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PubMed1983

Detection of Gardnerella vaginalis on vaginal smears by immunofluorescence.

An indirect fluorescence antibody (IFA) test was developed for the detection of Gardnerella vaginalis. Antisera were prepared in rabbits by using five strains of G. vaginalis. A pool of the antisera was tested for specificity with a variety of isolates known to colonize the human vagina and (or) morphologically resemble G. vaginalis. Six heterologous bacterial isolates reacted with the pooled antiserum at dilutions of 1:10, but none reacted at the working dilution of 1:200. Vaginal swab specimens were collected from symptomatic and asymptomatic patients in order to further evaluate the IFA procedure. The presence of G. vaginalis in the specimens was determined both by culture and by the IFA procedure. Absorbed antisera reacted with all isolates of G. vaginalis tested. In a clinical trial the IFA procedure detected the presence of G. vaginalis in smears from 23 (24.2%) of the patients with nonspecific vaginitis (NSV), from 22 (29.8%) of the asymptomatic individuals tested, and from 3 patients with vaginitis other than NSV. The presence of G. vaginalis in smears as detected by the IFA procedure was confirmed by cultures in all cases using Vaginalis agar supplemented with colistin and nalidixic acid (V-CNA). It is suggested that the IFA procedure may be of use in conjunction with V-CNA in epidemiological studies of the carriage and transmission of G. vaginalis in human populations. It appears that the IFA procedure, at least in our hands, is a useful test for the rapid detection of G. vaginalis even when this microorganism is not the predominant colonizer of the human vagina.

Evaluation Studies as Topic↗
PubMed2001

Anti-VP1 and anti-VP2 antibodies detected by immunofluorescence assays in patients with acute human parvovirus B19 infection.

Acute human parvovirus B19 infection is followed by an antibody response to the structural proteins of the viral capsid (VP1 and VP2). We used 80 sera collected from 58 erythema infectiosum and 6 transient aplastic crisis patients to test IgM and IgG antibodies against these two proteins in an immunofluorescence assay (IFA) using Sf9 cells infected with recombinant baculovirus expressing either VP1 or VP2 antigen. Although less sensitive than IgM capture enzyme immunoassay using native antigen (MACEIA), we could detect anti-VP1 or anti-VP2 IgM antibodies by IFA in 49 patients with acute infection (76.6%). Detection of IgG anti-VP1 and anti-VP2 by IFA, however, was as sensitive as IgG detection by indirect enzyme immunoassay. By applying IgG avidity IFA to sera of the 15 IgM IFA negative patients we were able to confirm acute infection in further 12 cases by IFA. Overall, acute infection was confirmed by IFA in 61 (95.3%) of the 64 patients.

Adolescent↗
PubMed1985

Tick-borne Borrelia infection in Sweden.

Spirochetes were cultivated from 17% of 114 Ixodes ricinus ticks in the Stockholm area. Three strains of these spirochetes were selected for studies by electron microscopy. These three strains had definite morphological similarities to spirochetes of the genus Borrelia, as judged by the number of flagella, absence of cytoplasmic tubules, and dimensions. The three strains were not identical, but seemed to consist of two different kinds of cells, one with eight and one with eleven flagella. The three strains were also shown to react with a monoclonal antibody that reacts with Lyme disease spirochetes (Borrelia burgdorferi), but not with strains of other Borreliae, Treponemes, or Leptospiras. These results indicate the possibility of transmission of Borrelia spirochetes from ticks to humans in Sweden. The antibody response to one of the spirochetal strains isolated from Swedish I. ricinus was studied in 37 patients with the typical clinical picture of erythema chronicum migrans (ECM), in 45 patients with chronic meningitis (CMe) cured by high-dose intravenous penicillin, in 298 patients with post-infectious arthritis, and in controls. The antibody response was estimated by indirect immunofluorescence assay (IFA) enzyme-linked immunosorbent assay (ELISA). The antibody levels differed significantly between patients with CMe and healthy individuals (p less than 0.001), both with respect to serum antibody levels and CSF-antibody levels. The antibody levels also differed significantly between patients with ECM and healthy controls as measured by ELISA (p less than 0.05), whereas the difference was not significant as measured by IFA. Five of 298 patients with post-infectious arthritis had higher titers than any of the controls, and two of these five patients had titers higher than any patient with CMe or ECM. These results indicate spirochetal aetiology of ECM, and in some patents with CMe or postinfectious arthritis. As a diagnostic test for ECM, both IFA and ELISA were of limited value, since only 5/37 (14%) ECM patients were positive by IFA, and 14/37 (38%) by ELISA. Regarding patients with CMe, 23/45 (51%) were seropositive by IFA and 30/45 (67%) by ELISA. However, measurement of CSF-antibodies were found to be a more sensitive method than measurement of serum antibodies both by IFA and ELISA, since 38/45 (84%) CMe patients were positive by IFA, and 41/45 (91%) by ELISA. In addition, estimation of CSF antibodies was also found to be a more specific method than estimation of serum antibodies.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1981

