Serum antibody response and Cryptosporidium parvum oocyst antigens recognized by sera from naturally infected sheep.

The response of specific serum immunoglobulins (IgG, IgM and IgA) and the major antigens of Cryptosporidium parvum recognized by these isotypes were investigated by using enzyme-linked immunosorbent assay and immunoblot techniques in lambs and ewes naturally infected throughout an outbreak of cryptosporidiosis. Serum samples were collected from 20 lambs the first day they showed diarrhoea (D1), and Days 11 and 22, in addition to single serum samples from 17 of their dams. Serum anti-C. parvum IgG, IgM and/or IgA antibodies were detected in lambs as early as Day 1. Levels of IgM antibodies remained steady from D1 to D11 and increased at D22, whereas the IgG response decreased from D1 to D11 and subsequently increased. In contrast, IgA antibodies rapidly fell from D1 and all lambs were seronegative at D11 and D22. The highest levels of specific antibodies were detected in sera from ewes. In fact, all ewes were seropositives for IgM and IgA isotypes and most (16/17) showed positive levels of IgG. Four protein fractions (37-39, 42-48, 51-57 and 60-69 kDa) were the most frequently recognized by IgG and IgM from lamb sera. A low molecular weight fraction (12-14 kDa) reacting with IgG and IgA in most lamb sera was scarcely recognized by IgM and three broad bands were frequently recognized by IgA antibodies (23-25, 51-57 and 90-95 kDa). The recognition pattern of 23-25 kDa peptides by IgA from lamb sera clearly increased with the age. Peptides of 42-48, 51-57, 60-69 and 71-78 kDa were most frequently recognized by IgG and IgM from ewe sera. In relation to IgA antibodies from ewe sera, a frequent immunoreactivity was found with proteins in the intervals between 12 and 22 kDa as well as between 32 and 34 kDa and practically all sera reacted with fractions from 42 to 95 kDa.     

Immunohistochemical distribution of antigens in liver of infected and immunized pigs with Ascaris suum

In the present work, we carry out an immunopathological study of the swine ascariosis, under different conditions (control, infection and immunization). Twenty-one Iberian pigs were used and divided in seven groups. Groups 1 and 2 were the uninfected and challenged controls, respectively. Groups 3 and 4 were weakly infected with increasing doses of Ascaris suum eggs and treated with pyrantel (Group 4). Groups 5-7 were immunized with 14, 42 and 97 kDa proteins from the parasite, respectively. Groups 2-7 were challenged with 10,000 infective eggs 7 days before the sacrifice. The focal parasitic granulomata with eosinophils and lymphocytes were the main histopathological lesions in the liver of reinfected pigs, while more marked cellular infiltrate and abundant connective tissue were seen in the livers of immunized animals. There were important deposits of antigens in the livers of immunized and infected pigs. Antigens were mainly located in the connective tissue, with positive staining detection of the somatic larvae antigen, the body wall from the adult worms and the 14-, 42- and 97-kDa proteins. However, cholangiols, biliary ducts and macrophages presented an immunohistochemical positive stain against excretory-secretory and somatic antigens from the larvae and the body fluid antigen from the adult parasite. The detection of A. suum antigens in the liver of infected pigs improves the diagnosis of swine ascariosis. It may be possible to apply these procedures for diagnosis of human ascariosis in liver biopsies since A. suum from swine have been previously used as a substitute for the study of the human parasite Ascaris lumbricoides.     

Cloning and expression in Escherichia coli of Mycoplasma gallisepticum antigens recognized by sera from infected chickens

A clone bank of Mycoplasma gallisepticum (MG) strain A5969 DNA was prepared in the expression vector phage lambda gt11. Approximately 75% of the resulting phages were recombinants, based upon the insertional inactivation of the lacZ gene of the vector. Clones were screened immunologically with serum prepared from specific-pathogen-free white leghorn chickens that had been infected with aerosolized MG. Approximately 250 clones, or less than 1% of the recombinant phage, reacted positively to various degrees with the test serum and failed to react with serum from uninfected specific-pathogen-free control chickens. A single clone was chosen at random for comparison with a vector control by western immunoblot, revealing a polypeptide of 140,000 molecular weight in the clone profile but not the control profile that reacted with immune serum. Clones expressing MG antigens recognized during infection may provide an improved means for antigen preparation for serologic diagnosis of mycoplasmosis.     

