Effects of β‐carotene‐enriched dry carrots on β‐carotene status and colostral immunoglobulin in β‐carotene‐deficient Japanese Black cows

Data from 18 β‐carotene‐deficient Japanese Black cows were collected to clarify the effects of feeding β‐carotene‐enriched dry carrots on β‐carotene status and colostral immunoglobulin (Ig) in cows. Cows were assigned to control or carrot groups from 3 weeks before the expected calving date to parturition, and supplemental β‐carotene from dry carrots was 138 mg/day in the carrot group. Plasma β‐carotene concentrations in the control and carrot groups at parturition were 95 and 120 μg/dL, and feeding dry carrots slightly improved plasma β‐carotene at parturition. Feeding dry carrots increased colostral IgA concentrations in cows and tended to increase colostral IgG₁, but colostral IgM, IgG₂, β‐carotene and vitamin A were not affected by the treatment. Feeding dry carrots had no effects on plasma IgG₁, IgA and IgM concentrations in cows, but plasma IgG₁ concentrations decreased rapidly from 3 weeks before the expected calving date to parturition. These results indicate that feeding β‐carotene‐enriched dry carrots is effective to enhance colostral IgA and IgG₁ concentrations in β‐carotene‐deficient cows.     

Experimental infections with Campylobacter fetus in bulls of different ages

Factors affecting the establishment of a carrier state of Campylobactor fetus subsp. fetus (venerealis) in preputial cavities of bulls were investigated by following infection in bulls of two different age groups until slaughter, 9–18 weeks post infection. Each of the four older bulls (66–74 months at infection) and three of the four younger bulls (41–49 months at infection) were culturally positive until slaughter, indicating no increased susceptibility with age. Relative proportions of immunoglobulin classes and albumin in preputial fluids were generally similar to those determined prior to infection, although protein concentrations decreased and ratios of IgG/IgA and IgG₁/IgG₂ increased in most of the bulls. An unexplained diminution of sample volumes occurred with progressive sampling. Changes in concentrations of proteins and in sample volumes bore no apparent relationship to infection of bulls with C. fetus. Low levels of C. fetus agglutinins were detected in sample obtained both before and after infection, but no appreciable rise in antibody titers occurred following infection. Alterations in superficial antigens of C. fetus isolates obtained during the course of infection were demonstrated in the majority of animals. The capacity of the organism to undergo antigenic variation and to provoke a minimal immune response may contribute to its prolonged survival in the preputial cavity.     

Measurement of immunoglobulins in reproductive tract fluids of bulls

Seminal, seminal vesicular, urethral and preputial fluids from bulls of two different age groups were assessed for quantitative differences in immunoglobulins. Selected markers were measured in individual samples to differentiate locally derived immunoglobulins from those present as a result of trauma or secretions from other accessory glands.Immunoglobulin levels in reproductive tract fluids from older bulls (5–6 years) were higher than those of younger bulls (3–4 years) and preputial fluids contained the highest concentration of immunoglobulins of all fluids examined. Similarities existed, however, among all fluids in the relative concentrations of immunoglobulins. IgG was generally in highest concentration, though the predominant subclass varied. A marked predominance of IgG₂ over IgG₁ occurred in preputial fluid samples of older bulls. IgA was in second highest concentration, and levels were often equal to or greater than those in serum. IgM was in low concentration and occasionally undetectable. IgG/IgA ratios did not exceed 5 in most of the reproductive fluids, whereas serum ratios were usually over 100. Proportional contents of albumin and immunoglobulin in reproductive tract fluids by comparison with those in serum indicated that substantial quantities of IgG as well as IgA were synthesized locally or derived by selective transport. Increased numbers of plasma cells in the lamina propria of the preputial and penile mucosa of older bulls were correlated with higher immunoglobulin concentrations in preputial fluid from older bulls, suggesting that differences in local synthesis were responsible.     

