Injection Of Sheep Red Blood Cells Research Articles

Combining supervised machine learning with statistics reveals differential gene expression patterns related to energy metabolism in the jejuna of chickens divergently selected for antibody response to sheep red blood cells

Since the 1970s, 2 lines of White Leghorn chickens, HAS and LAS, have been continuously divergently selected for 5-day postinjection antibody titer to injection with sheep red blood cells (SRBC). Antibody response is a complex genetic trait and characterizing differences in gene expression could facilitate better understanding of physiological changes due to selection and antigen exposure. At 41 d of age, randomly selected HAS and LAS chickens, which had been coraised from hatch, were either injected with SRBC (HASI and LASI) or kept as the noninjected cohort (HASN and LASN). Five days later, all were euthanized, and samples collected from the jejunum for RNA isolation and sequencing. Resulting gene expression data were analyzed combining traditional statistics with machine learning to obtain signature gene lists for functional analysis. Differences in ATP production and cellular processes were observed in the jejunum between lines and following SRBC injection. HASN vs. LASN exhibited upregulation of ATP production, immune cell motility, and inflammation. LASI exhibits upregulation of ATP production and protein synthesis vs. LASN, reflective of what was observed in HASN vs. LASN. In contrast, no corresponding upregulation of ATP production was observed in HASI vs. HASN, and most other cellular processes appear inhibited. Without exposure to SRBC, gene expression in the jejunum indicates HAS generates more ATP than LAS, suggesting HAS maintains a "primed" system; and gene expression of HASI vs. HASN further suggests this basal ATP production is sufficient for robust antibody responses. Conversely, LASI vs. LASN jejunal gene expression implies a physiological need for increased ATP production with only minimal correlating antibody production. The results of this experiment provide insight into energetic resource needs and allocations in the jejunum in response to genetic selection and antigen exposure in HAS and LAS which may help explain phenotypic differences observed in antibody response.

The Sea Star Invertebrate Primitive Antibody (IPA):Rosetting And PFC (Plaque-Forming Cell). Anti-SRBC Antibodies

Next to the sea star T and B lymphocytes, we find the IPA (Invertebrate Primitive Antibody). Rosetting test and PFC test after Injection of SRBC (Sheep red blood cells)were performed in the sea starAsterias rubens (Echinodermata). Positive results were obtained and summarized in this work. They indicated the presence of anti-SRBC antibodies in the sea star, according to the method of Cunningham.

Dietary supplementation of Aspergillus oryzae meal and its effect on performance, carcass characteristics, blood variables, and immunity of broiler chickens

This study investigated the effect of different levels and consumption periods of Aspergillus oryzae meal on performance, carcass characteristics, blood variables, and immunity of broiler chickens. A total of 270 (male and female) Ross 308 chicks were randomly assigned to 9 treatment groups. Two levels (2 g/kg diet and 4 g/kg diet as-fed) of Aspergillus oryzae meal (AO) and 4 consumption periods of AO (starter, grower, finisher, and entire period) in a 2 × 4 factorial arrangement were used. Compared with control, AO used during the entire rearing period increased weight gain, reduced relative weight of abdominal fat, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) serum levels, and increased antibody titers against influenza and Newcastle disease vaccination and sheep red blood cells injection. Few differences in the variables considered were found if AO was added to broiler diets only during specific consumption periods, and between the two supplementation levels of AO. In conclusion, the addition of AO to the broiler diet can have beneficial effects in terms of performance, carcass composition, and health, but these positive effects were mainly reached adding AO for the entire rearing period.

