Granulocyte colony-stimulating factor and antibiotics in the prophylaxis of a murine model of polymicrobial peritonitis and sepsis

In previous gel-shift assays, we identified a protein complex, referred to as GS1, that binds in a sequence-specific manner to single-stranded DNA and is highly enriched in brain. As an initial step in clarifying the function of this complex, we have undertaken studies aimed at defining its protein components. In particular, we focused on identifying two protein bands that were covalently labeled when the GS1-DNA complex was subjected to UV irradiation to induce cross-linking between the radiolabeled probe and GS1 components. By following GS1 binding activity through a series of conventional chromatographic steps, as well as an affinity column based on the DNA oligonucleotide used for gel-shift assays, we were able to achieve approximately 500,000-fold enrichment of GS1 compared with that in crude cerebellar extracts used as starting material. This highly purified fraction contained both protein bands detected by UV cross-linking in crude extracts. Sequencing of peptides derived from these proteins led to their identification as Translin and Trax, interacting proteins identified in studies of DNA recombination in lymphocytes. A distinct line of research has provided evidence that a complex containing Translin can bind to specific mRNAs and block their translation. Whether one or both of these proposed functions of the Translin/Trax complex explains the high basal level of GS1 binding activity present in the brain remains to be determined.     

Failure of prophylactic and therapeutic use of a murine anti-tumor necrosis factor monoclonal antibody in Escherichia coli sepsis in the rabbit

OBJECTIVE: To determine the efficacy of a murine anti-tumor necrosis factor (TNF) monoclonal antibody in the treatment of Escherichia coli peritonitis and sepsis in the rabbit. DESIGN: Prospective, paired, randomized, blinded, controlled animal trial. SETTING: Animal research laboratory. SUBJECTS: Male New Zealand white rabbits. INTERVENTIONS: Anesthetized rabbits were cannulated with indwelling femoral arterial and venous catheters. Peritonitis and sepsis were induced by intraperitoneal challenge using live E. coli O18ac bacteria. All animals were treated with gentamicin and ceftriaxone 1 hr after challenge. One group (prophylaxis experiment) consisting of ten rabbit pairs (the prophylaxis group), was treated with either murine anti-TNF monoclonal antibody or an equivalent volume of 5% albumin 3 hrs before E. coli challenge. A second group (therapeutic experiment) of 17 rabbit pairs, the treatment group, was also treated with murine anti-TNF monoclonal antibody or albumin control 1 hr after E. coli challenge. MEASUREMENTS AND MAIN RESULTS: All animals were bacteremic 1 hr after challenge. Physiologic measures of sepsis (heart rate, mean arterial pressure, serum bicarbonate, and arterial pH) did not differ between control, prophylaxis, and treatment groups. Peak serum TNF concentration was significantly (p < .01) lower in animals receiving anti-TNF monoclonal antibody, in both the prophylaxis and treatment groups, than in control animals. The survival rate was not improved significantly in either the prophylaxis or treatment group. CONCLUSIONS: Prophylactic and therapeutic use of anti-TNF monoclonal antibody in a rabbit model of E. coli peritonitis and sepsis significantly lowers TNF concentrations but does not ameliorate the physiologic effects of sepsis and does not significantly improve survival.     

Granulocyte colony-stimulating factor enhances bone marrow stem cell damage caused by repeated administration of cytotoxic agents

Despite the increasing use of cytokines to circumvent the acute dose-limiting myelotoxicity of cancer treatment, little is known about the combined effects of cytotoxic agents and cytokines on the primitive stem cells responsible for long-term hematopoiesis. In an experimental model, we administered cytotoxic agents that have variable effects on primitive stem cells in C57BL/6 (B6)-mice. Mice received six every-other-week doses of cyclophosphamide (CY, 84 mg/kg), VP-16 (24 mg/kg) + cisplatinum (2.4 mg/kg), carboplatinum (50 mg/kg), chlorambucil (12 mg/kg), BCNU (13.2 mg/kg), or TBI (80 cGy). Granulocyte colony-stimulating factor (G-CSF; 250 microg/kg/day) was administered subcutaneously twice daily on days 3 to 6 after each dose of the cytotoxic agent. Comparison with animals receiving the cytotoxic agent alone was made to investigate the effects of G-CSF on long-term hematopoiesis. Hematopoiesis was measured 20 weeks after the last dose of the cytotoxic agent by assessment of peripheral blood counts, marrow cellularity, progenitor cell content (colony-forming units-spleen; CFU-S), and primitive stem cell number (long-term repopulating ability and day 28 and day 35 cobblestone area-forming cell [CAFC] frequencies). Exposure to cytotoxic agents alone resulted in a significant decrease in primitive stem cells (as measured by repopulating units [RU] and day 28 and day 35 CAFC content) in animals given carboplatinum, chlorambucil, BCNU, and TBI, but not in animals treated with cyclophosphamide or VP-16 and cisplatinum. The addition of G-CSF resulted in a significant decrease in stem cell content when compared with no G-CSF administration in animals treated with chlorambucil, BCNU, or TBI. Thus, G-CSF administered after repeated exposure to cytotoxic agents, appeared to damage the primitive stem cell compartment when used in combination with agents known to damage primitive stem cells. These results, although obtained in an experimental model, should raise concerns for the indiscriminate use of G-CSF in the clinic.     

