have been purified from conditioned medium of the squamous carcinoma cells. HSF-I is a protein with an Mr = 18,000 and pI 5.5, and HSF-II is a glycoprotein with an Mr = 34,000 and a broad, neutral to basic charge. In H-35 cells, HSF-I predominantly stimulates the synthesis of complement C3 and haptoglobin and acts synergistically with dexamethasone to stimulate alpha 1-acid glycoprotein. HSF-II stimulates cysteine protease inhibitor, alpha 1-antichymotrypsin, alpha 1-antitrypsin, fibrinogen, and hemopexin, and acts synergistically with dexamethasone to stimulate alpha 2-macroglobulin. Each HSF is between 10 and 100 times less effective in regulating proteins of the other set. Human tumor necrosis factor and interleukin-1 increase complement C3, haptoglobin, and alpha 1-acid glycoprotein, as does HSF-I, but are unable to modulate any of the other acute phase proteins. The monokines differ from HSF-I is their low activity in HepG2 cells and rat hepatocytes.     

Influence of chronic inflammation on the level of mRNA for acute-phase reactants in the mouse liver

Systemic injuries provoke a coordinate change in the hepatic synthesis and circulating concentration of plasma proteins. To assess the effect of a transition from acute to chronic inflammation on the expression of the plasma protein genes, the qualitative and quantitative changes of liver mRNA were measured in males of the inbred strain C57BL/6 of Mus musculus during a 14-day period of inflammation. Inflammation was induced and maintained by repeated injections of the irritants, turpentine, lipopolysaccharides, and celite. At various times, total RNA was extracted from the liver. The concentration of specific mRNA was quantitated by cellfree translation and by blot hybridization with cDNA. The mRNA for the increased plasma proteins serum amyloid A, alpha 1-acid glycoprotein, haptoglobin, and alpha-fibrinogen showed essentially the same time course of changes. The concentrations were maximal 24 hr after initiation of inflammation and then declined gradually during the following days. During the progression from acute to chronic inflammation, there was a switch from a predominant expression of the gene for alpha 1-acid glycoprotein-1 to one of alpha 1-acid glycoprotein-2. The prolonged inflammation had an inverse effect on the two major negative acute-phase reactants, albumin and major urinary proteins. The concentration of albumin mRNA was reduced to 50% after 24 hr of inflammation but returned to the control level within 5 days. The mRNA for major urinary proteins, however, were lowered within 2 to 5 days of inflammation to 10 to 20% and were maintained at that level. These results suggest that different regulatory factors, humoral and/or cellular, are involved in controlling the expression of the genes for positive and negative acute-phase plasma proteins during acute and chronic inflammation.     

Recombinant human interleukin-6 (IL-6/BSF-2/HSF) regulates the synthesis of acute phase proteins in human hepatocytes

Recombinant human IL-6 (rhIL-6) is a potent inducer of the synthesis of acute phase proteins in adult human hepatocytes. A wide spectrum of acute phase proteins is regulated by this mediator. After labeling of rhIL-6 stimulated human hepatocytes with [35S]methionine acute phase protein synthesis was measured by immunoprecipitation. Serum amyloid A, C-reactive protein, haptoglobin, alpha 1-antichymotrypsin and fibrinogen were strongly induced (26-, 23-, 8.6-, 4.6- and 3.8-fold increases, respectively). Moderate increases were found for alpha 1-antitrypsin (2.7-fold) and alpha 1-acid glycoprotein (2.7-fold). RhIL-6 had no effect on alpha 2-macroglobulin, whereas fibronectin, albumin and transferrin decreased to 64, 56 and 55% of controls. In the cases of serum amyloid A, haptoglobin, alpha 1-antichymotrypsin, alpha 1-antitrypsin and alpha 1-acid glycoprotein, dexamethasone enhanced the action of rhIL-6. We conclude that rhIL-6 controls the acute phase response in human liver cells.     

Seasonal rhythms of "acute phase proteins" in humans

"Acute phase proteins" comprise a group of proteins whose concentrations increase or decrease by at least 25% after a damaging stimulus (burn, trauma, tissue damage, etc.) or during inflammation. We investigated the seasonal variation in the concentrations of several acute phase proteins--alpha1-antichymotrypsin (ACT), alpha1-acid glycoprotein (AGP), transferrin (Tf), alpha2-macroglobulin (alpha2-M), ceruloplasmin (Cp), antitrypsin (AT), and haptoglobin (Hp). Blood samples were collected from 15 healthy volunteers, who were subjected to the seasonal changes in illumination, were drawn at 08:00 h every 3 months (August, November, January/February, March/April, June/July). With the exception of Hp, all acute phase proteins showed an annual rhythm (ANOVA; p < 0.01). Lowest concentrations occurred in the winter months (November through February), with the exception of Tf, which was oppositely phased.     