Identification of Bordetella avium antigens recognized after experimental inoculation in turkeys

Sera and tracheal washings (TW) were used to identify antigens of Bordetella avium recognized during experimentally induced bordetellosis in young turkeys. Pooled sera and TW were examined for antibody by a microtitration agglutination test and by western immunoblotting. In addition, comparable samples collected from 1-day-old turkeys and uninoculated control turkeys also were examined. At least 8 outer membrane proteins of B avium were recognized in immunoblots of sera and TW from infected turkeys. Reactivity of TW in immunoblots was qualitatively similar but less intense, compared with reactivity of corresponding sera collected on postinoculation (PI) weeks 2, 3, and 4. Molecular weights of the major outer membrane proteins of B avium recognized by sera and TW at PI week 4 were 100,000, 97,000, 36,000, 31,000, 21,000, 18,000, 14,000, and less than 14,000. A protein with a molecular weight of 55,000 reacted nonspecifically in all samples tested. Antibody, detectable by microtitration agglutination, was in sera of 1-day-old turkeys and in sera and TW of B avium-infected turkeys during PI weeks 2 to 4.     

Encephalomyocarditis virus antibodies in sera from apparently normal pigs.

Antibodies which neutralise and precipitate encephalomyocarditis virus habe been found in the serum of more than 28 per cent of normal pigs in Britain. Neutralising activity was found in association with several size classes of antibody.     

Toxocara and ascaris infection in British pigs: a serological survey.

A serological survey of growing pigs from farms throughout Great Britain revealed that antibodies to toxocara and ascaris larval antigens were present in 4.5 per cent and 39.3 per cent respectively. Heavy infection with toxocara occurred only rarely and it is considered that this parasite is unlikely to be an important cause of chronic focal interstitial hepatitis. Antibodies to both nematodes were detected more frequently in heavy hogs than in pigs of lighter weight. Reginal differences in the prevalence of antibodies were also observed.     

Concurrent Ascaris suum and Oesophagostomum dentatum infections in pigs.

The aim of this study was to examine interactions between Ascaris suum and Oesophagostomum dentatum infections in pigs with regard to population dynamics of the worms such as recovery, location and length; and host reactions such as weight gain, pathological changes in the liver and immune response. Seventy-two helminth-na?ve pigs were allocated into four groups. Group A was inoculated twice weekly with 10000 O. dentatum larvae for 8 weeks and subsequently challenge-infected with 1000 A. suum eggs, while Group B was infected with only 1000 A. suum eggs; Group C was inoculated twice weekly with 500 A. suum eggs for 8 weeks and subsequently challenge-infected with 5000 O. dentatum larvae, whereas Group D was given only 5000 O. dentatum larvae. All trickle infections continued until slaughter. Twelve pigs from Group A and B were slaughtered 10 days post challenge infection (p.c.i.) and the remaining 12 pigs from the each of the four groups were slaughtered 28 days p.c.i.. No clinical signs of parasitism were observed. The total worm burdens and the distributions of the challenge infection species were not influenced by previous primary trickle-infections with the heterologous species. Until day 10 p.c.i. the ELISA response between A. suum antigen and sera from the O. dentatum trickle infected pigs (Group A) pigs were significantly higher compared to the uninfected Group B. This was correlated with a significantly higher number of white spots on the liver surface both on Day 10 and 28 p.c.i. in Group A compared to Group B. The mean length of the adult O. dentatum worms was significantly reduced in the A. suum trickle infected group compared to the control group. These results indicate low level of interaction between the two parasite species investigated.     

