anti-SRBC Antibody Research Articles

Augmentation of expression of immunocytes’ functions by seed extract of Ziziphus mauritiana (Lamk.)

Aim of the study The present study was carried out to evaluate the immunomodulatory potential of Ziziphus mauritiana (Lamk.) seed extract to ascertain the folkloric claim as immunomodulator. Materials and methods The aqueous-ethanolic seed extract (100–400 mg kg −1) of Z. mauritiana was investigated for immunomodulatory potential in mice. The extract was standardized with HPLC using betulinic acid as a marker. Functions of various immunocytes in the form of humoral (development of anti-SRBC (sheep red blood cells) antibody titers) and cell-mediated immune response (delayed type hypersensitivity, nitroblue tetrazolium reduction, inducible nitric oxide synthase activity and bactericidal activity) was studied in SRBC immunized mice. The cytokine, IFN-γ (interferon-gamma) and IL-4 (interleukin-4) secretion was also measured quantitatively by ELISA as the expression of functions of Th-1 and Th-2 respectively. Levamisole (2.5 mg kg −1) was used as standard drug. Results The seed extract demonstrated significant ( P < 0.05–0.001) up-regulation of cell-mediated, humoral immune response and Th-1 mediated cytokine IFN-γ and decline in Th-2 mediated cytokine IL-4. At higher dose of extract the results were comparable to that of the levamisole. Conclusion The immunostimulatory potential of this seed extract is likely to be mediated through its effect on macrophage function and Th-1 mediated immunity confirming the folkloric use of this plant.

Immunomodulatory Activity of 3β,6β‐Dihydroxyolean‐12‐en‐27‐oic Acid in Tumor‐Bearing Mice

3beta,6beta-dihydroxyolean-12-en-27-oic acid (1) is a pentacyclic triterpenoid isolated from the rhizomes of Astilbe chinensis. To evaluate the in vivo antitumor potential and to elucidate its immunological mechanisms, effect of 1 on the growth of mouse-transplantable tumors, and the immune response in naive and tumor-bearing mice were investigated. The mice inoculated with mouse tumor cell lines were orally treated with 1 at the doses of 40, 60, and 80 mg/kg for 10 days. The effects of 1 on the growth of mouse-transplantable S180 sarcoma and H22 hepatoma, splenocyte proliferation, cytotoxic T lymphocyte (CTL) activity, natural killer (NK) cell activity, and production of interleukin-2 (IL-2) from splenocytes in S180-bearing mice were measured. Furthermore, the effect of 1 on 2,4-dinitrofluorobenzene (DNFB)-induced delayed-type hypersensitivity (DTH) reactions and the sheep red blood cell (SRBC)-induced antibody response in naive mice were also studied. Compound 1 could not only significantly inhibit the growth of mouse transplantable S180 sarcoma and H22 hepatoma, increase splenocytes proliferation, CTL and NK cell activity, and the level of IL-2 secreted by splenocytes in tumor-bearing mice, but also remarkably promote the DTH reaction and enhance anti-SRBC antibody titers in naive mice. These results suggested that 1 could improve both cellular and humoral immune response, and could act as antitumor agent with immunomodulatory activity.

Immunomodulatory and antitumor activity of triterpenoid fractions from the rhizomes of Astilbe chinensis

Aim of the study The objectives of this study were to evaluate the in vivo antitumor potential of the triterpenoid fraction from the rhizomes of Astilbe chinensis (Saxifragaceae) (Saxifragaceae) (ATF) and to elucidate its immunological mechanisms by determining its effects on the growth of mouse transplanted tumors and the immune response in naïve and tumor-bearing mice. Materials and methods The mice inoculated with mouse tumor cell lines were treated per os with ATF at the doses of 20, 40, 60 mg/kg for 10 days. The effects of ATF on the growth of transplantable tumor, splenocyte proliferation, the activity of natural killer (NK) cells, and production of interleukin-2 (IL-2) from splenocytes in tumor-bearing mice were measured. Meanwhile, the effects of ATF on 2,4-dinitrofluorobenzene (DNFB)-induced delayed type hypersensitivity (DTH) reaction and the sheep red blood cell (SRBC)-induced antibody response in naïve mice were also studied. Results ATF could not only significantly inhibit the growth of mice transplantable tumor, but also remarkably increase splenocytes proliferation, NK cells activity, and the level of IL-2 secreted by splenocytes in tumor-bearing mice, promote the DTH reaction and enhance anti-SRBC antibody level in naïve mice, which indicated that the ATF could improve both specific and non-specific cellular and humoral immune response. Conclusions The antitumor activity of ATF might be achieved by improving immune response, and ATF could act as antitumor agent with immunomodulatory activity.

