Productive and reproductive performance in cattle infected with bovine leukosis virus

Economic losses caused by enzootic bovine leukosis (EBL) have been of interest since World War II, when the neoplastic form of EEL increased dramatically in Europe. Olson (1974) and House et al. (1975) ed that animals with lymphosarcoma caused by the bovine leukosis virus (BLV) had reduced milk yields. a less efficient reproductive performance and high veterinary costs and mortality rates, while many carcasses were rejected at slaughter. However, the actual impact of BLV infection in cattle without lymphosarcoma is not; clear. The purpose of the study reported here was to compare some productive and reproductive responses of cattle that were antibody-positive (BLV+) or negative (BLV-) for BLV.Holstein dairy cows in commercial dairy farms were used in this study. Blood samples were collected and subjected to BLV serological examination by the agar gel immunodiffusion test of Miller & van der Maaten (1976). Animals were then grouped as BLV+ or BLV- according to their serological response to the BLV antigen. Productive and reproductive histories were obtained from individual animal records and the following factors were considered: milk production, calving interval and birth rate. For milk production, we had the daily milk yields of 547 animals, and for calving interval the time between two successive parturitions for 444 cows. These values were examined by ANOVA and when this was significant a Student's t test was carried out for each age group. Birth rates, the percentage of animals that calved in 1 gear, were available for 557 animals and were examined with the Z-two proportion test. For all analyses, P < 0.05 was considered significant.

The role of interleukin-10 in the differential expression of interleukin-12p70 and its beta 2 receptor on patients with active or treated paracoccidioidomycosis and healthy infected subjects

Paracoccidioidomycosis patients present an antigen-specific Th1 immunosuppression. To better understand this phenomenon, we evaluated the interleukin (IL)-12 pathway by measuring IL-12p70 production and CD3(+) T cell expression of the IL-12 receptor (IL-12R)beta1/beta2 chains, induced with the main fungus antigen (gp43) and a control antigen, from Candida albicans (CMA). We showed that gp43-induced IL-12p70 production and IL-12Rbeta2 expression were significantly decreased in acute and chronic patients as compared to healthy subjects cured from PCM or healthy infected subjects from endemic areas. Interestingly, the healthy infected Subjects had higher gp43-induced IL12p70 production and beta2 expression than the cured subjects. The addition of a neutralizing anti-IL-10 antibody to the cultures increased IL12p70 levels and beta2 expression in acute and chronic patients to levels observed in Cured subjects. Conversely, addition of the cytokine IL-10 strongly inhibited both parameters in the latter group. In conclusion, we have shown that paracoccidioidomycosis-related Th1 immunosuppression is associated with down-modulation of the IL-12 pathway, that IL-10 may participate in this process, and that patients cured from paracoccidioidomycosis may not fully recover their immune responsiveness. (C) 2004 Elsevier B.V. All rights reserved.

Detection of immunoglobulin G antibodies to Neospora caninum in humans: High seropositivity rates in patients who are infected by human immunodeficiency virus or have neurological disorders

Considering that little is known about the epidemiology of Neospora caninum infection in humans, particularly in populations with high Toxoplasma gondii infection rates, the present study aimed to investigate the presence of antibodies to N. caninum in T. gondii-seropositive and -seronegative individuals. A total of 256 serum samples divided into four groups (61 samples from human immunodeficiency virus [HIV]-positive patients, 50 samples from patients with neurological disorders, 91 samples from newborns, and 54 samples from healthy subjects) were assessed for N. caninum and T. gondii serologies by indirect fluorescent-antibody test, enzyme-linked immunosorbent assay, and immunoblotting (IB). Immunoglobulin G antibodies to N. caninum were predominantly detected in HIV-infected patients (38%) and patients with neurological disorders (18%), while newborns and healthy subjects showed lower seropositivity rates (5% and 6%, respectively). Seropositivity to N. caninum was significantly associated with seropositivity to T. gondii in both HIV-infected patients and patients with neurological disorders. Seroreactivity to N. caninum was confirmed by IB, with positive sera predominantly recognizing the 29-kDa antigen of N. caninum. The results of this study indicate the presence of N. caninum infection or exposure in humans, particularly in HIV-infected patients or patients with neurological disorders, who could have opportunistic and concurrent infections with T. gondii. These findings may bring a new concern for the unstable clinical health of HIV-infected patients and the actual role of N. caninum infection in immunocompromised patients.

