Immunization of mice against infection with Taenia taeniaeformis using various antigens prepared from eggs,oncospheres, developing larvae and strobilocerci

Rajasekariah G. R., Rickard M. D. and Mitchell G. F. 1980. Immunization of mice against infection with Taenia taeniaeformis using various antigens prepared from eggs, oncospheres, developing larvae and strobilocerci. International Journal for Parasitology10: 315–324. Antigens were collected during in vitro incubation of oncospheres, 3-week-old larvae and strobilocerci of T. taeniaeformis. Supernatants of these in vitro products centrifuged at 500 g contained antigens which stimulated a significant degree of protective immunity when injected into mice. However, centrifugation of the strobilocercus preparation at 4500 g yielded supernatants which failed to induce immunity. Suspensions of eggs and oncospheres disrupted by sonication stimulated a high level of immunity as also did 4500 g supernatants of the sonicated preparations. Centrifugation of sonicated oncospheres at 100,000 g yielded a supernatant which stimulated significantly less immunity than the 4500 g supernatant, although the protective capacity was not totally abolished. The pellet from 100,000 g centrifugation of sonicated oncospheres induced almost absolute immunity. These results are consistent with the suggestion that the ‘functional’ antigens in the preparations tested may initially be membrane-associated or particulate in nature and that sonication causes partial solubilization. Supernatants prepared from homogenised strobilocerci and centrifuged at 4500 g also stimulated protective immunity and presumably contain soluble antigens. No evidence is available to suggest whether or not the strobilocercus antigens which stimulated protective immunity are identical to those found in oncospheral preparations. Immunity was stimulated by subcutaneous, intraperitoneal and intramuscular injections of antigen and both Freund's complete adjuvant and Bordetella pertusiss vaccine were effective as adjuvants. Using sonicated oncospheres, a high level of immunity was stimulated without the use of adjuvant.     

Detection of circulating antibodies in patients affected by Chromoblastomycosis by Cladosporium carrionii using double immunodiffusion

The antibodies in sera of patients affected by Chromoblastomycosis are detected using the technique of double immunodiffusion and the mycelial somatic antigens and the culture filtrates antigens of Cladosporium carrionii. From the 13 sera tested 8 have given positive results. The fresh serum from a patient under treatment gives 2 bands, while fresh serum from a non-treated patient gives 3 bands. The titre of antibodies was also determined for the two fresh sera, having found 1/4 for the patient under treatment and 1/32 for the non-treated one.     

Associations of BF2 alleles with antibody titres and production traits in commercial pure line broiler chickens

Three commercial broiler pure lines were evaluated for associations of sire BF2 (major histocompatibility complex class I) alleles with progeny phenotypic traits. Significant BF2 associations with a subset of traits were observed in two lines. The BF2*21 allele was positively associated with antibody titre to infectious bursal disease virus in both lines. Other associations were line-specific.     

Extraction and Preliminary Use for Diagnosis of Soluble Precipitating Antigen from Babesia bigemina*

Soluble antigen from bovine blood with a Babesia bigemina parasitemia of 5–6% formed 4 precipitin lines in gel diffusion tests with antiserum from infected cattle. Antigen was obtained from plasma and hemolysate by elution from DEAE cellulose columns and (NH₄)₂SO₄ precipitation as well as from washed parasite-erythrocyte stroma by sonication or freezethawing. About 5 ml of antigen suitable for diagnostic tests could be extracted from 200 ml of infected blood.     

A small variation in diet influences the Lactobacillus strain composition in the crop of broiler chickens

Feed composition has the potential to influence the activities of bacteria that colonize the digestive tract of broiler chickens with important consequences for animal health, well being, and food safety. In this study, the gut microbiota of two groups of broiler chickens raised in immediate vicinity but fed either a standard corn/soybean meal ration (corn–soy, CS) or a ration high in wheat middlings (high wheat, HW) was characterized. The findings revealed that this small variation in feed composition did not influence the distribution of microbial species present in the microbial community throughout the digestive tract. However, diet variation markedly influenced the Lactobacillus strain composition in the crop. Most striking, the dominant type in birds on the CS diet (Lactobacillus agilis type R5), which comprised 25% of the isolates, was not detected in birds fed the HW diet. The latter birds harbored a different strain of L. agilis (type R1) in a significantly higher ratio than birds on the CS diet. Several other strains were also specific to the particular diet. In conclusion, this study showed that a small variation in the composition of chicken feed that does not result in detectable differences in species composition can still have an impact on which microbial strains become dominant in the digestive tract. This finding has relevance in the application of probiotics and other direct-fed microbials in poultry husbandry.     