Evaluation of the Immune System in Rats and Mice Administered Linear Ammonium Perfluorooctanoate

Repeated high doses of ammonium perfluorooctanoate (APFO) have been reported to affect immune system function in mice. To examine dose-response characteristics in both rats and mice, male CD rats and CD-1 mice were dosed by oral gavage with 0.3-30 mg/kg/day of linear APFO for 29 days. Anti-sheep red blood cell (SRBC) IgM levels, clinical signs, body weights, selected hematology, and lipid parameters, liver weights, spleen, and thymus weights and cell number, selected histopathology, and serum corticosterone concentrations were evaluated. In rats, linear APFO had no effect on production of anti-SRBC antibodies. Ten and 30 mg/kg/day resulted in systemic toxicity as evidenced by decreases in body weight gain to 74 and 37%, and increases in serum corticosterone levels to 135 and 196% of control, respectively. In mice dosed with 10 and 30 mg/kg/day, marked systemic toxicity and stress were observed, as evidenced by a loss in body weight of 3.8 and 6.6 g, respectively (despite a tripling of liver weight), approximately 230% increase in serum corticosterone, and increases in absolute numbers of peripheral blood neutrophils and monocytes with an accompanying decrease in absolute lymphocyte numbers. Immune-related findings at 10 and 30 mg/kg/day that likely represent secondary responses to the systemic toxicity and stress observed at these doses include: decreased IgM antibody production at 10 (20% suppression) and 30 mg/kg/day (28% suppression); decreased spleen and thymus weights and cell numbers; microscopic depletion/atrophy of lymphoid tissue at 10 (thymus) and 30 mg/kg/day (spleen). In summary, no immune-related changes occurred in rats, even at doses causing systemic toxicity. In mice, immune-related changes occurred only at doses causing significant and profound systemic toxicity and stress.

Effects of methionine and arginine dietary levels on the immunity of broiler chickens submitted to immunological stimuli

The present study aimed at assessing the effects of methionine and arginine on the immune response of broiler chickens submitted to immunological stimuli. Three methionine concentrations (0.31, 0.51, and 0.66% from 1 to 21 days of age; 0.29, 0.49, and 0.64% from 22 to 42 days of age) and 2 arginine concentrations (1.33 and 1.83%; 1.14 and 1.64% for the same life periods) were tested. Birds were divided into two groups for immunological stimuli (3x2x2 arrangement). Vaccines against Marek’s disease, fowl pox, infectious bronchitis, Freund’s Complete Adjuvant, Sheep red blood cells (SRBC), and avian tuberculin were administered to one group as immunological stimuli; the other group did not receive any stimulus. The experiment was carried out with 432 one-day-old male Ross broilers, distributed into 12 treatments with 6 replicates of 6 birds each. Performance data were weekly collected. Anti-SRBC antibodies were collected by hemagglutination test and cell immune response (CIR) was measured by tubercularization reaction in one wattle 24 hours after administration of the second tuberculin injection at 42 days of age. The weight difference between the two wattles of each bird (one injected with tuberculin and the other not) was the measure of CIR. Arginine levels did not influence either bird performance or immune response. Methionine concentrations higher or lower than usually adopted in broiler production (0.51 and 0.49%) equally failed to influence the birds’ immune humoral response, but the best CIR was observed at the intermediate methionine level. Vaccines administered on the first day of age impaired bird performance up to the 21 st day of age.