EFFECT OF DIETARY SUPPLEMENTAL ZINC SOURCE AND LEVEL ON GROWTH PERFORMANCE, DIGESTIBILITY COEFFICIENTS AND IMMUNE RESPONSE OF NEW ZEALAND WHITE RABBITS

This study was carried out to investigate the effect of dietary zinc (Zn) supplementation in inorganic (zinc sulfate, ZnSO4) and organic (zinc methionine, Zn-Met) forms at two levels (100 or 200 mg/kg diet) on growth performance, digestibility coefficients and immune response of New Zealand White (NZW) male rabbits. One hundred male NZW rabbit (at 6 weeks of age, 808 ± 11g average body weight) were divided into five homogenous groups. The 1st group was fed basal diet including vitamins & minerals premix which contained 58 mg Zn as a control, the 2nd and the 3rd groups were fed on the same diet supplemented with 100 or 200 mg Zn/kg diet as zinc sulfate (ZnSO4, inorganic form) and the 4th and the 5th groups were fed on the same diet supplemented with 100 or 200 mg Zn/kg diet as zinc methionine (Zn-Met, organic form). Results showed that live body weight at 22 wks of age and total body weight gain of rabbits fed diets supplemented with Zn was significantly (P<0.01) higher than those fed diet without supplementation. Rabbits fed diet supplemented with 200 mg Zn-Met/kg diet had significantly heaviest body weight, followed by rabbits fed diet supplemented with 100 mg Zn-Meth/kg diet than groups fed diet supplemented with 200 and 100 mg ZnSO4. Rabbits fed diets supplemented with Zn-Met or ZnSO4 converted feed better than those fed diets without supplementation. Rabbits fed diets supplemented of Zn-Meth at 200 or 100 mg/Kg diets improved nutrients digestibility and nutritive values expressed as TDN and DCP of diets. Zn supplementation (Zn-Meth or ZnSO4) to rabbit diets significantly (P<0.01) affected cell-mediated immune response at different hours post injection of phytohemoagglutinins (PHA). Zn from Zn-Meth (200 or 100 mg/kg diets) significantly increased heighten cellular immunity than zinc from ZnSO4. Rabbits fed diets supplemented with Zn (Zn-Meth or ZnSO4) with any levels had significantly (P<0.01) higher antibody titer against sheep red blood cell (SRBC) at different weeks post immunization than those fed control diets. Zn-Meth improved significantly antibody titer against SRBC than zinc from ZnSO4. Inclusion 200 mg Zn-Met/kg diet significantly improved antibody titer post three weeks of SRBC injection than 100 mg Zn-Met. It can be concluded that dietary Zn methionine (organic form( at level of 200 mg/kg of rabbit diet improved nutrients digestibility and nutritive values of diets, which could be associated with better growth performance and immune efficiency.

Screening for genes involved in antibody response to sheep red blood cells in the chicken, Gallus gallus

Antibody response, an important trait in both agriculture and biomedicine, plays a part in protecting animals from infection. Dissecting molecular basis of antibody response may improve artificial selection for natural disease resistance in livestock and poultry. A number of genetic markers associated with antibody response have been identified in the chicken and mouse by linkage-based association studies, which only define genomic regions by genetic markers but do not pinpoint genes for antibody response. In contrast, global expression profiling has been applied to define the molecular bases of a variety of biological traits through identification of differentially expressed genes (DEGs). Here, we employed Affimetrix GeneChip Chicken Genome Arrays to identify differentially expressed genes for antibody response to sheep red blood cells (SRBC) using chickens challenged with and without SRBC or chickens with high and low anti-SRBC titers. The DEGs include those with known (i.e., MHC class I and IgH genes) or unknown function in antibody response. Classification test of these genes suggested that the response of the chicken to intravenous injection of SRBC involved multiple biological processes, including response to stress or other different stimuli, sugar, carbohydrate or protein binding, and cell or soluble fraction, in addition to antibody response. This preliminary study thus provides an insight into molecular basis of antibody response to SRBC in the chicken.

