A RhoGAP venom protein from Microplitis mediator suppresses the cellular response of its host Helicoverpa armigera.

Female parasitoid wasps normally inject virulence factors together with eggs into their host to counter host immunity defenses. A newly identified RhoGAP protein in the venom of Microplitis mediator compromises the cellular immunity of its host, Helicoverpa armigera. RhoGAP1 proteins entered H. armigera hemocytes, and the host cellular cytoskeleton was disrupted. Depletion of MmGAP1 by injection of dsRNA or antibody increased the wasp egg encapsulation rate. An immunoprecipitation assay of overexpressed MmGAP1 protein in a Helicoverpa cell line showed that MmGAP1 interacts with many cellular cytoskeleton associated proteins as well as Rho GTPases. A yeast two-hybrid and a pull-down assay demonstrated that MmGAP1 interacts with H. armigera RhoA and Cdc42. These results show that the RhoGAP protein in M. mediator can destroy the H. armigera hemocyte cellular cytoskeleton, restrain host cellular immune defense, and increase the probability of successful parasitism.

Defense of Scots pine against sawfly eggs (Diprion pini) is primed by exposure to sawfly sex pheromones.

Plants respond to insect infestation with defenses targeting insect eggs on their leaves and the feeding insects. Upon perceiving cues indicating imminent herbivory, such as damage-induced leaf odors emitted by neighboring plants, they are able to prime their defenses against feeding insects. Yet it remains unknown whether plants can amplify their defenses against insect eggs by responding to cues indicating imminent egg deposition. Here, we tested the hypothesis that a plant strengthens its defenses against insect eggs by responding to insect sex pheromones. Our study shows that preexposure of Pinus sylvestris to pine sawfly sex pheromones reduces the survival rate of subsequently laid sawfly eggs. Exposure to pheromones does not significantly affect the pine needle water content, but results in increased needle hydrogen peroxide concentrations and increased expression of defense-related pine genes such as SOD (superoxide dismutase), LOX (lipoxygenase), PAL (phenylalanine ammonia lyase), and PR-1 (pathogenesis related protein 1) after egg deposition. These results support our hypothesis that plant responses to sex pheromones emitted by an herbivorous insect can boost plant defensive responses to insect egg deposition, thus highlighting the ability of a plant to mobilize its defenses very early against an initial phase of insect attack, the egg deposition.

Effects of immune challenge on the oviposition strategy of a noctuid moth.

Infections can have detrimental effects on the fitness of an animal. Reproducing females may therefore be sensitive to cues of infection and be able to adaptively change their oviposition strategy in the face of infection. As one possibility, females could make a terminal investment and shift reproductive effort from future to current reproduction as life expectancy decreases. We hypothesized that females of the noctuid moth Heliothis virescens make a terminal investment and adapt their oviposition timing as well as their oviposition site selectivity in response to an immune challenge. We indeed found that females that were challenged with the bacterial entomopathogen Serratia entomophila laid more eggs than control females one night after the challenge. Additionally, bacteria-challenged females were less discriminating between oviposition sites than control females. Whereas control females preferred undamaged over damaged plants, immune-challenged females did not differentiate between the two. These results indicate that terminal investment is part of the life history of H. virescens females. Moreover, our results suggest that the strategy of terminal investment in H. virescens oviposition represents a fitness trade-off for females: in the face of infection, an increase in oviposition rate enhances female fitness, whereas low oviposition site selectivity reduces female fitness.

The effect of estrogen on the early cytotoxic response to IB virus infection in hen oviduct.