Purification and quantification of heavy‐chain antibodies from the milk of bactrian camels

Camel milk has a unique composition with naturally occurring heavy‐chain antibodies (HCAbs), which exert rehabilitating potencies in infection and immunity. To characterize HCAb in camel milk, immunoglobulin G (IgG) was isolated from the milk of Camelus bactrianus by a combination of affinity chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis to purify and size‐fractionate protein A and protein G, which were further identified by Western blotting, and were quantified by bicinchoninic acid (BCA) and ELISA. The results indicated that IgG₁ fraction contains molecules of 50 kDa heavy chains and 36 kDa light chains. The HCAbs (IgG₂ and IgG₃ fractions) devoid of light chains, contain heavy chains of 45 kDa and 43 kDa, respectively, the amounts of which were significantly higher than that of the IgG₁ in the milk of bactrian camels. Above all, we revealed the considerable amounts of HCAbs in the milk of bactrian camels, and developed a novel method for their purification and quantification. These findings provide the basis for developing potential effects of camel milk and its interface with the dairy industry, as well as future investigations of HCAb and its roles in human health and diseases.     

Effects of supplemental β‐carotene on colostral immunoglobulin and plasma β‐carotene and immunoglobulin in Japanese Black cows

Data from 26 Japanese Black cows were collected to clarify the effects of supplemental β‐carotene on colostral immunoglobulin (Ig) and plasma β‐carotene and Ig in the cows. Cows were assigned to control or β‐carotene groups from 21 days before the expected calving date to 60 days after parturition. Supplemental β‐carotene was provided at 500 mg/day in the β‐carotene group. Supplemental β‐carotene drastically increased plasma β‐carotene concentrations in the cows from parturition to 60 days after parturition, and plasma β‐carotene concentrations in the control and β‐carotene groups at parturition were 202 and 452 μg/dl, respectively. Supplemental β‐carotene had no effects on plasma IgG₁, IgA or IgM concentrations at parturition. Supplemental β‐carotene increased colostral IgG₁ concentrations in the cows, but colostral β‐carotene, IgA and IgM concentrations were not affected by supplemental β‐carotene. These results indicate that supplemental β‐carotene is effective to enhance colostral IgG₁ concentrations and plasma β‐carotene concentrations in Japanese Black cows.     

Colostrogenesis: candidate genes for IgG1 transcytosis mechanisms in primary bovine mammary epithelial cells

Bovine colostrogenesis is distinguished by the specific transfer of IgG₁ from the blood to mammary secretions. The process has been shown to be initiated by hormones and occurs during the last weeks of pregnancy when steroid concentrations of estradiol (E₂) and progesterone (P₄) are highly elevated. Rodent intestinal uptake of immunoglobulin G is mediated by a receptor termed Fc fragment of IgG, Receptor, Transporter, alpha (FcGRT) and supported by light chain Beta‐2‐Microglobulin (β2M). We hypothesized that steroid hormone treatments (E₂ and P₄) of bovine mammary epithelial cells in vitro would induce up‐regulation of IgG₁ transcytosis candidate gene mRNA expression suggesting involvement in IgG₁ transcytosis. Two different primary bovine mammary epithelial cell cultures were cultured on plastic and rat tail collagen and treated with hormonal combinations (steroids/lactogenic hormones). Evaluated mRNA components were bLactoferrin (bLf: a control), bFcGRT, β2M, and various small GTPases; the latter components are reported to direct endosomal movements in eukaryotic cells. All tested transcytosis components showed strong expression of mRNA in the cells. Expression of bFcGRT, bRab25 and bRhoB were significantly up‐regulated (p < 0.05) by steroid hormones. bRab25 and bRhoB showed increased expression by steroid treatments, but also with lactogenic hormones. Analysis for the oestrogen receptor (ER) mRNA was mostly negative, but 25% of the cultures tested exhibited weak expression, while the progesterone receptor (PR) mRNA was always detected. bRab25 and bRhoB and likely bFcGRT are potential candidate genes for IgG₁ transcytosis in bovine mammary cells.     

