Biomedical subjects

F Blecha

Publications and source records attributed to F Blecha.

At least 91 records · Page 5Linked to original sources

PubMed1989

Influence of isoprinosine on lymphocyte function in virus-infected feeder pigs.

Pseudorabies is a porcine herpesvirus of major importance in the swine industry. Isoprinosine is an immunomodulating drug that has been shown to be beneficial in treating herpesvirus infections. Twenty-four 7-week-old pigs were allotted within litters to 1 of 4 groups: control, isoprinosine (ISO), pseudorabies virus (PRV), or isoprinosine and pseudorabies virus (ISO-PRV). Isoprinosine was administered daily for 16 days to the ISO and ISO-PRV groups (75 mg/kg of body weight/day, PO). Immunity in pigs in the PRV and ISO-PRV groups was challenged with pseudorabies virus (10(5) TCID50 units) on day 4. Rectal temperatures and viral excretion were monitored daily; total and differential leukocyte counts, lymphocyte response to mitogens, and interleukin-2 production were monitored every 4 days. Pigs challenge-inoculated with pseudorabies virus became ill, with the ISO-PRV group most severely affected. Rectal temperatures were high (P less than 0.05) in virally challenged pigs on days 5 to 12 and 14 to 16; isoprinosine did not alter this effect. Pseudorabies virus-infected pigs had leukocytosis (P less than 0.05) on days 12 and 16, primarily caused by neutrophilia. Concanavalin A-stimulated lymphocyte proliferation was decreased (P less than 0.06) in both PRV and ISO-PRV groups on day 12, compared with control pigs, but only in the PRV group on day 16. Pokeweed mitogen-stimulated lymphocyte proliferation was decreased (P less than 0.02) in ISO-PRV pigs on day 8 of the experiment. Interleukin-2 concentrations, pooled over all sampling days, were decreased (P less than 0.03) in pseudorabies virus-infected pigs. Viral excretion was not altered by isoprinosine treatment. These data suggest that pseudorabies virus infection decreased lymphocyte proliferative responses and interleukin-2 production in pigs, and that isoprinosine did not mitigate these effects.

Animals↗

PubMed1989

Bovine herpesvirus-1 and parainfluenza-3 virus interactions: clinical and immunological response in calves.

Calves infected with bovine herpesvirus-1 (BHV-1) or both BHV-1 and parainfluenza-3 virus (PIV-3) developed clinical signs including fever, cough, and nasal and ocular discharges. Animals infected with both viruses appeared more depressed and showed higher rectal temperature, while calves inoculated with PIV-3 alone had a very mild clinical disease. Both BHV-1 and PIV-3 were recovered from nasal secretions up to six to eight days postinoculation. However, the virus titers were lower in calves with mixed infection. An increase in serum antibodies to both BHV-1 and PIV-3 was detected by serum neutralization and enzyme-linked immunosorbent assay. Antibody responses were delayed and significantly lower in calves given mixed infection than in calves infected with a single virus. Interleukin-2 activity in cultures of lymphocytes from BHV-1 and BHV-1 plus PIV-3 infected calves was higher compared to control calves.

Animals↗

PubMed1988

Influence of sodium diethyldithiocarbamate (Imuthiol) on lymphocyte function and growth in weanling pigs.

Mitogen-stimulated lymphocyte proliferation, delayed-type hypersensitivity (DTH) reactions, interleukin-2 (IL-2) production, and growth performance were evaluated in 3-week-old pigs treated with imuthiol. Lymphocyte proliferative responses to Con A and PWM were reduced (P less than 0.05) in pigs treated with imuthiol at 25 mg/kg; PHA proliferative responses were not influenced by imuthiol treatment. Imuthiol at 2.5 mg/kg lowered IL-2 production when compared to saline-treated controls. Delayed-type hypersensitivity responses to PHA were higher in 25 mg/kg imuthiol-treated pigs; however, 2.5 mg/kg imuthiol-treated pigs had lower DHT reactions. Imuthiol at 2.5 mg/kg and 25 mg/kg reduced (P less than 0.05) average daily feed intake. These data suggest that in vivo imuthiol treatment in pigs lowers lymphocyte proliferative responses, IL-2 production, and growth performance.

Adjuvants, Immunologic↗

PubMed1988

Characterization of anti-idiotype reagents to bovine herpesvirus-1 monoclonal antibody.