The aim of this study was to determine whether the egg-laying phase and estrogen affect the induction of cytotoxic cells in response to avian infectious bronchitis (IB) virus at early stage of infection in the oviduct. Attenuated IB virus (aIBV group) or its vehicle (control group) was introduced to the oviductal magnum lumen of White Leghorn hens in the laying and molting phase, as well as molting hens injected with estradiol benzoate (M-EB hens) or corn oil (M-oil hens). Oviductal isthmus and uterus were collected 24h after injection. The frequency of CD8(+) and TCRγδ(+) T cells expression was examined by immunohistochemistry, followed by image analysis. The expression of the genes of toll-like receptor 7 (TLR7), natural killer cell receptor (BNK), cytotoxic substances (granzyme, perforin), and cytokines (CXCL12, CX3CL1, and IFNγ) were examined by real-time polymerase chain reaction analysis. The frequency of CD8(+) and TCRγδ(+) T cells in the isthmus, and CD8(+) cells in the uterus was significantly higher in the aIBV group compared to the control group of laying and M-EB hens. The expression of all the genes examined in this study in the isthmus, and CX3CL1 and IFNγ expression in the uterus was significantly higher in the aIBV group in the laying and M-EB hens. These results suggested that infection with IB virus causes an immune response involving the influx of cytotoxic cells and upregulation of cytokines in the isthmus and uterus at early stage of infection. This response was stronger during the laying phase compared to the molting phase, probably due to the effect of estrogen.

Low transformation growth factor-β1 production and collagen synthesis correlate with the lack of hepatic periportal fibrosis development in undernourished mice infected with Schistosoma mansoni

Undernourished mice infected (UI) submitted to low and long-lasting infections by Schistosoma mansoni are unable to develop the hepatic periportal fibrosis that is equivalent to Symmers’ fibrosis in humans. In this report, the effects of the host’s nutritional status on parasite (worm load, egg viability and maturation) and host (growth curves, biology, collagen synthesis and characteristics of the immunological response) were studied and these are considered as interdependent factors influencing the amount and distribution of fibrous tissue in hepatic periovular granulomas and portal spaces. The nutritional status of the host influenced the low body weight and low parasite burden detected in UI mice as well as the number, viability and maturation of released eggs. The reduced oviposition and increased number of degenerated or dead eggs were associated with low protein synthesis detected in deficient hosts, which likely induced the observed decrease in transformation growth factor (TGF)-β1 and liver collagen. Despite the reduced number of mature eggs in UI mice, the activation of TGF-β1 and hepatic stellate cells occurred regardless of the unviability of most miracidia, due to stimulation by fibrogenic proteins and eggshell glycoproteins. However, changes in the repair mechanisms influenced by the nutritional status in deficient animals may account for the decreased liver collagen detected in the present study.

Low transformation growth factor-ß1 production and collagen synthesis correlate with the lack of hepatic periportal fibrosis development in undernourished mice infected with Schistosoma mansoni.

Undernourished mice infected (UI) submitted to low and long-lasting infections by Schistosoma mansoni are unable to develop the hepatic periportal fibrosis that is equivalent to Symmers' fibrosis in humans. In this report, the effects of the host's nutritional status on parasite (worm load, egg viability and maturation) and host (growth curves, biology, collagen synthesis and characteristics of the immunological response) were studied and these are considered as interdependent factors influencing the amount and distribution of fibrous tissue in hepatic periovular granulomas and portal spaces. The nutritional status of the host influenced the low body weight and low parasite burden detected in UI mice as well as the number, viability and maturation of released eggs. The reduced oviposition and increased number of degenerated or dead eggs were associated with low protein synthesis detected in deficient hosts, which likely induced the observed decrease in transformation growth factor (TGF)-ß1 and liver collagen. Despite the reduced number of mature eggs in UI mice, the activation of TGF-ß1 and hepatic stellate cells occurred regardless of the unviability of most miracidia, due to stimulation by fibrogenic proteins and eggshell glycoproteins. However, changes in the repair mechanisms influenced by the nutritional status in deficient animals may account for the decreased liver collagen detected in the present study.

Tick capillary feeding for the study of proteins involved in tick-pathogen interactions as potential antigens for the control of tick infestation and pathogen infection.

