Complement Fixation Test Results Research Articles

Development and validation of a chemiluminescent western blot assay for glanders (Burkholderia mallei) serodetection.

Glanders, caused by Burkholderia mallei, is a zoonotic disease of equids. Serologic testing for glanders is required by disease-free countries before international movement of equids. The World Organisation for Animal Health Terrestrial Manual recommends the complement fixation test (CFT) for clearance of individual animals for movement, but the CFT is prone to false-positive results. A colorimetric western blot (WB) assay was developed and validated to resolve false-positive CFT results; however, that assay is relatively time-consuming, and the interpretation is subjective. We present here a procedurally similar chemiluminescent WB assay that performs comparably to the validated colorimetric WB assay and offers noticeable benefits of decreased time-to-result and greater ease of interpretation.

Production of a Bacillus anthracis Secretome with Suitable Characteristics as Antigen in a Complement Fixation Test.

In this study, we cultured the Bacillus anthracis vaccine strain Sterne 34F2 in a medium containing EDTA, and we assessed the best conditions to inhibit the activity of zinc-dependent metalloproteases to obtain a secretome containing a high concentration of non-degraded PA (PA83), as evaluated by the SDS-PAGE analysis. Then, we used this secretome as the antigen in a Complement Fixation Test (CFT) to monitor the production of antibodies against PA83 in the sera of rabbits vaccinated with Sterne 34F2 and then infected with a B. anthracis virulent strain to evaluate the potency of the vaccine. The PAS-based CFT results were compared with those obtained by using a commercial ELISA kit. The two serological tests gave similar results in terms of specificity and sensitivity, as the kinetics of the antibodies production was very similar. The Sterne 34F2 vaccine induced an antibody response to PA83, whose titer was not inferior to 1:8 in PAS-based CFT and 42 kU/mL in PA83-based ELISA, respectively, in all vaccinated rabbits. Our opinion is that the PAS-based CFT can be successfully employed in humans and in animals for epidemiological retrospective studies or post-vaccination monitoring. We also suggest the use of our method to test the efficacy of veterinary anthrax vaccines.

METHOD FOR FMD VIRUS 146S COMPONENT CONCENTRATION DETERMINATION WITH REAL-TIME REVERSE TRANSCRIPTION – POLYMERASE CHAIN REACTION IN VACCINE RAW MATERIALS

Method for determination of foot-and-mouth disease (FMD) virus 146S component concentration with real-time reverse transcription – polymerase chain reaction (rtRT-PCR) in vaccine raw materials is developed. Negative regression model of С146S = (30.269 – Ct)/4.155 type allowing determination of FMDV 146S particle concentrations based on the amplification threshold cycle values (Ct) is proposed. It has been experimentally proven that the quantity of the 146S component determined by the real-time RT-PCR method using developed regression model and contained in the inoculation dose of FMD vaccine confers protection to the vaccinated animals against generalized FMD of A, O, Asia-1 types. rtRT-PCR method is highly sensitive and allows rapid and highly reliable estimation of the 146S antigen concentration in FMD vaccine. The method for 146S particle quantity determination by real-time RT-PCR using the regression model is reliable and demonstrates high correlation (95.5–99.0%) with the complement fixation test results.

METHOD FOR FMD VIRUS 146S COMPONENT CONCENTRATION DETERMINATION WITH REAL-TIME REVERSE TRANSCRIPTION – POLYMERASE CHAIN REACTION IN VACCINE RAW MATERIALS

Method for determination of foot-and-mouth disease (FMD) virus 146S component concentration with real-time reverse transcription – polymerase chain reaction (rtRT-PCR) in vaccine raw materials is developed. Negative regression model of С146S = (30.269 – Ct )/4.155 type allowing determination of FMDV 146S particle concentrations based on the amplification threshold cycle values (Ct ) is proposed. It has been experimentally proven that the quantity of the 146S component determined by the real-time RT-PCR method using developed regression model and contained in the inoculation dose of FMD vaccine confers protection to the vaccinated animals against generalized FMD of A, O, Asia-1 types. rtRT-PCR method is highly sensitive and allows rapid and highly reliable estimation of the 146S antigen concentration in FMD vaccine. The method for 146S particle quantity determination by real-time RT-PCR using the regression model is reliable and demonstrates high correlation (95.5–99.0%) with the complement fixation test results.