Immunocompetence of Two Broiler Strains Fed Marginal and High Protein Diets

Immunocompetence of broiler chicks fed marginal and high dietary protein levels was studied. Four hundred one-day-old broiler chicks (200 Cobb and 200 Hubbard) were divided into two equal groups within each strain. The marginal protein starter diet had 3075 Kcal ME/kg and 20% crude protein (CP) while the marginal protein fishier diet had 3152 Kcal ME/kg and 18% CP. The high protein starter diet and finisher diets contained 3086 Kcal ME/kg, 22% CP and 3130 Kcal ME/kg, 20% CP, respectively. Starter ration was provided for ad libitum consumption from hatching up to 3 weeks of age, while the finisher one was provided from 4 to 6 weeks of age. The average high and low ambient temperatures recorded during the experimental period were 21 and 18°C, respectively. At 3 weeks of age, 60 chicks (15 chicks/strain/treatment) were used for determined the cell-mediated immunity via Phytohemagglutinin-P (PHA-P) injection. Also, humoral immune responses were determined. On day 14, chicks were slaughtered and the bursa of Fabricius, spleen, thymus, liver and heart were removed and weighed to the nearest milligram. The present results showed that the body weights did not significantly affected by strain, dietary protein level and their interaction. However, the Hubbard broiler chicks significantly consumed more feed and had a better feed conversion ratio compared to Cobb ones. The broiler chicks fed a high protein diet significantly consumed less feed and had a better feed conversion ration compared to other that fed a marginal protein diet. With respect to immunocompetence, it could be noticed that the Hubbard broiler chicks had significantly hyper responder to PHA-P injection and significantly higher total anti-SRBCs antibody titer compared to Cobb ones. The high dietary protein level significantly increased the toe-web swelling and total anti-SRBCs antibody titer compared to marginal protein level. The relative lymphoid organs weight did not significantly affected by strain. Similar trend, except for bursa, was noticed for dietary protein level. The relationships between body weight and toe-web swelling measured at all times were very low in Cobb fed a marginal protein diet. Similar trend, but moderate, was noticed in Hubbard-H group. However, significantly positive relationships between body weight and toe-web swelling measured at all times were observed in Cobb fed a high protein diet and Hubbard fed a marginal protein diet. Negative relationship between body weight and total anti-SRBC antibody titer was observed in all groups. In conclusion, under winter season of Egypt, the Hubbard broiler chicks had lower mortality rate and better immune competence compared to Cobb ones. Also, the high protein level improved the immunity of the broiler chicks.

Antibody Response Against Sheep Red Blood Cells in Lines Congenic for Major Histocompatibility (B) Complex Recombinants

Six congenic lines containing B complex recombinants R1 = B-F/B-L24, B-G23; R2 = B-F/B-L2, BG23; R3 = B-F/B-L2, B-G23; R4 = B-F/B-L2, B-G23; R5 = B-F/B-L21, B-G19; and R6R6 = B-F/B-L21, B-G23 were tested individually for antibody response against SRBC. R2, R3 and R4 arose from independent recombination events but are serologically identical. Each B complex recombinant was crossed to inbred Line UCD 003 (B17B17). After ten backcross generations to the inbred line, B complex heterozyogtes were mated to produce recombinant homozygous lines having 99.9% background gene uniformity. Birds of each line were injected intravenously with 1 mL of 2.5% SRBC at four and 11 weeks of age to induce primary and secondary antibody responses, respectively. Blood samples were collected 7 days post-injection. Microtiter methods were used to assay total anti-SRBC and mercaptoethanol-resistant (MER) serum antibody. All antibody titers were evaluated by least squares ANOVA with hatch and B recombinant genotype as main effects. Fisher’s protected LSD was used to evaluate significant means. Genotypes R5R5 and R6R6 had significantly higher primary total antibody titer to SRBC compared with R1R1, R2R2, R3R3 and R4R4. Both R5 and R6 have BF21, a haplotype known for high antibody response to SRBC. Primary MER antibody response did not differ significantly among the genotypes. The total and ME-resistant secondary antibody titers of R5R5 chickens were significantly higher than the other five recombinants. These results indicate that congenic lines carrying six B complex recombinants differ in their primary and secondary antibody responses to SRBC.