BACKGROUND: Ticks represent a significant health risk to animals and humans due to the variety of pathogens they can transmit during feeding. The traditional use of chemicals to control ticks has serious drawbacks, including the selection of acaricide-resistant ticks and environmental contamination with chemical residues. Vaccination with the tick midgut antigen BM86 was shown to be a good alternative for cattle tick control. However, results vary considerably between tick species and geographic location. Therefore, new antigens are required for the development of vaccines controlling both tick infestations and pathogen infection/transmission. Tick proteins involved in tick-pathogen interactions may provide good candidate protective antigens for these vaccines, but appropriate screening procedures are needed to select the best candidates. METHODS: In this study, we selected proteins involved in tick-Anaplasma (Subolesin and SILK) and tick-Babesia (TROSPA) interactions and used in vitro capillary feeding to characterize their potential as antigens for the control of cattle tick infestations and infection with Anaplasma marginale and Babesia bigemina. Purified rabbit polyclonal antibodies were generated against recombinant SUB, SILK and TROSPA and added to uninfected or infected bovine blood to capillary-feed female Rhipicephalus (Boophilus) microplus ticks. Tick weight, oviposition and pathogen DNA levels were determined in treated and control ticks. RESULTS: The specificity of purified rabbit polyclonal antibodies against tick recombinant proteins was confirmed by Western blot and against native proteins in tick cell lines and tick tissues using immunofluorescence. Capillary-fed ticks ingested antibodies added to the blood meal and the effect of these antibodies on tick weight and oviposition was shown. However, no effect was observed on pathogen DNA levels. CONCLUSIONS: These results highlighted the advantages and some of the disadvantages of in vitro tick capillary feeding for the characterization of candidate tick protective antigens. While an effect on tick weight and oviposition was observed, the effect on pathogen levels was not evident probably due to high tick-to-tick variations among other factors. Nevertheless, these results together with previous results of RNA interference functional studies suggest that these proteins are good candidate vaccine antigens for the control of R. microplus infestations and infection with A. marginale and B. bigemina.

Genetic parameters and across-line SNP associations differ for natural antibody isotypes IgM and IgG in laying hens.

In an earlier study, serum levels of natural antibody isotypes IgM- and IgG-binding keyhole limpet hemocyanin were found to be indicative for survival through the laying period of hens and therefore considered as promising traits for future implementation in breeding programs for higher survival of layers. In the present study, we first estimated the genetic parameters for the two isotypes at 20, 40 and 65 weeks of age (IgM20, IgM40 and IgM65; IgG20, IgG40 and IgG65). Pooled genetic parameters were estimated from the total population of 2504 hens from nine purebred layer lines, with line included in the model to account for admixture. Moderate heritabilities (0.14-0.44) indicated that selection for isotype titers is feasible, especially for IgM. Secondly, associations between 1022 SNP markers and the above-mentioned six immunological traits were estimated in 650 genotyped hens from the nine lines. The association study was performed across lines to detect markers that are closer to the QTL and have the same phase of association in the entire population. Forty-three significant associations between SNPs and isotype titers were detected. The SNPs of interleukins IL10 and IL19 were associated with both isotypes; SNPs of tripartite motif containing 33 (TRIM33) and IL6 showed significant association with IgG20 and IgM20 respectively; SNPs of heat shock protein 90kDa alpha (cytosolic), class B member 1 (HSP90AB1) were associated with IgG titers at older ages. Some detected SNPs were also reported associated with other immune and behavioral traits.

Oral immunization with an attenuated Salmonella Gallinarum mutant as a fowl typhoid vaccine with a live adjuvant strain secreting the B subunit of Escherichia coli heat-labile enterotoxin.

BACKGROUND: The Salmonella Gallinarum (SG) lon/cpxR deletion mutant JOL916 was developed as a live vaccine candidate for fowl typhoid (FT), and a SG mutant secreting an Escherichia coli heat-labile enterotoxin B subunit (LTB), designated JOL1229, was recently constructed as an adjuvant strain for oral vaccination against FT. In this study, we evaluated the immunogenicity and protective properties of the SG mutant JOL916 and the LTB adjuvant strain JOL1229 in order to establish a prime and boost immunization strategy for each strain. In addition, we compared the increase in body weight, the immunogenicity, the egg production rates, and the bacteriological egg contamination of these strains with those of SG 9R, a widely used commercial vaccine. RESULTS: Plasma IgG, intestinal secretory IgA (sIgA), and cell-mediated responses were significantly induced after a boost inoculation with a mixture of JOL916 and JOL1229, and significant reductions in the mortality of chickens challenged with a wild-type SG strain were observed in the immunized groups. There were no significant differences in increases in body weight, cell-mediated immune responses, or systemic IgG responses between our vaccine mixture and the SG 9R vaccine groups. However, there was a significant elevation in intestinal sIgA in chickens immunized with our mixture at 3 weeks post-prime-immunization and at 3 weeks post-boost-immunization, while sIgA levels in SG 9R-immunized chickens were not significantly elevated compared to the control. In addition, the SG strain was not detected in the eggs of chickens immunized with our mixture. CONCLUSION: Our results suggest that immunization with the LTB-adjuvant strain JOL1229 can significantly increase the immune response, and provide efficient protection against FT with no side effects on body weight, egg production, or egg contamination.

