Topic:Complement Fixation
Complement fixation is an immunological reaction involving the binding of complement proteins to antibodies that have attached to specific antigens. In horses, this process is part of the innate immune response, contributing to the identification and elimination of pathogens. The complement system consists of a series of proteins that, when activated, enhance the ability of antibodies and phagocytic cells to clear microbes and damaged cells. This system also promotes inflammation and attacks the pathogen's cell membrane. The complement fixation test is a diagnostic tool used to detect the presence of specific antigens or antibodies in equine serum by observing the consumption of complement proteins. This page compiles peer-reviewed research studies and scholarly articles that explore the mechanisms, regulation, and diagnostic applications of complement fixation in equine immunology.
[An epidemiological survey of equine anaplasmosis (Anaplasma phagocytophilum) in southern France]. Anaplasmosis is caused by the bacterium Anaplasma phagocytophilum and transmitted by Ixodes spp. ticks. According to some reports the disease can be introduced into disease-free zones by migrating birds. The purpose of this study was to evaluate the seroprevalence of A. phagocytophilum in horses in the Camargue. Data concerning 424 horses were gathered and the sera were tested for A. phagocytophilum and for piroplasmoses using an enzyme-linked immunosorbent assay and a complement fixation test, respectively. The seroprevalence rates were 11.3 % for A. phagocytophilum, 64.4 % for Theileria equi...
Serodiagnosis of Burkholderia mallei infections in horses: state-of-the-art and perspectives. Burkholderia mallei causes glanders or farcy in solipeds, a disease that must be reported to the OIE (Office International des Epizooties, Paris, France). The number of reported outbreaks has increased steadily during the last decade. Serodiagnosis is hampered by the considerable number of false-positives and -negatives of the internationally prescribed tests. The major problem leading to low sensitivity and specificity of complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA) has been linked to the test antigens currently used, i.e. crude preparations of whole cells. Fut...
Antithymocyte globulin is associated with complement deposition in cardiac transplant biopsies. Polyclonal antithymocyte globulin preparations contain antibodies with reactivity to endothelial cells. Therefore, we investigated whether treatment with this reagent caused complement deposition in human cardiac transplants. Frozen tissue was available from endomyocardial biopsies of 75 patients, who were transplanted between April 1995 and April 2000. Nine of these patients were converted from cyclosporin A (CsA) to horse antithymocyte globulin (ATGAM) in the first month after transplantation. All of the biopsies were stained by immunofluorescence for C4d as evidence of activation of the cla...
Pre-infection frequencies of equine herpesvirus-1 specific, cytotoxic T lymphocytes correlate with protection against abortion following experimental infection of pregnant mares. In general, vaccines containing inactivated equine herpesvirus-1 (EHV-1) fail to prevent abortion in pregnant mares following infection with a virulent strain of EHV-1. We have tested the hypothesis that resistance to EHV-1-induced abortion in pregnant mares is associated with high frequencies of EHV-1 specific, major histocompatibility complex (MHC) class I-restricted, cytotoxic T lymphocytes (CTL) in the circulation. To test this theory, three groups of pregnant mares were assembled with varying backgrounds of infection or vaccination in an attempt to mimic the immune status of the general p...
A field study to estimate the prevalence of Trypanosoma equiperdum in Mongolian horses. From May to July 2000, a cross-sectional study was conducted to estimate the prevalence of Trypanosoma equiperdum in the horse population of the central province (Tuv aimag) of Mongolia. On average, four herds were selected from each of the 29 aimag subdivisions (119 herds). From each herd, 10 horses were sampled in proportion to sex and age categories in the respective herds (1190 horses). Sera from 1122 horses were analysed for T. equiperdum antibodies using two serological assays, the complement fixation test (CFT) and the enzyme-linked immunosorbent assay (ELISA). The crude estimate of the...
Apparent prevalence of dourine in the Khomas region of Namibia. A 15-year record of the results of horse sera from the Khomas region of Namibia tested by the complement fixation test for dourine at the Central Veterinary Laboratory in Windhoek before clearing the respective animals for export and competitive sport were subjected to statistical analysis. The range of percentage positive, taken as the apparent prevalence of dourine for the region, during the period of study, was 0-29.09%; the average regional level of apparent prevalence was 8.33%. These figures were thought to be lower than the real situation due to some bias in the sampling criteria. For m...
Absence of viral antigens on the surface of equine herpesvirus-1-infected peripheral blood mononuclear cells: a strategy to avoid complement-mediated lysis. Equine herpesvirus-1 (EHV-1) may cause abortion in vaccination- and infection-immune horses. EHV-1-infected peripheral blood mononuclear cells (PBMCs) play an important role in virus immune evasion. The mechanisms by which infected PBMCs can avoid destruction by EHV-1-specific antibody and equine complement were examined. The majority of EHV-1-infected PBMCs (68.6 %) lacked surface expression of viral antigens and these cells were not susceptible to complement-mediated lysis. In infected PBMCs with surface expression of viral antigens, 63 % showed focal surface expression, whereas 37 % showed ...
