Nippostrongylus brasiliensis: intestinal goblet-cell response in adoptively immunized rats.

Goblet-cell differentiation was studied in the intestinal epithelium of rats infected with the nematode Nippostrongylus brasiliensis. An increase in the proportion of goblet cells occurred at the time of worm expulsion in rats infected with 1000 or 4000 third stage larvae. Adoptive immunization of infected rats with immune-thoracic duct lymphocytes (TDL) induced extensive goblet-cell differentiation whereas the transfer of immune-TDL into normal rats had no effect. The extent of goblet-cell differentiation in adoptively immunized infected rats was proportional to the number of cells transferred. A goblet-cell response also occurred in adoptively immunized rats harboring implanted “normal” and “damaged” worms but recipients of normal worms which were not given cells were unable either to expel their worm burden or to induce a goblet-cell response. Experiments in which the parasites were expelled with an anthelmintic drug suggested that the goblet-cell increase was not simply a repair process associated with the expulsion of the parasites. In all situations where immune expulsion of the parasites occurred, there was a concomitant rise in the proportion of goblet cells. These experiments suggest that thoracic duct lymphocytes either directly or indirectly regulate the differentiation of intestinal goblet cells.     

Ovarian response to PMSG treatment in ewes immunized against oestradiol-17 beta

The effects of active immunization against oestradiol-17 beta on the ovarian response to pregnant mare serum gonadotrophin (PMSG) was investigated in Merino ewes. Immunized (79) and control (41) ewes were synchronized with intravaginal sponges, given either 750 or 1500 i.u. PMSG and then mated to rams or inseminated laparoscopically with fresh diluted semen. All control ewes mated naturally exhibited oestrus and 40 out of 41 control ewes ovulated. The ovulation rate was higher in the controls receiving 1500 i.u. PMSG than in those ewes which received 750 i.u. PMSG (10.2 v. 3.3). Immunization against oestradiol-17 beta resulted in antibody titres varying from 100 to more than 100 000 in plasma taken 1-4 days after mating. The ovarian response increased significantly in the lowest titre group (100-1000) in conjunction with stimulation with 1500 i.u. PMSG. In these ewes the ovulation rate increased over controls (16.7 v. 10.2) as did the total ovarian response, which includes follicles greater than 10 mm diameter (22.3 v. 11.1). The total ovarian response was also increased in those ewes given 750 i.u. PMSG which had titres in the 1000-10 000 and 10 000-100 000 range, but this was not accompanied by significant increases in the ovulation rate. In general, the higher titre levels (greater than 1000) were correlated with decreases in the proportion of ewes showing oestrus and ovulating and in the embryo recovery rate. The 1500 i.u. PMSG treatment group with the highest titres (greater than 10 000) also showed a significant drop in the ovulation rate as compared to the 1500 i.u. PMSG controls.     

Definition of the pulmonary antibody response to ovalbumin following local challenge in systemically immunized rats

The in vivo pulmonary immune response of rats to local stimulation with antigen was assessed by measuring antigen-specific antibody and antibody-secreting cells utilizing enzyme-immunoassay technology. Sprague-Dawley rats were immunized subcutaneously with ovalbumin (OA) emulsified in Freund's incomplete adjuvant, challenged with OA intratracheally on Day 19 and sacrificed 1, 2, 3, or 4 days later. Specific antibody-secreting cells in the lung-associated lymph nodes were enumerated with the ELISA-SPOT assay and antibody concentration in the pulmonary lavage fluids and sera was assessed with the ELISA. The greatest response for each parameter was on Day 2. Cellular infiltration of the lung was minimal. Cellular infiltrates consisted mainly of polymorphonuclear leukocytes and were most numerous in the lavage fluid on Days 1 and 2 and in the lung parenchyma on Day 2 after challenge. Local production versus serum transudation of antibody was evaluated by comparing the levels of OA-specific antibody to albumin in the lavage fluid and serum. The data showed that antibody in the lungs was primarily produced locally.     

Reduced inflammatory response in rats fed fat-rich diets: role of leukotrienes

The effect of fat-rich diets on the acute inflammatory response was examined. Male Wistar rats aged 21 days were fed, for 6 weeks, with a control diet (4% fat content), or a control diet supplemented with coconut or soybean oils (15% fat content). Carrageenan-induced paw oedema and pleurisy were evaluated. Prostaglandin (PG) E2 and leukotriene (LT) C4/D4 concentrations were determined in the pleural exudate (ELISA). Pleural samples were tested for their effect on cutaneous vascular permeability of control rats and the effect of a LTD4 receptor antagonist (L660-711; 10 mg/kg; i.v.) examined. Relative to controls, rats fed both fat-rich diets presented a significant reduction in protein leakage and oedema formation without affecting the number of migrating leukocytes. Production of LTC4/D4 in pleural exudate was significantly increased from 1.8 +/- 0.2 ng/ml in controls to 2.8 +/- 0.2 and 3.0 +/- 0.3 ng/ml in animals fed coconut and soybean oil enriched diets, respectively, without changes in PGE2 production. The activity of these samples on cutaneous vascular permeability was 50% reduced, returning to control values after treatment of testing animals with a LTD4 receptor antagonist. Rats fed fat-rich diets presented a reduced inflammatory response due, at least in part, to the LTC4/D4 mediated vasoconstrictor effect.     