The enzyme-linked immunosorbent assay (ELISA) for malaria. III. Antibody response in documented Plasmodium falciparum infections.

Serum specimens from patients in El Salvador, Central America, with slide-proven Plasmodium falciparum infections were examined for antibodies to P. falciparum using the enzyme-linked immunosorbent assay (ELISA) and the indirect fluorescent antibody (IFA) methods. Both serologic tests were positive in 78.1% of the 827 samples, both negative in 5.4%, the ELISA positive alone in 6.3%, and the IFA alone in 10.2%. Agreement between the serologic tests was better in the specimens with high positive titers (high IFA = high ELISA). Seropositivity rates and geometric mean titers were higher in the older (greater than or equal to 15 years) age groups for both ELISA and IFA; in such persons, the IFA was positive in 92% and the ELISA in 88%. The lowest seropositivity rates found by the ELISA were observed in children; 27.6% of 98 children less than or equal to 4 years of age were negative. A longer duration of infection as evidenced by the presence of gametocytes on the blood slide resulted in higher positivity rates by both ELISA and IFA. This phenomenon, particularly apparent in young children, supports the belief that the more important variable in determining the proportion of false negatives is previous malaria experience and not age. The results indicate that, while neither serologic test is appropriate as a diagnostic aid, both the ELISA and the IFA would be useful in epidemiologic investigations.

Adolescent↗
PubMed1999

Evaluation of serologic and viral detection methods for diagnosing feline herpesvirus-1 infection in cats with acute respiratory tract or chronic ocular disease.

OBJECTIVE: To determine the value of virus isolation (VI), immunofluorescent antibody (IFA) assay, serum neutralization (SN), and ELISA for the diagnosis of clinical feline herpesvirus-1 (FHV-1) infection in cats. ANIMALS: 46 clinically normal cats, 17 cats with signs of acute respiratory tract disease, and 38 cats with signs of chronic ocular disease. PROCEDURE: Conjunctival swabs for VI, conjunctival scrapings for IFA testing, and venous blood samples for SN or ELISA testing were obtained from all cats. RESULTS: FHV-1 was detected in 10.9 and 28.3% of clinically normal cats and in 18.2 and 33.3% of cats with FHV-1-associated disease by VI and the IFA assay, respectively. There were no significant differences in the viral detection rate between cats with acute respiratory tract disease and cats with chronic ocular disease or between diseased cats and clinically normal cats; however, FHV-1 was never detected by both methods in clinically normal cats. Overall FHV-1 seroprevalence was 97% when tested by ELISA and 66% when tested by SN. Seroprevalence did not vary significantly among the 3 groups for either serologic test. Magnitude of SN and ELISA titers varied greatly but independently of presence or absence of clinical signs of FHV-1-associated disease. Sensitivity, specificity, and positive and negative predictive values were assessed for VI and the IFA assay--jointly and individually--and for each SN and ELISA titer magnitude. Values never all exceeded 50%. CLINICAL IMPLICATIONS: Because FHV-1 can be detected commonly in clinically normal cats by the IFA assay or VI, neither test appears to aid in the clinical diagnosis of FHV-1 infection. Seroprevalence does not appear to vary between affected and clinically normal cats. SN, ELISA, VI, and the IFA assay appear to be of limited value in the diagnosis of FHV-1-associated disease in cats. Concurrent assessment of the IFA assay and VI results may permit exclusion of FHV-1 as an etiologic agent if results of both tests are negative.