A monoclonal antibody (MAb) to a neutralization epitope on the 97-kD glycoprotein of bovine herpesvirus-1 (BHV-1) was used to prepare an anti-idiotypic antibody in rabbits. Purified F(ab')2 fragments of the MAb were used to immunize the animals and the sera containing the greatest anti-idiotype activity were identified by ELISA. After digestion of the immunoglobulins with pepsin and purification by affinity chromatography, anti-idiotype F(ab')2 fragments reacted specifically with the MAb in ELISA. Binding of the anti-idiotypic (anti-id) antibody was inhibited by preincubation of the MAb with BHV-1. Using an ELISA inhibition assay with BHV-1, the anti-id reagent inhibited the binding of anti-BHV-1 MAb to BHV-1, suggesting that the anti-id mimics an epitope of the 97-kD glycoprotein by binding the antigen combining site of the MAb. Development and characterization of this anti-id and future studies of its immunomodulatory effects are discussed.

Animals↗

PubMed1988

Fluctuating ambient temperature for weaned pigs: effects on performance and immunological and endocrinological functions.

Following weaning at 3 wk of age, crossbred barrows and gilts were housed in temperature-controlled rooms for a 5-d adjustment period at 35 degrees C, then assigned to receive constant ambient temperature (CT) or fluctuating ambient temperature (FT) treatment for the nursery phase of the experiment. Pigs in FT received 12 h at 35 degrees C and 12 h at 15 degrees C daily for the initial 2 wk of the experiment, then 12 h at 29 degrees C and 12 h at 9 degrees C daily for the final 2 wk. Pigs in CT received 35 degrees C and 29 degrees C continuously for the first and final 2 wk, respectively. Weekly growth performance, feed intake and feed-conversion efficiency were not affected by treatment. Plasma glucose, serum cortisol, monocyte phagocytic function and antibody response to a commercial E. coli bacterin were similar in pigs exposed to CT and FT treatments. Concentrations of insulin in serum were similar between treatments at 0, 1 and 3 wk but were increased for pigs in FT at 2 (P less than .05) and 4 wk (P less than .01). Numbers of lymphocytes, band neutrophils and monocytes in pigs were not influenced by ambient temperature treatment. However, numbers of mature neutrophils for pigs in FT were increased (P less than .05) at 1 and 3 wk of treatment. Eosinophils were also elevated in FT pigs at 4 wk of treatment. Pairs of littermate pigs that had been given CT and FT treatments were selected randomly to continue on the finishing phase of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗

PubMed1988

Immunomodulation: a means of disease prevention in stressed livestock.

The ability to stimulate the immune response of cattle and pigs offers a new means of disease intervention. This review discusses current in vivo experiments that have evaluated immunomodulators in cattle and pigs. Levamisole, thiabendazole, imuthiol, avridine, isoprinosine, bovine recombinant interferon, human recombinant interleukin-2, bovine recombinant interleukin-2 and various supplemental vitamins and minerals have been used as immunomodulators in livestock with various degrees of success. Future research on immunomodulators, specific for domestic farm animals, will provide additional methods of treating immunosuppressed animals.

Animals↗

PubMed1988

Influence of sarcoptic mange and cold and ambient temperature on blastogenic responses of lymphocytes and serum cortisol concentrations of pigs.

Blood samples from sarcoptic mite-infested pigs were evaluated for effects of mite infestation and cold and ambient temperatures on lymphocyte blastogenic responses and for effects of mite infestation on serum cortisol concentrations. In experiment 1, sarcoptic mite-infested and noninfested pigs were housed in cold (5 to 15 C fluctuating) and thermoneural (25 C) environmental chambers for 5 weeks. Differences were not observed (P greater than 0.10) in blastogenic responses to phytohemagglutin or pokeweed mitogen between lymphocytes from infested and noninfested pigs on postinfestation days (PID) 7, 21, 28, and 35 in either environmental chamber. When lymphocytes from noninfested pigs were cultured with sera from infested pigs, alterations of blastogenic responses were not detected. Cortisol values were higher (P less than 0.05) in sera from sarcoptic mite-infested pigs, compared with those from noninfested pigs, at 4 PM on PID 14 and 4 AM and 10 AM on PID 15. Cortisol values were higher (P less than 0.05) in sera obtained at 10 AM on PID 14 and at 10 AM on PID 15 from pigs housed in cold chambers, compared with those from pigs housed in thermoneutral chambers. Interactive effects between sarcoptic mite infestation and cold ambient temperatures were not observed. At 4 AM on PID 15 (experiment 2), cortisol values were higher (P less than 0.05) in sera of infested pigs, compared with those in noninfested pigs. Seemingly, sarcoptic mange in pigs did not alter mitogen-induced lymphocyte blastogenic responses, but did increase serum cortisol concentrations, indicating that sarcoptic mange may be a stressor in pigs.