Anti-enzyme antibodies in rabbits and pigs against Hyostrongylus rubidus (Hassall and Stiles, 1892)

Ether extracts of Hyostrongylus rubidus adult worms isolated on days 14, 35 and 64 of intection were found to contain two isoenzymes of malic dehydrogenase (MDH) and three of acid phosphatase. Sera from rabbits immunized against these extracts and sera from pigs experimentally infected with H. rubidus were tested for their anti-enzyme activity by two different techniques.Sera from rabbits actively immunized with a Day 14 worm extract contained an antibody which complexed only with a slow migrating isoenzyme of acid phosphatase but not with isoenzymes of MDH or acetylcholinesterase (AChE). No antibodies against worm acid phosphates or MDH were detectable by this technique in the sera of pigs which were experimentally infected with H. rubidus.A different technique, however, where the worm extracts were incubated at 60°C either with rabbit anti-H. rubidus serum, or serum from infected pigs, indicated the presence of anti-AChE globulin in both immunized rabbits and infected pigs. When individual immunoglobulins isolated from infected pigs were incubated with the same worm extract it was seen that activity was associated with IgG₁ but not with IgG₂, IgM or IgA. IgG₁ prepared from worm-free pigs did not complex with worm AchE. There was no interaction between the third stage larval AChE and pig IgG₁. Levels of AChE were highest in worms isolated at a period of infection when the hosts immune responses were beginning to manifest themselves and lowest in those worms surviving the population crisis.     

Effect of transportation and weaning on humoral immune responses of calves

Transportation exposes cattle to stress and results in increased morbidity and mortality. An investigation was made of the effects of transport and another important stressor, weaning, on the immune function of calves by determining Immoral immune responses to keyhole limpet haemocyanin (KLH). In a 2 × 2 factorial designed experiment, suckled calves were either (1) weaned at housing (day 0) and not transported, (2) weaned at housing and transported, (3) weaned while still at pasture nine to 13 days prior to housing and not transported or (4) weaned at pasture and transported. All calves were immunized with KLH at housing (day 0) and serum samples were collected subsequently to determine class and subclass anti-KLH antibody responses (IgG₁, IgG₂, IgA and IgM) by direct elisa. Increased anti-KLH IgG₁ and IgG₂ concentrations were shown in calves that were weaned prior to housing and transported on day 10 (P<0·05 and P<0·01 respectively). Transported calves had increased IgGI concentrations on day 20 (P<0·05) compared with calves that were not transported. However, calves weaned at housing and not transported had increased IgA and IgM responses on day 30 compared with the other groups of calves (P<0·05). This study shows that transportation and weaning affect the Immoral immune responses of suckler calves and that the effects persist for several weeks. However, the effects of the treatments were not consistent for all antibody classes measured.     

Antibody-dependent cell-mediated cytotoxicity in sheep

The ability of sheep leukocytes to mediate antibody — dependent cell-mediated cytotoxicity (ADCC) and that of sheep serum IgG₁ and IgG₂ to induce ADCC were investigated. Partial characterization of effector cells was attempted. These investigations revealed that ADCC occurs in sneep. With chicken erythrocytes (CRBC) as the target cells, polymorphonu-cleated cells (PMN), and monocytes, were the most effective leukocytes. Ovine peripheral blood lymphocytes (PBL) also mediated ADCC, and within the PBL population, T-cells were capable of mediating ADCC. The T-cells were obtained by nylon wool fractionation and selective agglutination by peanut agglutinin (PNA) and Helix pomatia agglutinin (HPA). Both nylon wool adherent and non-adherent fractions were active in ADCC, although the former were more active, implying heterogeneity in nylon wool adherence among ovine K-cells. Depletion of B (SIg⁺) cells did not affect ADCC activity of the remaining cells. Depletion of Fc⁺ cells markedly reduced cytotoxic activity of PBL. Both sheep IgG₁ and IgG₂ anti-CRBC immunoglobulins were able to induce ADCC.     

