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Results for “Immunization, Passive”

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At least 109 records · Page 6Linked to original sources
PubMed2000

Production of bovine herpesvirus type 1-seronegative latent carriers by administration of a live-attenuated vaccine in passively immunized calves.

The consequences of the vaccination of neonatal calves with the widely used live-attenuated temperature-sensitive (ts) bovine herpesvirus type 1 (BHV-1) were investigated. The ts strain established acute and latent infections in all vaccinated calves either with or without passive immunity. Four of seven calves vaccinated under passive immunity became clearly BHV-1 seronegative by different serological tests, as did uninfected control calves after the disappearance of maternal antibodies, and they remained so for long periods. A cell-mediated immune response was detected by a BHV-1 gamma interferon assay, but this test failed to detect the seronegative latent carriers (SNLCs). While they are not detected, SNLCs represent a threat for BHV-1-free herds or countries. This study demonstrates that SNLCs can be easily obtained by inoculation with a live-attenuated BHV-1 under passive immunity and that latent carrier animals without any antibody do exist. Consequently, this situation could represent a good model to experimentally produce SNLCs.

Animals↗
PubMed1990

Gonadotropin secretion in ovariectomized ewes: effect of passive immunization against gonadotropin-releasing hormone (GnRH) and infusion of a GnRH agonist and estradiol.

Gonadotropin secretion was examined in ovariectomized sheep after passive immunization against gonadotropin-releasing hormone (GnRH). Infusion of ovine anti-GnRH serum, but not control antiserum, rapidly depressed serum concentrations of luteinizing hormone (LH). The anti-GnRH-induced reduction in serum LH was reversed by circhoral (hourly) administration of a GnRH agonist that did not cross-react with the anti-GnRH serum. In contrast, passive immunization against GnRH led to only a modest reduction in serum concentrations of follicle-stimulating hormone (FSH). Pulsatile delivery of the GnRH agonist did not influence serum concentrations of FSH. Continuous infusion of estradiol inhibited and then stimulated gonadotropin secretion in animals passively immunized against GnRH, with gonadotrope function driven by GnRH agonist. However, the magnitude of the positive feedback response was only 10% of the response noted in controls. These data indicate that the estradiol-induced surge of LH secretion in ovariectomized sheep is the product of estrogenic action at both hypothalamic and pituitary loci. Replacement of the endogenous GnRH pulse generator with an exogenous generator of GnRH-like pulses that were invariant in frequency and amplitude could not fully reestablish the preovulatory-like surge of LH induced by estradiol.

Animals↗
PubMed1990

Polymerase chain reaction evidence for human immunodeficiency virus 1 neutralization by passive immunization in patients with AIDS and AIDS-related complex.

We tried to assess the long-term safety and potential efficacy of passive immunization in AIDS-related-complex (ARC) and AIDS patients. We also wanted to establish whether hyperimmune plasma from healthy human immunodeficiency virus 1 (HIV-1)-infected individuals clears the cell-free virus from circulation. Using the polymerase chain reaction (PCR), we were able to provide conclusive evidence that hyperimmune plasma is effective and maintains long-term neutralization of viremia. Using the cell test, we found that in most patients the total antibody level was maintained; in one of the ARC patients, it actually increased 8-fold and has remained at that level for nearly 2 years. The CD4+ cell count decreased in the AIDS patients but was stable in the ARC patient. Clinically, there was an initial improvement in all patients, but five of six of the advanced/terminal AIDS patients had died by month 17. Our studies suggest that passive immunization may be safe in ARC and AIDS patients. It reduces HIV-1 viremia to levels undetectable even by PCR. To advanced/terminal patients, the benefit is of limited duration, while to ARC patients it may be long-term. Therefore, passive immunization should start early in the disease.

AIDS-Related Complex↗
PubMed1990

Passive immunization against Cryptococcus neoformans with an isotype-switch family of monoclonal antibodies reactive with cryptococcal polysaccharide.

The in vivo properties of an immunoglobulin isotype-switch family of monoclonal antibodies specific for the polysaccharide capsule of Cryptococcus neoformans were examined in a murine model of cryptococcosis. Subclass-switch variants were isolated by sequential sublining of an immunoglobulin G subclass 1 (IgG1)-secreting cell line. Antibodies of the IgG1, IgG2a, and IgG2b isotypes with identical reactivities with cryptococcal polysaccharide were prepared. The antibodies had the distinct biological properties associated with the heavy chains of each respective isotype. The antibodies were used prophylactically or therapeutically in an attempt to alter the course of cryptococcal infection in mice. Survival of mice and a tissue census of the numbers of viable cryptococci in the lung, spleen, and brain were used as indicators of efficacy. Passive immunization with the IgG2a and IgG2b antibodies effected a reduction in the numbers of cryptococci in lung and spleen. Passive immunization with the IgG1 antibody was markedly less effective. Passive immunization had little or no effect on the numbers of cryptococci in brain tissue, regardless of the immunoglobulin isotype. Despite apparent efficacy with regard to reduction in the numbers of yeast cells in the lung and spleen, the results showed no improvement in survival from murine cryptococcosis. Our results indicate that passive immunization produces a modest effect on the course of murine cryptococcosis in tissues other than brain. However, under the experimental conditions used, such treatment does not have a measurable impact on the ultimate outcome of the infection.