Human keratinocytes and monocytes release factors which regulate the synthesis of major acute phase plasma proteins in hepatic cells from man, rat, and mouse

Human keratinocytes and activated monocytes produces factors which can stimulate the proliferation of thymocytes. The same activity has also been implicated in regulating the expression of plasma proteins in liver cells during the acute phase reaction. To assess whether factors produced by such cells can directly influence liver cells to change the production of acute phase plasma proteins, we studied in tissue culture the response pattern of hepatic cells from three species: human hepatoma cells ( HepG2 cells), and primary cultures of rat and mouse hepatocytes. Conditioned media from the squamous carcinoma COLO-16 cells, normal epidermal cells, and activated peripheral monocytes were able to stimulate the synthesis of specific acute phase plasma proteins: alpha 1-antichymotrypsin in HepG -2 cells, alpha 1-antichymotrypsin, alpha 1-acid glycoprotein, alpha 1-acute phase protein, and alpha 2-macroglobulin in rat hepatocytes, and alpha 1-acid glycoprotein, haptoglobin, and hemopexin in mouse hepatocytes. Only in rat cells, dexamethasone was found to have further enhancing effect. The increased production of plasma proteins could be explained by an elevated level of functional mRNA. Comparing thymocyte-stimulating activities with the effects on plasma protein production, we found some difference both between the conditioned media of epidermal cells and monocytes, and between the responses of the three hepatic cell systems. Furthermore, gel chromatography of conditioned media resulted in partial separation of activities regulating liver cells and thymocytes. Since there is no strict correlation between thymocyte- and hepatocyte-stimulating activities, the presence of different sets of specific factors is assumed.     

High-performance liquid chromatography determination of alpha1-acid glycoprotein in small volumes of plasma from neonates

In order to investigate how the alpha1-acid glycoprotein (AGP) concentrations of neonates change in response to surgical stress, a simple high-performance liquid chromatography (HPLC)-assay for the measurement of alpha1-acid glycoprotein levels was developed. A fraction containing alpha1-acid glycoprotein was isolated from the bulk of plasma protein by addition of 0.6M perchloric acid and was then analysed directly on a short PLRP-S 4000A reversed phase column column. The method was validated by analysis of pooled plasma from healthy adults both in comparison with a calibration curve and by standard additions. The procedure was able to isolate alpha1-acid glycoprotein rapidly (<30 min) and required only 50 microl of plasma. The mean extraction recovery was 79.1% (CV 6.4%). The within-run precision for the analysis of three replicates of quality control sample ranged from +/-1.2 to +/-3.8% and the between-run precision was +/-6.1%. The method was linear (r(2)=0.988) over a concentration range from 6 to 100.0 mg/100 ml. The AGP levels in neonatal samples ranged from 25 to 93 mg/100 ml.     

Factors affecting the occurrence of postpartum prolonged luteal activity in clinically healthy high-producing dairy cows

The objective was to characterize risk factors affecting the occurrence of prolonged luteal phase (PLP) in postpartum, clinically healthy, high-producing dairy cows. Transrectal ultrasound examinations of the reproductive tract were performed twice weekly, from the 1st to 8th wk after calving in 151 multiparous clinically healthy lactating Holstein cows (mean ± SD of peak milk yield = 56.7 ± 7.4 kg). Serum samples were collected twice weekly to measure progesterone and every 2 wk to detect β-hydroxybutyrate (βHB), and α1-acid glycoprotein (AGP). Body condition score (BCS) was recorded weekly after calving. Based on the serum progesterone profile, 52 (34.4%) cows had normal ovarian activity (NLA), whereas 36 (23.8%) cows had a prolonged luteal phase (PLP), the most prevalent type of abnormal pattern of luteal activity. Furthermore, 63 cows with short luteal activity, delayed first ovulation, or cystic ovaries were excluded from this study. Serum AGP concentrations, as an indication of postpartum chronic endometritis, were not different (P > 0.05) between cows with NLA and PLP. Categories of peak milk yields (kg) were positively correlated with the incidence (%) of cows with PLP (r = 0.87, P = 0.02). Furthermore, milk yield peak, day of milk yield peak, mean milk yield (8 wk in milk), and milk yield on the expected day of luteolysis were higher (P < 0.05) in cows with PLP than NLA, and cows with PLP had greater loss of BCS (P = 0.007) than those with NLA. The likelihood of cows with PLP decreased by 0.9-fold for every 1 d delay of commencement of luteal activity (C-LA). Moreover, the likelihood of cows with PLP increased by 1.8-fold for each 1 mmol/L increase in the 1st wk serum βHB concentrations. In conclusion, higher mean of milk yield, greater BCS loss, earlier C-LA, and later peak milk yield were the major risk factors affecting the occurrence of postpartum PLP in clinically healthy, high-producing dairy cows.     