Centrosema is a promiscuous legume nodulated by several new putative species and symbiovars of Bradyrhizobium in various American countries

Centrosema is an American indigenous legume that can be used in agroecosystems for recovery of acidic and degraded soils. In this study, a Centrosema-nodulating rhizobial collection of strains isolated in a poor acid savanna soil from Venezuela was characterized, and the members of the collection were compared to other Centrosema strains from America. The analysis of the rrs gene showed that the strains nodulating Centrosema in American countries were closely related to different species of the genus Bradyrhizobium. However, the analysis of the atpD and recA genes, as well as the 16S–23S ITS region, showed that they formed several new phylogenetic lineages within this genus. The Venezuela strains formed three lineages that were divergent among themselves and with respect to those formed by Centrosema strains isolated in other countries, as well as to the currently described species and genospecies of Bradyrhizobium. In addition, the symbiotic genes nodC and nifH carried by Centrosema-nodulating strains were analyzed for the first time, and it was shown that they belonged to three new phylogenetic lineages within Bradyrhizobium. The nodC genes of the Centrosema strains were divergent among themselves and with respect to the genistearum and glycinearum symbiovars, indicating that Centrosema is a promiscuous legume. According to these results, the currently known Centrosema-nodulating strains represent several new putative species and symbiovars of the genus Bradyrhizobium.     

Serological comparison of Australian and South American strains of Babesia argentina and Anaplasma marginale

The indirect fluorescent antibody test was used for the serological comparison of the parasites called Babesia argentina and Anaplasma marginale in Australia and Bolivia, South America. Cross-testing performed with antigens and antisera prepared in the two continents proved serological identity for both parasites. Because a similar study by Goldman & Rosenberg (1974) showed serological identity between B. bovis and B. argentina, by the law of priority the small Babesia of Australia and South America should be called B. bovis. The findings have implications in vaccination.     

Experimental Neospora caninum infection in chickens (Gallus gallus domesticus) with oocysts and tachyzoites of two recent isolates reveals resistance to infection

The importance of birds in the biological cycle of Neospora caninum is not clear. We report unsuccessful Neospora infection in chickens (Gallus gallus domesticus) using two isolates of N. caninum. In experiment #1, 30 White Leghorn chickens were orally inoculated with viable N. caninum oocysts (NC-SP1 isolate, 200 oocysts per bird) via the crop at 21 days of age. Groups of three birds were euthanised at intervals of 7 days (a total of 9 weeks) and one group was challenged with the same oocyst dose at 37 days p.i. and observed for 11 weeks. Blood samples were collected weekly, and sera were tested using IFAT. Chicken tissues were collected for PCR, quantitative PCR and immunohistochemistry. Two dogs approximately 45 days of age were fed with tissues from chickens euthanised at 138 and 159 days p.i. The results indicated that the chickens were resistant to neosporosis as revealed by failure to seroconvert, to detect parasite DNA or N. caninum antigen by immunohistochemistry in inoculated bird tissues, and by no oocyst excretion by the dogs fed avian tissues. Similar results were obtained in experiment #2, in which 34 1-week-old chickens were each s.c. inoculated with 100,000 tachyzoites of the NcWTDMn1 isolate of N. caninum. The chickens were euthanised on days 7, 15, 22, 28, 36 and 60 p.i. At necropsy, all tissues and serum from each bird were collected. All chickens remained asymptomatic, and N. caninum antigen was not detected by immunohistochemistry. Seven chickens euthanised at day 60 p.i. demonstrated low (1:25 dilution) levels of antibodies by using the Neospora agglutination test. Two 12-week-old dogs fed tissues pooled from 10 inoculated chickens euthanised at day 60 p.i. did not excrete N. caninum oocysts. This investigation indicates that chickens are resistant to experimental infection by N. caninum.     

Ascaris suum and Toxocara canis: Egg extract antigens in guinea pigs and the macrophage migration inhibition test

Guinea pigs immunized with 500 μg of either Ascaris suum or Toxocara canis egg extracts, emulsified with Freund's complete adjuvant, were skin tested with both the homologous and heterologous antigens. Cross-reactions were observed in both groups. Migration of macrophages from sensitized animals was more inhibited by homologous than by heterologous antigens. Lymph-node lymphocytes from sensitized animals were stimulated to incorporate [⁸H]thymidine similarly by both antigens.     

The immunological response of CBA mice to Trypanosoma musculi: Elimination of the parasite from the blood

Agglutinating antibodies against Trypanosoma musculi could not be demonstrated in sera from parasitaemic, immune or immunized mice.Immune, non-adherent cells from peritoneal exudates of mice which had recovered from infection, accelerated the elimination of parasites when adoptively transferred to infected mice in which the parasitaemia was stable (plateau phase) and the parasites had reached the adult (non-dividing) stage. This effect was not influenced by the simultaneous administration of immune adherent cells and/or immune serum and, although the mechanism by which the blood infection is e radicated has not been established, the action of the sensitized cells does not appear to be due to formation of antibody which has a direct, trypanocidal effect.     

