Neonatal calf serum immunoregulation of lymphocyte blastogenic responses

The ability of lymphocytes from newborn calves to undergo blastogenic responses to the mitogens Concanavalin A (Con A), phytohemagglutinin (PHA), or Pokeweed Mitogen (PWM), and immunomodulation of these responses by neonatal calf serum was assessed as a function of age. Lymphocytes were obtained from thymus, spleen, and mesenteric lymph nodes of 1-, 2- to 3-, 5- to 7-, and 9- to 10-d-old calves, aliquoted and incubated (+/- mitogens) in sera from 1-, 2-, 3-, or 7- to 10-d-old calves. Lymph-node lymphocytes responded least when cultured in sera from 1-d-old calves, regardless of mitogen or age of cell donor; the response increased as age of serum donor increased (P less than .05). Splenic lymphocytes responded similarly (P less than .005). However, when cultured in sera from older calves, splenic lymphocytes from older calves responded greater to PWM than did those from younger calves. Thymic lymphocytes responded minimally to PWM and PHA. Their response to Con A increased (P less than .005) with age of serum donor calf, but the effect was greatest on lymphocytes from 5- to 7-d-old calves. Mixing experiments with varying ratios of 1-d-old calf serum: 10-d-old calf serum suggested that serum from 1-d-old calves contained suppressive activity. Serum cortisol level (measured by radioimmunoassay) was 30 +/- 4.6 ng/ml in calves at 6 h of age and declined to 5.5 +/- 1.1 ng/ml by 10 d. Charcoal treatment to remove steroids did not enhance blastogenesis. Addition of cortisol (50 ng/ml) to charcoal-treated sera resulted in inhibition of response to PHA, but no change in response to Con A or PWM. Further investigation is indicated to characterize this immunosuppressive activity and to establish its relationship to disease susceptibility.     

Potential use of lymphocyte blastogenic responses in diagnosis of bovine tuberculosis

A comparison of in vitro lymphocyte responses and delayed type tuberculin skin test responses was made in an animal experimentally exposed to a Mycobacterium bovis-infected animal and in cattle naturally infected with M. bovis. Tuberculin skin tests did not suppress in vitro lymphocyte responses to M. bovis PPD and to M. avium PPD tuberculin. The whole blood test used in these studies provided for considerable savings in time as compared to use of purified lymphocytes for evaluating in vitro cellular responses. Variations in the responsiveness of lymphocytes to specific mycobacterial antigens was observed, therefore, it is recommended that profiles be established using three or more tests conducted at 14-day intervals.     

Kinetics of levamisole-induced potentiation of lymphocyte blastogenic responses inMycobacterium bovis sensitized lymphocyties

A study was conducted to determine the kinetics of levamisole-induced potentiation of lymphocyte blastogenesis inMycobacterium bovis sensitized and nonsensitized cattle lymphocytes. It was observed that levamisole significantly potentiated PPD-induced blastogenic responses when it (levamisole) was added toM. bovis sensitized lymphocyte cultures 24 hours prior to the addition of PPD. Levamisole-induced either minimal or suppressed the PPD-induced lymphocyte stimulation response inM. bovis nonexposed control lymphocytes. The implications of possible use of levamisole in cellularin vitro assays for studying anergy or general unresponsiveness are discussed.     

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.     

Experimentally induced Cooperia oncophora infection in calves: lymphocyte blastogenic and delayed hypersensitivity responses

Lymphocytic responses in peripheral blood and visceral lymph to Cooperia oncophora antigen and skin tests were determined in 35 Holstein male calves that were inoculated orally with single or multiple doses of C oncophora infective larvae. Several calves were vaccinated or given immune serum before larvae were inoculated. Antigen-specific in vitro blastogenesis of blood and lymph lymphocytes and delayed-type hypersensitivity reactions were observed in several inoculated, vaccinated, and/or passively immunized calves. Most calves that had delayed skin reactions also had in vitro lymphocyte responses to C oncophora antigen. The lymphocyte and skin responses were inconsistent and variable in time of onset--the earliest lymphocyte response occurring 7 days after calves were inoculated. A cellular immune response was induced by both dermal vaccination and oral inoculation; however, passive immunization by IV administration of immune serum simultaneously with inoculation did not have an apparent effect on the cellular response, as measured by the lymphocyte blastogenesis test or dermal testing. Although cellular immune responses were observed in several calves infected with C oncophora, there was no apparent relationship between the specific responses and number of nematodes establishing infection in calves after either single- or multiple-dose oral inoculations.     