Animals↗

PubMed1987

Influence of isoprinosine on bovine herpesvirus type-1 infection in cattle.

A study was conducted to determine the in vivo efficacy of isoprinosine (ISO) in calves infected with bovine herpesvirus type-1 (BHV-1). Calves were infected with BHV-1 on day 0 and received ISO daily for 14 days. Clinical signs of disease, shedding of BHV-1, lymphocyte proliferative responses to mitogens, interleukin-2 production, and alveolar macrophage bactericidal activity were monitored during the study. Rectal temperatures were increased (P less than 0.05) in BHV-1 and ISO-BHV-1 calves at days 3 to 7 postinfection (PI). Isoprinosine did not influence BHV-1 shedding in calves. Lymphocyte proliferative responses to phytohemagglutinin (PHA) were lower (P less than 0.01) in BHV-1 calves when compared to control or ISO calves at day 4 PI, but ISO did not ameliorate this effect. Interleukin-2 activity was greater (P less than 0.05) in ISO-BHV-1 calves on days 4 and 8 PI in PHA-stimulated lymphocytes and on day 8 PI in concanavalin A-stimulated lymphocytes when compared to control, ISO or BHV-1 calves. Isoprinosine treatment of BHV-1-infected calves tended to decrease alveolar macrophage bactericidal activity. These data suggest that ISO does not reverse BHV-1 suppression of lymphocyte proliferation, but may enhance IL-2 production in BHV-1 infected calves.

Animals↗

PubMed1987

Isoprinosine and levamisole immunomodulation in artificially reared neonatal pigs.

An experiment was conducted to determine the capability of isoprinosine (ISO) and levamisole (LEV) to augment delayed-type hypersensitivity and lymphocyte blastogenic reactions in artificially reared pigs. Sow-reared pigs (n = 15) were kept with their dams; artificially reared pigs (n = 15) were removed from sows within 2 days after parturition and reared artificially for 21 days. Isoprinosine was administered orally (75 mg/kg/day) from days 0 to 10. Levamisole (2 mg) was injected subcutaneously on days 5 and 10. Control pigs were given distilled water orally from days 0 to 10 and injected subcutaneously with 0.15M NaCl on days 5 and 10. Lymphocyte proliferative responses to phytohemagglutinin, concanavalin A, and pokeweed mitogen were evaluated at week 2. The phytohemagglutinin skin-test responses were evaluated in all pigs at weeks 1 and 3 of the trial. Hematologic values, body weight, and mortality were evaluated each week. The skin-test responses and mitogen-induced lymphocyte proliferative responses were lower (P less than 0.05) in artificially reared controls when compared with responses in sow-reared pigs. However, ISO and LEV enhanced (P less than 0.05) the responses in the artificially reared pigs to values comparable with those of the sow-reared controls. Body weight was greater (P less than 0.01) in sow-reared pigs than in artificially reared pigs; drug treatment did not influence weight gain. These data indicated that immunopotentiation of the cellular immune responsiveness of artificially reared pigs may be possible with ISO or LEV.

Adjuvants, Immunologic↗

PubMed1986

The effect of sarcoptic mange on growth performance, leukocytes and lymphocyte proliferative responses in pigs.

The effects of a single artificial infestation with sarcoptic mite (Sarcoptes scabiei var. suis DeGeer) on weight gain and lymphocyte blastogenic responses were studied in untreated and fenvalerate-treated pigs. Average daily feed intake, average daily gain and feed efficiency were monitored for 5 weeks in 32 infested and 16 uninfested pigs. Total and differential leukocyte counts were determined and lymphocyte proliferative responses, using a mitogen-stimulated lymphocyte blastogenesis assay, were evaluated in 24 pigs. Sarcoptic mite infestation or treatment for sarcoptic mange did not affect total or differential leukocyte counts (P greater than 0.10). Differences were not observed in weight gain or lymphocyte blastogenic responses between infested and uninfested pigs.

Analysis of Variance↗

PubMed1986

Effect of cortisol in vitro and in vivo on production of bovine interleukin 2.