Immunological responses of male White Leghorn chicks kept on ochratoxin A (OTA)-contaminated feed

This study was designed to evaluate some immunological responses of male White Leghorn (WL) chicks kept on an ochratoxin A (OTA)-contaminated diet. For this purpose, 350 1-day-old male WL chicks were divided into five groups (A–E). Group A was kept as control, while Groups B, C, D, and E were fed OTA-contaminated feed at 0.1, 0.5, 1.0, and 1.5 mg/Kg diet, respectively, for 21 days, and then basal ration for the remaining period. At 14- and 16-days of age, random chicks (n = 10) from each group were used for analyses of phagocytic function of the reticuloendothelial system or for measuring the lymphoproliferative responses to intradermally-administered T-cell mitogen, phytohemagglutinin-P (PHA-P), respectively. At 30-days of age, abdominal macrophages were collected from 15 chicks/group and utilized for determination of their phagocytic potential and for nitrite production. Antibody (Ab) titers (i.e., total antibodies, IgM, and IgG) against sheep red blood cells (SRBC) were determined at 7 and 14 days after a primary (at 7 days of age) and a booster (given 14 days after primary [at 21-days of age]) dose (intravenous) of the antigen. Data from the present study showed that the relative weight of the bursa of Fabricius of chicks fed OTA for 14 and 21 days and the spleen of chicks fed OTA for 21 days were significantly lower than their control counterpart. Phagocytic function of reticuloendothelial system evaluated by carbon clearance, and lymphoproliferative response to PHA-P, of chicks kept on OTA-contaminated diet were significantly lowered. The percentage of abdominal macrophages displaying phagocytosis of SRBC, the number of SRBC/macrophage, and nitrite production were each significantly lower in cells from chicks in the OTA-fed groups. Total Ab (at days 7 and 14 post-booster SRBC injection) and IgG (at day 14 post-primary and day 7 post-booster SRBC injection) titers against SRBC showed significant reductions in the groups fed OTA-contaminated diet. The findings of this study are in line with the previous work suggesting the immunosuppressive effect of OTA in male WL chicks regarding functional impairment in some of the components of the immune system.

Influence of dietary fish oil supplementation on humoral immune response and some selected biochemical parameters of broiler chickens

Influence of dietary fish oil supplementation on humoral immune response and some selected biochemical parameters of broiler chickensThe objective of this experiment was to evaluate the influence of fish oil (FO) supplementation in the diet of broiler chickens on the humoral immune response as well as some blood parameters. Two hundred and sixteen one day old broiler chickens were divided into four dietary groups 0, 1, 2, or 4% FO with 3 replicates of 18 birds. Four chicks randomly selected and marked from each replicate were immunized intramuscularly with 0.2 ml of 5% sheep red blood cells (SRBC) as a non-infectious antigen, at the ages of 15 and 35 days and blood samples were taken 7 days after each immunization. The highest BW was observed in the 2% FO dietary group (T3), followed by T2 (P&lt;0.01). The serum cholesterol and triglyceride levels significantly decreased in the FO groups at the age of 42 days (P&lt;0.01). In addition, the inclusion of FO in broiler diets significantly increased the blood glucose (G) level and decreased the total protein (TP), albumin (A) and globulin (GL) concentrations. Fish oil-treated birds had significantly more serum antibody (predominantly immunoglobulin M, IgM) to SRBC than the control group. The highest response to primary and secondary injections of SRBC after 7 days, were detected for group 4 (4% FO), followed by 2% FO group (P&lt;0.05). The results indicate that the addition of 2 % FO to broiler chick's diet may stimulate the development of the immune response and improve blood indices, while 4% level was not recommended because of probable off-flavours in the product.

