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PubMed1979

Dissociation of erythema and basophil accumulation in Jones-Mote type hypersensitivity in the guinea-pig.

Relationship between delayed-in-onset erythema and infiltrating leucocytes in the skin reaction site of Jones-Mote type hypersensitivity was observed in guinea-pigs. Guinea-pigs were immunized with formalin-fixed (F-SRBC) or native form (N-SRBC) of sheep red blood cells in incomplete Freund's adjuvant (IFA). Elicitation was carried out with intradermal injection of F-SRBC or N-SRBC in saline 1 or 3 weeks after immunization. One week after immunization with F-SRBC or N-SRBC in IFA, erythema accompanied by basophil infiltration was detected, but antibody production was negative. Erythema reached a peak at 24 h, but basophil infiltration reached a peak at 48 h or later. In the skin reaction site elicited with N-SRBC, high levels of basophil infiltration were detected persistently even after erythema had disappeared. Three weeks after immunization, low titres of PCA (passive cutaneous anaphylaxis) were detected in guinea-pigs immunized with F-SRBC in IFA. At that time erythematous skin reaction was detected, but the level of basophil infiltration was lower than that of 1 week after immunization. In guinea-pigs immunized with N-SRBC in IFA, skin reaction of the Arthus type accompanied by haemorrhage was observed at the site elicited with N-SRBC.

Animals↗
PubMed1983

Detection of antibody to BK virus by enzyme-linked immunosorbent assay compared to hemagglutination inhibition and immunofluorescent antibody staining.

The enzyme-linked immunosorbent assay (ELISA), hemagglutination inhibition test (HAI), and immunofluorescent antibody staining (IFAS) test were compared for their ability to detect IgG antibody to BK virus (BKV). Antibody titers to BKV antigen were determined for 35 sera by each of the three assays. The ELISA tests agreed with either HAI or IFAS with regard to BKV antibody status in all but one serum. On this basis the HAI accounted for four discordant determinations while IFAS was not in agreement in three cases. Geometric mean titers of ELISA and HAI were similar but greater than that of IFAS. The ELISA is particularly well suited for use in large-scale seroepidemiological studies since automated spectrophometric equipment can provide rapid, objective, numerical data.

BK Virus↗
PubMed1983

Diagnosis of giardiasis by two methods. Immunofluorescence and enzyme-linked immunosorbent assay.

Antibody response in giardiasis was measured by indirect fluorescent antibody (IFA) and enzyme-linked immunosorbent assays (ELISA) on serum samples of 125 patients. Twenty-nine of these patients had symptomatic giardiasis; 30 were asymptomatic (carriers); 40 had other parasitic infections; 16 had inflammatory bowel diseases; ten were normal subjects. It was found that those patients with symptomatic giardiasis had higher IFA titers compared with all patients who did not have giardiasis and patients who had asymptomatic giardiasis. Serum samples with titers of 1:64 or greater in Giardia IFA were absorbed with Giardia and other parasite antigens. Only absorption with Giardia caused the titers to fall significantly. The ELISA technique was less specific than the IFA technique. Giardiasis elicits a specific host antibody response that may be used as an adjunct in its diagnosis.

Antibodies↗
PubMed1984

[A new weaning procedure (inspiratory flow assistance)].

Inspiratory Flow Assistance (IFA) refers to new breathing mode, able to diminish the work of breathing of a patient during spontaneous breathing with a respirator. By combination of IFA with CPAP or IMV it is especially useful during weaning from the respirator. The part of work of breathing done by the respirator. The part of work of breathing done by the respirator is only indirectly determinable. The measurements done on 10 long term ventilated patients during the weaning period show that only an IFA up to an airway pressure of 10 cm H2O above CPAP guarantees mainly spontaneous breathing, while an IFA up to higher airway pressures is more and more similar to an assisted ventilation.

Adult↗
PubMedDate not supplied

Immunodiagnostic tests for Lyme disease.

Standardized serologic tests for Lyme disease are needed, as isolation or in situ demonstration of the spirochete has proved difficult. At the Centers for Disease Control (CDC), an indirect immunofluorescence assay (IFA) was modified from a previously described IFA, and an enzyme-linked immunosorbent assay (ELISA) was developed with soluble spirochetal antigens. Both tests were evaluated with sera from Lyme disease patients, normal controls, and patients with other diseases. They were highly specific for Lyme disease when sera from patients with syphilis were excluded. Sensitivity varied with disease stage: for patients with erythema chronicum migrans alone, the IFA was 53 percent sensitive and the ELISA was 67 percent sensitive. In contrast, all patients with complicated Lyme disease had at least one serum specimen positive in both tests. Twenty-six percent of the sera from 289 patients with suspected Lyme disease that were submitted to CDC in 1983 had IFA titers greater than or equal to 256 and thus were considered positive. Both tests should be useful diagnostic and epidemiologic aids.