Granulocyte colony-stimulating factor enhances endotoxin-induced decrease in biliary excretion of the antibiotic cefoperazone in rats

We have recently reported that endotoxin (lipopolysaccharide [LPS]) derived from Klebsiella pneumoniae dramatically decreased the biliary excretion of the beta-lactam antibiotic cefoperazone (CPZ), which is primarily excreted into the bile via the anion transport system, in rats. The present study was designed to investigate the effect of human recombinant granulocyte colony-stimulating factor (G-CSF), which is reported to be beneficial in experimental models of inflammation, on the pharmacokinetics and biliary excretion of CPZ in rats. CPZ (20 mg/kg of body weight) was administered intravenously 2 h after the intravenous injection of LPS (250 microgram/kg). G-CSF was injected subcutaneously at 12 microgram/kg for 3 days and was administered intravenously at a final dose of 50 microgram/kg 1 h before LPS injection. Peripheral blood cell numbers were also measured. LPS dramatically decreased the systemic and biliary clearances of CPZ and the bile flow rate. Pretreatment with G-CSF enhanced these decreases induced by LPS. The total leukocyte numbers were increased in rats pretreated with G-CSF compared to the numbers in the controls, while the total leukocyte numbers were decreased (about 3,000 cells/microliter) by treatment with LPS. Pretreatment with G-CSF produces a deleterious effect against the LPS-induced decrease in biliary secretion of CPZ, and leukocytes play an important role in that mechanism.     

Granulocyte colony-stimulating factor and azole antifungal therapy in murine aspergillosis: role of immune suppression

Outbred ICR mice were immune suppressed either with hydrocortisone or with 5-fluorouracil and were infected intranasally with Aspergillus fumigatus. Beginning 3 days before infection some groups of mice were given recombinant human granulocyte colony-stimulating factor (G-CSF), SCH56592 (an antifungal triazole), or both. Corticosteroid-pretreated mice responded to SCH56592 and had reduced counts in lung tissue and prolonged survival. In these mice, G-CSF strongly antagonized the antifungal activity of SCH56592. Animals treated with both agents developed large lung abscesses with polymorphonuclear leukocytes and large amounts of Aspergillus. In contrast, mice made neutropenic with 5-fluorouracil and then infected with A. fumigatus conidia benefited from either G-CSF or triazoles, and the effect of the combination was additive rather than antagonistic. Host predisposing factors contribute in different ways to the outcome of growth factor therapy in aspergillosis.     

Granulocyte colony-stimulating factor in the newborn neutropenic patient

Dural tears located at the base of the skull are difficult to repair due to the difficulties in the appropriate access and the fragility of the dura in such areas. In our experience the biggest problem when attempting to perform a dural repair in a deep narrow field is not to place the stitches, but rather to set the knots. A newly designed, easy-to-learn technique has been developed for dural closure in these situations. We present here a new technique for dural suturing of special interest when the space available is limited. In our hands it is possible to obtain a watertight dural closure in most microsurgical operations performed through a small hole and/or into a narrow, deep surgical field. These techniques can also be applied during a secondary procedure following development of a postoperative CSF leak. While simple and easy to learn, these techniques require practice in the laboratory setting before clinical application.     