Comparison of two immunochromatographic assays and the indirect immunofluorscence antibody test for diagnosis of Trypanosoma cruzi infection in dogs in south central Louisiana

Two rapid tests evaluated in dogs considered to be of high risk of Infection with the Chagas parasite Trypanosoma cruzi using two immunochromatographic assays. Trypanosoma Detect (TM) for canine, InBios, Seattle, WA and CHAGAS STAT-PAK (TM) assay, Chembio Diagnostic Systems, Medford, NY, in south central Louisiana. For this purpose a serological survey was carried out in a total of 122 dogs and a serum bank was created. These 122 animals were first tested by IFAT that was used as the standard test From the serum bank 50 samples were tested using the two rapid Chagas assays and results compared to the standard test IFAT The serological survey using IFAT showed it prevalence of T cruzi infection in 22.1% of the tested dogs. In the immunochromatographic assays. 13 and 11 animals were positive on rapid assay Trypanosoma Detect (TM) for canine, InBios and CHAGAS STAT-PAK (TM), Chembio Diagnostic Systems, respectively compared to 11 positive by IFAT. These two immunochromatographic tests have shown high susceptibility and specificity compared to our standard method IFAT. The rapid, easy and accurate screening assays used in conjunction with confirmatory tests, would be an excellent tool for veterinarians to diagnose T cruzi infection. Early detection of T cruzi infection may prevent complications through an effective treatment. Greater awareness by veterinarians of the risk. clinical findings, history along with diagnostic methods will contribute greatly to an understanding of the true prevalence of Chagas disease in dogs in Louisiana. (c) 2009 Elsevier B.V. All rights reserved.

Evaluation of macrophage activity and antibody production in genetically selected mice infected with Leptospira serovar pomona

The aim of the present study was to evaluate the role of macrophage activity and antibody production in experimental infection with Leptospira Pomona in mice genetically selected for high (H) or low (L) humoral immune response. To evaluate macrophage activity, reactive oxygen and nitrogen intermediates were determined. Also, the production of tumor necrosis factor (TNF-alpha) and the recovery of Leptospira-specific antibodies in the kidneys and liver were assessed; histological lesions were analyzed using the hematoxylin-eosin technique, and Leptospira antigens in tissues were determined by immunohistochemistry. Results showed that recovery of microorganisms from the analyzed organs was lower in LIV-A mice. However, HIV-A animals showed total restraint since the 14th day after infection, whereas LIV-A mice still had bacteria in the liver at the 21st post-infection day. Immune response against Pomona serovar in those lineages was characterized as high production of antibodies, mainly in late periods of the infectious process. The production of reactive oxygen and nitrogen intermediates also contributed to the elimination of Leptospira Pomona in all two lineages; H2O2 production was an important factor in HIV-A mice, as well as NO production in the LIV-A animals, mainly at the latest post-inoculation periods. The same occurred regarding TNF-alpha production. Severe renal lesions were observed at periods in which larger numbers of leptospires were isolated using the culture technique. Tissue alterations persisted in LIV-A mice, even at periods in which leptospires were not recovered. Immunohistochemistry showed to be more sensitive than culturing. However, both techniques were appropriate for the agent identification in the studied lineages. Results suggest that such lineages could represent an important model to investigate pathogenesis and immune response against the varied serovars of leptospires.

Detection of cross infections by Leishmania spp. and Trypanosoma spp. in dogs using indirect immunoenzyme assay, indirect fluorescent antibody test and polymerase chain reaction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efficacy of the Bm86 antigen against immature instars and adults of the dog tick Rhipicephalus sanguineus (Latreille, 1806) (Acari: Ixodidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Maternal antibody transfer to broiler progeny varies among strains and is affected by grain source and cage density