Antibody responses in hyperthyroid rats

This study evaluated antibody production against sheep red blood cells (SRBC) in hyperthyroid rats during treatment with triiodothyronine (T 3). The immune response was evaluated by measuring plaque forming cells (PFC) in the spleen and by enzyme-linked immunosorbent assay (ELISA) in serum of male Wistar rats (180 ± 10 g) treated with 25 μg/day of triiodotironine (T 3) during 7–12 days and immunized with SRBC at the 8th day of treatment. The results showed that anti-SRBC antibody production was significantly decreased in animals treated for 12 days when compared to normal rats immunized with the same antigen, as evaluated by the two assays. These results show that in this experimental model hyperthyroidism decreases antibody response. We previously observed the opposite effect, that is, an increase in this response in hypothyroid rats resulting from the treatment with propylthyouracil, a blocker of thyroid hormone biosynthesis. It is suggested that antibody production is affected by thyroid hormone levels.

Humoral and Cellular Response of Pheasants Vaccinated against Newcastle Disease and Haemorrhagic Enteritis

The purpose of the experiment was to define whether and to what extent can prophylactic vaccinations against Newcastle disease (ND) and haemorrhagic enteritis (HE) affect the humoral and cellular response in pheasants. The evaluation of humoral response was performed on a basis of agglutinin titre after administered antigen and the cellular immunity index was the delayed type hypersensitivity (DTH) reaction. The pheasants were prophylactically vaccinated against Newcastle Disease (ND) on the 1st, 28th and 56th day of life. Moreover, on the 49th day of life, part of the birds was given in the drinking water a vaccine containing the HEV (Haemorrhagic Enteritis Virus). Fourteen days after the HEV vaccination, the birds were intravenously given 0.5 ml of the 10% SRBC (sheep red blood cells) suspension. Simultaneously with the SRBC administration the delayed hypersensitivity test was performed by intradermal administration of phytohaemagglutinin (PHA). It was shown that in pheasants vaccinated with NDV and additionally with HEV, the specific agglutinin anti-SRBC titre was significantly (p &lt; 0.05) lower than in birds vaccinated against ND only. It also appeared that, the antibodies resistant to 2-mercaptoethanol were 43% of the total pool of specific anti-SRBC antibodies in the NDV vaccinated birds, whereas in birds vaccinated also with HEV they were 75%. No significant differences were found in the DTH test. Only in the HEV vaccinated pheasants the tendency to increase the wing index value was noted. The results confirm the observations concerning immunosuppressive effects of simultaneous vaccinations. They also indicate that overloading the pheasants with many antigens (ND and HEV vaccination) may weaken the humoral response to administered SRBC.

Long-term effects of early life L-arginine supplementation on growth performance, lymphoid organs and immune responses in Leghorn-type chickens

1. The effects of a short-term dietary arginine supplementation after hatching on subsequent growth and the immune system were assessed in growing male Leghorn-type chickens. 2. An arginine-deficient basal diet (6·7 g/kg) supplemented with 0 (control), 2·7 (LA) or 5·4 (HA) g L-arginine/kg, was offered ad libitum to 1-d-old male ISA Brown chicks for 4 weeks, then all birds were offered ad libitum a commercial pullet grower feed (8·9 g arginine/kg) for another 8 weeks. 3. Supplemented birds had higher growth rates and feed intake than control birds during the 4-week supplementation period, but these effects did not persist into the subsequent periods. 4. When the supplementation ceased at week 4, no differences in lymphoid organ weights relative to body weight (BW), primary serum antibody levels against sheep red blood cells (SRBC) or cutaneous reactivity of toe webs to phytohaemagglutinin (PHA) were detected. 5. LA-fed birds had lower immunoglobulin (Ig) G levels against bovine serum albumin (BSA) than the control at week 4, but this effect did not persist at weeks 8 and 12. 6. No difference in anti-BSA IgM levels was detected among birds at week 4; at week 12, however, the LA-fed birds had a significantly higher anti-BSA IgM level than the control. 7. An increased anti-SRBC antibody level and a reduced relative bursa weight in HA-fed birds were evident at week 8, without any prior effects. 8. It is concluded that short-term supplementary L-arginine had minimal effects on immunity, but some enhancement of SRBC antibody responses in later stages of growth was observed with previous L-arginine administration.