Modulating effects of nonselective and selective phosphodiesterase inhibitors on lymphocyte subsets and humoral immune response in mice

Phosphodiesterase (PDE) inhibitors can regulate the activity of immune cells by increasing intracellular levels of cyclic nucleotides. The aim of this study was to determine the effects of milrinone, a selective PDE3 inhibitor, sildenafil, a selective PDE5 inhibitor, and aminophylline, a nonselective PDE inhibitor, on lymphocyte subsets and humoral immune response in mice when administered in vivo. Aminophylline (20mg/kg, im), milrinone (1mg/kg, im) or sildenafil (1mg/kg, po) were administered to mice either once or five times at 24h intervals. Some mice were immunized with a sheep red blood cell (SRBC) suspension administered ip either 2h after the single dose or 2h after the second of the five doses. In non-immunized mice treated five times with PDE inhibitors, the subsets of T lymphocytes in the thymus and T and B lymphocytes in the spleen and mesenteric lymph nodes were determined 12, 24 or 72h after the last dose. The humoral immune response was determined on days 4, 7 and 14 after SRBC injection in SRBC-immunized mice treated with PDE inhibitors. Amodulating effect of the drugs on lymphocyte subpopulations was observed. The greatest impact was observed in splenocyte subpopulations, and resulted in decreased percentages of B cells (CD19+) and increased percentages of T cells (CD3+, CD4+, CD8+). No effect or slight influence of the drugs on anti-SRBC hemagglutinins was observed, but the number of plaque-forming splenocytes was increased. The drugs under investigation did not show a significant immunosuppressive effect.

Physiological actions of corticosterone and its modulation by an immune challenge in reptiles

Hormones are an important interface between genome and environment, because of their ability to modulate the animal’s phenotype. In particular, corticosterone, the stress hormone in lizards, is known to reallocate energy from non-essential functions to affect morphological, physiological and behavioral traits that help the organism to deal with acute or chronic stressors. However, the effects of corticosterone on life history stages are still unclear primarily because of the dependence of life history stages on both internal and external factors. Using a cross-design, we tested the effect of elevated levels of exogenous corticosterone on the physiology of pregnant females in different immune contexts in a wild population of common lizards ( Lacerta vivipara). Immune challenge was induced by the injection of sheep red blood cells (SRBC) and corticosterone levels were increased using a transdermal administration of corticosterone. Thereafter, reproductive traits, metabolism and cellular immune responses were measured. The elevation of corticosterone in pregnant females significantly altered reproductive and physiological performance. The corticosterone treatment decreased clutch success, juvenile size and body condition, but enhanced measures of physiological performance, such as metabolism and catalase activity. These first results reinforce the understanding of the physiological actions of corticosterone in reptiles. The data also demonstrated different direct impacts of immune challenge by SRBC on inflammatory response and antioxidant activity. The injection of SRBC stimulated the SOD activity in larger females. Finally, we demonstrated experimentally the modulation of the corticosterone action by the immune challenge on stamina and hatching date.

Effects of prenatal diesel exhaust inhalation on pulmonary inflammation and development of specific immune responses

There is increasing evidence that exposure to air pollutants during pregnancy can result in a number of deleterious effects including low birth weight and the incidence of allergic asthma. To investigate the in utero effects of DE exposure, timed pregnant BALB/c mice were exposed to 0, 0.8 or 3.1 mg/m 3 of DE during gestation days (GD) 9 to GD 18. The number of successful pregnancies was 15/20 in the air controls and 10/20 in each of the diesel exposures. Immune function in the 6-week-old offspring as determined by development of delayed type hypersensitivity (DTH) reactions to bovine serum albumin (BSA), antibody titers to injected sheep red blood cells (SRBC), splenic T cells expressing CD45 +CD3 +CD8 + and CD3 +CD25 +, and mRNA expression of TNF-α, TLR2, SP-A, TGF-β and Foxp3 in the lung were not affected by prenatal DE exposure. On the other hand, lung TLR4 mRNA expression, the number of neutrophils in the bronchoalveolar lavage fluid (BALF) and splenic T cells expressing CD45 +CD3 +CD4 + and CD4 +CD25 + were differentially affected depending on the DE concentration and gender. When additional groups of mice were sensitized and challenged via the respiratory tract with ovalbumin to induce allergic airway inflammation, female mice had higher protein levels in the BALF compared to males and this was reduced by prenatal exposure to either concentration of DE. No other changes in allergen-induced immunity, lung function or severity of inflammation were noted. Collectively, the results show that in utero exposure to DE altered some baseline inflammatory indices in the lung in a gender-specific manner, but had no effect on development of specific immune responses to experimental antigens, or the severity of allergic lung inflammation.