Effect of host sex on passive immunity in mice infected with Nematospiroides dubius

Dobson C. & Owen M. E. 1978. Effect of host sex on passive immunity in mice infected with Nematospiroides dubius. International Journal for Parasitology8: 359–364. Female C₃H but not Quackenbush (Q) mice harboured fewer Nematospiroides dubius than male C₃H and Q mice. Both strains lost worms 21 days after infection. C₃H and Q mice became progressively immune to infection following 4 sequential doses of N. dubius larvae and showed a sex resistance to infection. Hypothymic nu/nu CBA Balb/c mice did not show these effects on N. dubius infection. The reciprocal transfer of male and female immune mesenteric lymph node cells (IMLNC) to syngeneic male and female recipients showed that the female environment enhanced the protective qualities of both male and female IMLNC but the male environment suppressed these effects. Gonadectomized male and female recipients of male and female IMLNC had levels of infection similar to the entire female recipients. Serum from immune female donor mice protected both male and female recipients better than immune serum from male donors, but female mice in each treatment group were better protected than male mice. Immune serum transferred greater levels of protection then IMLNC to recipient mice against N. dubius infections. These data are consistent with the conclusion that the male environment suppresses lymphocyte activity and the production of protective antibodies and additionally may depress the effectiveness of sensitized lymphocytes and antibodies in ejecting N. dubius. On the other hand the female environment does not appear to adversely affect the mobilization of the protective immune response and may enhance immune effector mechanisms in protecting mice against N. dubius infections.     

Fasciola hepatica: some properties of a precipitate which forms when metacercariae are cultured in immune rat serum.

When Fasciola hepatica metacercariae are cultured in immune rat serum a precipitate forms on their teguments which is a complex of parasite metabolic antigen and rat immunoglobulin, possibly IgG. Continuous secretion of the antigen by the parasite and its precipitation with antibody leads to the eventual appearance of precipitate in the culture medium. Ouchterlony double diffusion tests indicate that only one antigen/antibody interaction appears to be involved in precipitate formation. When rats were vaccinated with precipitate emulsified with Freund's complete adjuvant then given an oral challenge with metacercariae, there was a reduction of as much as 50% in their worm burdens compared with controls. This evidence suggests that the precipitate contains a functional antigen of the parasite. The rat immunoglobulin component is therefore presumed to be protective antibody.     

Immunological studies of the mechanism of anaemia in experimental Trypanosama evansi infection in rats

Pathological changes in the blood of rats acutely infected with Trypanosoma evansi and the probable mechanism of the accompanying anaemia, were investigated. A severe anaemia, together with rreticulocytosis and hepato-splenomegaly, were regularly observed. Histological examination of the liver, spleen and bone-marrow confirmed the increasedin erythropoietic activity that the observed anaemia was due to increasedextravascular destruction of erythrocytes rather than by inhibition of haemopoietic activity. All the infected rats showed significant immune responses to the infecting trypanosome peak agglutinin titres occurring 10–12 days after injection, coincidentally with maximun destruction of erythrocytes. Serological examination of sera and erythrocytes from all infected and control rats did not reveal the presence of either circulating or adsorbed erythrocyte auto--antibodies. Furthermore, there was no in vivo trypanosomal antigen coating of the erythrocytes from either infected or multiple antigen-injected rats. Repeated intraveoous injections into rats of more than 100 μg per g body weight of soluble T. evansi antigen resulted in moderately severe, probably antibody-mediated, haemolytic anaemia. It is considered that an immunologically-mediated mechanism may be responsible for the development of the anaemia accompanying T. evansi infection.     

Age-associated responses in susceptible and resistant rats to infection with Fasciola hepatica

Rajasekariah G. R. and Howell M. J. 1981. Age-associated responses in susceptible and resistant rats to infection with Fasciola hepatica. International Journal for Parasitology11: 59–65. Groups of susceptible (5-week-old) and age resistant (25-week-old) outbred male Wistar rats were infected with metacercariae of Fasciola hepatica and the establishment of the parasite was assessed in terms of worm reocvery, and haematological, histopathological and immunological criteria, 2, 4, 6 and 8 weeks after infection. Apart from 2 weeks after infection, there was a significant difference between groups in the recovery of F. hepatica, with resistant rats infected with consistently fewer parasites than susceptible animals. The juvenile worms which invaded the livers of resistant rats elicited a number of host reactions, marked by an intensive cellular infiltration into migratory tracks of the parasite, heavy deposition of fibrous tissue in the liver parenchyma and a rapid antibody response. These responses were not as striking in susceptible animals even though more worms were present. The ability of resistant rats to mount an enhanced response seems related to the maturation of their haemopoietic system.     