Embryo losses in Rasa Aragonesa ewes actively immunized against androstenedione or passively immunized against testosterone

Two-day-old embryos from untreated ewes were transferred to the oviducts of ewes actively immunized against androstenedione (n=26, Group A), passively immunized against testosterone (n=19, Group B) or left untreated (n=25, Group C). Donor ewes superovulated after treatment with follicle-stimulating hormone and fluorogestone acetate (FGA). Recipient ewes were treated with FGA and pregnant mare serum gonadotropin (PMSG, 300 I.U.). Group A received two injections of Fecundin at a 4-wk interval. FGA sponges were inserted when the second injection was given. Group B was treated with antitestosterone antiserum (35 ml) at sponge withdrawal. Each recipient received two morphologically viable embryos 52 to 62 h after the onset of estrus. Antibody titre at embryo transfer and progesterone concentration on Days 2, 4, 6, and 12 after estrus were determined. Fertility was lower in Group A when compared to Group C (42.3 vs 84.1%; P<0.01) while that of Group B (63.2%) did not differ from those of Groups A and C. In immunized groups, most of the embryo losses occurring were complete (both embryos were lost), resulting in a decreased fertility, while in the untreated group embryo losses were mainly partial (only one embryo was lost), hence lowering prolificacy. Fertility in immunized groups changed according to the antibody titre reached. Ewes from Groups A and B with higher antibody titres displayed lower fertility than control ewes. On Days 4 and 12 of the cycle, Group A plasma progesterone concentrations positively correlated with antibody titres and were higher with respect to those of Group C (P<0.05). Progesterone levels in Group B were similar to those of Group C. These results indicate that ewes reaching higher antibody levels had more embryo losses, attributable to the adverse influences of the oviductal and/or uterine environment on embryo development.     

Histological evaluation of scar tissue inflammatory response: the role of hGH in diabetic rats

This paper describes a polymer site-specific delivery system containing human growth hormone in an in vivo model of scarring in the diabetic state. Copolymer discs with the hormone were introduced into incisions made in rats previously injected with streptozotocin in order to induce diabetes. Tissue specimens for evaluation were obtained at 3, 7 or 10 days after the procedure. Study groups were healthy rats and diabetic rats untreated or treated with/without the hormone. Histological sections were prepared for light microscopy examination of wound zones. Three and 7 days after surgery, polymer remains could be observed in the subcutaneous tissue. These remnants induced a moderate foreign body reaction. The number of macrophages detected was directly related to neovessel formation and metalloelastase expression. The CD4+/CD8+ ratio was low during the initial follow up stages (3 and 7 days) in untreated diabetic rats, yet an increased ratio corresponding to areas around the polymer remains was noted in the animals treated with copolymer loaded with the growth hormone. Copolymer is biodegradable in vivo and may be used as a vehicle for the slow release of active substances. The presence of the hormone at the site of skin injury induces cell proliferation and enhances the repair process.     

Anti-pre-S2 antibody response in subjects vaccinated against hepatitis B and in naturally immunized subjects

Serum samples from individuals immunized with a pepsinized or non-pepsinized vaccine and from patients who had recovered from acute hepatitis B or who developed a chronic form of the disease, were analysed for the presence of antibody against the pre-S2 epitope of the hepatitis B virus.Anti-pre-S2 antibody was absent in all but one individual immunized with the pepsinized vaccine. Thirty-eight percent of the subjects who responded by anti-HBs production to the non-pepsinized preparation showed anti-pre-S2 antibody one year after complete vaccination. Among subjects who did not produce anti-HBs after immunization with this vaccine, 1 single individual produced anti-pre-S2 antibody. Anti-preS2 antibody was detectable after one year in 38% of the patients who recovered from acute hepatitis B, but in none of those with chronic hepatitis B. The kinetics of anti-pre-S2 antibody response to a booster injection was also analysed 1 month and 1 year after the 3rd injection and 1 month after the 4th injection of the non-pepsinized vaccine.     