Anti-tick monoclonal antibody applied by artificial capillary feeding in Rhipicephalus (Boophilus) microplus females.

The tick Rhipicephalus microplus is an ectoparasite harmful to livestock, a vector of disease agents that affects meat and milk production. However, resistance to acaricides reflects the need for alternative tick control methods, among which vaccines have gained increasing relevance. In this scenario, monoclonal antibodies can be used to identify and characterize antigens that can be used as vaccine immunogens. Capillary tube artificial feeding of partially engorged R. microplus females with monoclonal antibodies against proteins from the gut of tick were used to test the effects of immunoglobulins in the physiology of the parasite. The results of artificial feeding showed that female ticks over 25mg and under 60 mg in weight performed better in the artificial feeding process, with a 94-168% weight increase after 24h of feeding. Results showed that artificial feeding of ticks proved to be a viable technique to study the effects of antibodies or drugs in the physiology of the parasite. One monoclonal antibody (BrBm2) induced decreased oviposition. Moreover, the antigen recognized by BrBm2 was identified as a 27-kDa protein and immunolabeled on digestive vesicles membranes of digestive cells of partially and fully engorged females.

The probiotic Bacillus licheniformis ameliorates heat stress-induced impairment of egg production, gut morphology, and intestinal mucosal immunity in laying hens.

We investigated the effect of a 12-d exposure to 34°C plus dietary inclusion of the probiotic Bacillus licheniformis on the egg production, gut morphology, and intestinal mucosal immunity of laying hens. Ninety-six commercial hens (Hy-Line Brown) at the age of 60 wk were randomly allocated to 4 groups. After a period of laying rate adjustment (14 d), all the hens were subjected to 2 temperature treatments (12 d). Birds in 1 group were raised at 21°C and fed a basal diet, and birds in the other 3 groups were raised at 34°C and fed a basal diet supplemented with 0, 10(6), or 10(7) cfu of B. licheniformis per gram of feed, respectively. Rearing at 34°C depressed egg production and feed intake (P < 0.05). Compared with birds kept at 21°C, birds kept at 34°C had elevated serum levels of tumor necrosis factor-α (d 6), IL-1 (d 6 and 12), and corticosterone (d 6); decreased villus height (ileum: d 6; cecum: d 6 and 12) and ratio of villus height to crypt depth (ileum: d 6; cecum: d 6 and 12); fewer intraepithelial lymphocytes (ileum: d 6; cecum: d 6) and IgA-secreting cells (ileum: d 6; cecum: d 6 and 12); and more mast cells (ileum: d 6; cecum: d 6 and 12; P < 0.05). The number of goblet cells in the cecum increased at d 6 in heat-treated birds, and then deceased at d 12 (P < 0.05). Moreover, morphological examination showed injury to the villi of birds kept at 34°C. In general, inclusion of 10(7) cfu/g of B. licheniformis in the diet of heat-stressed hens was effective in overcoming the observed decline in egg production and feed intake, restoring the impaired villus structure, and sustaining a balanced mucosal immune response. Therefore, the probiotic B. licheniformis may be useful for ameliorating the adverse influence of heat on the egg production and gut health of laying hens.

Effects of lipopolysaccharide on the expression of proinflammatory cytokines and chemokines and the subsequent recruitment of immunocompetent cells in the oviduct of laying and molting hens.