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.     

Changes in blastogenic responses of lymphocytes and delayed type hypersensitivity responses after vaccination in dogs.

To clarify the immunologic effects of vaccination in dogs, we monitored total leukocyte and lymphocyte counts, humoral antibody responses, blastogenic responses of lymphocyte, and delayed type hypersensitivity (DTH) responses after vaccination. Mixed vaccines were administered on day 0 except for canine parvovirus (CPV) vaccine which was readministered on day 21. The puppy and adult dogs had a significant decrease in leukocyte and lymphocyte counts on day 7. The puppies showed a significant increase in the blastogenesis of lymphocytes after each vaccination, whereas the adult dogs had no significant changes. However, the adult dogs were divided into two groups, high responders and low responders in blastogenesis of lymphocytes. The dogs with higher or lower response in SI values on day 0 tended to show decrease or increase after the first vaccination, respectively. Since almost all dogs developed high titers of humoral antibody, it is considered that vaccination acts in an immunomodulative fashion. DTH responses to phytohemagglutinin (PHA) and CPV vaccine monitored at 0, 3, and 8 weeks after the first vaccination produced strong reactions, in particular those to CPV vaccine rose significantly after vaccination and maintained the higher responses for at least 2 months. These results suggest that DTH responses to PHA and CPV vaccine are helpful to monitoring non-specific and specific immune functions in vivo, therefore, DTH could be used as simple and rapid immunologic tests in canine practice.     

The effects of bovine respiratory syncytial on normal ovine lymphocyte responses to mitogens or antigens in vitro

In the present study peripheral blod mononuclear cells (MNC) obtained from normal uninfected lambs were used to study the possible effects of bovine respiratory syncytial virus (BRSV) on lymphocyte responses to the mitogens, phytohaemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM) in vitro. Live BRSV had a depressive effect on the proliferative responses of normal MNC to PHA, Con A and PWM. Inactivated BRSV and a commercial preparation of prostaglandin E2 were also found to depress the proliferative responses of normal ovine MNC to PHA but recombinant tumour necrosis factor-alpha (TNF-alpha) had no such effect. Serum samples obtained from BRSV-infected lambs contained substances inhibitory to PHA-driven lymphocyte blastogenesis. Memory blastogenic responses to border disease virus (BDV) of lymyphocytes obtained from lambs previously primed with BDV were significantly reduced when lymphocytes were exposed to infectious BRSV.     

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.     

Effect of sodium diethyldithiocarbamate, Corynebacterium parvum and mycobacterium cell wall extract on in vitro blastogenic responses of bovine blood lymphocytes

In vivo inoculation of three-month-old calves with sodium diethyldithiocarbamate (DTC), killed Corynebacterium parvum or mycobacterium cell wall extract (MCWE) resulted in an enhancement of in vitro peripheral blood lymphocyte blastogenic responses to mitogens phytohemagglutinin (PHA) and Concanavalin A (Con A) in the first three days after treatment. In a separate experiment, blood lymphocytes isolated from a healthy nontreated calf were incubated in vitro in presence of each of the same immunostimulating agents and tested for their blastogenic responses to PHA and Con A. The results showed that all immunostimulants, excepting DTC, enhanced the in vitro blastogenic responses of lymphocytes to PHA and Con A. Finally, addition of MCWE to cultures of blood lymphocytes isolated from calves vaccinated intramuscularly with bovine rotavirus and adjuvant resulted in an enhancement of the in vitro lymphocyte transformation to rotavirus. Our study demonstrated that DTC, killed Corynebacterium parvum and mycobacterium cell wall extract were able to enhance bovine T cell proliferation in vitro.     