Vaccination against the nematode Trichostrongylus colubriformis. III. Some observations on factors influencing immunity to infection in vaccinated guinea-pigs

Rothwell T. L. W. 1978. Vaccination against the nematode Trichostrongylus colubriformis. III. Some observations on factors influencing immunity to infection in vaccinated guineapigs. International Journal for Parasitology8: 33–37. Guinea-pigs were protected against infection with T. colubriformis when soluble material extracted from fourth-stage larvae was administered by the subcutaneous, intradermal, intraperitoneal and intraduodenal but not oral routes. The level of immunity following vaccination by the various effective routes was similar. Mature animals were found to respond significantly better to vaccination than immature animals. Significant immunity was present 10 days after vaccination but higher levels were found after 20 and 40 days. A single dose of vaccine was as effective as three divided doses. Finally, it was found that the adjuvant aluminium hydroxide gel, but not B. pertussis vaccine or levamisole improved the level of immunity to infection which followed vaccination.     

Changes in fat metabolism of black-bone chickens during early stages of infection with Newcastle disease virus

Experiments were conducted to determine the effects of Newcastle disease on chicken fat metabolism. Thirty black-bone chickens were infected intraocularly with the Newcastle disease virus (NDV). Six birds were killed at 0, 12, 24, 48 and 72 h post infection, respectively. Results showed that the NDV infection decreased concentration of high-density lipoprotein cholesterol and increased concentrations of total cholesterol and low-density lipoprotein cholesterol in the plasma. Concentrations of triglycerides and free fatty acid were decreased after their initial increase. NDV infection also dramatically raised the activities of lipoprotein lipase (LPL), hepatic lipase and lipases in the serum. Furthermore, PCR results showed that the incipient infection up-regulated mRNA expression of LPL, adipose triglyceride lipase and nuclear factor peroxisome proliferator-activated receptor alpha (PPARα), but down-regulated them at later stage. Similarly, mRNA expression of fatty acid synthase, acetyl-CoA carboxylase and nuclear factor PPARγ, fatty acid transport protein 1 (FATP1), and 4(FATP4) decreased, whereas fatty acid translocase and fatty acid-binding protein increased initially. Data from Western blotting analysis showed that the changes in protein levels were consistent with mRNA expression. These results indicated that fat metabolism of the chicken was affected by the NDV infection. At the beginning of NDV infection, lipogenesis was inhibited, whereas lipolysis was strengthened. After lipolysis was strengthened, fat metabolism was found to be maximally depressed.     

In vivo and in vitro studies of the effects of immune rat serum on Fasciola hepatica

Significant protection against infection with 10 or 30 metacercariae of Fasciola hepatica was conferred on naive rats by the passive transfer of serum derived from rats which had been exposed to primary and challenge infections with 5 or 10 and 30 or 20 metacercariae respectively. Immune serum did not have a pronounced effect on the mortality of metacercariae in vitro. However, its presence was associated with the formation of a precipitate on the tegument of each metacercaria and in the culture medium. The precipitate contained rat antibody and other components, presumably parasite antigens, which elicited the formation of antibody when the precipitate was injected into rats. Viability of metacercariae cultured in immune and normal sera as well as freshly excysted specimens was tested in rats by intraperitoneal infection. Metacercariae cultured in immune serum did not develop. By comparison with the viability of freshly excysted metacercariae, that of some metacercariae cultured in normal serum was impaired; this was attributed to inadequacies in the culture technique. A relationship between precipitate formation in vitro and impaired viability of metacercariae in vivo has yet to be established.     

Polyoxygenated ent-kauranes and water-soluble conjugates in seed of Phaseolus coccineus

C-α and C-β, previously isolated from seed of Phaseolus coccineus, are shown respectively to be the bis-O-isopropylidene and the 16,17-mono-O-isopropylidene derivatives of ent-6α,7α,16β,17-tetrahydroxykauranoic acid. By GC-MS characterization of the products of acidic, basic and enzymatic hydrolysis, water soluble conjugates of the following compounds have been shown to occur in P. coccineus seed: GA₈, GA₁₇, GA₂₀, GA₂₈, ent-6α,7α,13-trihydroxykaurenoic acid, ent-6α,7α,17-trihydroxy-16β-kauranoic acid, ent-6α,7α,16β,17-tetrahydroxykauranoic acid, 7β,13-dihydroxykaurenolide and abscisic acid.