Versatile microfluidic complement fixation test for disease biomarker detection

The complement fixation test (CFT) is a serological test that can be used to detect the presence of specific antibodies or antigens to diagnose infections, particularly diseases caused by microbes that are not easily detected by standard culture methods. We report here, for the first time, a poly(dimethylsiloxane) (PDMS)/glass slide hybrid microfluidic device that was used to manipulate the solution compartment and communication within the microchannel to establish sampler and indicator systems of CFT. Two types of on-chip CFT, solution-based and solid phase agar-based assays, were successfully demonstrated for biomarker carcinoembryonic antigen (CEA) and recombinant avian influenza A (rH7N9) virus protein detection. In addition, the feasibility of the on-chip CFT in assaying real biopsy was successfully demonstrated by specifically detecting rH7N9 and CEA in human serum. The results demonstrated that the miniaturized assay format significantly reduced the assay time and sample consumption. Exemption from protein immobilization, blocking, complicated washing steps and expensive enzyme/fluorescein conjugates highlights the merits of on-chip CFT over ELISA. Most attractively, the on-chip agar-based CFT results can be imaged and analysed by smartphone, strengthening its point-of-care application potential. We anticipate that the on-chip CFT reported herein will be a useful supplemental or back-up tool for on-chip immunoassays such as ELISA for disease diagnosis and food inspection.

Old and new diagnostic approaches for Q fever diagnosis: Correlation among serological (CFT, ELISA) and molecular analyses

The objective of this study was to evaluate the performance of the complement fixation test (CFT) with respect to ELISA for the serological diagnosis of Q fever and to assess the role of serology as a tool for the identification of the shedder status. During 2009-2010, sera from 9635 bovines and 3872 small ruminants (3057 goats and 815 sheep) were collected and analyzed with CFT and ELISA. In addition, 2256 bovine, 139 caprine and 72 ovine samples (individual and bulk tank milk samples, fetuses, vaginal swabs and placentae) were analyzed with a real-time PCR kit. The relative sensitivity (Se) and specificity (Sp) of CFT with respect to ELISA were Se 26.56% and Sp 99.71% for cattle and Se 9.96% and Sp 99.94% for small ruminants. To evaluate the correlation between serum-positive status and shedder status, the ELISA, CFT and real-time PCR results were compared. Due to the sampling method and the data storage system, the analysis of individual associations between the serological and molecular tests was possible only for some of the bovine samples. From a statistical point of view, no agreement was observed between the serological and molecular results obtained for fetus and vaginal swab samples. Slightly better agreement was observed between the serological and molecular results obtained for the individual milk samples and between the serological (at least one positive in the examined group) and molecular results for the bulk tank milk (BTM) samples. The CFT results exhibited a better correlation with the shedder status than did the ELISA results.

An evaluation of Irish cattle herds with inconclusive serological evidence of bovine brucellosis.

Since 1998, there has been a steady decline in herd restrictions and de-populations in Ireland due to bovine brucellosis. There is concern that the interpretation of laboratory results may become increasingly problematic, as brucellosis prevalence falls in Ireland. Therefore, the purpose of the current study was to evaluate the infection status of Irish herds and animals with inconclusive serological evidence of bovine brucellosis. During 12 months from September 1, 2004, laboratory and observational epidemiological data were collected from all Irish herds where animal testing identified at least one animal with a complement fixation test (CFT) reading greater than zero and/or a positive result to the indirect enzyme-linked immunosorbent assay (iELISA). Due to the observational nature of the study, we have robust estimates of the relative, but not the absolute, performance of the CFT, iELISA and brucellin skin test (BST). Herds were divided into three categories (Group A, B or C) on the basis of test results at initial assessment. A total of 639 herds were enrolled into the study, and observed for at least two years following enrolment. A rising CFT titre, with a CFT reading of 111 International CFT Units (IU) or greater at the subsequent blood test, was generally associated with herds where other evidence of infection was also available. Knowledge of the CFT reading at the initial and a subsequent blood test proved useful in distinguishing false-positive and true-positive brucellosis results. There was poor correlation between the CFT and iELISA results, and between the CFT and BST results. As a result of this study, national policy has been modified to include re-sampling of all animals with CFT readings of 20 IU or greater. This project has also led to a reduction in the number of herds restricted, as well as restriction duration. It has also contributed to a reduction in the number of herds listed for contiguous tests, and therefore the potential for contiguity testing of false positive results.