Acute Disease↗
PubMedDate not supplied

Mechanisms of hyperthermia- and 4-hydroperoxy-ifosfamide-induced cytotoxicity in T cell leukemia.

The prognosis of patients with early ALL (acute lymphoblastic leukaemia) relapse is poor with conventional chemotherapy alone. Thus, intensified chemotherapy strategies are required. The application of hyperthermia enhances the efficacy of certain antineoplastic drugs such as ifosfamide. In this study, the effects and molecular mechanisms of ifosfamide (4hydroperoxy-ifosfamide = 4OOH-IFA)- and/or hyperthermia-induced cell death are investigated in CEM cells. Hyperthermia enhanced the efficacy of 4OOH-IFA in a subaddictive manner. Analysis of caspase activation revealed an early hyperthermia-induced stimulation of caspase-3 and -6 directly after the heating pulse, while maximum activation following stimulation with 4OOH-IFA was obtained after 24 hours of culture. The combination of 4OOH-IFA and hyperthermia mediated an overaddictive caspase stimulation directly following the heating phase. At this time also an overaddictive cytotoxic effect was noticed, being mainly responsible for the enhancing effects of hyperthermia on 4OOH-IFA cytotoxicity. In conclusion, hyperthermia enhanced the cytotoxic effect of 4OOH-IFA on CEM cells by stimulation of an early 4OOH-IFA effect. Thus, thermochemotherapy might be considered as an intensifying treatment option in relapsed T cell leukemias.

Antineoplastic Agents, Alkylating↗
PubMed2004

[Comparison among four kits in detection of anti-SARS-CoV IgG in sera of SARS patients].

OBJECTIVE: To compare the sensitivity and specificity of four kits for detection of anti-severe acute respiratory syndrome (SARS)-CoV IgG in sera of SARS patients. METHODS: Anti-SARS-CoV IgG was detected in 99 serial sera from 18 SARS patients and in 123 negative reference sera, using two enzyme linked immunosorbent assays (EIA No. A and No. B) and two indirect immunofluorescence assays (Australian IFA and Euroimmun IFA). RESULTS: Anti-SARS-CoV IgG was not detected in sera collected from SARS patients at the first week after onset by any of the four kits, however, it was detectable in sera obtained at the second week of illness by EIA No. B, and two IFA, but not by EIA No. A, with the positive rates of 57.1% (4/7), 57.1% (4/7) and 42.9% (3/7), respectively. The anti-SARS-CoV IgG was first determined in sera on the 9th day by Euroimmun IFA, 12th day by EIA No. B, 13th day by Australian IFA, and 16th day by EIA No. A. The positive rates of antibody on the 3rd week after onset were 84.2% (16/19), 94.7% (18/19), 78.9% (15/19) and 52.6% (10/19) respectively. They were identical since the 4th week after the disease onset. Through detection of 123 negative reference sera, the specificity of EIA No. A and two IFA was 100%, with exception of 94.9% for EIA No. B. CONCLUSION: The sensitivity and specificity of the two IFAs were relatively higher than that of the two EIAs. The quality of the two homemade EIAs should be improved.

Antibodies, Viral↗
PubMed1988

The E. coli immunosorbent as used in serodiagnosis of Legionella infections studied by crossed immunoelectrophoresis.