Chromium(III) Nanoparticles Affect Hormone and Immune Responses in Heat-Stressed Rats

This study was conducted to evaluate the effects of chromium nanoparticles (CrNano) on the hormone and immune responses of rats in heat stress condition. A total of 80 male Sprague-Dawley rats were randomly assigned to four dietary treatment groups (n = 20). The first group was offered a basal diet as a control. The second, third, and fourth groups received basal diet supplemented with 150, 300, and 450 microg/kg Cr, respectively, in the form of CrNano. At the end of the 8-week trial, growth performance, food utilization, and sera concentrations of hormones, immunoglobulins, and alexins were determined. Lymphocyte proliferation activity, antibody response to injected sheep red blood cells (SRBCs), and phagocytosis of peritoneal macrophages were determined by (3)H-thymidine uptake method, plaque-forming cells (PFC) assay, and ingesting chicken red blood cells test, respectively. The results indicated that rats that received CrNano exhibited no changes in growth rate and food efficiency compared to the control group. However, dietary supplementation of 150, 300, and 450 microg/kg Cr from CrNano significantly decreased serum concentrations of insulin and cortisol, increased sera levels of insulin-like growth factor I and immunoglobulin G, and enhanced the lymphoproliferative response, anti-SRBC PFC response, and phagocytic activity of peritoneal macrophages. These results suggest that dietary supplementation of Cr as CrNano affects hormone and immune status in heat-stressed rats.

A temporal analysis of the relationships between social stress, humoral immune response and glutathione-related antioxidant defenses

The exposure to different kinds of stress impacts on the reactive oxygen species production with potential risk to the integrity of the tissues. Psychological or biological stress is responsible for a significant increase in the oxidative stress markers and also for activation of the antioxidant defense system. In this study, we analyzed the relationships between social stress, humoral immune response and glutathione-related antioxidant defenses. Groups of male Swiss mice were subjected to different lengths of social stress exposure (social confrontation) which varied from 1 up to 13 days. As a biological stressor, 10 9 sheep red blood cells (SRBC)/mL were injected by intraperitoneal route. As controls, animals not subjected to social stress and/or injected with vehicle solution were used. The serum samples and the cerebral cortex were collected at 4 h, 3, 5, 7, 9, 11, and 13 days after the end of social confrontation. The results indicated that the antioxidant enzymes activities were affected by psychological as well as by biological stressor. These alterations were dependent on the timing of stress exposure which resulted in a positive or in a negative correlation between the antibody titres to SRBC and antioxidant enzymes. We also discuss the possible role of SRBC injection in the modulation of the effects of psychosocial stress on antioxidant metabolism.

Intensified Postgrafting Immunosuppression Failed to Assure Long-Term Engraftment of Dog Leukocyte Antigen-Identical Canine Marrow Grafts After 1 Gray Total Body Irradiation