Cyclic response of hypophysectomized rats to ovulation induced by LHRH agonist: mediation by prostaglandins

Further confirmation that the LHRH/LHRH agonist-induced ovulation in the hypophysectomized (hypx) rat is due to a direct ovarian effect and not mediated by LH release from residual pituitary tissue or other CNS sites is provided by the persistence of this effect despite concomitant median eminence lesion or passive immunization to LH. Adrenalectomy did not affect the ovulatory activity of the LHRH agonist, D-Trp6-N alpha MeLeu7-DesGly10-Pro9-NHEt-LHRH (Wy-40,972), in the hypx rat. Prior administration of a potent LHRH antagonist blocked ovulation induced in hypx proestrous rats by Wy-40,972 but not by LH-S19. Ovulation can be induced by Wy-40,972 one day earlier (e.g. metestrus) in the intact rat than it can in the hypx rat. Results in the hypx metestrous rat indicate that the ovulatory responsiveness of the intact rat at this stage of the cycle may occur by complementary action of Wy-40,972-stimulated endogenous LH release and a direct ovarian effect of the agonist. Prostaglandins (PG) are involved in the ovulatory mechanism of Wy-40,972 in the hypx proestrous rat as evidenced by the dose-dependent inhibition of this effect by PG synthetase inhibitors, indomethacin and Fentiazac. Moreover, there were significant increases in ovarian concentrations of PGF2 alpha and PGE2-PGE1 in response to Wy-40,972 that could be prevented by indomethacin. However, exogenous administration of either of these PG's was not effective in inducing ovulation in the hypx rat.     

Mucosal damage induced by preferential COX-1 and COX-2 inhibitors: role of prostaglandins and inflammatory response

Nonsteroidal anti-inflammatory drugs (NSAID) are well known to induce gastric mucosal damage including bleeding, ulceration and perforation in humans and animals too. These effects are related with the inhibition of the enzyme cyclooxygenase, which is the main established mechanism of action for these drugs. Fasted rats were given piroxicam, preferential COX-1 inhibitor (10-20 mg/kg) or meloxicam, preferential COX-2 inhibitor (7.5-15 mg/kg) orally. Six or nine hours (h) later, respectively, the stomach was excised, the severity of the damage assessed and myeloperoxidase (MPO) activity measured, as well as prostaglandin PGE(2) content. Furthermore, in order to assess the effects of these oxicams over previously damaged gastric mucosa, 1 ml of 0.6 N HCl was administered p.o. followed, 1 h after, of the correspondent dose of each NSAID, and the same parameters were determined. Oral administration of both drugs dose-dependently caused acute gastric haemorrhage erosions. Myeloperoxidase activity was significantly increased by piroxicam administration. In addition, PGE(2) content was significantly reduced. The association between the administration of the acid and NSAID caused a worsening of the damage and, while myeloperoxidase activity did not modify by both piroxicam and meloxicam, PGE(2) levels were reduced. These results suggest that the PG derived from both COX-1 and COX-2 pathway plays a beneficial role in the gastroprotection, and thus caution should be exercise in the clinical use of preferential COX-2 inhibitors.     

Trypanosoma cruzi: cellular and antibody response against the parasite in mice immunized with a 19-amino acid synthetic peptide

Several monoclonal antibodies were prepared against the flagellar fraction of Trypanosoma cruzi epimastigotes (Tulahuén strain, stock Tul 2). One of them, FCH-F8-4, has previously shown biologic activity against the parasite (complement-mediated lysis and neutralization of the trypomastigote infectivity). Immunopurified antigens using this monoclonal antibody elicited a protective immune response in mice. Two recombinant cDNA clones were detected with this anti-flagellar fraction monoclonal antibody on a lambda gt11 expression library prepared from T. cruzi epimastigote mRNA. The insert of one of these cDNA clones, lambda(FCH-F8-4)1 (150 bp) coded for a 19-amino acid peptide (PAFLGCSSRFSGSFSGVEP). This insert hybridized with a 5.0-kb mRNA from epimastigotes. The beta-galactosidase fusion protein was produced in lysogenic bacteria. The monoclonal antibody recognized the epitope present in the fusion protein after western blotting of the crude lysate. A synthetic peptide (SP4) containing the complete sequence of lambda(FCH-F8-4)1 was constructed on solid phase. This peptide was able to inhibit the ELISA reactivity (in a range from 13 to 52%) of flagellar fraction immunized mouse sera and when administered (coupled to KLH or alone) to BALB/c mice with Bordetella pertussis as adjuvant, it induced a humoral and cellular immune response which was detected by ELISA, immunofluorescence, blotting, and DTH reactions against T. cruzi antigens. The immune response obtained indicates that this synthetic peptide resembles the parasite antigen conformation and could be useful for diagnosis purposes or be able to elicit immunoprotection against T. cruzi infection.