清瘟败毒饮治疗猪链球菌病

猪链球菌病是由链球菌感染引起的一种急性、热性传染病 ,呈散发 ,一年四季均可发生。笔者共治疗该病 46例 ,其中用西药治疗 6例无效死亡 ;用清瘟败毒饮合西药治疗治愈 36例 ,死亡 4例 ,有效率90 % ,并且早期使用清瘟败毒饮治疗 ,疗效显著。1　症状多数病猪突然少食 ,发热 ,微渴 ,继则出现高热 ,T 41～ 42℃ ,不食 ,口渴 ,喜饮污水 ,全身颤抖 ,畏寒 ,磨牙 ,耳根、胸腹四肢内侧有出血斑点 ,后期低热 ,便秘 ,行走摇晃 ,有的卧地不起 ,衰竭而死。2　辨证高热、口渴 ,皮肤血斑 ,属中兽医学热毒炽盛的证候范畴 ,根据病程可分为三个阶段。第一阶段…     

Effectiveness of antigens from various developmental stages of Ascaris suum in the deomonstration of the migratory phase of experimental ascariasis in pigs]

Tests of the efficiency of antigens prepared from different developmental stages of Ascaris suum in indirect haemagglutination test in the course of proving the migration phase of experimental ascariasis in pigs show that the antigens prepared by ultrasound from the invasive larval stage of A. suum in comparison with antigens of sexually mature stages have higher serological activity. By using this antigen it is possible to prove specific antibodies in experimentally invaded pigs from 6 to 120 days after invasion as opposed to the other tested antigens (the detectability of antibodies from the 7th-8th day to the 64th day after invasion).     

Presence of immunoglobulins and antigens in serum, lung and small intestine in Ascaris suum infected and immunised pigs

The immunodetection of local Ascaris suum antigens and local and systemic antibodies were analysed in pigs reinfected with eggs or immunized with the 14, 42 and 97 kilodalton (kDa) fractions from A. suum. Twenty-one Iberian pigs were divided in 7 groups of 3 pigs. Groups 1 and 2 were uninfected and challenge control groups, respectively. Groups 3 and 4 were infected weekly with increasing doses of A. suum eggs and Group 4 was additionally treated with pyrantel pamoate. Groups 5, 6 and 7 were immunised with the 14, 42 or 97 kDa fractions from adult worms, respectively. Groups 2-7 were challenged with 10,000 infective eggs. Animals of Groups 3 and 4 showed a pulmonary granulomatous reaction with moderate number of eosinophils and leukocytes, while Groups 5-7 presented higher number of cells, especially in animals immunized with the 42 kDa fraction. These immunized groups presented abundant deposition of Ascaris body fluid (BF) and body wall (BW) antigens as well as the 14 and 42 kDa fractions in the pulmonary and intestinal tissues, while lower deposition of antigens was observed in animals of Groups 3 and 4. The immunized pigs of Groups 5 and 6 showed the highest systemic IgG titres in serum and these antibodies were negatively correlated with the number of larvae recovered in the lungs, suggesting that the IgG response may have a protective function against the ascariosis. The highest concentrations of IgA-bearing cells were observed in animals of Groups 3 and 4 compared to the immunised pigs (Groups 5-7), suggesting that local IgA production may be involved in the protection against migrating larvae. The main localisations of IgA-bearing cells were the bronchial and peribronchial areas of lungs and the lamina propia of duodenum. Low numbers of local IgG-bearing cells were observed in all animals and no IgM-bearing cells were detected in the local tissues.     