Interaction between equine semen and the endometrium: the inflammatory response to semen. Insemination of mares with bacteria-free equine spermatozoa results in an influx of polymorphonuclear neutrophils (PMNs) into the uterine lumen. In vitro studies have demonstrated that equine spermatozoa activate complement, resulting in cleavage of factors C5a and C3b. Since uterine secretion is rich in complement, it is likely that an interaction between spermatozoa and uterine secretion results in C5a-mediated chemotaxis and migration of PMNs into the uterine lumen. Once in the uterine lumen, the PMNs phagocytize bacteria and spermatozoa, which is an important part of sperm elimination from...
An enzyme-linked immunosorbent assay for the convenient serodiagnosis of contagious equine metritis in mares. An enzyme-linked immunosorbent assay (ELISA) was developed for the serodiagnosis of contagious equine metritis (CEM), a sexually transmitted disease caused by Taylorella equigenitalis. Antigen preparation was simple, and antigens derived from both classical and atypical forms of T. equigenitalis enabled detection of antibody responses elicted in horses experimentally exposed to either form of the bacterium. Sera serially obtained from these horses from 0 to 63 days postexposure were tested by the traditional complement fixation test (CFT) for CEM and with the ELISA, using both antigens separat...
Prevalence of antibodies to Brucella spp. in cattle, sheep, goats, horses and camels in the State of Eritrea; influence of husbandry systems. Samples from 2427 cattle, 661 goats, 104 sheep, 98 camels and 82 horses were screened for brucella infections by the Rose Bengal Test and positive reactors confirmed by the complement fixation test. In cattle, the highest individual seroprevalence was in dairy herds kept under the intensive husbandry system, with an individual prevalence of 8.2% and unit (herd) seroprevalence of 35.9%. This was followed by the pastoral husbandry system in the Western Lowlands with 5.0% individual but a higher unit (vaccination site) prevalence of 46.1%. The lowest was in the mixed crop-livestock system in the ...
Application of a type-specific enzyme-linked immunosorbent assay for equine herpesvirus types 1 and 4 (EHV-1 and -4) to horse populations inoculated with inactivated EHV-1 vaccine. A type-specific enzyme-linked immunosorbent assay (ELISA) using equine herpesvirus types 1 (EHV-1) and 4 (EHV-4) glycoprotein G was applied for sero-epizootiology of EHV infections in Japan. Recently, an inactivated EHV-1 vaccine has been administered to racehorses for prevention of upper respiratory disease. To examine the effect of the vaccination on the result of the ELISA, 6 horses were experimentally inoculated three times intramuscularly or intranasally with inactivated EHV-1 vaccine. Sera collected from these horses were used to the type-specific ELISA and complement-fixation (CF) test....
Oral vesicular lesions in horses without evidence of vesicular stomatitis virus infection. To report clinical and serologic findings in horses with oral vesicular lesions that were consistent with vesicular stomatitis (VS) but apparently were not associated with VS virus (VSV) infection. Methods: Serial case study. Methods: 8 horses. Methods: Horses were quarantined after appearance of oral lesions typical of VS. Severity of clinical signs was scored every 2 to 5 days for 3 months. Serum samples were tested for antibodies by use of competitive ELISA (cELISA), capture ELISA for IgM, serum neutralization, and complement fixation (CF). Virus isolation was attempted from swab specimens ...
[Demonstration of Chlamydia from an equine abortion]. The isolation and identification of a chlamydial agent from an equine fetus is reported. The fetus was aborted by a mare with respiratory disease and fever in the 9th month of pregnancy. The serum of the mare was investigated by the compliment fixation test. Specific antibodies were detected for chlamydial antigen in a titer of > 1:40 and for equine herpes virus 1 antigen in a titer of 1:32. Pathological lesions were not found in the organs of the fetus. Chlamydiae were detected in the placenta by ELISA and subsequently isolated by cell culture. Using PCR technique the agent was identified ...
Procedurally similar competitive immunoassay systems for the serodiagnosis of Babesia equi, Babesia caballi, Trypanosoma equiperdum, and Burkholderia mallei infection in horses. Procedurally similar competitive enzyme-linked immunoassay (cELISA) methods were developed for the serodiagnosis of Babesia equi and Babesia caballi (piroplasmosis), Trypanosoma equiperdum (dourine), and Burkholderia mallei (glanders) infections in horses. Apparent test specificities for the B. equi, B. caballi, T. equiperdum, and B. mallei cELISAs were 99.2%, 99.5%, 98.9%, and 98.9%, respectively. Concordances and kappa values between the complement fixation (CF) and the cELISA procedures for the serodiagnosis of B. equi, B. caballi, T. equiperdum, and B. mallei infections in experimentally e...