Mitogen and mixed lymphocyte culture responses of isolated bovine lymphocyte subpopulations

Examinations were made of the mitogen and mixed lymphocyte culture (MLC) responses of subpopulations of bovine lymphocytes isolated by density sedimentation following sequential E-rosetting with aminoethylisothiouronium bromide- and neuraminidase-treated sheep erythrocytes (EAET, EN). These procedures consistently separated 3 populations of E-rosetting T cells from a 4th population of non-E-rosetting cells (B and null cells). The isolated B and null cell population did not respond to phytohemagglutinin, concanavalin A, or pokeweed mitogen and responded minimally in mixed lymphocyte culture. Conversely, isolated T cells responded well to each of these stimuli. Moreover, differences in responsiveness were found among the 3 T-cell populations isolate by differential rosetting. T cells with receptors for both EAET and EN rosette formation were the most responsive to the mitogens used and demonstrated maximum activity in MLC. T cells with only EAET receptors had equivalent activity in MLC and less activity in response to mitogens. Cells with only EN receptors were the least active T-cell population in these assays. The different reactivities of these T-cell populations in lymphoproliferative assays indicated that they represent distinct subsets of bovine T cells.     

The effect of selenium deficiency in goats on lymphocyte production of leukocyte migration inhibitory factor

The effect of dietary selenium on caprine leukocyte migration inhibitory factor (LMIF) production was examined $\text{in vitro}$ using lymphocytes from goats fed a diet deficient in selenium. Selenium deficiency was determined by decreased plasma glutathione peroxidase (GSH-Px). The ability of peripheral blood lymphocytes to produce LMIF induced by concanavalin A (Con A) was significantly (P < 0.05) inhibited when cells from selenium-deficient and selenium-adequate goats were compared. In contrast, no significant (P > 0.05) differences were found between lymphocytes from selenium-deficient and selenium-adequate goats for Interleukin-2 (IL-2) production and blastogenesis induced by Con A. These data suggest that selenium deficiency may selectively impair LMIF production and hence the ability of lymphocytes to modulate neutrophil migration.     

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.     

Effect of corticosteroid on porcine leukocytes: age-related effects of corticosteroid inhibition on porcine lymphocyte responses to mitogens

The effects of prednisolone sodium succinate on the responses of porcine lymphocytes to phytohemagglutinin (PHA) and pokeweed mitogen (PWM) were investigated. Sensitivity of peripheral blood lymphocytes (PBL) to the synthetic glucocorticoid, prednisolone, was related to age of the lymphocyte donor. The greatest sensitivity was found in PBL from animals less than one week old; PBL from animals between 2 to 4 months retained some glucocorticoid sensitive cells; whereas, PBL from animals older than 6 months were exceptionally resistant to steroid. Similar age-associated sensitivities were found for lymphocytes from lymph node, spleen and thymus. Significant differential sensitivities among the various lymphoid organs were found with the thymic lymphocyte possessing the greatest sensitivity to steroid and the PBL lymph node and splenic lymphocytes possessing the highest resistance to the suppressive effects of steroid. The age related differences in sensitivity to steroid did not appear to be caused by differences in the number of steroid receptors because lymphocytes from susceptible and resistant animals had similar numbers of receptors. The results suggest that the age related sensitivity may be associated with a higher percentage of sensitive thymic-derived lymphocyte in the PBL, lymph node and spleen of the younger animals. Results of this study also suggest that the adult pig (6 months) should be classified as a steroid resistant species.     

Effect of selenium on sheep lymphocyte responses to mitogens

The effect of selenium (Se) on sheep lymphocyte response to mitogens was studied. In an indoor experiment lambs were fed a basal diet containing 0.13 mg Se kg-1, and supplemented with, respectively, 0.1 or 0.5 mg Se kg-1, either as sodium selenite or as selenomethionine. Enhancement of the proliferative response of lymphocytes to phytohaemagglutinin (PHA), pokeweed mitogen (PWM) and concanavalin A was found in lambs following selenium supplementation at the lower levels. The highest dietary selenium content, however, induced decreased mitogen response. Transient increases in lymphocyte response to PHA and PWM by ewes supplemented with selenium was demonstrated in one field study and a combined effect of selenium and vitamin E was seen in another. There was no stimulatory effect on the mitogen response of lymphocytes from sheep supplemented with dietary vitamin E alone.     

Kinetics of detection of blastogenic responses of neonatal calves inoculated in utero with tetanus toxoid, killed Mycobacterium bovis, and killed Brucella abortus.