A plasmid encoding murine granulocyte-macrophage colony-stimulating factor increases protection conferred by a malaria DNA vaccine

Using the murine parasite Plasmodium yoelii (Py) as a model for malaria vaccine development, we have previously shown that a DNA plasmid encoding the Py circumsporozoite protein (PyCSP) can protect mice against sporozoite infection. We now report that mixing a new plasmid PyCSP1012 with a plasmid encoding murine granulocyte-macrophage colony-stimulating factor (GM-CSF) increases protection against malaria, and we have characterized in detail the increased immune responses due to GM-CSF. PyCSP1012 plasmid alone protected 28% of mice, and protection increased to 58% when GM-CSF was added (p < 0.0001). GM-CSF plasmid alone did not protect, and control plasmid expressing inactive GM-CSF did not enhance protection. GM-CSF plasmid increased Abs to PyCSP of IgG1, IgG2a, and IgG2b isotypes, but not IgG3 or IgM. IFN-gamma responses of CD8+ T cells to the PyCSP 280-288 amino acid epitope increased but CTL activity did not change. The most dramatic changes after adding GM-CSF plasmid were increases in Ag-specific IL-2 production and CD4+ T cell proliferation. We hypothesize that GM-CSF may act on dendritic cells to enhance presentation of the PyCSP Ag, with enhanced IL-2 production and CD4+ T cell activation driving the increases in Abs and CD8+ T cell function. Recombinant GM-CSF is already used in humans for medical purposes, and GM-CSF protein or plasmids may be useful as enhancers of DNA vaccines.     

Suppression of the granulocyte colony-stimulating factor response to Escherichia coli challenge by alcohol intoxication

Alcohol's suppressive effects on polymorphonuclear leukocyte (PMN) production and function increases host susceptibility to a wide variety of infections and impairs the ability of these effector cells to seek and destroy invading pathogens. Granulocyte colony-stimulating factor (G-CSF), an important regulator of PMN production and function, is known to be increased in the plasma during infectious episodes. In previous studies we found acute alcohol intoxication to suppress the tumor necrosis factor-alpha (TNF alpha) response to in vivo challenges with bacteria or lipopolysaccharide. The present study was initiated to determine the impact of alcohol intoxication on the plasma G-CSF response to gram-negative infection. For this purpose, rats received an intravenous challenge of Escherichia coli (10(6) CFU) 30 min after an intraperitoneal injection of ethanol (5.5 g/kg) or an equivalent volume of saline (control). Ethanol-intoxicated rats had a greater 48 hr mortality to live E. coli injection than did unintoxicated animals (45% vs. 8%). Despite an increased bacterial burden in both the lung and liver at 24 hr after initiating E. coli infection in alcohol-intoxicated animals, PMN tissue recruitment, indexed as myeloperoxidase activity, did not differ between control and alcohol-treated rats. Moreover, alcohol suppressed blood PMN phagocytic capacity to a greater extent in animals given alcohol than controls at 5 and 24 hr after initiating infection. In control animals after intravenous E. coli injection, bioactive G-CSF increased in plasma and peaked near 300 ng/ml at 8 hr. In rats pretreated with alcohol, the plasma G-CSF response was markedly suppressed in response to intravenous E. coli (p < 0.05). In a second experiment, neutralization of the E. coli-induced plasma TNF alpha response by pretreatment with anti-TNF alpha antibody similarly inhibited the plasma G-CSF response. These results support the postulate that alcohol-induced inhibition of TNF alpha directly contributes to the adverse effects of alcohol on PMN function by suppressing the normal autocrine amplification pathway responsible for G-CSF production.     

Granulocyte colony-stimulating factor improves host defense to resuscitated shock and polymicrobial sepsis without provoking generalized neutrophil-mediated damage