In this study we investigated an immunosorbent, E. coli blocking fluid (BF), proposed for use in the Legionella Indirect Fluorescent Antibody Test (IFA). With crossed immunoelectrophoresis (CIE) of clinically relevant Legionella species, only one heat-stable antigen (no. 1) cross-reacted with the BF preparation. Patients' sera with elevated Legionella IFA titres did not react with this antigen in CIE. Out of 23 IFA positive patients' sera, six had titres lowered significantly to negative, when BF was applied as serum diluent for the titration (IFA BF negative sera). All six sera were negative in the micro agglutination test (MA). None of the IFA BF negative sera contained any Legionella precipitins in CIE, whereas nine out of the remaining 17 IFA BF positive sera unchanged by BF contained one or more precipitins. CIE results could not explain the effect of BF in Legionella IFA, and further studies are needed to sufficiently define the use of immunosorbents in diagnostic Legionella serology.

Antibodies, Bacterial↗
PubMed1986

[IgM ISAGA test in the diagnosis of acute acquired Toxoplasma infections].

An immunoglobulin M immunosorbent agglutination assay (IgM ISAGA) was tested in 1804 outpatients' samples. The test was negative in all 1091 sera from individual negative in the total indirect immunofluorescence antibody (IFA tot) test and in the passive hemagglutination (HA) test and in 15 sera with inconclusive results in these two tests. The 698 sera positive in the IFA tot and HA tests were also tested with direct IgM enzyme-linked immunosorbent assay (IgM ELISA). The 74 sera positive in the IgM ISAGA and/or IgM ELISA were also tested in the IgM immunofluorescent (IgM IFA) test. These sera belong to 42 individuals, 26 of whom were followed for previous positive results in the IgM ELISA test. 51 samples (68.9%) were found positive in both IgM ISAGA and IgM ELISA tests. Only 13 (25.5%) of these 51 samples were found positive in the IgM IFA. 9 samples (12.2%) were positive only in the IgM ISAGA test. Conversely another 9 samples (12.2%) were positive only in the IgM ELISA test, performed on serum as well as on chromatographic IgM fraction. Finally five samples (6.7%) yielded false positive results in the IgM ELISA test, and three of them were found false positive also in the IgM IFA test. All these five samples in fact were found negative on IgM chromatographic fraction in both tests. In conclusion, IgM ISAGA appears to be more specific than direct IgM ELISA or IgM IFA test for the detection of Toxoplasma gondii IgM. Sensitivity of IgM ISAGA test seems to be as good as in the direct IgM ELISA and better than in the IgM IFA test for the diagnosis of acute acquired toxoplasma infection.

Acute Disease↗
PubMed1983

Use of immunofluorescence, Gram's staining, histologic examination, and seroagglutination in the diagnosis of porcine colibacillosis.

An indirect fluorescent antibody (IFA) test of ileal impression smears for K88, K99, and 987P pilus antigens was compared with histologic examination and seroagglutination of Escherichia coli isolates for efficacy in determining colibacillosis in pigs. Histologic examination appeared to be more effective than the IFA test in revealing colonization of the ileum by bacteria. However, histologic examination revealed little about the nature of the colonizing bacteria. Correlation between bacterial adherence, as observed in histologic sections of ileum, and the presence of bacteria with adherence pili, as determined by IFA testing, was 91%. Results of seroagglutination for pilus antigens correlated with results of histologic examination in only 84% of the cases. Pilus antigens were not identified by IFA testing or seroagglutination in 5% of the cases in which adherent bacteria were observed in histologic sections of the small intestine. Because little preparation time was required for the IFA test, results were available within 2 hours of necropsy. In contrast to histologic examination, the IFA test made possible identification of the colonizing organism as E coli and revealed the type of pilus antigen present. Adherence pili were identified more frequently by IFA testing than by seroagglutination. Examination of Gram's-stained ileal impression smears was useful in screening for colibacillosis in pigs. Bacterial adherence was found in positive correlation with the number of gram-negative bacilli observed. Bacterial adherence rarely was observed in histologic sections of ileum when smears contained less than or equal to 10 gram-negative bacilli/1,000 X microscopic field. Each diagnostic test compared offered advantages and disadvantages over the other tests. Seemingly, concurrent use of several of these tests, rather than one, should be used in the diagnosis of porcine colibacillosis.