Pharmacokinetics of ampicillin and sulfadimidine in pigs infected experimentally with Streptococcus suum

Twenty-three hybrid pigs (23 ± 3 kg body wt) were assigned to three groups to investigate the pharmacokinetics of ampicillin (APC, 10 mg/kg) administered intravenously (i.v.) and intramuscularly (i.m.), and sulfadimidine (SDM, 50 mg/kg) administered intravenously as a bolus injection. In the first series of experiments the animals remained healthy. Subsequently, the pigs were infected with Streptococcus suum by subcutaneous (s.c.) inoculation and the experiments were repeated. The total apparent distribution volume of APC given intravenously was increased from 0.512 ± 0.026 L/kg in uninfected pigs to 0.68 ± 0.06 L/kg (P < 0.01) in infected pigs, whereas there were no significant changes in the same parameter for SDM (P > 0.05). The clearance of APC was increased markedly from 0.52 ± 0.07 L/kg/h in uninfected pigs to 0.62 ± 0.10 L/kg/h in infected pigs. In contrast, SDM clearance was decreased markedly from 0.023 ± 0.003 L/kg/h to 0.017 ± 0.003 L/kg/h (P < 0.05). As a result, the biological half-lives of the drugs were altered to varying degrees in infected pigs. The half-life of SDM was increased from 15.0 ± 3.0 h in uninfected pigs to 20 ± 7h in infected pigs (P < 0.05), but differences in APC half-lives between uninfected and infected animals were not observed (P > 0.05). There were no statistically significant differences in pharmacokinetic parameters of APC administered by intramuscular injection between the healthy and the diseased status, although its half-life was shortened from 0.76 ± 0.22 h in the healthy to 0.57 ± 0.23 h in the diseased. The results suggest that blood concentrations of APC and SDM are affected differently by the same disease due to its specific effects on their distribution and elimination.     

Ixodid-host immune interaction. Identification and characterization of relevant antigens and tick-induced host immunosuppression

Ixodid ticks are the most important vectors of pathogens to domestic and wild animals. It is established that cattle and laboratory animal species acquire resistance to tick infestation; acquired resistance has an immunological basis consisting of cell-mediated, antibody-mediated and complement-dependent effector mechanisms. Even though acquired resistance to tick feeding is expressed, host immune competence is possibly impaired during the course of tick feeding. Ixodid-induced transient immunosuppression could possibly facilitate the transmission of vector-borne pathogens and/or enhance tick feeding capabilities in the presence of a host immune response to the hematophagous arthropod. Tick tissue extracts have been used to artificially induce resistance to ixodid feeding, and this has become an area of increasing interest as a possible strategy for tick control. It is essential to have defined antigenic molecules for analysis of host responses to infestation, characterization of immunopathologic processes and for vaccine development. This report focuses on attempts to identify, characterize and isolate tick immunogens. Protein immunoblotting, utilizing sera from animals of different genetic composition and infestation patterns, was used to detect a number of tick polypeptides which are reactive with sera of infested hosts. It is clear that infestation with one ixodid species stimulates antibodies reactive with molecules derived from the sensitizing species and/or tick species in the same genus or different genera. This approach is used to identify molecules that are good candidates for use in immunization studies and for analysis of mechanisms involved in acquisition and expression of resistance to tick feeding.     

Detection of Sarcocystis antigens in the sera of experimentally-infected pigs and mice by an immunoenzymatic assay

Immunoglobulins raised against Sarcocystis miescheriana and Sarcocystis muris cystozoite antigens were isolated from rabbit immune sera by affinity chromatography (using CNBr-activated Sepharose 4B for antigen immobilization). The specific immunoglobulins were incorporated into double-antibody sandwich immuno-enzymatic assays which were firstly quantitated and then used to detect soluble Sarcocystis antigens in the sera of experimentally-infected pigs and mice. Assays employing immunoglobulins attached to the solid-phase at concentrations of 80 micrograms/ml were capable of detecting homologous soluble cystozoite and sporozoite reference antigens at concentrations as low as 8 micrograms/ml. Circulating antigens were detected both in the presence and absence of acute clinical disease in pigs experimentally-infected with high and low doses of S. miescheriana sporocysts. The antigenemia detected was transitory (occurring from 3-20 days post-inoculation: dpi) and coincided well with the sporozoite and merozoite phases of parasite development. Circulating antigens were also detected during subclinical infections in mice (from 4-49 dpi) following their experimental infection with low doses of S. muris sporocysts. Specific immuno-enzymatic assays for circulating Sarcocystis antigens may therefore prove useful in the clinical diagnosis of acute sarcocystosis.     