The goal of this study was to examine whether lipopolysaccharide (LPS) induces the expression of proinflammatory cytokines and chemokines and recruits T cells in the lower part of the oviduct, and whether that response to LPS is different between the laying and molting phase. White Leghorn laying and molting hens were intravenously injected with saline (control) or LPS. The uterus and vagina of oviducts were collected 3 or 6 h after injection, and used for reverse transcription PCR analysis of IL-1ß, IL-6, IL-8 (CXCLi2), and lymphotactin (Lptn), and for immunohistochemical analysis for the frequency of CD4+ and CD8+ T cells. The expressions of IL-1ß, IL-6, and CXCLi2 in the uterus and that of IL-1ß in the vagina were upregulated in response to LPS 3 or 6 h after injection in both laying and molting hens. The CXCLi2 expression in the vagina was upregulated by LPS in laying hens, whereas those effects of LPS were not significant in molting hens. Expression of Lptn showed a tendency to be downregulated after 3 h, with recovery by 6 h after LPS injection. The frequency of CD4+ T cells tended to increase in response to LPS after 6 h in the lamina propria of the uterus and vagina in both laying and molting hens. The CD8+ T cell frequencies in the lamina propria of the uterus and vagina of laying hens increased in response to LPS after 6 h. However, in the molting hens, LPS stimulation resulted in CD8+ T cell increase in the vagina only and not in the uterus. These results suggest that expressions of proinflammatory cytokines and CXCLi2 chemokine are upregulated in association with T cell recruitment in response to LPS in the lower part of the oviduct, although CD8+ T cells in the uterus may be depressed during the molting phase. These immunoresponses may play roles in the defense against infection of the oviduct.

Characterization of Aedes albopictus akirin for the control of mosquito and sand fly infestations.

The control of arthropod vectors of pathogens that affect human and animal health is important for the eradication of vector-borne diseases. Recent evidences showed a reduction in the survival and/or fertility of mosquitoes, sand flies and poultry red mites fed in vitro with antibodies against the recombinant Aedes albopictus akirin. These experiments were the first step toward the development of a multi-target arthropod vaccine. In this study, we showed that the oviposition of A. albopictus and Phlebotomus perniciosus fed on mice vaccinated with recombinant A. albopictus akirin was reduced by 17% and 31%, respectively when compared to controls. However, Aedes aegypti mosquitoes were not affected after feeding on vaccinated mice. These results showed that recombinant A. albopictus akirin could be used to vaccinate hosts for the control of mosquito and sand fly infestations and suggested new experiments to develop improved vaccine formulations.

Effects of diets containing different concentrations of propolis on hematological and immunological variables in laying hens.

To evaluate the effect of 4 different levels of propolis supplementation on the hematological and immunological parameters of laying hens, a trial was conducted with 60 White Leghorn layer hens. The experiment was conducted by using a randomized design with 5 treatments, 4 replicates, and 3 hens in each replicate. Treatments included basal diet (control) and basal diet plus 0.5, 1, 3, and 6 g of propolis/kg of diet, respectively. At the end of the 12-wk treatment period, samples of blood were collected to determine hematological and immunological values. The results showed that the addition of propolis at 3 g/kg in the diet resulted in significant increases (P < 0.05) in the serum IgG and IgM levels and significant decreases (P < 0.05) in the peripheral blood T-lymphocyte percentage compared with those of the control and other treatment groups. In addition, the level of 3 g/kg of propolis supplementation significantly increased (P < 0.05) erythrocyte count (red blood cells) compared with the other treatments. On the other hand, hemoglobin and hematocrit values and total leucocyte (white blood cells) and differential leucocytes counts were not influenced by propolis supplementation. These results indicate that the inclusion of propolis at the level of 3 g/kg of diet may have a positive effect on humoral immunity of laying hens.

Utilizing fungus myceliated grain for molt induction and performance in commercial laying hens.