Animals↗
PubMed2001

Passive immunization against nicotine prevents nicotine alleviation of nicotine abstinence syndrome.

Passive immunization against nicotine interferes with its locomotor and pressor effects. The current study determined whether immunization could prevent another nicotine action: the reversal of nicotine abstinence syndrome. IgG containing 4.4-5.6% nicotine-specific antibody was isolated from rabbits immunized with 3'-amino-methyl-nicotine conjugated to a carrier protein. Twenty rats were rendered dependent by 7 days of subcutaneous infusion of 3.15 mg/kg/day nicotine (expressed as the base). Upon termination of nicotine infusion, each rat was injected intraperitoneally with 150 mg of IgG from normal serum (n=13) or from nicotine antiserum (n=7). Twenty-two and one-half hours later, all rats were observed over 15 min for baseline nicotine abstinence signs. Two and one-half hours after baseline observations, seven of the 13 rats pretreated with control IgG and all seven rats pretreated with nicotine-specific IgG were then challenged by 0.12 mg/kg (sc) nicotine. The remaining six rats pretreated with control IgG were challenged with saline alone. All rats were then observed again for abstinence signs. Nicotine injection caused significantly less reduction of abstinence signs in the immunized rats. The nicotine effect in immunized rats was comparable to the saline effect in nonimmunized rats. Immunization also significantly reduced free serum nicotine concentration and nicotine distribution to the brain. These results raise the possibility that immunization might prevent nicotine consumption from relieving the discomforts of smoking cessation.

Analysis of Variance↗
PubMed1983

The effect of active and passive immunization against oxytocin on ovarian cyclicity in ewes.

Active and passive immunization of ewes against oxytocin prolonged the luteal phase of the oestrous cycle, as evaluated by oestrus behaviour and determination of progesterone. Between the animals there was a high variability in response. In general animals with prolonged cycles had lower concentrations of free oxytocin. But in some animals oxytocin antibodies had no effect on cyclicity. Therefore, an individual minimal threshold concentration for oxytocin was presumed. In control or treated animals circulating oxytocin concentrations increased parallel with progesterone concentrations but decreased earlier during the mid luteal phase of the cycle. A new increase in oxytocin concentrations was only observed if a new corpus luteum was formed.

Animals↗
PubMed1992

Effect of passive immunization with purified specific or cross-reacting immunoglobulin G antibodies against Treponema pallidum on the course of infection in guinea pigs.

Whole immune serum or highly purified immunoglobulin G (IgG) antibodies to Treponema pallidum exhaustively adsorbed with three strains of nonpathogenic treponemes (TPI-IgG) were used for passive immunization of inbred strain 2 guinea pigs before and after intradermal challenge with 3.4 x 10(7) virulent T. pallidum Nichols organisms. Before challenge, control animals received a similarly purified IgG fraction containing either a cocktail of antibodies against three nonpathogenic treponemes (NPTI-IgG) or IgG prepared from normal guinea pig serum (NGPS-IgG). The purified fractions contained both IgG1 and IgG2 isotypes. The antibody levels (detected by fluorescent treponemal antibody test and enzyme-linked immunosorbent assay) and molecular specificities (immunoblot) of sera obtained from recipient animals before infection reflected those of the purified fractions used for immunization. Three protocols of passive immunization were used. Whole immune serum containing specific and cross-reacting antibodies afforded better protection than TPI-IgG even though asymptomatic animals were not fully protected. A single intradermal injection (0.1 ml) of TPI-IgG or NPTI-IgG into one hind leg 22 h before infection at the same site provided relatively higher protection than multiple intravenous injections (total, 15 ml) of the respective individual preparations. Since purified NGPS-IgG injected in the same animals, into the opposite hind leg, failed to protect against the challenging infection, it is reasonable to assume that specific and cross-reacting antitreponemal antibodies of the IgG1 subclass, which in guinea pigs are homocytotropic, play a relevant role in local protection.