Evaluation of 3 Assays for Failure of Passive Transfer in Calves

This study examined the sensitivity, specificity, predictive values, and classification accuracy of 3 commonly used screening tests for failure of passive transfer: the sodium sulfite turbidity test, the zinc sulfate turbidity test, and re-fractometry relative to serum immunoglobulin G₁, (IgG₁) concentrations determined by radial immunodiffusion. Serum samples were obtained from 242 calves ranging from 1 to 8 days of age. Using a serum concentration of 1,000 mg/dL IgG₁ to define adequate passive transfer, the zinc sulfate test had a sensitivity of 1.00 and a specificity of 0.52 in the detection of inadequate passive transfer. The endpoint of the test appeared to be higher than desired; calves testing negative had mean serum IgG₁ concentration of 955 mg/dL and a large proportion of calves with adequate passive transfer were misclassified as positive for failure of passive transfer. Using the qualitative zinc sulfate test, the percentage of calves correctly classified with regard to passive transfer status was less than that observed with either the sodium sulfite test or refractometry. The sensitivity of the sodium sulfite assay was 0.85 at a 1+ endpoint and 1.00 at a 2 or 3+ endpoint. The specificity of the sodium sulfite assay varied from 0.87 at a 1+ endpoint and 0.56 at a 2+ endpoint. The sensitivity and specificity of refractometry varied from 0.01 to 1.00 depending on the choice of endpoint. Refractometry correctly classified the largest proportion of calves with regard to their passive transfer status at test endpoints of 5.0 and 5.5 g/dL, 83% and 82% respectively. The highest percentages of calves correctly classified occurred with the sodium sulfite test using a 1+ endpoint (86.30%) and refractometry using a 5.0 g/dL endpoint (83.00%). A regression equation was developed that permitted calculation of an optimal endpoint for refractometric determinations of total serum protein concentration. A serum protein concentration of 5.2 g/dL was equivalent to 1,000 mg/dL serum IgG₁. Optimal selection of tests for passive transfer status in calves will be governed by the prevalence of failure of passive transfer, test performance, and the anticipated costs of classification errors.     

Camelid Immunoglobulins and Their Importance for the New‐Born – A Review

Camelid immunoglobulins differ from all other known antibodies and contradict all common theories on antibody diversity. It was demonstrated that up to 75 % of all serum proteins are immunoglobulin G (IgG) molecules lacking light chains. IgG₂ and IgG₃, which only consist of heavy chains, have a low molecular weight which improves their biodistribution and allows a better tissue penetration. Of special importance is the long complementary determining region (CDR) loop which inserts deep into the active site of an enzyme. This binding property was only observed in experiments to gain structural data and to point out the extraordinary value of heavy chain antibodies as biochemical and pharmacological tools. The acquisition and absorption of adequate amounts of colostral immunoglobulins are essential to the health of the neonate. Pre‐colostrum serum IgG levels in camelids are low, with concentrations of 0.26 ± 0.23 mg/ml. Maximum IgG levels are reached after 24 h and kept at a plateau with concentrations of 24.52 ± 8.8 mg/dl. IgG concentrations above 10 mg/ml indicate a successful passive transfer. IgG levels decline after 2–5 weeks and a marked increase is observed between 1 and 2 months, indicating that the immune system of the neonate has started to mature. A number of different tests are available for the assessment of IgG serum levels. Single radial immunodiffusion (SRID) is the only method that specifically measures serum IgG concentrations. It is a reliable assay to test failure of passive transfer (FPT). FPT is a major factor in neonatal mortality in camelids, but very little has been published so far. Therapeutic administration of colostrum will provide passive protection against infectious diseases for a 2–3‐week period of risk, and the intravenous administration of 20–40 ml of camelid plasma helps to combat FPT.     

Production and characterization of monoclonal antibodies against excretory-secretory products of Fasciola hepatica