Studies on immunocompetence status in two turkey varieties in India

1. Two hundred and twenty-seven adult turkeys of both sexes, of two varieties (104 Black and 123 White) were used to evaluate their immunocompetence status and body weights. 2. Response to sheep red blood cells (SRBC) (humoral immunity) was measured by Haemagglutination (HA) test 5 days post immunisation (dpi) and expressed as log2 values. Mercaptoethanol resistant (MER) antibodies representing IgG were determined by Mercaptoethanol HA test and Mercaptoethanol sensitive (MES) antibodies, representing IgM as the difference in total HA titre and IgG. Serum lysozyme concentrations were estimated by ‘Lysoplate assay’ and expressed in log2 values. 3. Least squares analysis of variance revealed that the White variety had higher adult body weight (4·788 ± 0·040 kg) than the Black (3·774 ± 0·044 kg). Sexual dimorphism was apparent and meals were heavier then females in both varieties. The interaction effect of variety and sex on body weight was also significant. 4. Least squares means for immunological traits, namely, total anti-SRBC antibodies, MER, MES titres and serum lysozyme were 7·161 ± 0·189, 0·801 ± 0·071, 6·362 ± 0·160 and 1·766 ± 0·043 µg/ml, respectively. The Black variety had a higher MES antibody titre than the White. 5. Sex had an effect on all the immunological traits except on MER titres. Females generally had higher anti-SRBC, MER and MES titres and serum lysozyme. The variety × sex interaction effect was significant for MES titres and serum lysozyme. White males had the lowest MES titres.

Immunmilk® Feeding Increases Growth and Immune Responses in Broiler Chicks

A study was conducted to measure baseline immunocompetence of Arbor Acre broiler chicks after the birds were raised on hyperimmune bovine colostrum product 'Immunmilk®' for first 7 d of age . Immunological parameters measured were in vivo and in vitro lymphoproliferation, macrophage functions which included phagocytosis, nitric oxide production and E. coli clearance from circulation; and antibody response against SRBC. In addition, body weights (BW) and lymphoid organ weights were also determined. Immunmilk®-treated chicks exhibited significantly higher BW at 7 (18.1% heavier) and 13 d (26% heavier) of age when compared with the chickens in control group. In vitro lymphoproliferative response of bloo d leukocytes to Concanavalin-A was increased (P = 0.0024) while in vivo lymphoproliferation to Phytohemagglutinin-P was down-regulated (P < 0.01) in Immunmilk®-treated group. Macrophage phagocytic potential against SRBC was significantly higher and nitric oxide production was reduced in macrophages from Immunmilk® treated chicks. Systemic E. coli clearance after i.v. challenge was much more rapid in Immunmilk®-treated chicks. Immunmilk® treatment also increased total and IgM anti-SRBC antibody levels (P < 0.05) during secondary antibody response. The results of this study showed that Immunmilk® increased growth as well as immune performance of chickens as measured by humoral (antibody) response, mononuclear phagocytic system function as well as lymphoproliferation. However, inflammatory processes such as in vivo mitogen-induced T-lymphocyte proliferation and LPS-mediated nitric oxide production by macrophages were down regulated.

Effect of l-arginine on restraint stress induced modulation of immune responses in rats and mice