Changes in acute phase proteins after anti-tumor necrosis factor antibody (infliximab) treatment in patients with Crohn's disease

Acute phase proteins and markers of proteosynthetic activity reflect the clinical activity in Crohn's disease (CD). The impact of anti-tumor necrosis factor antibody (anti-TNF) therapy on serum levels of acute phase proteins and proteosynthetic markers was studied. Fourteen patients with active CD were treated with 5 mg per kg of anti-TNF in intravenous infusion. Clinical activity (assessed by Crohn's disease activity index - CDAI), alpha-1-acid glycoprotein, haptoglobin, cholinesterase and prealbumin were assessed before and in months 1 and 5 after treatment. A sustained decrease in CDAI was observed. This was accompanied by a significant decrease in alpha-1-acid glycoprotein and haptoglobin in month 1 (p=0.005 and p=0.01, respectively) while in month 5 the levels of both acute phase proteins rose significantly (p=0.003 for alpha-1-acid glycoprotein and p=0.02 for haptoglobin). Cholinesterase and prealbumin significantly increased in month 1 after the treatment (p=0.02 and p=0.0006, respectively), the increase was sustained in cholinesterase while prealbumin levels diminished in month 5. We conclude that the clinical improvement after anti-TNF therapy for CD is accompanied by changes of acute phase proteins and proteosynthetic markers. The assessment of these laboratory markers may be useful in the management of CD patients treated with anti-TNF.     

Evaluation of cytokine expression by blood monocytes of lactating Holstein cows with or without postpartum uterine disease

Whereas neutrophils are the main phagocytic leukocytes, monocytes and macrophages are actively involved in immunomodulation after infection. Recent studies have demonstrated that neutrophil function is impaired by the state of negative energy balance around parturition, and that cows that develop uterine disease have a greater degree of negative energy balance than healthy cows. The objectives of this study were to compare monocyte gene expression and protein secretion of selected cytokines from calving to 42 d after calving in Holstein cows that did or did not develop uterine disease. Real time quantitative RT-PCR (Tumor necrosis factor-α (TNFα), Interleukin (IL)-1β, IL-6, IL-8 and IL-10) and ELISA (TNFα, IL-1β and IL-8) were used to evaluate cytokine response following in vitro stimulation of blood-derived monocytes with irradiated E. coli. Relative to unstimulated cells, E. coli-stimulated monocytes from cows with metritis had lower gene expression of key pro-inflammatory cytokines than healthy cows from calving to 14 d after calving (TNFα at 0, 7, and 14 d after calving, IL-1β and IL-6 at 7 and 14 d after calving; P < 0.05). There were no significant differences between groups for expression of IL-8 or the anti-inflammatory cytokine IL-10. This was due, in part, to higher gene expression in unstimulated monocytes (TNFα, IL-1β, IL-6 and IL-10) in early lactation from cows with metritis. Expression of mRNA in stimulated cells (relative to housekeeping genes) was lower for TNFα (7 and 14 d postpartum) and for IL-10 (7 and 14 d postpartum) in cows with metritis. Concentration of TNFα was lower in the culture medium of E. coli-stimulated monocytes from cows with metritis than healthy cows at calving and 7 and 21 d after calving (P < 0.05). Circulating cytokine concentrations were not different between groups for IL-8 and were below the limits of detection for TNFα and IL-1β. Cytokine gene expression and production were similar between healthy cows and cows that developed endometritis, diagnosed cytologically at 42 d after calving. We concluded that altered levels of expression and production of pro-inflammatory cytokines postpartum could contribute to impaired inflammatory response and predispose cows to development of metritis.     