Late graft rejection after conditioning with 1 Gy of total body irradiation (TBI) was consistently seen in historical dogs given two postgrafting immunosuppressive drugs. Here, 16 dogs were given four different three-drug combinations of cyclosporine, mycophenolate mofetil, sirolimus, or methotrexate after 1 Gy TBI and dog leukocyte antigen-identical marrow grafts. In addition, we assessed the effects of TBI doses of 0.5, 1.0, 2.0, or 3.0 Gy, respectively, on immune functions in six dogs not given marrow grafts. All dogs showed initial engraftment, 13 rejected, and three had sustained grafts beyond 26 weeks. The dogs with durable grafts had received greater median numbers of nucleated marrow cells compared with the 13 dogs that rejected their grafts (6.14 vs. 3.6 x 10(8) per kg; P=0.03). In a Cox proportional hazard model, which included data from 16 historical dogs, each increase in transplanted marrow cell numbers by 1 x 10(8) per kg decreased the hazard ratio of rejection by 0.5. Decreasing percents of remaining CD3, CD4, and CD8 cells in peripheral blood and lymph nodes were observed with increasing TBI doses. Further, greater suppressions of B-cell- and T-cell-dependent production of IgM and IgG antibodies in response to sheep red blood cell injections were observed after 2 Gy compared with 1 Gy TBI. Overall, triple postgrafting immunosuppression after 1 Gy TBI was well tolerated but failed to prevent graft rejection in this model. In vivo radiation studies have shown higher numbers of remaining host lymphocytes and better T-cell-dependent antibody production after 1 Gy compared with 2 Gy TBI.

Radial Segmentation of Blood Lymphocytes Nuclei in Pheasants Vaccinated against Newcastle Disease and Haemorrhagic Enteritis

The purpose of the experiment was to investigate the influence of the pheasant vaccination with a vaccine containing live attenuated virus of haemorrhagic enteritis, (HE) on the ability of peripheral blood lymphocytes to form a nuclei deformation described as the radial segmentation (RS). This feature is identified with cytoskeletal rearrangement of the cells. The pheasants were vaccinated against Newcastle disease (ND) on the 1st, 28th and 56th day of life. Moreover, on the 49th day of life, a part of the birds was given the vaccine containing HEV (Haemorrhagic enteritis virus) in drinking water. Fourteen days after the HEV vaccination, the birds were administered intravenously 0.5 ml of the 10% SRBC (Sheep red blood cells) suspension. Blood samples were collected on the 21st day after HEV vaccination, on the 7th day after SRBC injection. It was shown that in pheasants the percentage of cells undergoing RS induced by oxalates was low, approximately 3.75%, whereas in HEV vaccinated birds this percentage increased twice (p &lt; 0.05). Pheasant immunization with SRBC led to significant reduction of the ability to form RS, whereas in HEV vaccinated birds after SRBC administration the percentage of cells with RS remained on the level of the control group. Based on these results, the authors suggest that immunosuppressive effects of some viruses may be a result of both sensitivity and rearrangement ability changes in cytoskeletal proteins of the cells involved in immunological response.

EFFECT OF SELECTION FOR HIGH AND LOW ANTIBODY RESPONSE AGAINST SHEEP RED BLOOD CELLS ON HORMONAL PROFILE DURING IMMUNE RESPONSE IN CHICKENS

SUMMARY Two experiments were conducted in this study using two lines of Fayoumi chickens divergently selected for high (H) and low (L) antibody response against sheep red blood cells (SRBC) for four generations. The objectives of this study are to compare humoral and cell mediated immune responses between the lines, as well as to monitor the T3 and corticosterone hormone profile during the initiation of the immune responses. In the first experiment one hundred male chicks of each line were primary injected intramuscular with either 1 ml 25% SRBC suspension or saline at 50 and secondary reinjected at 80 days of age. Blood samples were collected at 0, 1, 3, 6, 9, 12 and 24 h and at 3, 7 and 10 days following primary and secondary injection. The results showed that H line produced significantly higher primary and secondary antibody titer than L line at 7 and 10 days post injection. The results showed that T3 levels decreased significantly at 3 h in H line and at 3, 6 and 9h in L line, then remained at low levels till 10 days post primary SRBC injection as compared to 0 h. Within both H and L lines, the T3 level showed insignificant differences between 0 hr and at any time post secondary SRBC or saline injection ( except that in H line at 3h post SRBC injection). In both line there was a significant increase in corticosterone levels at 24h as well as at 3, 7 and 10 days post primary, and at 3,7 and 10 days post secondary SRBC injection as compared to 0 h. In the second experiment, one-hundred and twenty male chicks of each line were injected intradermally into wattle with either 100 μg PHA-P or saline at 56 days of age to monitor the delayed type hypersensitivity (DTH) reaction. Blood samples were collected at 0, 3, 6, 9, 12 and, 24 hs post injection. The results indicate that H line had higher DTH value at 12 and 24 h than that in L line at the same time point. There was no remarked change in the level of T3 or corticosterone between PHA-P and saline injected birds at any time point following injection within both lines. In conclusion, the results of T3 or corticosterone levels in the current study may explain that the initiation of humoral immune response involves the activation of HPT- and HPA-axis. While this axis is not involved in delayed type hypersensitivity reaction.