The role of seminal plasma in post-breeding uterine inflammation. The effect of seminal plasma on polymorphonuclear neutrophil (PMN) chemotaxis, PMN phagocytosis and complement-induced cytolysis was determined using blood plasma pooled from four horses and seminal plasma pooled from two stallions. To investigate chemotaxis, complement in blood plasma was activated with E. coli lipopolysaccharide in the presence of 0-50% seminal plasma diluted with a standardized volume of McCoy's medium and placed in a chemotactic chamber. Chemotaxis of blood derived equine PMNs toward the chemoattractants was determined after incubation at 37 degrees C for 45 min. To invest...
Control of equine piroplasmosis in Brazil. The importance of equine piroplasmosis control in endemic countries has increased in recent years and plays an important role to maintain the international market open to the horse industry. The purpose of this study was to demonstrate the occurrence of equine piroplasmosis (Babesia equi or Theileria equi and Babesia caballi) in Brazil--a country where the disease occurs endemically--in different climatic conditions, and to evaluate the results of a strategy for tick control in order to decrease infection rates. Blood samples were taken from 720 horses on 28 farms from different regions and su...
Babesia equi field isolates cultured from horse blood using a microcentrifuge method. Babesia equi, a causative agent of equine piroplasmosis, was isolated from horses in the Chaco Province of Argentina, a known piroplasmosis endemic region. Fifteen B. equi field isolates were acquired by culture from 23 actively working horses from 2 ranches. The horses appeared healthy with no clinical signs or histories indicative of equine piroplasmosis. All 23 horses had B. equi-specific antibody activity by the indirect fluorescent antibody test and 18 were also complement fixation test positive for B. equi. Equine erythrocytes were prepared for parasite culture using a microcentrifuge tu...
Case report: field-acquired subclinical Babesia equi infection confirmed by in vitro culture. A horse with no prior clinical history of equine piroplasmosis tested negative for Babesia caballi and Babesia equi in the complement fixation test before importation into the United States from France. After 5 years in residence in the United States, the animal tested serologically positive for B. equi by the complement fixation test, the immunofluorescent antibody test, and Western blot analysis. The carrier status of the horse was confirmed by culture of B. equi parasites. In vitro culture offers an efficient and comparatively inexpensive method to determine the carrier status of horses sus...
Antiphagocytic properties of uterine isolates of Streptococcus zooepidemicus and mechanisms of killing in freshly obtained blood of horses. A total of 22 clinical streptococcal isolates, predominantly Streptococcus zooepidemicus, associated with endometritis in horses were tested for their ability to withstand the natural bactericidal properties of freshly obtained blood. During a 3-hour incubation in blood from a single horse, 8 of these isolates survived and grew, the remainder were killed. To determine whether this ability to grow extended to blood of other horses, 5 of these growing isolates were tested for their ability to grow in the blood of 5 additional horses. The same 5 horses were used for each isolate. The isolates gre...
Hemolytic complement activity and concentrations of its third component during maturation of the immune response in colostrum-deprived foals. Six foals were deprived of colostrum for the first 36 hours after birth and, instead, received reconstituted powdered milk. Five control foals suckled their dams naturally. Blood samples were obtained from all the foals after birth and at approximately weekly intervals until at least 5.5 months of age. Sera were analyzed for hemolytic complement activity, complement component C3, and correlating IgG concentration. Hemolytic complement (P = 0.0145) and C3 (P = 0.0002) values were significantly higher in colostrum-deprived foals (CDF) than in naturally nursed foals at 2 to 5 days of age. In addi...
Diagnosis of Babesia caballi infections in horses by enzyme-linked immunosorbent assay (ELISA) and western blot. From Babesia caballi in vitro cultures a preparation of 100% infected erythrocytes was obtained. From this, B. caballi antigens were extracted with the detergent 3-[(3-Cholamidopropyl)-dimethylammonio]-1-propane-sulfonate (CHAPS) and used as ELISA antigens. A control antigen of normal erythrocytes from the same donor horse was prepared in an identical manner. The ELISA and Western blot were validated by testing of sera from horses experimentally infected with B. caballi or B. equi or not infected with Babesia spp. ELISA and Western blot results were compared with those obtained by the immunofl...
Isolation and identification of African horse sickness virus during an outbreak in Lagos, Nigeria. An outbreak of African horse sickness involving two horse stables in Lagos, Nigeria, was investigated. Inoculation of blood from infected horses into suckling albino mice resulted in isolation of a virus which was identified as African horse sickness virus by the complement fixation test. The clinical, pathological and epizootiological findings (reported elsewhere) were consistent with African horse sickness. Potential threats of the epidemic to international horse trade are briefly highlighted.