Four monoclonal antibodies (mAbs) (9.49, 24.27, 46.71 and 179.57) were produced against Fasciola hepatica excretory-secretory products. Isotype analysis revelead the antibodies to be IgM, IgG₃, IgG₁, and IgM. In immunoblot assays, the mAbs recognized different antigenic polypeptides migrating between 29 and 180 kDa. Specificity of the mAbs was evaluated by ELISA against antigens of Fascioloides magna, Anoplocephala magna, Stichorchis subtriquetrus, Haemonchus contortus, sheep liver extract (SLE), bovine liver extract (BLE), bovine serum albumin (BSA), bovine viral diarrhea virus (BVDV), and Madin-Darby bovine kidney (MDBK) cells. Monoclonals 9.49 and 24.27 were specific, and reacted only with Fasciola hepatica antigens. However, mAb 46.71 cross-reacted with antigens of Fascioloides magna, A. magna, Stichorchis subtriquetrus, and H. contortus but not with SLE, BLE, BSA, BVDV or MDBK cells. Monoclonal antibody 179.57 cross-reacted with Fascioloides magna, A. magna, S. subtriquetrus, H. contortus, SLE, and BLE, but not with BSA, BVDV, or MDBK cells.     

Akabane virus infection in the pregnant ewe. 1. Growth of virus in the foetus and the development of the foetal immune response

Three different pools of the CSIRO 16 strain of Akabane virus differing in their laboratory passage histories were used to inoculate 39 ewes between 32 and 36 days pregnant; 22 pregnant ewes received inocula containing no virus. There was no difference in the development, duration and titre of the viraemia and neutralising antibody response between the three infected groups of ewes. Both infected and control ewes had 141% foetuses when autopsied at 69 to 105 days gestation. Of the 55 foetuses from infected ewes 44 (80%) had gross developmental abnormalities.At autopsy of the dams Akabane virus was isolated only from the uterine caruncle. From foetal samples virus was isolated from a wide range of tissues, from one foetus at 69 days and from the blood of four foetuses at 95 to 106 days gestation. Virus was also isolated from 24 of the choriolllantoic fluid samples and from 37 placentomes of the 44 foetuses with developmental defects, in concentrations ranging from 10² to 10^5.5 TCID₅₀/ml or/g. No virus was isolated from the tissues of the control ewes or their foetuses.Neutralising antibody to Akabane virus was detected in 78% of the foetal sera from the infected group, titres ranging from 2 to 64. IgM and IgG₁ and neutralising antibody were detected in sera of 40 foetuses with developmental abnormalities including three that were of 76 to 78 days gestation. Neutralising antibody was detected only in serum that contained IgG₁ but may also have been associated with IgM in infected foetuses. IgM was detected in the serum of most foetuses including the non-infected controls, but sera from the control foetuses did not contain IgG₁ or neutralising antibody to Akabane virus. No IgG₂ or IgA were detected in any foetal serum.     

Evaluation in mice of Brucella ovis attenuated mutants for use as live vaccines against B. ovis infection

Brucella ovis causes ram contagious epididymitis, a disease for which a specific vaccine is lacking. Attenuated Brucella melitensis Rev 1, used as vaccine against ovine and caprine brucellosis caused by B. melitensis, is also considered the best vaccine available for the prophylaxis of B. ovis infection, but its use for this purpose has serious drawbacks. In this work, two previously characterized B. ovis attenuated mutants (Δomp25d and Δomp22) were evaluated in mice, in comparison with B. melitensis Rev 1, as vaccines against B. ovis. Similarities, but also significant differences, were found regarding the immune response induced by the three vaccines. Mice vaccinated with the B. ovis mutants developed anti-B. ovis antibodies in serum of the IgG₁, IgG_2a and IgG_2b subclasses and their levels were higher than those observed in Rev 1-vaccinated mice. After an antigen stimulus with B. ovis cells, splenocytes obtained from all vaccinated mice secreted similar levels of TNF-α and IL12(p40) and remarkably high amounts of IFN-γ, a crucial cytokine in protective immunity against other Brucella species. By contrast, IL-1α -an enhancer of T cell responses to antigen- was present at higher levels in mice vaccinated with the B. ovis mutants, while IL-10, an anti-inflammatory cytokine, was significantly more abundant in Rev 1-vaccinated mice. Additionally, the B. ovis mutants showed appropriate persistence, limited splenomegaly and protective efficacy against B. ovis similar to that observed with B. melitensis Rev 1. These characteristics encourage their evaluation in the natural host as homologous vaccines for the specific prophylaxis of B. ovis infection.     