Animals↗
PubMed1980

Calcium regulatory action of endogenous rat calcitonin demonstrated by passive immunization with calcitonin antibodies.

The calcium regulatory role of calcitonin (CT) in murine physiology was evaluated with a combination of immunological techniques, bioassays, and gland ablation. Passive immunization of rats with neutralizing CT antibodies caused an immediate but transient increase in plasma calcium with a time course similar to that observed in thyroparathyroidectomized animals. In animals fasted during the day and fed at night (1700-0700 h), acutely decreasing endogenous CT (< 100 pg/ml) by thyroparathyroidectomy or by passive immunization with CT antibodies resulted in a greater increase in plasma calcium in the preprandial (1600 h) than in the postprandial inverse correlation between immunoreactive CT and plasma calcium, a known secretagogue for CT. In these animals on a restricted feeding schedule, a sharp preprandial (1600 h) rise in immunoreactive and bioactive CT and a circadian rhythm in plasma calcium were also observed. The onset of the increase in circulating CT preceded the onset of feeding and coincided with or shortly preceded the daily nadir of plasma calcium. These findngs establish that CT has a primary calcium regulatory role in murine physiology. More specifically, they demonstrate that 1) the postthyroparathyroidectomy increase in plasma calcium is due specifically to the loss of CT, 2) passive immunization is a feasible technique for evaluating the actions of endogenous CT, 3) the role of CT in calcium regulation cannot be restricted to that of preventing prandial and postprandial increase in blood calcium, and 4) factors other than calcium must be involved in the control of CT secretion in the nonfed state.

Animals↗
PubMed1997

Effect of oestradiol on mRNA encoding GnRH receptor in pituitary tissue of orchidectomized sheep passively immunized against GnRH.

The effect of oestradiol on tissue concentrations of GnRH receptor and mRNA encoding GnRH receptor was assessed in orchidectomized sheep (wethers) made deficient in GnRH by passive immunization. Wethers were assigned to one of four groups (n = 6 animals per group). Animals in groups 2 and 4 received ovine anti-GnRH sera (200 ml; i.v.) at passive immunization, while antisera against the carrier protein was administered to wethers in groups 1 and 3. Oestradiol was delivered as a continuous infusion (2 micrograms h-1) to wethers in groups 1 and 2. Animals in groups 3 and 4 were infused with vehicle alone. Anterior pituitary tissue was collected at the end of the 48 h infusion. Anti-GnRH sera induced a rapid reduction in the serum concentration of LH. Continuous delivery of oestradiol resulted in a twofold increase (P < 0.05) in tissue concentration of GnRH receptor. This oestradiol-induced response was manifest even in wethers in which endogenous GnRH had been neutralized by passive immunization. Conversely, infusion of oestradiol increased (P < 0.05), and intravenous administration of anti-GnRH sera decreased (P < 0.05), concentrations of mRNA encoding GnRH receptor in pituitary tissue. When delivered in combination, anti-GnRH sera reduced (P < 0.05), but did not eliminate, the oestradiol-induced augmentation of steady-state concentrations of mRNA encoding GnRH receptor. These data demonstrate that the basal concentration of mRNA encoding GnRH receptor is dependent on continued GnRH stimulation. In contrast, the oestradiol-induced increase in steady-state concentration of mRNA encoding GnRH receptor is manifest even in the absence of GnRH.

Animals↗
PubMedDate not supplied

Prevention of hepatitis B infections by passive immunization.

Experience with the use of standard immune serum globulin (ISG) and the more recently available hepatitis B immune globulin (HBIG) is reviewed. The biologic phenomena which could be affected by passive immunization are discussed, as are recommendations for the use of these forms of passive immunization in the prevention of hepatitis B infections.

Adult↗
PubMed1984

Active and passive immunization against Rift Valley fever virus infection in Syrian hamsters.

The protection by active and passive immunization of Golden Syrian hamsters challenged with Rift Valley Fever (RVF) virus intraperitoneally was studied. Six groups of 10 hamsters were inoculated with different amounts of immune serum while five groups were actively immunized with different doses of a formalin-inactivated RVF vaccine. One day after passive and three weeks after active immunization all hamsters were challenged with 5000 plaque-forming units of RVF virus. Plaque reduction neutralization tests (PRNT) were performed with serum samples collected immediately before challenge. A PRNT titer of 10-20 or more was required for full protection against the RVF challenge in both actively and passively immunized hamsters. Actively immunized hamsters and control animals that succumbed to the infection died within the first 4 days after virus challenge, whereas some passively immunized hamsters died as late as 11 days post virus challenge. Animals that died early had developed massive liver necrosis, whereas late death was caused by encephalitis.

Animals↗