Antibodies, Bacterial↗
PubMed1980

Control of autologous immune complex nephritis. I. Suppression of the disease in the presence of T cell sensitization.

Pretreatment of Lewis and Sprague-Dawley rats with the nephritogenic antigen, Fx1A, in incomplete Freund's adjuvant (IFA) reduced the incidence of autologous immune complex nephritis in rats subsequently challenged with Fx1A in complete Freund's adjuvant (CFA). The suppression was evidenced by a decrease in antibody production, in glomerular deposition of immunoglobulins, and in the incidence of proteinuria, and it was antigen specific. In vitro blastogenesis to Fx1A of lymphocytes from Fx1A-IFA-pretreated animals was normal. Rats pretreated with Fx1A-IFA initially developed a normal antibody response after challenge with Fx1A-CFA, but the response was not sustained. These results indicate that the Fx1A-IFA-induced suppressor mechanism does not inhibit sensitization, but rather modifies specific antibody production.

Animals↗
PubMed1984

[Clinico-functional characteristics of idiopathic fibrosing alveolitis (Hamman-Rich syndrome)].

The clinical and functional features of idiopathic fibrosing alveolitis (IFA) were analyzed in 31 patients. In 24 patients, the diagnosis was confirmed by histological study of the pulmonary tissue obtained by means of open lung biopsy or at autopsy. Progressive dyspnea was the earliest clinical symptom of IFA. High temperature, weight loss, cyanosis and other symptoms were characteristic of an acute disease course. Crepitation was the most characteristic symptom as far as the objective data are concerned. Detailed examination of respiratory function with the use of spirography, general plethysmography, forced oscillation technique, study of the diffuse capacity of the lungs and blood gases, and other methods showed that the most characteristic functional features of pulmonary respiration in IFA involved a decrease in the static pulmonary volumes, an increase in elastic pulmonary resistance, normal patency of the large and medium bronchi, and a diminution of the diffuse capacity of the lungs during respiratory arrest, as well as that of the diffuse capacity of the alveolocapillary membrane. The data obtained indicate that today one can discuss only the most characteristic rather than the pathognomonic clinical and functional symptoms of IFA.

Adolescent↗
PubMed1984

Susceptibility of Giardia lamblia trophozoites to the lethal effect of human serum.

To define the potential role of complement and antibody in host defense against Giardia lamblia, the effect of human serum on axenically cultured G. lamblia trophozoites was studied. Sera from patients without a history of giardiasis and with no detectable antibody by an indirect immunofluorescence antibody (IFA) assay (IFA titers less than 1:2) killed from 8 to 76% of trophozoites (n = 23 sera). Whereas less than 10% of parasites incubated in phosphate-buffered saline alone were killed, 16 sera killed from 10 to 25% and six sera killed from 25 to 75%. One serum with an anti-G lamblia antibody titer of 1:128 killed greater than 98% of the parasites. The complement dependency of killing was demonstrated by abrogation of the lethal effect when serum was chelated with EDTA (7 mM) or was heat-inactivated (56 degrees C, 30 min), and, in an immunofluorescence assay, by detection of C3 on parasites killed by normal serum. When the classical complement pathway was selectively blocked by using serum chelated with Mg+2 (2 mM)-EGTA (8 mM), or serum congenitally deficient for the second component of complement, there was no killing; thus, killing was dependent on the presence of an intact classical pathway. In each of three sera from donors with negative IFA titers, an absorbable factor specific for G. lamblia, possibly antibody not detected by IFA, was required for classical pathway activation. To determine if alteration of the surface of G. lamblia would render it an activator of the alternative pathway of complement, trophozoites were studied after cell death or after treatment with neuraminidase or trypsin. In MgEGTA-chelated serum, dead trophozoites activated the alternative pathway as determined by consumption of Factor B and deposition of C3 on their surface. In contrast, untreated or enzyme-treated living parasites did not activate the alternative pathway.

Adult↗
PubMed1984

Immunisation of goats against contagious caprine pleuropneumonia using sonicated antigens of F-38 strain of mycoplasma.

Three groups of 15 goats each were immunised against contagious caprine pleuropneumonia (CCPP) using sonicated antigens of the F-38 strain of mycoplasma incorporated in incomplete Freund's adjuvant (IFA), emulsified in aluminium hydroxide and phosphate buffered saline respectively. Three months after immunisation, five goats from each group were challenged by the in-contact method. The goats immunised with the antigen incorporated in IFA were all solidly immune to the challenge whereas only two of five of the goats in the other two groups were protected. When the remaining 10 animals from each group were challenged six months after immunisation, those immunised with the antigen in IFA were still solidly immune while only two goats from each of the other two groups were protected. These results show that effective immunity against CCPP caused by the F-38 strain can be induced by vaccination with sonicated F-38 antigens emulsified in IFA.