The influence of cortisol in vitro and in vivo on lymphocyte proliferative responses and interleukin 2 (IL2) production was evaluated in Hereford feeder calves. Cortisol, added to bovine mononuclear cell cultures, reduced (P less than 0.05) mitogen-stimulated lymphocyte proliferative responses and IL2 production. Lower IL2 activity from cortisol-treated cell cultures was not caused by a cortisol-mediated cytotoxicity or a residual cortisol effect on the IL2-indicator cell line. Calves given ACTH (1.0 IU/kg of body weight, IM) twice daily for 2 days had increased (P less than 0.001) plasma cortisol concentrations when compared with those of saline-treated controls. Leukocytosis (P less than 0.002), characterized mainly by a neutrophilia (P less than 0.007), was evident in ACTH-treated calves. Lymphocyte proliferative responses to the phytomitogens, concanavalin A, phytohemagglutinin, and pokeweed mitogen were decreased (P less than 0.05) in calves with increased plasma cortisol concentrations. Interleukin 2 production was lower (P less than 0.05) in concanavalin A-stimulated lymphocyte cultures from ACTH-treated calves. Seemingly, lower lymphocyte proliferative responses in cortisol-treated mononuclear cell cultures and in ACTH-treated calves were caused partly by lower IL2 production.

Animals↗

PubMed1986

Decreased mononuclear cell response to mitogens in artificially reared neonatal pigs.

The influence of two rearing methods for neonatal pigs on mononuclear cell responses to mitogens was studied. Littermate pigs were reared artificially or on the sow. Artificially reared pigs displayed a leukocytosis (P less than 0.05) characterized by an increase (P less than 0.05) in mature and immature neutrophils. Skin-test responses to intradermal injections of phytohemagglutinin were less (P less than 0.05) in artificially reared pigs than in sow-reared controls. Lymphocyte proliferative responses to mitogenic stimulation were approximately 50% lower (P less than 0.05) in artificially reared pigs than in sow-reared pigs. These data suggest that artificial rearing lowers in vivo and in vitro lymphocyte responses in neonatal pigs.

Analysis of Variance↗

PubMed1985

Immunologic reactions of pigs regrouped at or near weaning.

Using 64 pigs, 2 experiments (32 pigs each) were conducted to evaluate the effects of regrouping nonlittermate pigs at weaning or 2 weeks after weaning on mitogen-induced lymphocyte blastogenesis, intradermal reactions to phytohemagglutinin, and primary antibody responses to sheep erythrocytes. Plasma cortisol concentrations were determined in all pigs and behavior of regrouped pigs was monitored. Compared with control values, plasma cortisol concentrations were higher in nonlittermate pigs regrouped at weaning (P less than 0.001) or 2 weeks after weaning (P less than 0.01). However, regrouping pigs at weaning or 2 weeks after weaning did not influence lymphocyte blastogenesis, phytohemagglutinin skin-test responses, or antibody titers to sheep erythrocytes. Plasma cortisol concentrations were not related to agonistic behavior in regrouped pigs or to lymphocyte blastogenic or phytohemagglutinin skin-test responses; however, higher plasma cortisol concentrations were related (P less than 0.05) to lower sheep erythrocyte antibody titers. These data indicate that regrouping nonlittermate pigs at weaning or 2 weeks after weaning is an acute stressor that does not detrimentally affect mitogen-induced lymphocyte blastogenesis, intradermal reactions to phytohemagglutinin, or primary antibody responses to sheep erythrocytes.

Agonistic Behavior↗

PubMed1984

Shipping suppresses lymphocyte blastogenic responses in Angus and Brahman X Angus feeder calves.

An experiment using 40 Angus or Brahman X Angus preconditioned feeder calves was conducted to evaluate the influence of shipping on cellular immune reactivity. Steers were allotted on the basis of weight and breed to a control or shipped group. Shipped steers were trucked 700 km to a feedlot; control steers remained at the ranch of origin. Total and differential leukocyte counts, phytohemagglutinin skin-test responses, lymphocyte blastogenic responses, monocyte phagocytic function, packed cell volumes and concentrations of plasma cortisol were determined before, immediately after and 1 wk after shipment. At unloading, total leukocytes were increased (P less than .05) in shipped Angus steers. Shipped steers also had higher (P less than .01) numbers of neutrophils. Skin-test responses to phytohemagglutinin were higher (P less than .05) in Angus than in Brahman X Angus steers, but shipping did not influence the reaction. Lymphocyte blastogenic responses were lower (P less than .05) in shipped steers; however, cortisol levels in plasma were not elevated (P greater than .10) in shipped calves. Monocyte phagocytosis and packed cell volume were not influenced by shipping. These data suggest that shipped steers have suppressed lymphocyte blastogenic responses.