Oral immunisation of pigs with fimbrial antigens of enterotoxigenic E. coli: an interesting model to study mucosal immune mechanisms

The intestinal mucosal immune system can discriminate actively between harmful pathogenic agents and harmless food antigens resulting in different immune responses namely IgA production and oral tolerance, respectively. Recently, a pig model has been developed for studying intestinal mucosal immune responses in which F4 fimbrial antigens of enterotoxigenic Escherichia coli (F4 ETEC) are used as oral antigens. A unique feature of this model is that soluble F4 antigens can be administered to pigs which have a receptor for this fimbriae (F4R(+)) on their small intestinal villous enterocytes and pigs which do not have this receptor (F4R(-)). Oral administration of F4 to the F4R(+) pigs results in an intestinal mucosal immune response that completely protects the pigs against a challenge infection. In F4R(-) pigs such an intestinal mucosal immune response does not occur. However, a priming of the systemic immune system can be seen similar to the priming in pigs fed with the same dose of a food antigen, suggesting that F4 in F4R(-) pigs behaves as a food antigen. The fact that different mucosal immune responses can be induced with soluble F4, makes it an interesting model to study mucosal immune mechanisms in the pig.     

Persistent activity of doramectin and ivermectin against Ascaris suum in experimentally infected pigs.

A study was conducted to investigate the persistent nematocidal activity of two avermectins against experimentally-induced infections of Ascaris suum in swine. Seventy-two nematode-free cross-bred pigs of similar bodyweight were randomly allotted to nine treatment groups of eight pigs each. Eight of the groups were treated with injectable solutions containing 300 microg of doramectin/kg (IM) or 300 microg of ivermectin/kg (SC) either 0 (same day), 7, 14, or 21 days prior to an oral challenge of 50000 embryonated A. suum eggs. The ninth group (control) was challenged in parallel without any avermectin treatment. At 41 or 42 days after challenge, pigs were euthanatized and adult and larval stages of A. suum were collected from the gastrointestinal tract of each pig and counted. Both avermectins significantly (P < 0.0002) reduced nematode counts when given on the day of challenge (0 days prior), and the efficacy was 100% and 97.5% for doramectin and ivermectin, respectively. Doramectin given 7 days prior to challenge significantly (P < 0.0001) reduced nematode counts, and the efficacy was 98.4%. For all other avermectin-treatment groups, nematode counts were not significantly reduced compared to those in control pigs. These data indicated that anthelmintic activity of ivermectin against A. suum persisted for less than 7 days and the activity of doramectin persisted for more than 7, but less than 14 days.     

Immunization of pigs with culture antigens of Taenia solium

An evaluation has been made of the protective effect of immunizing pigs with excretory-secretory homologous antigens on Taenia solium infections. This procedure reduced the number of cysticerci established from a challenge infection.     

Tumour-associated antigens in bovine ocular squamous cell carcinoma: studies with sera from tumour-bearing animals

Sera from 21 cattle (10 bovine ocular squamous cell carcinoma (BOSCC) bearing and 11 controls) were tested for antibody reactivity against various cultured cells (BOSCC, normal skin and tumours other than BOSCC), by an indirect immunofluorescence technique. Most of the BOSCC sera reacted with autologous and allogeneic BOSCC cells and did not show any significant reactivity with normal skin cells (autologous or allogeneic). These sera when further tested on 7 different allogeneic or xenogeneic tumour cell types (other than BOSCC), showed significant reactivity only with cultured equine sarcoid and cutaneous papilloma cells. Three of the BOSCC sera did not react with autologous BOSCC cells but reacted indiscriminately with all other allogeneic BOSCC, normal cells and other tumour cells. Most of the control sera did not show any significant reactivity against BOSCC cells except sera from one cow bearing ocular papilloma and 2 healthy normals that were in contact with BOSCC bearing animals. This study suggests that BOSCC cells possess tumour associated antigens that are common to most (if not all) BOSCC cells.