Molting in poultry is used to rejuvenate hens for a second or third laying cycle. Feed withdrawal was once the most effective method used for molt induction; however, it has being phased out due to food safety and animal welfare concerns. This study evaluated the utilization of fungus myceliated grain as a safe and effective alternative for inducing molt, enhancing immunity, reducing Salmonella growth, and returning to egg production. Laying hens were subjected to 1 of 5 treatments: 1) nonfed (NF), 2) full-fed (FF), 3) fungus myceliated meal (FM), 4) 90% fungus myceliated meal+10% standard layer ration (FM-90), and 5) 90% alfalfa meal+10% fungus myceliated meal (AF-90). Each treatment condition was replicated 9 times during a 9-d molt period. The results revealed that egg production for treatments 1 and 3 ceased completely by d 5, whereas hens in treatments 4 and 5 ceased egg production by d 6. The percentage of BW loss decreased significantly (P<0.05) in treatments 1 (57%), 2 (8%), 3 (35%), 4 (37%), and 5 (44%). Ovary weights of hens fed all molting diets decreased significantly from the full-fed control but did not differ significantly (P<0.05) from each other. Salmonella population in the crop, ovary, and ceca from hens differed significantly (P<0.05) among treatments. Return to egg production differed between treatments with higher production beginning in treatment 3 and ending in treatment 5. Antibody titers did differ (P<0.05) among treatments. From these results, fungus myceliated meal appears to be a viable alternative to conventional feed withdrawal and other methods for the successful induction of molt and retention of postmolt performance.

Monitoring of laying capacity, immunoglobulin Y concentration, and antibody titer development in chickens immunized with ricin and botulinum toxins over a two-year period.

One of the key benefits in using chickens for immunization is the high yield of antibodies obtainable. It is known that egg production decreases over time, while animal maintenance costs remain stable. It would, however, be desirable to keep hens as long as possible to obtain maximal amounts of antibodies. To identify a suitable length of time that animals can be kept and to optimize the cost:yield ratio, we monitored the number of eggs laid, the total amount of chicken IgY, and the specific antibody titer from individually prepared eggs over a 2-yr period. The plant toxin ricin and the Clostridium botulinum neurotoxins type A and B were used to immunize 4 chickens. The number of eggs laid in 2 yr was approximately 600 per hen (about 80% of the maximum egg number), yielding about 20 to 40 g of total IgY per hen. A stable antibody titer of 1:100,000 to 1:1,000,000, as measured by ELISA, was obtained following up to 11 injections of 10 to 20 microg of immobilized native toxin. Laying capacities were found to decrease, on average, from 7 eggs/wk at the point of first immunization to 2 eggs/wk after more than 2 yr. In parallel, the yield of total and specific IgY increased over time, so that the antibody recovery remained high, even after prolonged immunization times. Using purified IgY preparations, classical immunological assays such as ELISA and Western blotting were performed. Furthermore, the IgY showed neutralizing capacity when used to block the functional activity of the toxins both in vitro and in vivo. Analysis of the total IgY content over time demonstrated a complex biological oscillation (and the antigen-specific titer), with a shorter time period of around 7 d (circaseptan rhythm). In summary, we successfully immunized chickens with ricin and botulinum neurotoxins and monitored laying capacity, IgY concentration, and specific antibody titer over an extended period of 2 yr.

Production of hen egg yolk immunoglobulins simultaneously directed against Salmonella enteritidis and Salmonella typhimurium in the same egg yolk.

The present study was an attempt to raise hen egg yolk Ig (IgY) simultaneously directed against Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) in the same egg yolk. The immunopotentiating effect of 2 different adjuvants -- Freund's adjuvants (FA) and immunostimulating complexes matrix (IM) -- on antibody response was also evaluated. Bacterial outer membrane proteins (OMP) were selected as target antigens. The ISA Brown hens, specific-Salmonella spp.-free status, divided into 6 groups were intramuscularly injected with a mono-compound antigen preparation: SE-OMP (treatment SE-FA or SE-IM) or ST-OMP (treatment ST-FA or ST-IM), or a combined antigen preparation: (1/2) SE-OMP and (1/2) STOMP (treatment SEST-FA or SEST-IM). Titers of antibodies in yolk were evaluated biweekly with ELISA. There was no antigen x adjuvant interaction on antibody titers. Anti-SE IgY titers in hens that received treatment SEST-FA or SEST-IM were statistically similar (P > 0.05) as compared with those obtained from hens immunized with treatment SE-FA or SE-IM. Anti-ST IgY titers in hens immunized with treatment SEST-FA or SEST-IM were slightly lower than those of hens that received treatment ST-FA or ST-IM. The cross-reactivity of anti-SE IgY, induced by treatment SE-FA or SE-IM, with ST-OMP antigen and that of anti-ST IgY, induced by ST-FA or ST-IM, with SE-OMP antigen were arbitrarily assessed on d 43 and 155 by ELISA. The average cross-reactivity of anti-SE IgY with ST-OMP antigen was 71.7%. The average cross-reactivity of anti-ST IgY with SE-OMP antigen was 78.8%. In FA groups, antibody titers were found higher (P < 0.05) than those in IM groups. Furthermore, no extensive lesions or clinical abnormalities were detected in hens injected with FA. These findings showed the opportunity to raise IgY antibody against 2 Salmonella serovars in the same yolk and that FA was more efficient than IM in mediating antibody response.