Comparison of serum, milk and urine as samples in an enzyme immunoassay for bovine leukaemia virus infection

Serum, milk and urine specimens were taken from 15 bovine leukaemia virus (BLV)-positive and 20 BLV-negative cattle which had been determined previously to be infected or not by the use of a monoclonal enzyme-linked immunosorbent assay (ELISA). An ELISA was performed on the samples for the detection of IgG₁ antibodies to the BLv surface glycoprotein, gp 51. The three types of samples had parallel optical density (OD) values apart from three urine samples which, although accepted as- negative for anti-BLv antibodies, had numerically higher ODS than those of control BLV-negative animals. Therefore, detection of IgG₁ antibodies against BLv in the urine of naturally infected animals could be an indication for the use of urine for diagnosis of BLV infection.     

Phagocytosis of Bacteroides nodosus by ovine peripheral blood leucocytes

Phagocytosis of Bacteroides nodosus by ovine peripheral blood leucocytes (PBL) was examined after organisms had been opsonized in sera from normal sheep, or from animals immune to, or infected with ovine footrot. Ingestion of bacteria, as assessed microscopically or by counting isotopically-labelled organisms spectrometrically was effected in suspensions by polymorphonuclear leucocytes (PMN). Opsonization of bacteria in immune serum, particularly its IgG₂ isotype, enhanced the rate of phagocytosis by PMN compared with that promoted by normal serum or medium alone. Whereas IgG₂ from immune serum also increased the rate of ingestion of B. nodosus by adherent PMN, IgM and IgG₁ from immune serum also initiated phagocytosis of bacteria by adherent ovine monocytes. Leucocytes from normal, immune or infected sheep of different breeds ingested B. nodosus with equal facility.     

Autoimmune haemolysis in the dog: relationship between anaemia and the levels of red blood cell bound immunoglobulins and complement measured by an enzyme-linked antiglobulin test.

A direct enzyme-linked antiglobulin test (DELAT) was used to measure the levels of red blood cell (RBC) bound IgG, IgM, IgA and C3 in dogs with autoimmune haemolytic anaemia (AIHA). At presentation, one or more DELAT parameters was raised in each AIHA case, and the RBC were typically coated with immunoglobulin of more than one class, together with C3. There was no relationship between the levels of RBC-bound IgG, IgM or IgA and the severity of the anaemia, although a significant negative correlation (rs = -0.66, P < 0.02) was found between bound C3 and blood haemoglobin concentration. These results indicate that the level of sensitisation of erythrocytes with IgG alone is not a reliable predictor of the severity of haemolysis in different cases, and that the pathogenesis of AIHA can be complex, involving multiple immunoglobulin classes and complement in the destruction of RBC. A significant relationship (rs = 0.63, P < 0.02) was found between serum IgG concentration and haemoglobin levels, and it is suggested that this may be due to free IgG inhibiting the interaction of IgG-sensitised RBC with macrophages. Serial measurements from individual AIHA cases during treatment revealed that the levels of RBC-bound immunoglobulins fell simultaneously with improvements in anaemia. In one dog, a relapse was associated with increases in bound IgG and IgM. Transient relative reticulocytopenia at presentation was common, but was not related to the severity of the anaemia. However, in other cases there was a persistent failure to increase RBC production, which was associated with slower recovery.     

Immunoglobulins and immunoglobulin-containing cells in the reproductive tracts of rams naturally infected with Brucella ovis