BACKGROUND: Granulocyte colony-stimulating factor (G-CSF) increases production and release of neutrophil precursors and activates multiple functions of circulating polymorphonuclear neutrophils (PMNs). G-CSF has therapeutic effects in many experimental models of sepsis; its actions with superimposed reperfusion insults are unknown. In traumatic conditions, G-CSF could exacerbate unregulated, PMN-dependent injury to otherwise normal host tissue or, it could partially reverse trauma-induced immune suppression, which may improve long-term outcome. This study tested whether stimulating PMN proliferation and function with G-CSF during recovery from trauma+sepsis potentiated reperfusion injury or whether it improved host defense. METHODS: Anesthetized swine were subjected to cecal ligation and incision, 35% hemorrhage, and 1 hr of hypotension. Resuscitation consisted of intravenous G-CSF (5 microg/kg) or placebo followed by shed blood and 40 mL/kg of lactated Ringer's solution. The control group received laparotomy only. G-CSF or placebo was given daily. Animals were killed at 4 days. Observers, blind to the protocol, graded autopsy samples for localization of infection and quality of abscess wall formation. Data included complete blood count, granulocyte oxidative burst after phorbol myristate acetate stimulation in vitro (GO2B), bronchoalveolar lavage (BAL) cell count, BAL noncellular protein, lipopolysaccharide-stimulated tumor necrosis factor production in whole blood in vitro (lipopolysaccharide-tumor necrosis factor), and lung tissue myeloperoxidase (MPO). RESULTS: Neutrophilia and localization of infection, were significantly improved by G-CSF. Variables altered by G-CSF, though not significantly, showed GO2B potential increased by 50%, lipopolysaccharide-tumor necrosis factor decreased by 50%, and improved survival versus placebo (100% vs. 70%). G-CSF did not increase lung MPO, BAL cell count, or BAL protein. Both arterial and venous O2 saturations were unaltered. CONCLUSIONS: Our data show that G-CSF initiated at the time of resuscitation reduced the sequelae of posttrauma sepsis by increasing PMN proliferation and function without potentiating PMN-mediated lung reperfusion injury.     

Degradation studies on Escherichia coli capsular polysaccharides by bacteriophages

The mouse peripheral blood micronucleus assay, a measure of DNA damage in erythroblastic cells, was used to determine: (1) the incidence of spontaneously occurring micronucleated reticulocytes (MNRETs) as a function of age, and (2) the induction of micronuclei following treatment of young and old animals with mitomycin C. Male C57BL/6 mice, 92 weeks of age, exhibited a significantly higher frequency of spontaneously occurring peripheral blood MNRETs than mice that were 6 or 10 weeks of age. Mice that were 5-6 weeks or 91-92 weeks old were treated with one dose, or two consecutive doses of mitomycin C; this resulted in dose-related increases in the frequency of MNRETs. Mitomycin C, at a single dose of 1 or 2 mg/kg, induced one-third as many MNRETs in the older animals as compared to the younger animals. When treated with a split dose of mitomycin C (total dose 0.5 to 2 mg/kg), older animals displayed on average two-thirds the mutagenic response of the younger animals. However, analysis of variance performed on these data indicated that the age of the animals did not have a significant effect on their mutagenic response to mitomycin C at any dose level. It appears that aging mice may not be more sensitive to the mutagenic effects of chemically-induced DNA damage than younger mice, suggesting that the higher spontaneous mutation frequency in older mice could be the result of an increased load of accumulated DNA damage.     

Granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor and macrophage colony-stimulating factor in the treatment of acute myeloid leukemia and acute lymphoblastic leukemia

To explore the role of perfectionism across anxiety disorders, 175 patients with either panic disorder (PD), obsessive compulsive disorder (OCD), social phobia, or specific phobia, as well as 49 nonclinical volunteers, completed two measures [Frost, R. O., Marten, P., Lahart, C., & Rosenblate, R., (1990). The dimensions of perfectionism. Cognitive Therapy and Research, 14, 449-468; Hewitt, P. L., & Flett, G. L., (1991). Perfectionism in the self and social contexts: Conceptualization, assessment and association with psychopathology. Journal of Personality and Social Psychology, 60, 456-470.] that assess a total of nine different dimensions of perfectionism. Relative to the other groups, social phobia was associated with greater concern about mistakes (CM), doubts about actions (DA), and parental criticism (PC) on one measure and more socially prescribed perfectionism (SP) on the other measure. OCD was associated with elevated DA scores relative to the other groups. PD was associated with moderate elevations on the CM and DA subscales. The remaining dimensions of perfectionism failed to differentiate among groups. The clinical implications of these findings are discussed.     

Interferon-gamma enhances megakaryocyte colony-stimulating activity in murine bone marrow cells