The present study investigates the role of nitric oxide (NO) on restraint stress (RS)-induced modulation of humoral and cell-mediated immune responses in rats and mice. RS produced suppression of humoral immune response, i.e., anti-SRBC antibody titre (7.38±0.32 versus 4.13±0.30; mean±S.E.M., P<0.001). In case of cell-mediated immunity, in delayed type hypersensitivity (DTH) response the change in paw volume decreased from 0.069±0.003 mm (mean±S.E.M.) in control non-stressed group to 0.038±0.002 mm in the stressed group ( P<0.001) while percentage leucocyte migration inhibition (% LMI) decreased from 39.7±1.95 in control non-stressed animals to 15.2±1.07 in animals subjected to stress ( P<0.01). Pretreating the animals with an NO precursor, l-arginine (1000 mg kg −1, i.p.) antagonized the effect of RS on humoral (anti-SRBC antibody titre 6.50±0.27 versus 4.13±0.30, P<0.001) and cell-mediated (DTH response 0.066±0.002 mm versus 0.038±0.002 mm, P<0.001; % LMI 41.5±1.46 versus 15.2±1.07, P<0.01) immune responses. Administration of 7-nitroindazole (7-NI, 50 mg kg −1, i.p.), an inhibitor of neuronal NO synthase, alone further enhanced the immunosuppressive effect of RS (anti-SRBC antibody titre 2.75±0.25 versus 4.13±0.30, P<0.001; DTH response 0.019±0.002 mm versus 0.038±0.002 mm, P<0.001; % LMI 5.0±1.08 versus 15.2±1.07, P<0.01). However, when given before l-arginine treatment, 7-NI reversed the effect of the latter drug on stress-induced immunomodulation (anti-SRBC antibody titre 3.00±0.27 versus 6.5±0.27, P<0.001; DTH response 0.043±0.003 mm versus 0.066±0.002 mm, P<0.001; % LMI 12.0±0.93 versus 41.5±1.46, P<0.01). Unlike its effect on RS-induced immune responsiveness, l-arginine (250, 500, 1000 mg kg −1) when given for 5–7 days to naive non-stressed animals produced dose dependent suppression of both humoral (anti-SRBC antibody titre 6.4±0.32 versus 5.4±0.32, 4.0±0.27, 3.1±0.30, respectively) and cell-mediated (DTH 0.065±0.003 mm versus 0.064±0.004 mm, 0.039±0.003 mm, 0.020±0.002 mm, respectively and % LMI 37.52±1.58 versus 30.48±1.07, 28.18±1.22, 19.76±0.83, respectively) immune responses. 7-NI significantly blocked these immunosuppressive effects of l-arginine (anti-SRBC antibody titre 6.0±0.38 versus 3.1±0.030, P<0.001; DTH response 0.056±0.004 mm versus 0.020±0.002 mm, P<0.001; % LMI 34.76±1.31 versus 19.76±0.83, P<0.01). However, 7-NI when given to non-stressed animals failed to modulate immune responsiveness. Thus, NO appears to play an important role in RS-induced immunomodulation and these effects are different from its effect on immune responsiveness in non-stressed animals.

Effect of Lipopolysaccharide (LPS) Injection on the Immune Responses of LPS-Sensitive Mice

The effect of lipopolysaccharide (LPS) on humoral and cell-mediated immunity was assessed using LPS-sensitive C3H/HeN mice. A single injection of LPS significantly decreased the anti-sheep red blood cells (SRBC) antibody titers, but not the number of anti-SRBC antibody producing spleen cells. In contrast, double LPS injection did not significantly decrease the anti-SRBC titers and even increased the number of anti-SRBC antibody producing spleen cells. Similarly, single LPS injection significantly suppressed the swelling of the footpad, but double LPS injection caused milder suppression. These results suggest that a difference in the level and timing of exposure to LPS may influence the immune response to infection or vaccination.

Augmentation effects of lymphocyte activation by antigen-presenting macrophages on FDG uptake

Research on FDG-uptake by blood cells has revealed that FDG is incorporated by macrophages and granulocytes, as well as activated lymphocytes. These characteristics of FDG suggest the possibility of visualizing the distribution of immunocytes in target organs. The aim of this study was to investigate if mouse spleen-derived lymphocytes, activated by macrophages presenting sheep red blood cell (sRBC) antigens, could be traced by FDG. One percent of a sRBC suspension was injected into the peritoneal cavity of mice thereby creating immunity to the sRBC antigen. The splenocytes, consisting mostly of lymphocytes, were isolated, and serum containing the anti-sRBC antibody was mixed with sRBC to prepare sRBC-antibody complexes (sRBC-AbCs). Then five percent of a thioglycolate medium was injected into the peritoneal cavity of the same mice, and macrophages of ascitic cell origin were obtained. These macrophages were added to the sRBC-AbCs to induce sRBC antigen presenting macrophages. These were incubated with splenocytes obtained from sRBC immunized mouse (sRBC immunized splenocytes) or non-immunized splenocytes to induce a T cell immune response. [3H]deoxyglucose ([3H]DG) and FDG were incorporated in splenocytes, and the quantity of their uptake was measured. [3H]DG uptake by sRBC-immunized splenocytes was about eleven times as high as that of non-immunized splenocytes. In contrast, [3H]DG uptake by sRBC-immunized splenocytes, co-cultured with macrophages phagocytizing sRBC-AbCs, was about 40 times higher compared with non-immunized splenocytes. Splenocytes in non-immunized mice picked up very little [3H]DG, despite co-culture with macrophages phagocytizing sRBC-AbCs. Similar tendencies were observed with FDG. These results suggest that the SUV calculated in PET reflects not only the number of lymphocytes, but also the activation state of the lymphocytes themselves. In addition, the biodistribution of antigen specific lymphocytes, that have been taken up FDG in vitro and returned to the body, can be observed through PET.