Agglutination Tests↗
PubMed1995

Effectiveness of a dot-blot immunoassay of anti-Rickettsia tsutsugamushi antibodies for serologic analysis of scrub typhus.

We compared a commercially available dot-blot immunoassay system with the indirect immunofluorescence assay (IFA) in tests of known negative and known positive sera from scrub typhus cases. Using a panel of 100 sera from patients with various rickettsial and nonrickettsial infections, we observed that the IFA was 99% specific and the dipstick assay was 98% specific. In tests of 91 sera (30 negative and 61 positive for scrub typhus antibodies) from a study of febrile patients in Malaysia, using the standard of an IFA titer < 1:64 as negative, an IFA titer > 1:128 as positive, and an IFA titer = 1:64 as either positive or negative (supported by clinical records), dipsticks were 83% specific and 90% sensitive. The quantitative correlation of the dipsticks to IFA titers was confirmed by significant differences in geometric means of inverse IFA titers corresponding to the number of positive dipstick spots (no dots = 8.5, one dot = 43.3, two dots = 206.7, and three dots = 676.9). The assay would enable physicians and public health workers who deal with patients to quickly diagnose and appropriately treat most cases of the disease, especially in areas of high prevalence where the proportion of false-positive results to true-positive results would be low.

Antibodies, Bacterial↗
PubMed1994

Comparison of the indirect immunofluorescence assay with western blot for the detection of HIV antibody.

With the increase in the prevalence of human immunodeficiency virus (HIV) infection in India, there is an urgent need to explore cost-containing methods of HIV antibody detection. We compared the indirect immunofluorescence assay (IFA) with the widely used but expensive confirmatory test, the Western blot (WBT). A panel of sera comprising 42 WB positive, 46 antibody negative (27 ELISA negative and 19 ELISA reactive but WB negative) and 58 sera with indeterminate WB profiles were tested by a commercial IFA kit. The sensitivity of IFA was found to be 97.6 per cent and specificity 97.8 per cent. Of the indeterminate sera, 18 (31%) were positive in IFA while 26 (45%) were negative and 14 (24%) were equivocal. In general, the IFA positivity was associated with the presence of the gag and env antibodies of HIV while negativity associated with the presence of lone antibodies. The cost of testing by IFA is less than 20 per cent of that of WB testing. Thus IFA appears to be a cost-containing alternative to WB in centres in India where immunofluorescent microscopy is routinely done.

Blotting, Western↗
PubMed2002

Comparison of four enzyme immunoassays for the detection of immunoglobulin G antibody against glomerular basement membrane.

Goodpasture syndrome is a life-threatening autoimmune kidney and pulmonary disease that is characterized by pulmonary hemorrhage, renal failure, and the presence of autoantibodies against glomerular basement membrane (GBM) by indirect fluorescent antibody (IFA) techniques. In 1988, these antibodies were found to be specific for the noncollagen region of the alpha3 collagen IV chain. The antigen is characterized by a restricted tissue distribution occurring mainly in the kidneys and lungs. Specific enzyme immunoassays (EIAs) for anti-GBM have now been developed for in vitro diagnostic use in the laboratory. Our objective in this study was to compare the results obtained using four different EIAs for detecting anti-GBM IgG antibody with those using the standard IFA method using tissue from human kidney. Thirty-two patients with suspected Goodpasture syndrome, and 10 control sera were included in the study. GBM EIAs were purchased from or donated by the following vendors: Scimedx Corporation (Denville, NJ), INOVA Diagnostics (San Diego, CA), The Binding Site (Birmingham, England), and Wieslab (distributed by DiaSorin, Inc., Stillwater, MN). Percent agreement, sensitivity, and specificity were calculated for each EIA as compared to IFA. The results were as follows: Binding Site: 83.3, 100.0, and 72.0%; Wieslab: 95.2, 94.1, and 96.0%; INOVA: 96.2, 100.0, and 92.3%; and Scimedx: 81.0, 100.0, and 68.0%. We conclude that the INOVA and Wieslab GBM IgG EIAs compared well with the standard GBM IFA method using tissue from human kidney. The Scimedx and Binding Site EIAs had eight and seven false-positive results, respectively, when compared to GBM IFA using human kidney. The authors recommend conducting thorough evaluations of EIAs that screen for anti-GBM antibody before their implementation in the clinical laboratory. We also recommend confirming GBM EIA-positive sera by the standard IFA method using tissue from human kidney.