We have demonstrated previously that interferon-gamma (IFN-gamma) accelerates platelet recovery in mice with 5-FU induced-marrow aplasia in vivo. However, the mechanism for the regulation of megakaryocyte development induced by IFN-gamma in bone marrow cells in vivo remains unknown. To further study the effects of IFN-gamma on megakaryocyte development, various steps during IFN-gamma-mediated accelerated differentiation of the megakaryocytes were investigated in serum-free cultures of murine bone marrow cells in vitro. IFN-gamma markedly induced acetylcholine esterase (AChE) activity, a marker of murine megakaryocytic cells, accompanied by increased colony formation of the megakaryocyte lineage. A prominent increase in megakaryocyte number was observed after IFN-gamma treatment. All of these effects were dependent on the presence of IL-3, and, therefore, these results suggest that IFN-gamma acts as a megakaryocyte potentiator (Meg-POT). However, IFN-gamma did not enhance megakaryocyte maturation with respect to increase in cell size. The effects of IFN-gamma on megakaryocyte maturation were similar to those observed after treatment with higher doses of IL-3 alone. Meg-POT is defined as a factor that induces megakaryocyte maturation. Since IFN-gamma enhanced IL-3-dependent megakaryocyte colony formation and proliferation rather than megakaryocyte maturation, the effects on megakaryocyte development, which were induced by IFN-gamma treatment, seem to be different from the effects of a Meg-POT. We, therefore, propose a new function for IFN-gamma as an enhancer of megakaryocyte colony-stimulating factor activity. The effect of IFN-gamma in vitro appears to correlate well with the acceleration of platelet recovery in vivo.     

Granulocyte colony-stimulating factor activates a 72-kDa isoform of STAT3 in human neutrophils

A series of dextran molecular weight markers were encapsulated in decylamine carboxymethylcellulose microcapsules to serve as probes of capsule retentivity. The capsules were prepared by allowing microdrops of aqueous sodium carboxymethylcellulose to fall into aqueous decylamine acetate solution. Salt exchange reaction at the droplet pseudointerface resulted in self-assembling films which essentially instantaneously enclosed the droplets. Concentrations of anionic polymer were varied in the range from 1-3%. Chromophore-bearing dextrans were incorporated into these capsules by blending the dextrans with the carboxymethylcellulose prior to the encapsulation step. Four dextrans of differing (light scattering) molecular weights were used: 2 x 10(6), 6 x 10(5), 7 x 10(4), and 1.9 x 10(4) amu. The mass balance of dextran retained in the capsules, released on washing the capsules or which escaped encapsulation was determined spectrophotometrically. To measure total dextran in a population of washed capsules, the capsules were lysed in a 0.3 M solution of sodium chloride. To monitor dextran release, washed capsules were suspended in water and dextran concentration in the supernatant was measured. Encapsulation efficiency exceeded 80% for high molecular weight dextran but was lower with the smaller dextrans.     

Granulocyte colony-stimulating factor in combination with intensive chemotherapy in the treatment of acute myeloid leukemia

BACKGROUND: Certain ultrasonographic findings identified in a fetus suspected of having a skeletal dysplasia may be predictive of a lethal outcome. METHODS: We evaluated 27 fetuses suspected of having a skeletal dysplasia using targeted ultrasonography between 16 and 31 weeks' gestation. Clinical examination and skeletal radiography were done after delivery. RESULTS: A skeletal dysplasia was confirmed and a diagnosis established in all but one case. The skeletal dysplasia was lethal in 23 cases and, in each case, the outcome was accurately predicted prenatally; however, three of the infants survived several months. In 11 of the 23 cases (48%), the specific diagnosis was correctly determined before birth. Ultrasonographic findings not considered to reflect a lethal outcome, were accurately predicted in two other cases. In an additional two, sonographic examination suggested a lethal osteochondrodysplasia, though both survived. Findings consistent with a lethal skeletal dysplasia included a femur length < 1st centile, combined with either a bell-shaped thorax, decreased bone echogenicity, or both. Using these criteria provided a positive-predictive value for neonatal deaths of 80% (20/25), and 92% (23/25) if the three that died in infancy were included. CONCLUSIONS: In the fetus suspected of having a skeletal dysplasia, certain findings on targeted ultrasonography frequently are predictive of a lethal outcome; the ability to predict this appears greatest when more than one of these abnormalities is present.     

A combination of stem cell factor and granulocyte colony-stimulating factor enhances the growth of human progenitor B cells supported by murine stromal cell line MS-5