Effect of selection for phagocytosis in dwarf chickens on immune and reproductive characters.

In current study, phagocytosis product (PP) of peripheral blood monocytes was detected among 920 dwarf chickens (460 per sex) at 20 wk of age, and based on discrepancies of PP, the flock was grouped (the highest group, the medium group, and the lowest group). Then serum hemagglutination inhibition antibody titers and subpopulations of T-lymphocytes of each group were examined after inoculations of avian influenza virus H5N2 inactivated vaccine (20 wk of age), avian influenza virus H9 inactivated vaccine (24 wk of age), and Newcastle disease virus-egg drop syndrome virus bigeminal inactivated vaccine (28 wk of age), respectively, to study the relationship between PP and immune response. To gain insight into effects of selection for PP on number of eggs, mean egg weight, fertilization rate, hatchability, and rate of healthy chicks, 9 (3 x 3) mating combinations were conducted. The results showed that (1) selection for higher PP in both sexes benefited to humoral immunity but not CD8(+) T-lymphocyte mediated immunity in dwarf chickens; (2) there were effects of selection for higher PP in hens on fertilization rate (P < 0.05), hatchability (P < 0.05), rate of healthy chicks (P < 0.05), and level of IgY antibody (P < 0.0001); however, hens' PP had no effects on number of eggs (P > or = 0.05) or egg weight (P > or = 0.05) and cocks' PP had no effect (P > or = 0.05) on any trait mentioned above. The results indicated that phagocytosis of peripheral blood monocytes might be an indicator of humoral immunity in dwarf chickens; furthermore, selection of hens with higher PP was not only beneficial to fertilization rate, but also benefited to hatchability and rate of healthy chicks in that the hens had stronger humoral immunity, which might contribute to maternal antibody in eggs.

Reproductive costs of the immune response of the autogenous mosquito Culex pipiens molestus against inoculated Dirofilaria immitis.

Culex pipiens molestus is an autogenous mosquito, a vector of Dirofilaria immitis in Madeira Island, and it mounts a melanotic encapsulation response when inoculated intrathoracically with D. immitis microfilariae (mf). Because Cx. p. molestus is autogenous, this mosquito is a good model from which to gain a better understand the relationship between oviposition and melanization, independent of the signaling pathways related to blood feeding. The present work assessed the impact follicle growth might have on melanization of intrathoracically inoculated mf. The ovaries from mosquitoes undergoing melanotic encapsulation developed more eggs than those that could not melanize the mf. Possible explanations are discussed in this article.

Sterile wounding is a minimal and sufficient trigger for a cellular immune response in Drosophila melanogaster.

An attack and oviposition by parasitic wasp Leptopilina boulardi induces a vigorous cellular immune response in Drosophila melanogaster larvae. This response is manifested by the appearance of a specialized subset of blood cells, the lamellocytes, which are the key players in the encapsulation and killing of the parasite. The formation of lamellocytes involves the activation of the Toll, the Jun kinase and the JAK/STAT pathways however the minimal requirement for initiation of lamellocyte development in the course of the cellular immune response has not been defined yet. In this study, we tested whether or not the mechanical injury itself, caused by oviposition, could provide a sufficient signal for lamellocyte development. We found that sterile wounding, comparable to that occurring during oviposition, induces normal lamellocyte development. We propose therefore that mechanical damage of the cuticle and subsequent disruption of the basal lamina is a minimal and sufficient single signal for normal lamellocyte development in the course of the cellular immune response of Drosophila.