Animals↗

PubMed1984

Lung delayed-type hypersensitivity in stressed mice.

The influence of an immobilization stressor on lung cellular immune responses was studied. Delayed-type hypersensitivity to sheep erythrocytes was used to evaluate in vivo lung cellular immunity. Mice were sensitized intravenously and challenged intratracheally with sheep erythrocytes. Three hours prior to challenge all mice were injected intravenously with chromium-51 labeled mononuclear cells from syngeneic mice. The delayed-type hypersensitivity response was measured by counting the radioactivity within the lung 48 hours after challenge. Immobilization for 2.5 hours immediately before challenge suppressed lung delayed-type hypersensitivity. Adrenalectomy abolished the immobilization-induced decrease in delayed-type hypersensitivity. These data indicate an adrenal gland involvement in stress-induced decreases in lung cellular immune reactions.

Adrenal Glands↗

PubMed1983

Weaning pigs at an early age decreases cellular immunity.

An experiment involving 118 pigs was conducted to evaluate the influence of weaning pigs at four different ages on in vivo and in vitro cell-mediated immunity. One-half of each litter was weaned at 2, 3, 4 or 5 wk of age; the other one-half remained with the sow as nonweaned controls. Phytohemagglutinin skin-test responses were determined on all pigs. Blastogenic responses of mitogen-stimulated lymphocyte cultures were determined before and after weaning. The intradermal response to phytohemagglutinin was reduced (P less than .001) in pigs weaned when 2 or 3 wk old and was suppressed (P less than .05) in those weaned when 4 wk old. In vivo cellular immunity was not altered by weaning in 5-wk-old pigs. The capability of lymphocytes to undergo blastogenesis in response to phytohemagglutinin was decreased in pigs weaned at 2 and 3 wk of age (P less than .001 and P less than .01, respectively). Pokeweed mitogen-stimulated blastogenesis was lower (P less than .01) in pigs weaned at 2 wk of age. Mitogen-stimulated lymphocyte blastogenesis was similar (P greater than .10) in control pigs and those weaned when 5 wk old. These data suggested that weaning pigs when younger than 5 wk old causes physiological changes detrimental to cellular immune reactivity. Those changes could alter disease susceptibility in young pigs.

Animals↗

PubMed1983

Suppressed lymphocyte blastogenic responses and enhanced in vitro growth of infectious bovine rhinotracheitis virus in stressed feeder calves.

Hereford steers were stressed on a large-animal treadmill operating at speeds of 1.8 to 2.2 m/s. Blood samples were collected from indwelling jugular catheters before, during, and after exercise. Peripheral blood lymphocytes from stressed calves at 5 and 30 minutes after exercise had less (P less than 0.01) mitogen-induced blastogenic responses when compared to pre- or 60-minute postexercise values. Serum from stressed calves incorporated into lymphocyte cultures from nonstressed steers resulted in less (P less than 0.01) lymphocyte blastogenic responses. Infectious bovine rhinotracheitis viral growth in bovine kidney cell cultures was enhanced 4-fold when cultured with serum from stressed calves. These data indicate that acute physical exertion may cause physiologic alterations in calves that modulate cellular immunity and viral replication.

Animals↗

PubMed1982

Cold exposure and absorption of colostral immunoglobulins by neonatal pigs.

To investigate the effect of cold exposure on absorption of colostral immunoglobulins, 56 piglets were weaned at birth and placed in either a thermoneutral (35 C) or cold (21 C) environmental chamber. Thermoneutral piglets had a survival rate of 62% at 48 h, but survival among cold-exposed piglets was only 36% (P less than .10). Cold aid reduced (P less than .01) rectal temperature by more than 6 C after 24 h of exposure. A constant amount of bovine colostrum was administered orally at 4 h after initiation of thermal treatments. Bovine immunoglobulin G1 (IgG1) was readily absorbed and reached a serum level of 17 mg/ml after 24 h. Bovine IgM also was absorbed and increased to approximately 2 mg/ml at 24 h. However, absorption of colostral IgG1 and IgM was not affected by cold exposure. Cold air increased (P less than .05) incidence of diarrhea by over five fold after 72 h, and severity of diarrhea was nearly doubled (P less than .01). Hematocrit was also higher (P less than .05) in cold-exposed piglets. These data demonstrate that a cold stressor sufficient to induce hypothermia does not impair absorption of colostral macromolecules in piglets. However, cold exposure was related to increase incidence and severity of diarrhea.

Animals↗