Two experiments were conducted to examine the effects of broiler breeder dietary grain source and cage density on maternal antibody (MatAb) transfer to progeny in 2 genetic strains (A and B). Broiler breeders were assigned to 16 litter floor pens and fed either corn- or wheat-based diets. Breeders were administered 4 live vaccines against Newcastle disease virus (NDV). At 23 wk of age, pullets and cocks, which reflected the full BW distribution from each treatment, were moved to a cage breeder house and placed at 1 or 2 hens/cage. Breeders were artificially inseminated at 44 wk (experiment 1) and 52 wk of age (experiment 2). Eggs were collected for 8 d, incubated, and placed in individual pedigree bags at d 19 of incubation. Blood samples from 5 chicks per treatment combination were collected at hatch in both experiments. Spleen and bursa were collected from the same chicks for histomorphometry analyses in experiment 2. In the second experiment, 12 chicks per treatment were placed in cages. Progeny were provided diets based on the same grain (corn or wheat) as their parents. Serum samples were collected at 5, 9, and 13 d of age and analyzed for anti-NDV MatAb. Data were analyzed as a 2 x 2 x 2 factorial design considering strain, dietary grain source, and cage density as main factors. Interaction effects were observed in breeders and progeny. Experiment 1 showed that strain A chicks had lower levels of MatAb when hens were housed at 2 hens/cage rather than 1 hen/cage. The MatAb levels of strain B chickens were not affected by cage density in either experiment. Experiment 2 demonstrated similar effects of cage density on MatAb levels and the area of bursa follicles for both strains. Progeny of breeders fed corn-based diets had smaller spleen white pulp only when hens were housed at 2 hens/cage compared with 1 hen/cage. The results of these experiments suggest that breeder strain and cage-density conditions affected MatAb transfer to progeny and embryo development of spleen and bursa.

The Paracoccidioides brasiliensis gp70 antigen is encoded by a putative member of the flavoproteins monooxygenase family

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of broiler breeder genetic, diet type, and feeding program on maternal antibody transfer and development of lymphoid tissues in chicken progeny

Maternal antibody (MatAb) transfer is important for early chicken survivability. Diet composition and the amount of feed given to breeder pullets during rearing may affect the development of immunity and the transfer of MatAb to progeny, and could affect progeny performance and resistance to disease. The effects of broiler breeder nutrition and feeding management practices were evaluated for the transfer of MatAb to progeny and for spleen and bursa development at hatching in 2 genetic strains (A and B). In this experiment, the levels of MatAb against Newcastle disease virus were assessed by enzyme-linked immunosorbent assays in serum samples taken of pedigreed chicken progeny from hatching to 13 d of age. Chickens were fed corn-and wheat-based diets, as were their parents. The breeder feeding program and diet type altered the Newcastle disease virus MatAb found in progeny at hatching and affected how long these antibodies were maintained in circulation. Bursal follicle size at hatching was influenced by an interaction among all factors evaluated. Percentage of white pulp in the spleen was affected mainly by genetic strain and diet type, but responses varied according to the breeder feeding program. It was concluded that breeder feeding programs influence MatAb transfer and half-life, and may also affect the early development of lymphoid tissues.

Human leukocyte antigen-G expression after kidney transplantation is associated with a reduced incidence of rejection

HLA-G is a non-classic Human Leukocyte Antigen (HLA-G) Class I of low polymorphism and restricted tissue distribution that displays tolerogenic functions. In heart transplantation and in combined liver/renal allograft transplantation, the expression of HLA-G has been associated with a lower incidence of acute graft rejection episodes and absence of chronic dysfunction. Since the expression of HLA-G in renal biopsies has been investigated only in few patients who received a combined kidney and liver transplant, in this study we performed a cross-sectional study, systematically comparing the expression of HLA-G in post-transplanted renal grafts, stratifying patients according to the presence or absence of rejection.Patients and Methods: Seventy-three renal specimens (10 with acute rejection and 13 with chronic allograft nephropathy, and 50 with no signs of rejection) were immunohistochemically evaluated for HLA-G expression.Results: In the group as a whole, HLA-G molecules were detected in 40 cases (54.8%). Among specimens that presented HLA-G expression, 2 out of 40 (5%) exhibited acute rejection, 2 (5%) exhibited chronic allograft nephropathy, and the remaining 36 (90%) exhibited no signs of rejection. The comparison between patients with rejection and those without rejection showed that the expression of HLA-G was significantly increased in specimens exhibiting no signs of rejection (p<0.0001). Considering only patients with acute rejection, 8 out of 10 patients showed no HLA-G expression in their kidney biopsies when compared to patients exhibiting no signs of rejection and absence of HLA-G was observed in 14 out of 50 (p=0.0032). Similarly, considering only patients with chronic allograft nephropathy, absence of HLA-G expression was observed in I I out of 13 specimens, whereas in patients without rejection absence of HLA-G was observed in 14 out of 50 (p=0.003). Therapy with tacrolimus was significantly associated with the expression of HLA-G and a better graft prognosis. Conclusions: Our results suggest that HLA-G expression in the kidney allograft and the use of tacrolimus are associated with a lower frequency of acute renal rejection and chronic allograft nephropathy. (c) 2007 Elsevier B.V. All rights reserved.

IgG subclass profile of serum antibodies to Leishmania chagasi in naturally infected and vaccinated dogs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)