Concentration-dependent bifunctional effect of TGF-β 1 on immunoglobulin production: a role for Smad3 in IgA production in vitro

Injury to the liver results in rapid induction of transforming growth factor-beta1 (TGF-β 1) consistent with a role for TGF-β 1 in repairing damaged tissue. In addition to its ubiquitous role in injury repair, TGF-β 1 is also well established as a critical regulator of immune homeostasis; however, its mechanisms of action remain enigmatic. We have previously demonstrated that the hepatotoxic chlorinated hydrocarbon, carbon tetrachloride, suppresses helper T-lymphocyte function in a TGF-β 1-dependent manner. Here, we report that, in opposition to its immunosuppressive effects at picomolar concentrations, femtomolar concentrations of TGF-β 1 augment T cell-dependent anti-sRBC IgM antibody forming cell (AFC) and T cell-independent DNP-Ficoll-induced AFC responses. These data support a concentration-dependent bifunctional effect by TGF-β 1 on humoral immune responses in vitro. We further investigated a putative mechanistic role for Smad3, an intracellular mediator of TGF-β 1 signaling, in propagating the inhibitory effects of TGF-β 1 on humoral immune responses. Relative to wild type littermates, splenocytes from mice homologous for a null mutation in the gene encoding the TGF-β receptor-activated Smad3 (Smad3 Exon8−/−) were less sensitive to inhibition by TGF-β 1 following anti-sRBC- and LPS-sensitization in vitro. In agreement, inhibition of IgM protein production by TGF-β 1 was also dampened in LPS-sensitized Smad3 Exon8−/− splenic B cells. Moreover, stimulation of IgA by TGF-β 1 was abrogated in LPS-sensitized Smad3 Exon8−/− splenocytes suggesting an additional role for Smad3 in regulating IgA production in vitro. Our results suggest that the effects of TGF-β 1 on humoral immune responses fundamentally differ in a concentration-dependent manner and are mediated, in part, through Smad3 signaling.

Immunomodulatory properties of Alternanthera tenella Colla aqueous extracts in mice.

Plants from the genus Alternanthera are thought to possess antimicrobial and antiviral properties. In Brazilian folk medicine, the aqueous extract of A. tenella Colla is used for its anti-inflammatory activity. The present study investigated the immunomodulatory property of A. tenella extract by evaluating the antibody production in male albino Swiss mice weighing 20-25 g (10 per group). The animals received standard laboratory diet and water ad libitum. The effect of A. tenella extract (5 and 50 mg/kg, ip) was evaluated in mice immunized with sheep red blood cells (SRBC 10%, ip) as T-dependent antigen, or in mice stimulated with mitogens (10 micro g, Escherichia coli lipopolysaccharide, LPS, ip). The same doses (5 and 50 mg/kg, ip) of A. tenella extract were also tested for antitumor activity, using the Ehrlich ascites carcinoma as model. The results showed that 50 mg/kg A. tenella extract ip significantly enhanced IgM (64%) and IgG2a (50%) antibody production in mice treated with LPS mitogen. The same dose had no effect on IgM-specific response, whereas the 5 mg/kg treatment caused a statiscally significant reduction of anti-SRBC IgM-specific antibodies (82%). The aqueous extract of A. tenella (50 mg/kg) increased the life span (from 16 +/- 1 to 25 +/- 1 days) and decreased the number of viable tumor cells (59%) in mice with Ehrlich ascites carcinoma. The present findings are significant for the development of alternative, inexpensive and perhaps even safer strategies for cancer treatment.