Prévalence réelle de la brucellose bovine dans le centre de la Côte d’Ivoire

Lors de l’enquête de sérosurveillance active de la peste bovine organisée en Côte d’Ivoire de juillet à août 2005, 660 sérums ont été collectés dans les régions administratives du N’Zi Comoé et des Lacs, au centre du pays. Ces sérums ont été utilisés pour faire une estimation de la prévalence réelle de la brucellose bovine en utilisant une approche statistique bayésienne avec quatre tests de diagnostic sérologiques : la séro-agglutination lente de Wright (SAW), le test du rose bengale (TRB), l’Elisa indirect (iElisa) et le test de fixation du complément (TFC). Les résultats de ce dernier n’ont pas été pris en compte dans cette étude. Les analyses sérologiques ont donné des séroprévalences individuelles de 6,2 p. 100 à la SAW, 5,1 p. 100 au TRB et 7,0 p. 100 à l’iElisa. L’analyse bayésienne faite avec ces mêmes résultats sérologiques a permis d’obtenir une estimation de la prévalence réelle de la brucellose de 8,8 p. 100 (intervalle de crédibilité à 95 p. 100 : 5,0–16,4). Ces résultats constituent une bonne indication de l’importance de la brucellose dans cette partie de la Côte d’Ivoire et confirment l’attention qui doit être accordée à cette maladie.

Serological evidence of antibodies to certain arboviruses in desert rodent sera in Egypt

Introduction : Small rodents inhabiting the wadis close to St Katherine in the mountains of the Sinai Peninsula, Egypt, were trapped and antibodies to Sindbis (SIN) , West Nile (WN) and Quaranfil (QRF) viruses in their sera were studied. Materials and Methods One mouse had Haemagglutination–inhibition (HI) antibodies against SIN antigen in his serum, 3 mice had HI antibodies against WN antigen in their sera. The titers is low to be of any significance. Conclusion: It seems that natural cycle of transmission of SIN and WN viruses involving rodents does not exist. Seven mice had Complement-fixation (CF) antibodies in their sera against Quaranfil antigen. Conclusion, the CF test results suggest the existence of another mammal vector cycle.

Serological evidence of antibodies to certain arboviruses in desert rodent sera in Egypt

Introduction : Small rodents inhabiting the wadis close to St Katherine in the mountains of the Sinai Peninsula, Egypt, were trapped and antibodies to Sindbis (SIN) , West Nile (WN) and Quaranfil (QRF) viruses in their sera were studied. Materials and Methods One mouse had Haemagglutination–inhibition (HI) antibodies against SIN antigen in his serum, 3 mice had HI antibodies against WN antigen in their sera. The titers is low to be of any significance. Conclusion: It seems that natural cycle of transmission of SIN and WN viruses involving rodents does not exist. Seven mice had Complement-fixation (CF) antibodies in their sera against Quaranfil antigen. Conclusion, the CF test results suggest the existence of another mammal vector cycle.

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 CFT and the ELISA seroprevalence was 7.6 and 6.7%, respectively. Concordance between the CFT and ELISA results was high (96%). The highest number of CFT positive animals was detected in one herd in Möngönmorit (6/10), followed by herds in Bayandelger (5/10) and in Bayantsagaan (5/10). Poor body condition was significantly correlated with positive serological status in both CFT and ELISA. A history of abortion appeared to be a risk factor for both CFT and ELISA seropositivity. Blood samples of all horses belonging to herds with at least three (3/10) seropositive animals (CFT and/or ELISA) were analysed by light microscopy and by PCR using a Trypanosoma ( Trypanozoon) brucei specific primer pair. No trypanosomes or any other haemoparasites could be detected in Giemsa stained thin blood smears. Eight out of the 130 samples (6.2%) analysed by PCR gave positive signals. Seven out of the eight PCR positive horses were also serologically positive. One PCR (and ELISA) positive stallion from Möngönmorit showed emaciation, scrotal and preputial oedema and an oedematous skin plaque. From the serological and DNA-based results it is concluded, that trypanosome infections occur in horses in the Tuv aimag of Mongolia. Since at present neither serological nor DNA-based tests allow a subspecies specific identification within the subgenus Trypanozoon, no definitive diagnosis can be given for T. equiperdum. Whether the examined herds are infected with T. equiperdum or with T. evansi, the causative agent of surra, remains an open question. However, based on the clinical findings, the negative parasitological results and the concentration of conspicuous seroprevalences in single herds, circumstantial evidence supports the existence of infections with the causative agent of dourine.