Nine pregnant cows were laparotomized and their fetuses were immunized with tetanus toxoid, killed Brucella abortus, and killed Mycobacterium bovis. Blastogenesis assays and total leukocyte and differential counts were done when the calves were 1, 2, 3, 7, 14, 21, 28, and 60 days of age. Initial blastogenesis responses to antigens, phytohemagglutinin, and concanavalin A were not positive as frequently as were the responses obtained when the calves were 2 to 3 weeks of age. The probability of obtaining a positive response to an antigen was positively correlated with the magnitude of the response, as determined by delayed-type hypersensitivity skin reactions. Leukocyte and differential WBC counts in immunized calves were similar to those of unimmunized calves. The mean leukocyte count for the immunized calves remained near 16,000 cells/mm3; blood obtained in the first few days after birth contained a greater number of neutrophils than lymphocytes, whereas lymphocyte-to-neutrophil ratio gradually approached those of adult cattle, in which lymphocytes predominate.     

The effects of florfenicol on lymphocyte subsets and humoral immune response in mice

Florfenicol is a broad-spectrum bacteriostatic antibiotic used in domestic animals. The aim of the study was to determine the effect of florfenicol on the total number of lymphocytes in the thymus, spleen and mesenteric lymph nodes and the percentage and the absolute number of T cell subsets (CD4+CD8+, CD4-CD8-, CD4+, CD8+) in the thymus and T (CD3+, CD4+, CD8+) and B (CD19+) lymphocytes in the peripheral lymphatic organs in non-immunized mice and humoral immune response in sheep red blood cells (SRBC)-immunized mice. Florfenicol was administered orally at a dose of 30 mg/kg six times at 24 h intervals to non-immunized mice and four or seven times at 24 h intervals to SRBC-immunized mice. SRBC was injected 2 hours prior to the first dose of the drug. Florfenicol increased the percentage of CD4CD8- thymocytes and the absolute number of CD4+ and CD8+ thymocytes on day 7. The increased percentage and absolute number of CD3+, CD4+ and CD8+ lymphocytes in mesenteric lymph nodes and decreased percentage of lymphocytes B were also observed 24 hours from the last administration of florfenicol. Florfenicol administered after SRBC immunization reduced the number of plaque forming cells (PFC) and the production of anti-SRBC antibodies on days 4 and 7 after priming.     

The pharmacokinetics, pharmacological responses and behavioral effects of acepromazine in the horse

After intravenous (i.v.) injection, acepromazine was distributed widely in the horse ( V_d = 6.6 litres/kg) and bound extensively (>99%) to plasma proteins. Plasma levels of the drug declined with an α phase half-life of 4.2 min, while the β phase or elimination half-life was 184.8 min. At a dosage level of 0.3 mg/kg acepromazine was detectable in the plasma for 8 h post dosing. The whole blood partitioning of acepromazine was 46% in the plasma phase and 54% in the erythrocyte phase.
Penile prolapse was clearly evident at doses from 0.01 mg/kg to 0.4 mg/kg i.v., and the duration and extent of protrusion were dose related. Hematocrit levels were significantly lowered by administration of 0.002 mg/kg i.v. (about 1 mg to a 500 kg horse) and increasing dosages resulted in greater than 20% lowering of the hematocrit from control levels. Pretreatment of horses with acepromazine also reduced the variable interval (VI 60) responding rate in all horses tested.
These data show that hematocrit changes are the most sensitive pharmacological responses to acepromazine, followed by changes in penile extension, respiratory rate, VI responding and locomotor responses. Acepromazine is difficult to detect in plasma at normal clinical doses. However, because of its large volume of distribution, its urinary elimination is likely prolonged, and further work on its elimination in equine urine is required.     

工蜂幼虫,蛹对小鼠T淋巴细胞转化功能的影响

用工蜂幼虫、蛹、蜂王幼虫分别灌喂小鼠１２天后，通过Ｔ淋巴细胞转化试验发现，工蜂幼虫、蛹与蜂王幼虫一样，均可显著提高小鼠的Ｔ淋巴细胞转化功能。结果表明，工蜂幼虫、蛹在提高机体免疫功能方面，与蜂王幼虫有同样的药理作用。