We have developed a long-term culture system using the murine bone marrow stromal cells MS-5 to support the growth of progenitor B cells with CD34-, CD10+, CD19+, and cytoplasmic mu chain (C mu)-negative surface phenotype from human CD34+ cells purified from umbilical cord blood (CB). When 10(3) CD34+ cells/well were seeded on MS-5 stromal cells at the beginning of culture in the absence of exogenously added cytokines, progenitor B cells first appeared after 14 days, and the maximal cell production was achieved during the 6th week of culture. Intriguingly, the addition of recombinant human stem cell factor (rhSCF) and granulocyte colony-stimulating factor (rhG-CSF), but not rhIL-7, strikingly enhanced the growth of progenitor B cells from CB CD34+ population cultured on MS-5 stromal cells. The culture of progenitor B cells could be maintained until the 6th week of culture when some cells were revealed to have a C mu phenotype, and a small number of cells had immunoglobulin mu chain on their cell surface in the presence of both rhSCF and rhG-CSF. When CD34+ cells were cultured physically separated from the stromal layer by membrane, supportive effects of MS-5 stromal cells for the growth of progenitor B cells were not observed. These results suggest that the present culture system could generate progenitor B cells to proliferate from CB CD34+ cells, that some of these progenitor B cells could differentiate into immature B cells in conjunction with rhSCF and rhG-CSF, and that a species-cross-reactive membrane-bound factor(s), which stimulates early human B lymphopoiesis, may exist in MS-5 stromal cells. Further studies are required to investigate the mechanism how rhG-CSF acts on progenitor B cells to allow their proliferation and differentiation.     

Granulocyte macrophage colony-stimulating factor is the main cytokine enhancing survival of eosinophils in asthmatic airways

Interleukin (IL)-3, IL-5 and granulocyte macrophage colony-stimulating factor (GM-CSF) prolong the survival of eosinophils, which are conspicuous in asthmatic airways, but it is still controversial which one plays a major role in enhancing the survival of eosinophils in asthmatic airways. The role of these cytokines in airway eosinophilia was investigated using bronchoalveolar lavage (BAL) fluids from 11 symptomatic and nine asymptomatic patients with asthma and eight normal subjects. Eosinophil survival-enhancing activity (ESEA) was measured by a numerical change in viable eosinophils isolated from the peripheral blood of atopic patients and cultured with BAL fluids. ESEA was characterized by neutralization with antibodies to IL-3, IL-5 and/or GM-CSF. The differential count of BAL cells was achieved using Diff-Quik stain. T-cell subsets and activated T-cells were analysed by flow cytometry with dual stain using monoclonal antibodies to CD3, CD4, CD8 and CD25. ESEA was detected in eight of 11 BAL fluids of symptomatic asthma, but not in those of normal controls or asymptomatic asthmatics. In six symptomatic asthmatics, the mean percentage of inhibition in ESEA by anti-GM-CSF was higher than that of anti-IL-5 as well as anti-IL-3 (p<0.05). A mixture of antibodies to IL-3, IL-5 and GM-CSF totally inhibited the ESEA in four cases. The ESEA correlated with the percentage of eosinophils (p<0.05) and that of CD25(+)CD4 lymphocytes (p<0.05) of BAL cells. In conclusion, granulocyte macrophage colony-stimulating factor, rather than interleukin-3 or -5, is associated with eosinophil survival-enhancing activity inside the airways of symptomatic asthmatics. The activation of CD4 lymphocytes is related to the elevation of such activity.     

Seminal transforming growth factor beta1 stimulates granulocyte-macrophage colony-stimulating factor production and inflammatory cell recruitment in the murine uterus

Mating in rodents evokes an inflammatory-like reaction within the uterine endometrium, characterized by extensive infiltration and activation of macrophages, dendritic cells, and granulocytes. This response is initiated when seminal vesicle gland-derived factors in the ejaculate stimulate uterine epithelial cells to release proinflammatory cytokines including granulocyte-macrophage colony-stimulating factor (GM-CSF). Experiments in which seminal vesicle secretions were fractionated by Sephacryl S-400 chromatography and assayed in vitro for GM-CSF-stimulating activity revealed that the seminal moiety coeluted with transforming growth factor beta1 (TGFbeta1) in the 150-440-kDa range and was neutralized by anti-TGFbeta1 antibodies. Comparable amounts of recombinant TGFbeta1 stimulated GM-CSF release in cultures of uterine epithelial cells from estrous mice and, when instilled into the uterine lumen, caused an increase in GM-CSF content and an infiltration of leukocytes into the endometrium similar to the postmating response. These results show that seminal vesicular fluid contains TGFbeta1 at levels sufficient to be the primary causative agent in the postmating inflammatory cascade through induction of GM-CSF synthesis by uterine epithelial cells. Seminal TGFbeta1 is thus implicated as a key factor in initiation of the remodeling events and immunological changes that occur in the uterus during the preimplantation period of pregnancy.