Effects of vaginal Brucella ovis infection of red deer hinds on reproductive performance, and venereal transmission to stags

AIMS: To investigate the effects of vaginal Brucella ovis infection on the reproductive performance of red deer (Cervus elaphus) hinds. To determine whether stags may become infected with B. ovis by venereal transmission from mating infected hinds. METHODS: Thirty mixed-age red deer hinds serologically negative for B. ovis antibodies were synchronised for oestrus on 22 March 2000. B. ovis was inoculated into the vagina of each hind at oestrus and again, 18 days later. At oestrus, hinds were randomly allocated to six groups, each joined with a 16-month-old red deer stag seronegative for B. ovis, for 55 days. Hinds were blood sampled and scanned for pregnancy using rectal ultrasonography at monthly intervals. Six pregnant and four non-pregnant hinds were slaughtered pre-calving and three hinds were slaughtered post-calving. Reproductive tracts and foetuses were examined grossly, histologically and microbiologically. Calves were identified and blood sampled within 3 days of birth. Hinds and calves were blood sampled in February and May 2001 and vaginal swabs were collected from hinds for B. ovis culture. Blood was collected from stags, 5 and 19 days after mating and semen was collected for B. ovis culture. The 17 remaining hinds were mated in 2001 to two mixed-age wapiti (Cervus canadensis) stags. Both stags were blood sampled after mating. Sera were tested in a B. ovis complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA). RESULTS: All 30 hinds developed B. ovis antibody levels, measurable using either the CFT or ELISA, but these did not remain elevated. There was no evidence of infection, either by gross pathology, histopathology or microbiological culture in the ten hinds or six foetuses slaughtered pre-calving. All remaining 20 hinds produced normal calves, 15 of which survived until weaning. Three hinds experienced dystocia and gave birth to dead calves and two calves died within 4 days of birth. One hind which had dystocia was euthanased. Samples from this hind and from 3/5 dead calves showed no evidence of B. ovis infection. B. ovis was cultured from the vagina of 1/19 hinds 48 weeks after inoculation, at which time B. ovis CFT and ELISA results for this hind were negative. Most calves had B. ovis serum antibodies at 1–3 days of age but levels were negligible when sampled at 10–15 weeks of age. Foetuses and dead calves were all seronegative. Three of the five red deer stags used for mating in the first year became infected with B. ovis. The two wapiti stags used to mate the remaining 17 hinds the following year remained seronegative. CONCLUSIONS: B. ovis is unlikely to have significant detrimental effects on the reproductive performance of red deer hinds. Venereal transmission via the vagina of hinds is a possible route of transmission between stags. It is possible that survival of the organism in the vagina of some hinds could create difficulties in disease control programmes. CLINICAL RELEVANCE: B. ovis infection of hinds at the time of mating is unlikely to cause significant reproductive losses. Venereal transmission of B. ovis between stags via the hinds may occur when groups of hinds are joined with more than one stag.

Field validation of the use of RB51 as antigen in a complement fixation test to identify calves vaccinated with Brucella abortus RB51.

In order to confirm the efficiency of an experimental RB51-based complement fixation (CF) test in identifying cattle vaccinated with Brucella abortus strain RB51, 831 sera from 110 vaccinated and 48 unvaccinated Hereford heifers of Iowa, collected for studies conducted in different years, were sent to Italy without coding to be tested in a CF test using RB51 as antigen. Most of the calves, aged from 3 to 10 months, were vaccinated subcutaneously with the recommended dosage of 10(10) CFU of RB51 commercial vaccine, while only six calves received 10(9) CFU of the same vaccine. Serum samples for serologic testing, collected until 16 postinoculation weeks (PIW), were also tested by routine surveillance tests for brucellosis such as rose bengal plate and CF tests performed with B. abortus smooth strain 99 as control antigen. RB51 CF test results obtained by testing sera from cattle vaccinated in 1999 indicate that the sensitivity of the reaction is 97% at 2 to 3 PIW and 90% until 8 PIW and decreases to 65% at 12 PIW, the specificity remaining at 100%. Collectively, the results of this study confirm that serologic standard tests fail to detect antibodies to RB51 while the RB51-based CF test is able to monitor antibody responses to RB51 until 15 to 16 PIW with a specificity of 100%. In addition, unlike the RB51-based dot blot assay, which is the only test currently used to monitor antibody responses to RB51, the CF test also detected specific responses following vaccination with 10(9) CFU of RB51, although seroconversion was only 50% at 8 PIW. In conclusion, because of high specificity and sensitivity, the CF test described here can be used to efficaciously monitor serologic responses following RB51 vaccination in cattle and could also be employed to detect RB51 infection in humans exposed to this strain.