Anti-Glomerular Basement Membrane Disease↗
PubMed2001

Longitudinal sero-reactivity to human herpesvirus 8 (KSHV) in the Swiss HIV Cohort 4.7 years before KS.

The relationship between viral infection with Kaposi sarcoma-associated herpesvirus (KSHV) and the onset of Kaposi sarcoma (KS) in AIDS patients is incompletely understood. This study investigates the use of three serological assays to predict the development of KS in HIV-positive patients. Serially collected serum samples from 36 patients with KS and matched controls in the Swiss HIV Cohort Study (SHCS) were analyzed in a case control study. Three serologic assays to detect antibodies against KSHV (nuclear and membrane antigen immunofluorescence assay, N-IFA, M-IFA and ORF 65.2 ELISA) were used to determine the predictive value of KSHV-seropositivity. Serial samples from the cases were also analyzed to determine longitudinal patterns of seroreactivity and identify cases of seroconversion. Assay sensitivity for detection of KSHV antibodies was highest for M-IFA (83%), followed by N-IFA (74%) and 65.2 ELISA (52%). At the time of initial serum sampling (median 4.7 years before KS), only the N-IFA distinguished case and control sera (61% vs. 32%) and no assay was clearly predictive of subsequent onset of clinical KS. Moreover, an unexpectedly high rate of reversions to seronegativity were observed by N-IFA (27/33) as well as by 65.2 ELISA (11/26) in the longitudinal analysis. Analysis of the ORF65.2 ELISA index indicated that these reversions before the clinical onset of KS were associated with antibody levels that frequently hovered around the level of detectability. A marked increase in ORF 65.2 antibody titer occurred in a third of the patients at the time of KS diagnosis. Only two seroconversions were documented. KSHV infection within the SHCS is likely to have preceded HIV infection. KSHV infection alone is not highly predictive of KS development in this cohort of HIV-infected homosexual men as compared with matched controls. Three KSHV serologic assays, though sensitive at the time of clinical KS are inconsistently positive before the development of AIDS-related KS.

AIDS-Related Opportunistic Infections↗
PubMed2001

Balance of Th1/Th2 cytokines associated with the preventive effect of incomplete Freund's adjuvant on the development of adjuvant arthritis in LEW rats.

Complete Freund's adjuvant (CFA) could induce adjuvant arthritis (AA) in LEW rats and incomplete Freund's adjuvant (IFA) could induce oil induced arthritis (OIA) in DA but not in LEW rats. Lymph node cells (LNCs) from these AA and OIA rats showed increased mRNA expression of IFN-gamma, IL-2 and TNF-alpha but not IL-4. LNCs from IFA immunized LEW rats showed increased expression of IL-4, reduced expression of IFN-gamma and TNF-alpha and no IL-2, in contrast to IFA immunized DA rats. The pretreatment of IFA before CFA challenge could completely prevent AA in LEW rats and their LNCs showed increased expression of IL-4 and IFN-gamma but not IL-2 and TNF-alpha. In F1 (LEW x DA) rats, IFA could not induce OIA but the pretreatment of IFA before CFA challenge could induce very mild AA with 80% incidence, LNCs showing an elevated expression of all the above cytokines. These findings suggest that increased Th1 cytokine expression is associated with disease development and that increased IL-4 expression or the balance of Th2 over Th1 cytokine expression plays an important regulatory role in disease development.