SUMMARY Thirteen rams with serological evidence of Brucella ovls exposure (CFT of 1:8 or greater), but with no or only mild epididymitis, were selected from a ram flock. Serum, semen, preputial washings and fluids from the accessory sex glands (ASGF) and testis and epididymis (TEF) were examined and immunoglobulin (lg) concentrations estimated. Genital tissues were examined histologically and the percentages of class specific immunoglobulin containing cells (ICC) determined. Eleven of these rams had histological evidence of active inflammation consistent with B. ovis infection; the organisam was cultured from the semen of 7. IgA concentration was high in semen (mean ± standard deviation of 5.03 ± 1.78 mg/ml) and ASGF (9.18 ± 7.28 mg/ml). These levels were much higher than those recorded in noninfected rams. IgA concentration was low in serum (0.78 ± 0.55 mg/ml) and TEF (0.59 ± 0.78 mg/ml). The concentrations of IgG¹, IgG², and IgM were low in all genital fluids sampled and not significantly different from those recorded in noninfected rams. This indicated that infection with B. ovis results in a pronounced IgA response in secretions, mostly from the accessory sex glands. Examinations of ICC, however, revealed that the plasma cell infiltrates of the epididymis, vas deferens, ampulla and seminal vesicle were predominantly IgG-containing (92.4, 97.2, 79.4 and 91.9% respectively). Fewer IgM-containing cells were scattered throughout these tissues, constituting 3.9, 6.3, 0.3 and 6.5% of all ICC, respectively. IgA-containing cells were most frequently seen in the ampulla (9.6% of ICC) where they were located directly beneath the epithelium, suggesting the ampulla as the most prominant location for the local production of IgA. These results indicate that although the tissue ICC response was predominantly IgG, IgA was selectively transferred into secretions with the exclusion of most IgG and IgM. ICC percentages in bulbourethral and prostate glands, and beneath pelvic urethral and preputial epithelia, were similar to those found in noninfected rams.     

Immunohistological observations on pulmonary tissues from dogs infected withDirofilaria immitis

Pulmonary tissues from non-infected dogs, naturallyDirofilaria immitis-infected dogs and experimentally infected puppies, selectively necropsied after infection, were assessed using peroxidase-antiperoxidase (PAP) staining technology. Sequential sections of pulmonary tissue were PAP stained with anti-freshD. immitis serum, anti-paraffin processedD. immitis serum, anti-dog immunoglobulin (IgG, IgG Fc, IgM) sera and anti-dog complement (C₃) serum, and examined for antibody, complement and forD. immitis antigen. The extent of alveolar septal thickening was positively correlated with infection status. Cellular infiltration was most evident surrounding obstructed areas whereD. immitis werein situ. Antigenic material (microfilariae, eggs, fragmented filariae) labelled by PAP was identified in the pulmonary arteries, alveolar capillaries and alveolar septa. Deposits of complement and IgG, presumably associated with immune complex formation, were also observed in some of the infected dogs. Identification of antigen, antibodies and complement associated with alveolar septal pathology suggested that immune mechanisms were active in its development.Abbreviations FW fresh worm - PAP peroxidase-antiperoxidase - PW processed worm     

Investigation of repeated vaccination as a possible cause of glomerular disease in mink

The search for antigens capable of causing immune-complex-mediated glomerulonephritis continues. Modified live-virus vaccines commercially available for veterinary use are a possible source. In this study, repeated vaccination of mink with live-virus vaccines was investigated as a model for vaccine-induced glomerular injury. Three groups of 10-wk-old mink, 15 per group, were vaccinated once with 4-way vaccine against distemper, Pseudomonas aeruginosa infection, botulism and mink viral enteritis. Subsequently, all mink in each group each were vaccinated either with the 4-way vaccine, a monovalent canine distemper vaccine, or saline. Glomerular function was assessed at 2-wk intervals by determining the urinary protein:creatinine (P:C) ratio. Kidney sections taken at necropsy, 20 wk after the 1st vaccination, were examined by light and immunofluorescent microscopy for deposition of immunoglobulin and complement. There was no statistically significant difference between the treated and control groups based on average urinary P:C ratio medians. Light microscopic changes were detected in glomeruli, but Fisher's exact test showed no significant differences between any of the treatment groups. Deposition of immunoglobulin but not complement was significantly more frequent (P < 0.05) in the glomeruli of animals that received multiple injections of the 4-way vaccine than in the glomeruli of those given only the monovalent canine distemper vaccine or saline. These findings suggest that repeated vaccination may increase the glomerular deposition of immunoglobulin. Further studies are required to determine if the increased deposition of immunoglobulin contributes to the development of glomerular damage and to identify the antigens driving production of the deposited immunoglobulin.