Purification and characterization of equine complement factor C3. A rapid method for purifying equine C3 which yields milligram quantities of pure C3 is described. Protein from equine plasma was selectively precipitated with polyethylene glycol, and the C3 was purified by anionic and cationic exchange HPLC. The yield from this procedure was 12%. The purified C3 was composed of an alpha chain (118 kD) and a beta chain (68 kD) linked by at least one disulfide bond, and it had an isoelectric point of 4.7. Amino acid analysis indicated a strong conservation of amino acid usage between equine and human C3. The N-terminal sequences of the alpha and beta chains wer...
Seroepidemiological survey of chlamydial infections in light horses in Japan. To investigate the overall prevalence of chlamydial infections in light (i.e. non-draught) horses in Japan, 599 sera obtained from 12 localities in 1991 were tested for complement fixation antibodies. The mean antibody positive rates of the all sera were 15.2% (91/599) and the regional positive rates were higher in Honshu (19.1%, 48/251) and Kyushu (20.0%, 20/100) than in Hokkaido (9.3%, 23/248). In Honshu, the highest rate (56.0%, 28/50) was observed in Utsunomiya. Analysis of the positive rate in different age groups showed that the 2-5 years age-group had the highest prevalence of chlamydia...
Culture confirmation of the carrier status of Babesia caballi-infected horses. Culture of horse blood for Babesia caballi identified four carrier horses among nine previously infected horses. Three of the carriers had no detectable parasitemias on stained blood smears, and sera from two carrier horses were complement fixation test negative. Three cultures were continuously cultivated. Cryopreserved fourth-passage B. caballi was successfully reestablished in vitro. Blood from a 10th horse previously subinoculated with blood from a suspected carrier was cultured, with negative results.
The contribution of complement to opsonic activity in the uterine secretions of mares free of endometritis. The aim of the present study was to investigate if complement contributes to opsonic activity in the uterine secretions of mares with normal reproductive functions. Five mares with a mean age of 9 years were used in the study. The mares were considered to be free of endometritis based upon clinical history, palpation per rectum and ultrasonogaraphy of the genital tract, videoendoscopic inspection of the uterus, electronmicroscopy of endometrial biopsies, and bacteriological and cytological examination of swabs from the endometrium. The hormonal status of the mares was also determined. Uterine ...
Antibody responses of Japanese horses to influenza viruses in the past few years. A total of 305 horse sera collected in the Hidaka district of Hokkaido in the years 1988-90 were tested for the presence of hemagglutination-inhibition (HI) antibodies to A/equine/Newmarket/1/77 (H7N7), A/equine/Tokyo/2/71 (H3N8) and A/equine/Kentucky/1/81 (H3N8, Kentucky) strains of equine influenza (EI) virus. Antibodies to the 3 strains were detected in hardly of the 45 sera from 2-years-old horses which were collected before vaccination. Many of the 51 horses, after vaccination with inactivated EI virus, had HI antibodies to the 3 strains in 37 to 88 per cent. However, the number of positi...
Serological responses of specific pathogen-free foals to equine herpesvirus-1: primary and secondary infection, and reactivation. Serum antibody (virus neutralisation, complement fixation, IgM and IgG) responses to equine herpesvirus-1 (EHV-1) infection were measured in six foals which were initially free from EHV-1 and EHV-4 infection and maternally-derived antibodies. Following primary infection, high titres of virus neutralisation and complement fixation antibodies were detectable against EHV-1, however, corresponding antibody levels against EHV-4 were low or inapparent, although the two viruses share a number of cross-reactive epitopes. In addition, following the primary infection with EHV-1, IgM levels increased bef...
Demonstration of the humoral immune response of horses to Babesia caballi by western blotting. Babesia caballi-infected or normal equine erythrocytes were solubilized in sodium dodecyl sulfate (SDS) buffer and analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. Antigens were allowed to react with sera from horses experimentally or field-infected with B. caballi and with sera from non-infected horses. Major babesial antigens recognized by immune sera had apparent mol. wts of 141, 112, 70, 50, 48, 34, and 30 kDa. The polypeptides at 50 and 48 kDa were recognized earliest and throughout infection, but also weakly by 3/100 equine sera tested negative and 1/33...
Preliminary findings for an inactivated African horsesickness vaccine using binary ethyleneimine. Investigation studies on inactivated African horsesickness vaccine using binary ethyleneimine were conducted. The inactivation process of virulent type-9 strain using the above inactivant revealed complete virus inactivation at 18, 48 and 84 h post-treatment with inactivant concentrations of 0.004, 0.003 and 0.002M, respectively, without detection of residual virus. An inactivant concentration of 0.003M is recommended and no changes in viral antigenic properties were noticed in complement fixation test. The physical parameters in oil-emulsion vaccine using the incomplete Freund's adjuvant, wer...