Animals↗
PubMed1995

Prevalence of Legionella pneumophila serogroup 1 antibodies in blood donors.

The prevalence of anti-Legionella pneumophila serogroup 1 antibodies in 777 blood donors of the Turin area was determined by the indirect immunofluorescence assay (IFA) and by the microagglutination test (MA). Low titers (IFA of 1/16 and MA of 1/8) were found in 0.3% of the subjects. A statistically significant difference was not observed by sex and by age for IFA titers, but was noted by sex for MA titers of > or = 1/4 (p < 0.05). The upper limit of normal titer was < 1/8 by IFA and < 1/4 by MA at 15% cutoff level and 1/8 by IFA and 1/4 by MA at 1% cutoff level. In conclusion, the prevalence of antibodies in the Turin area was very low; IFA titers of > or = 1/64 and MA titers of > 1/16 can be considered as presumptive of infection in a single serum specimen of a patient with pneumonia; no change in the epidemiology of the disease was observed in the recent years.

Adolescent↗
PubMed1980

A comparison of the complement fixation and immunofluorescent antibody tests in a survey of the prevalence of Babesia equi and Babesia caballi in horses in the Sultanate of Oman.

The incidence of antibodies to Babesia equi and B. caballi in horses in the Royal Stables of His Majesty the Sultan of Oman was assessed by complement fixation (CF) and immunofluorescent antibody (IFA) tests. Two series of samples taken with a 2-year interval, mainly from animals reared in Oman, indicated a stable but high prevalence of antibodies. On the 2 occasions 94.6 and 97.7% respectively were positive to B. equi by IFA and 76.8 and 75.0% were positive by CF. For B. caballi the corresponding percentage figures were lower--67.9 and 40.9 by IFA and 30.4 and 40.9 by CF. A group of animals tested within 4 months of importation gave 60.4% positive reactions by IFA and 62.5% by CF to B. equi; 6.3% positive to B. caballi by IFA and 8.3% by CF. These figures are consistent with the probable relative prevalence of the parasites. The discrepancy between the results obtained by the 2 serological tests was probably due to the greater sensitivity of the IFA test and the faster decay of the antibodies detectable by the CF test.

Animals↗
PubMed1988

Crossed immunoelectrophoretic studies of whole body extracts and venom from the imported fire ant Solenopsis invicta.

Although allergic reactions occur after imported fire ant (IFA) sting, currently, only IFA whole body extract (IFAWBE) is available for diagnosis and immunotherapy of IFA-sensitive individuals. We report our crossed immunoelectrophoretic studies comparing antigenicity and allergenicity of Solenopsis invicta IFAWBE and IFA venom (IFAV). Rabbits were hyperimmunized with IFAWBE prepared from S. invicta or with IFAV obtained from S. invicta by an electric shock method. Crossed immunoelectrophoresis with anti-IFAWBE detected at least 29 precipitin lines in IFAWBE and three lines in IFAV, but none in a synthetic venom, transpiperidine. Anti-IFAV detected six precipitin lines in IFAV and five lines in IFAWBE, but no lines were detected with transpiperidine. Crossed-line immunoelectrophoresis confirmed the IFAV origin of at least three of the peaks in IFAWBE. Crossed radioimmunoelectrophoresis with 11 IFAWBE RAST-positive sera elicited radiostaining with five antigens in IFAWBE that were probably IFAV associated. One of these allergens was recognized by all sera; the other allergens were recognized by 8, 7, 5, and 4, respectively, of the 11 sera. Four of the antigens present in IFAV preparations had allergenicity. These findings indicate that IFA allergens probably originate in IFAV, but that transpiperidine, a major constituent of IFAV, does not appear to be immunogenic. The results suggest that IFAV may be a more appropriate reagent than IFAWBE for laboratory testing and for clinical diagnosis and immunotherapy of IFA-sensitive individuals.

Animals↗