Immune challenge mediates vocal communication in a passerine bird: an experiment

Secondary sexual characters may have evolved in part to signal resistance to parasites. Avian song has been hypothesized to be involved in this process, but the role of parasites in modulating acoustic communication systems in birds remains largely unknown, owing to lack of experiments. We studied the relationship between parasitism, testosterone, song performance, and mating success in male collared flycatchers (Ficedula albicollis) by experimentally challenging their immune system with a novel antigen. We predicted that a challenge of the immune system would reduce song performance, and that this reduction would be conditional on the size of a visual sexual signal, the forehead patch that was previously found to reflect resistance. An antagonistic linkage between testosterone and immune function would predict that a challenge of the immune system should suppress testosterone level. An immunological treatment by sheep red blood cells (SRBCs) triggered a decrease in body mass, testosterone level, and song rate, but other song traits were not significantly affected by the antigen challenge. Initial testosterone level was associated with forehead patch size and all song traits except song rate. SRBC injection caused stronger reduction in song rate among males with smaller forehead patches, and the change in song rate was also predictable by song features such as strophe complexity and length. We show that song rate and other song characteristics may be important cues in male-male competition and female choice. These results suggest that parasite-mediated sexual selection has contributed in shaping a complex acoustic communication system in the collared flycatcher, and that testosterone may play an important role in this process. Parasitism may drive a multiple signaling mechanism involving acoustic and visual traits with different signal function.

Testosterone, dominance signalling and immunosuppression in the house sparrow, Passer domesticus

The immunocompetence handicap hypothesis (ICHH) suggests that dominance signals are costly because their development is controlled by testosterone, which is immunosuppressive. Signal control therefore links an increased disease risk with a high quality signal. The chest bib of the house sparrow, Passer domesticus, is a signal known to be related to dominance and under control of testosterone levels. We experimentally manipulated testosterone in male sparrows during the breeding season and again independently during the post-breeding period to test whether variation in levels of testosterone could cause variation in levels of immunocompetence. There was no effect of testosterone manipulation on the cell-mediated response of birds to phytohaemagglutinin injection, nor did testosterone levels appear to affect either white blood cell ratios or red blood cell counts. In contrast, both breeding season and post-breeding season testosterone levels had significant effects upon the humoral response of the birds to sheep red blood cell injections. However, whilst testosterone during the breeding season appeared to act immunosuppressively, the role of post-breeding levels is less clear. In concordance with a previous study, there was an indication that corticosterone is involved in mediating the immunosuppressive effects of testosterone. The strength of the secondary humoral response and the cell-mediated response were negatively related suggesting the possibility of a trade-off between the different arms of the immune system. These results provide some support for the ICHH as a mechanism promoting the evolution of costly badges of status, although the results question whether the immunosuppressive cost can be mediated by testosterone at the time of badge development.