Acute phase protein alpha 1-acid glycoprotein interacts with plasminogen activator inhibitor type 1 and stabilizes its inhibitory activity.

alpha(1)-Acid glycoprotein, one of the major acute phase proteins, was found to interact with plasminogen activator inhibitor type 1 (PAI-1) and to stabilize its inhibitory activity toward plasminogen activators. This conclusion is based on the following observations: (a) alpha(1)-acid glycoprotein was identified to bind PAI-1 by a yeast two-hybrid system. Three of 10 positive clones identified by this method to interact with PAI-1 contained almost the entire sequence of alpha(1)-acid glycoprotein; (b) this protein formed complexes with PAI-1 that could be immunoprecipitated from both the incubation mixtures and blood plasma by specific antibodies to either PAI-1 or alpha(1)-acid glycoprotein. Such complexes could be also detected by a solid phase binding assay; and (c) the real-time bimolecular interactions monitored by surface plasmon resonance indicated that the complex of alpha(1)-acid glycoprotein with PAI-1 is less stable than that formed by vitronectin with PAI-1, but in both cases, the apparent K(D) values were in the range of strong interactions (4.51 + 1.33 and 0.58 + 0.07 nm, respectively). The on rate for binding of PAI-1 to alpha(1)-glycoprotein or vitronectin differed by 2-fold, indicating much faster complex formation by vitronectin than by alpha(1)-acid glycoprotein. On the other hand, dissociation of PAI-1 bound to vitronectin was much slower than that from the alpha(1)-acid glycoprotein, as indicated by 4-fold lower k(off) values. Furthermore, the PAI-1 activity toward urokinase-type plasminogen activator and tissue-type plasminogen activator was significantly prolonged in the presence of alpha(1)-acid glycoprotein. These observations suggest that the complex of PAI-1 with alpha(1)-acid glycoprotein can play a role as an alternative reservoir of the physiologically active form of the inhibitor, particularly during inflammation or other acute phase reactions.     

Induction of acute phase proteins by dexamethasone in rat hepatocyte primary cultures

The effect of dexamethasone on the synthesis of acute phase proteins has been studied in primary cultures of rat hepatocytes. In the absence of dexamethasone no detectable amounts of alpha 2-macroglobulin were synthesized by hepatocytes cultured for 1 day. alpha 2-Macroglobulin synthesis was induced by dexamethasone concentrations of 10(-8) M or higher with a maximum at a concentration of 10(-7) M. alpha 1-Acid glycoprotein was synthesized in the absence of dexamethasone; however, its synthesis was also greatly stimulated by dexamethasone concentrations of 10(-8)-10(-6) M. Synthesis of alpha 1-proteinase inhibitor was stimulated only 1.4-fold at a dexamethasone concentration of 10(-7) M. The kinetics of induction of alpha 2-macroglobulin and alpha 1-acid glycoprotein were studied at a dexamethasone concentration of 10(-7) M. After an initial lag phase of 3 h the synthesis of both proteins showed a steady increase during 2 days. Synthesis of albumin remained unchanged under these experimental conditions. Unlike alpha 2-macroglobulin and alpha 1-acid glycoprotein tyrosine aminotransferase activity increased already during the first 3 h of induction by dexamethasone with a maximum at 12 h followed by a slight decrease.     

Changes in the blood level and affinity to concanavalin A of rat plasma glycoproteins during acute inflammation and hepatoma growth.

Plasma concentrations of ten individual proteins were measured by electroimmunoassay in young male Buffalo rats following injection of turpentine oil or implantation of Morris hepatoma 7777. The highest relative responses to inflammation and tumour growth were found for alpha 2-macroglobulin, alpha 1-acute-phase globulin and alpha 1-acid glycoprotein. As shown by crossed immuno-affinoelectrophoresis the concanavalin A-reactive fractions of the latter two glycoproteins were predominantly increased in plasma from injured and tumour-bearing rats.     

Simplified elimination of rabbit anti-rat acute phase protein IgG that shows cross reactivity with albumin

Antibody preparations against rat acute phase proteins were tested for cross reactivity with other serum proteins, including rat albumin. Rabbit anti-rat a alpha1-acid glycoprotein and ceruloplasmin IgG purified on protein A-Sepharose did not show any cross reactivity with rat albumin, hemoglobin or transferrin. Rabbit anti-rat haptoglobin and -macroglobulin IgG purified on protein A-Sepharose showed a 39% and 30% cross reactivity with rat albumin and a 20% and 19% cross reactivity with rat hemoglobin. Because these proteins in whole serum were not adsorbed on Cibacron Blue F3-GA Sepharose, the albumin would be adsorbed on Cibacron Blue F3-GA Sepharose by the use of whole rat serum. Rabbit anti-rat haptoglobin and alpha2-macroglobulin IgG showing cross reactivity with albumin was simply eliminated.     