Improved sensitivity and specificity of enzyme immunoassays with P1-adhesin enriched antigen to detect acute Mycoplasma pneumoniae infection

An in-house P1-enriched (168-kDA protein) Mycoplasma pneumoniae antigen preparation was compared in IgG, IgA and IgM enzyme immunoassays (EIAs) to the respective EIAs employing crude antigen lysate, antigen prepared by Triton X-114 partition and two commercial antigens, one of which was an ether-extracted antigen and the other a P1-enriched antigen. In addition, three commercial kits from Sanofi Pasteur, Novum Diagnostica and Savyon Diagnostics were also assessed for comparison. Diagnostic sensitivity was studied with paired samples from adults ( n=37) with acute respiratory illness interpreted as acute, recent or past infection to M. pneumoniae on the basis of the results of complement fixation test (CFT). If the consensus of at least two methods is taken as the true positive for acute infection, the diagnostic sensitivities of combined IgG and IgM EIAs were 100% for the Platelia®, Sero™ MP and in-house EIAs whereas for the Novum EIAs and CFT- 97% and 74%, respectively. Moreover, the sensitivity of the P1-enriched antigen was proven superior on the basis of systematically highest OD 405 nm ratios between convalescent and acute serum samples. Analytical specificity was studied by screening serum samples from 92 Finnish blood donors and 111 serum samples from cord blood. Diagnostic specificity was studied in a blind testing of 30 paired serum samples from infants with pneumonia of variable etiology. No single misinterpretation of acute infection from the group of samples with other respiratory diseases did occur. The present study confirmed and extended the earlier observations of the usefulness of P1-enriched antigen for reliable serologic diagnosis of acute M. pneumoniae infection.

Detection of equine antibodies to babesia caballi by recombinant B. caballi rhoptry-associated protein 1 in a competitive-inhibition enzyme-linked immunosorbent assay.

A competitive-inhibition enzyme-linked immunosorbent assay (cELISA) was developed for detection of equine antibodies specific for Babesia caballi. The assay used recombinant B. caballi rhoptry-associated protein 1 (RAP-1) and monoclonal antibody (MAb) 79/17.18.5, which is reactive with a peptide epitope of a native 60-kDa B. caballi antigen. The gene encoding the recombinant antigen was sequenced, and database analysis revealed that the gene product is a rhoptry-associated protein. Cloning and expression of a truncated copy of the gene demonstrated that MAb 79/17.18.5 reacts with the C-terminal repeat region of the protein. The cELISA was used to evaluate 302 equine serum samples previously tested for antibodies to B. caballi by a standardized complement fixation test (CFT). The results of cELISA and CFT were 73% concordant. Seventy-two of the 77 serum samples with discordant results were CFT negative and cELISA positive. Further evaluation of the serum samples with discordant results by indirect immunofluorescence assay (IFA) demonstrated that at a serum dilution of 1:200, 48 of the CFT-negative and cELISA-positive serum samples contained antibodies reactive with B. caballi RAP-1. Four of five CFT-positive and cELISA-negative serum samples contained antibodies reactive with B. caballi when they were tested by IFA. These data indicate that following infection with B. caballi, horses consistently produce antibody to the RAP-1 epitope defined by MAb 79/17.18.5, and when used in the cELISA format, recombinant RAP-1 is a useful antigen for the serologic detection of anti-B. caballi antibodies.

Evaluation of Anaplasma marginale from tick cell culture as an immunogen for cattle.

Anaplasma marginale has been propagated and continuously passaged in an Ixodes scapularis cell line. Anaplasma development was characterized and cultures with a high density of rickettsiae were harvested at a predictable rate. Culture-derived A. marginale (CAM) remained infective for cattle and was used effectively as antigen in diagnostic tests with the sensitivity to identify bovine carriers of A. marginale. This study presents results of an initial trial using the CAM as an immunogen for cattle. CAM was mechanically disrupted, frozen at -70 degrees C, and inactivated with beta-propiolactone. Two intact yearling cattle were immunized with CAM and Freund's adjuvant, receiving 4 subcutaneous injections at 3-4 week intervals. Two control yearling cattle received adjuvant and PBS. Serum samples were evaluated by competitive ELISA (C-ELISA) using CAM as antigen and the standard complement fixation test (CFT). All cattle were subsequently challenged with A. marginale-infected blood from a carrier cow. An additional intact calf was inoculated with live CAM from the same passage and screened by C-ELISA and CFT. Sera collected from immunized cattle were negative or suspicious by CFT throughout the immunization study. The same sera were strongly positive by C-ELISA two weeks after the first injection and throughout the study. All cattle became infected following challenge-exposure with blood, but immunized cattle exhibited longer prepatent periods as well as lower parasitemias and percent reduction of packed cell volumes as compared with the controls. The calf receiving live CAM became infected and underwent a mild clinical reaction with positive C-ELISA and CFT results and did not become clinically ill following blood challenge. This preliminary study suggests that the CAM antigen is highly immunogenic in cattle. Furthermore, the CFT did not identify immunized animals whereas the C-ELISA (using CAM) was highly sensitive for detection of both immunized and infected animals.