Cimetidine prevents suppression of delayed hypersensitivity in an animal model of haemorrhagic shock

Background: Cimetidine reverses immunosuppression following trauma, however, its effect on pure haemorrhagic shock is unknown. Methods: Mice sensitized by injection of sheep red blood cells (SRBCs), were subjected to cardiac puncture and randomized to a control group-A ( n=11) and three shock groups (35% of blood volume extracted): group-S had no treatment ( n=16), group-CP received cimetidine 50 mg/kg intraperitoneally ( n=16), group-CW received oral cimetidine (200 mg/kg per day, n=16). After 5 days, animals were challenged by injection of SRBCs into the foot-pad of the right hind paw (same volume of saline was injected into left paw). Foot-pad thickness ratios (FPTRs) were determined at 16 and 40 h, and inflammatory response was assessed histologically. Results: At 16 h, FPTRs were greater in group-CW than group-S ( P=0.01). There were no differences at 40 h. More animals in groups-CP and -CW had grade 3/4 inflammation, whilst group-S had the least inflammatory response (NS). Conclusions: Cimetidine prevents suppression of delayed hypersensitivity in this model.

Arginine Enhances In Vivo Immune Responses in Young, Adult and Aged Mice

Arginine supplementation enhances in vitro lymphocyte proliferation in healthy adult humans and in rodent models. Studies examining the effect of arginine supplementation on in vivo immune responses are lacking. The purpose of this study was to determine whether arginine supplementation could enhance in vivo immune responses in adult mice and reverse known age-associated alterations in immune function of young and aged mice. Mice (1, 10 and 33 mo old) were fed a 2% arginine or an isonitrogenous diet for 2 wk. Delayed-type hypersensitivity to 2,4-dinitrofluorobenzene-challenged ears and changes in popliteal lymph node weights to injected sheep red blood cells were measured. The mean percentage of increase in ear thickness in challenged vs. unchallenged ears was 27, 35 and 24% with arginine supplementation and 7, 12 and 0% with the isonitrogenous diet in the 1-, 10- and 33-mo-old mice, respectively (P </= 0.05 for each age). Across all ages, the mean differences in popliteal lymph node weights were 1.9 +/- 0.3 vs. 1.0 +/- 0.3 mg with the arginine and isonitrogenous diets, respectively (P </= 0. 05). Only the 33-mo-old mice fed the isonitrogenous diet did not respond to this immune challenge. These findings suggest that arginine supplementation may enhance in vivo immune responses and/or reverse age-associated changes.

Immunomodulatory Screening Test of Corn Oil Administered Orally to Female Mice: Effect of Timing of Dosing Within 24 Hours

The effect of varying the dose-delivery time within a 24h period (12:12 light-dark cycle) on the immunomodulatory properties of corn oil administered by gavage to 120 B6C3F1 female mice was investigated. Mice, housed in six separate boxes equipped with timers to regulate light onset and offset (staggered by 4h increments), were treated for 5 consecutive days by intragastric (ig) administration of 5 mL/kg corn oil. Negative and positive control mice were given sham injections (needle inserted, but no injection). Sheep red blood cells (SRBCs) were injected intraperitoneally (ip) on the fifth day. Three days later, positive control mice were given cyclophosphamide intraperitoneally (80 mg/kg). Four days after SRBC injection, mice were weighed and killed, and spleens and thymuses were removed and weighed. Spleens were brought to single-cell suspensions and tested for an antibody response to the SRBC. Plaque-forming cells (PFCs), as measured per spleen, per 106 viable spleen cells or per 106 total spleen cells, exhibited significant circadian rhythms for mice given corn oil, but not for sham-ga-vage- and cyclophosphamide-treated mice. The peak response (acrophase, ø) occurred at 21h, 22h, and 23h after lights on (HALO), respectively, with PFC values significantly different between the different time points. Corn oil and sham gavage affected the circadian pattern of antibody production; there was a high-amplitude (21-27%) rhythm observed when mice were treated with corn oil and no rhythm when mice received the sham-gavage treatment. In addition to testing mice near the end of the daily dark span andor early light span to obtain a maximum immune response, this finding points to the importance of including as controls a group of animals that are not treated at all and a group given vehicle alone. rather than only sham-treated animals, for comparison with experimentally treated animals.