Synthesis and regulation of acute phase plasma proteins in primary cultures of mouse hepatocytes

Adult mouse hepatocytes respond in vivo to experimentally induced acute inflammation by an increased synthesis and secretion of alpha 1-acid glycoprotein, haptoglobin, hemopexin, and serum amyloid A. Concurrently, the production of albumin and apolipoprotein A-1 is reduced. To define possible mediators of this response and to study their action in tissue culture, we established primary cultures of hepatocytes. Various hormones and factors that have been proposed to regulate the hepatic acute phase reaction were tested for their ability to modulate the expression of plasma proteins in these cells. Acute phase plasma and conditioned medium from activated monocytes influenced the production of most acute phase plasma proteins, and the regulation appears to occur at the level of functional mRNA. Purified hormones produced a significant anabolic response in only a few cases: dexamethasone was found to be effective in maintaining differentiated expression of the cells; and glucagon produced a specific inhibition of haptoglobin synthesis. When cells were treated with a combination of conditioned monocyte medium and dexamethasone, secretion of proteins was markedly reduced. The carbohydrate moieties of all plasma glycoproteins were incompletely modified, apparently as a result of decreased intracellular transport of newly synthesized plasma proteins. Although primary hepatocytes were not phenotypically stable in tissue culture, the cells nevertheless retained a broad response spectrum to exogenous signals. We propose this as a useful system to study the production of plasma proteins and thereby pinpoint the nature and activity of effectors mediating the hepatic acute phase reaction.     

Spontaneous uterine infections are associated with elevated prostaglandin F(2)alpha metabolite concentrations in postpartum dairy cows

Postpartum Holstein (n=21) and Jersey (n=4) cows were used to determine if uterine infections are associated with elevated plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F(2)alpha (PGFM). Based upon clinical examinations and bacterial content of intrauterine fluid samples, cows detected with uterine infections between 21 and 28 d post partum were used (infected; n=14). These cows were matched with herdmates that were free of infection (control; n=11). Beginning on the day the cows were assigned to the experiment (Day 1), blood samples were collected on alternate days for the next 14 to 15 d. Plasma samples were stored at -20 degrees C until assayed. From Day 1 until the end of the experiment, uterine fluid samples were collected transcervically twice weekly for aerobic bacterial culture. Endometrial biopsies were collected between Days 6 and 8 and Days 13 and 15. Control cows did not show signs of uterine infection throughout the trial, and bacterial cultures indicated that there were no significant bacterial populations in the uteri of the control cows. The uteri of infected cows harbored numerous microbes. Actinomyces pyogenes was most prominent. Various species of Streptococcus and Pasteurella were also prevalent in the infected cows. Escherichia coli was present in the uterus of both infected and control cows. Biopsies showed that infected cows had more (P<0.05) neutrophils, plasma cells and lymphocytes in the endometrium than did the control cows. As determined by plasma progesterone concentrations, 83% of the control and 50% of the infected cows had functional luteal tissue during the 2-wk sampling period. Plasma PGFM profiles were linear (P<0.03) and did not differ between treatment groups (P>0.01). However, average plasma PGFM concentrations were greater (P<0.0001) in infected than in control cows. These data indicate that plasma PGFM concentrations are greater in postpartum cows with spontaneous uterine infections then in herdmates free of infection.     

Acute phase mediated change in glycosylation of rat alpha 1-acid glycoprotein in transgenic mice.

Transgenic mouse lines carrying the gene for rat alpha 1-acid glycoprotein (AGP) express the protein in the plasma at concentrations equal to or exceeding that of acute phase rats. Owing to the high basal level, these transgenic mice represent a unique experimental system for defining the largely unknown function of AGP. Since the carbohydrate moiety of AGP has been found to be changed during acute phase and the oligosaccharide structure to be important for immunomodulating activity of the protein, the rat AGP in transgenic mice was characterized by lectin-affinity immuno-electrophoresis. Unlike in the rat, the AGP in the transgenic mouse plasma consisted primarily of strongly concanavalin A-reactive forms. Acute phase mediated a several-fold increase in the total plasma concentration of AGP concomitant with a shift toward moderately concanavalin A-reactive forms. A similar change in concanavalin A-reactive forms was observed for the endogenous acute phase plasma protein haptoglobin. To define the role of inflammatory factors in AGP production, primary cultures of hepatocytes were prepared. In contrast to in vivo, the AGP recovered from tissue culture medium represented primarily the concanavalin A-non-reactive form. Treatment of the cells with recombinant human interleukin-1, interleukin-6 and dexamethasone stimulated the production of concanavalin A-reactive AGP forms. The data indicate that the glycosylation pattern of plasma-resident AGP is modulated by acute phase, but that the profile of AGP forms does not coincide with that secreted by hepatocytes in tissue culture. This finding demands an assessment of which of the possible glycosylated forms of AGP is functionally significant in vivo.