Comparison of Immune Responses of Inducible Nitric Oxide Synthase (iNOS) Hyper-and Hypo-responsive Genotypes of Chickens

genotypes for iNOS gene expression and activity. Two trials were conducted to compare these lines for immune parameters. For mononuclear phagocytic function quantification, 5 chickens per group were injected i.v. with Black India Ink at a rate of 1 mL/kg body weight (BW) at 4 wk. Blood samples were drawn and optical density measured at 640 nm on plate reader. K-strain was significantly better in clearing carbon (P = 0.04) than the GB1 and GB2 chickens at 10 min post i.v. injection. Lymphoproliferation was measured in vitro by incubating 0.2 x 10 peripheral blood leukocytes with 25 µg Concanavalin A. K-strain chicks had the highest 6 lymphoproliferation index than the GB1 and GB2. On the contrary, K-strain chicks had a weaker PHAPmediated toe-web swelling response as compared with the GB1 and GB2 chicks. No differences were observed between genotypes for the total or IgG anti-SRBC antibodies in primary or secondary immunization response (one trial). However, K-strain exhibited greater persistence (P < 0.05) of IgM levels than GB2 chicks during the decline phase of the booster response. While K chicks had heavier BW (P < 0.01), they had smallest bursal, thymic and splenic weights (relative to BW) vs. GB1 and GB2 in both trials. These findings show that the iNOS hyper responder K-strain chickens also perform better for monocyte/macrophage, Tlymphocyte and perhaps even B-lymphocyte functions even though their lymphoid organ growth lagged behind the iNOS hyporesponder (GB1 and GB2) genotypes.

PARAMETERS OF THE IMMUNOLOGICAL PROFILE IN CHICKENS TREATED WITH A CALENDULA OFFICINALIS EXTRACTION

Tests were carried out on thirty, 42 days old Rock x Cornish chickens, divided into three experimental groups: I - control injected with saline, II - injected with a Calendula officinalis extraction supplemented with Bayol and III - treated with Bayol. The effects of the in vivo treatments and simultaneous antigen priming (0.5 ml of a 5 % suspension of SRBC) on their humoral (lysozyme, anti-SRBC antibodies) and cell-mediated (leucocyte blast transformation) responses were investigated. Lysozyme (51.50 ± 32.30, 56.80 ± 41.27, 29.50 ± 22.73 μg/ml)(p<0.05), and anti-SRBC antibody titers (2.35 ± 0.86, 2.05 ± 0.65 and 1.90 ± 0.55) were the lowest in Bayol treated group. Spontaneous stimulation index was positively influenced by the in vivo Bayol therapy (57.20 ± 8.88 per cent), when compared to that recorded for the other groups (31.06 ± 18.93 group I, 33.37 ± 19.26 group II).

Evaluation of immunomodulatory potential of Ocimum sanctum seed oil and its possible mechanism of action

The present study investigates the effect of Ocimum sanctum seed oil (OSSO) on some immunological parameters in both non-stressed and stressed animals. An attempt has also been made to explore the possible mechanism of immunomodulatory activity. OSSO (3 ml/kg, ip) produced a significant increase in anti-sheep red blood cells (SRBC) antibody titre and a decrease in percentage histamine release from peritoneal mast cells of sensitized rats (humoral immune responses), and decrease in footpad thickness and percentage leucocyte migration inhibition (LMI) (cell-mediated immune responses). Restraint stress (RS) produced a significant reduction in the anti-SRBC antibody titre, foot pad thickness and percentage LMI (% LMI). The effects of RS on humoral as well as cell-mediated immune responses were effectively attenuated by pretreating the animals with OSSO. Co-administration of diazepam (1 mg/kg, sc), a benzodiazepine (BZD), with OSSO (1 ml/kg, ip) enhanced the effect of OSSO on RS-induced changes in both humoral and cell-mediated immune responses. Further, flumazenil (5 mg/kg, ip), a central BZD receptor antagonist inhibited the immunomodulatory action of OSSO on RS-induced immune responsiveness. Thus, OSSO appears to modulate both humoral and cell-mediated immune responsiveness and these immunomodulatory effects may be mediated by GABAergic pathways.