Chlamydia pneumoniae as a cause of community-acquired pneumonia in hospitalized patients in Berlin.

The incidence of community-acquired pneumonia due to Chlamydia pneumoniae was evaluated in a 1-year prospective study of 236 hospitalized patients with 237 manifestations of pneumonia. The microbiological diagnosis was based on results of cultures of blood and sputum or bronchoalveolar lavage fluid and results of complement fixation tests and indirect immunofluorescence of acute- and convalescent-phase sera for C. pneumoniae, Mycoplasma pneumoniae, Legionella species, Coxiella burnetii, and respiratory viruses. Diagnosis of acute C. pneumoniae infection was made on the basis of the results of microimmunofluorescence of paired serum samples. A microbiological diagnosis was obtained in 160 cases (67.5%). C. pneumoniae was the causative agent in 27 patients (11.4%). The following organisms were the other etiologic agents of pneumonia: Streptococcus pneumoniae, 30 cases (12.7%) (bacteremia occurred in 53.3%); Mycoplasma pneumoniae, 22 (9.3%); respiratory viruses, 22 (9.3%); and Enterobacteriaceae, 18 (7.6%). The prevalence of C. pneumoniae antibody in our study population was 47.5%. As has been increasingly reported in recent years and confirmed by this study, C. pneumoniae appears to be a common etiologic agent of community-acquired pneumonia and upper respiratory tract infection in Germany.

La réaction de fixation du complément pour le diagnostic sérologique de la péripneumonie contagieuse bovine : application et interprétation des résultats

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (small colony variant), is a disease which has been recognised for a long time. Serological testing is used most often for diagnosing CBPP in live animals. This method is based on a complement fixation test (CFT), the technique recommended by the Office International des Epizooties, which has an important role in detecting infected herds in regions known to be affected by the disease. Although this serological test is the most reliable method currently available, it has some major shortcomings in sensitivity and specificity. The author discusses the reasons for these limitations, which can raise difficulties in the interpretation of CFT results, and the possibilities and potential applications of the test.

Eosinophilic pleocytosis in coccidioidal meningitis: Frequency and significance

purpose: Coccidioidal meningitis (CM) is a major source of. morbidity and mortality in endemic regions. The diagnosis of CM is a clinical challenge. Eosinophilic pleocytosis (EP) is an uncommon finding and present in a relatively limited number of conditions. In order to determine the frequency and the prognostic significance of EP in CM, we conducted the present study. patients and methods: Retrospective chart review of all patients diagnosed as having CM between 1986 and 1991 at Kern Medical Center. All patients had clinical and cerebrospinal fluid (CSF) findings confirmatory of CM. results: Nineteen patients (70%) in the study group had EP, and of these, 8 patients (30%) met the criteria for eosinophilic meningitis (greater than or equal to 10 eosinophils/mm 3). No correlation was found between EP and age, sex, race, results of complement fixation test for coccidioidal antigen in CSF or serum, peripheral eosinophilia, or outcome. conclusion: The presence of EP is a frequent observation in CM. Although we did not demonstrate any prognostic correlation with EP, this finding is of major diagnostic significance and its presence should bring attention to the diagnosis of CM.

Demonstration of the humoral immune response of horses to Babesia caballi by western blotting

Böse R. and Daemen K. 1992. Demonstration of the humoral immune response of horses to Babesia caballi by Western blotting. International Journal for Parasitology 22: 627–630. 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 sera tested false positive by the complement fixation test (CFT) and immunofluorescence antibody test (IFAT). Thus, further characterization and purification of B. caballi antigens are required to identify target antigens for an improved enzyme immuno assay. Until such an assay is available. Western blotting can provide a specific tool for the diagnosis of B. caballi infections, particularly in cases of contradicting CFT and IFAT results.