Animals↗
PubMed1981

Evaluation of in-vitro-cultured Plasmodium falciparum as antigen for malaria serology.

A handicap in developing seroepidemiology for malaria in India is the lack of homologous antigens. Aotus monkeys, in which human plasmodia can be propagated, are not easily available in India. Other alternatives include the use of infected human blood or the in-vitro culture of Plasmodium falciparum, using the candle-jar technique of Trager & Jensen (1976). With certain modifications, the in-vitro culture technique has been established at the St John's Medical College (SJMC) to obtain a regular and high yield of P. falciparum to use as a source of antigen in serological tests. Antigens prepared from in-vitro-cultivated P. falciparum have been tested against positive and negative reference sera by the indirect haemagglutination (IHA) and immunofluorescent antibody (IFA) tests. These reference sera were also tested with the IHA test by using P. falciparum-sensitized human "O' erythrocytes received from the Center for Disease Control (CDC), Atlanta. IHA test results with both types of antigens were comparable (Spearman rank correlation coefficient, rS=0.8440, P less than 0.01). The antigen from in-vitro culture was also found suitable for use in the IFA test. The IFA titres obtained were comparable to those found at the CDC (Spearman rank correlation coefficient, rS=0.7940, P less than 0.01). These results indicate that P. falciparum parasites prepared from in-vitro continuous culture can be used as a source of antigen for use in the IHA and IFA tests for malaria.

Antigens↗
PubMed1995

Serologic responses to Bartonella and Afipia antigens in patients with cat scratch disease.

OBJECTIVE: To assess the serologic response to Afipia and Bartonella, previously named Rochalimaea, in patients with cat scratch disease (CSD) and a healthy control group. DESIGN: Prospective, controlled trial. SETTING: Referral clinic and hospitalized patients in a university medical center. PARTICIPANTS: Eighty patients with CSD and 57 healthy control subjects of similar age. MAIN OUTCOME MEASURES: The immune responses to Afipia felis and Bartonella henselae were evaluated by a newly developed enzyme-linked immunosorbent assay (ELISA) in patients with CSD and healthy control subjects. Responses to B henselae were also measured by indirect fluorescent antibody (IFA) tests. Antibody levels to Bartonella quintana were measured by ELISA and IFA in a limited number of patients and control subjects. RESULTS: Of the 80 patients with clinical CSD, 56 had positive results of CSD skin tests. ELISA antibody levels to A felis did not differ between patients and control subjects, but immunoglobulin M (IgM) and IgG ELISA antibodies to B henselae and B quintana were significantly higher in patients than in control subjects. IFA responses to B henselae and B quintana were also significantly higher in patients than in control subjects. CONCLUSION: Patients with CSD had significant serologic responses to B henselae and B quintana but not to A felis, suggesting that the causative agent of CSD is antigenically related to the Bartonella genus and not to Afipia. The Bartonella IgM ELISA and IFA assay were both sensitive and specific and may be used to establish the diagnosis of CSD.

Adolescent↗
PubMed1993

[Solid-phase immunoenzyme analysis in the differential diagnosis of pulmonary tuberculosis and other infectious diseases with respiratory organ involvement].

The authors studied the information efficiency of stable-phased immunofermental analysis (IFA) in differential diagnosis of infectious diseases of respiratory system and pulmonary tuberculosis. IFA method was used on 60 infectious patients with non-tuberculous pathology, 64 patients with pulmonary tuberculosis and 200 donors. It was found out that the minimal diagnostical IFA titer in pulmonary tuberculosis was 1:320 (antibody revealing frequency--up to 89.2%; specificity--95%). IFA method with phosphatide antigen has a great practical significance in differential diagnosis of influenza, acute respiratory viral infections and pneumonias with pulmonary tuberculosis.

Antibodies, Bacterial↗
PubMedDate not supplied

[Heterogeneity of the gastric intrinsic factor autoantibodies of types I and II].

Variable results were obtained in a study of the immunologic reaction of the intrinsic factor (IF)-autoantibodies (IFA) to the human, hog and rat IF antigens. Effectively, some IFA I were unable to block completely all the binding sites of B12 to IF. As to the IFA II, some did not show a total effectiveness in neutralizing the activity of IF in certain human gastric juices. In another study conducted on patients with pernicious anemia, the antibodies obtained from their sera reacted differently to the hog and rat IF; some reacted identically to homologous and heterologous IF others were less and even not effective on the heterologous IF. From these results it was suggested that, within the two main branches of IFA, there would be subdivided groups with selective effect on different antigenic sites of IF.

Animals↗
PubMed1996

Sensitization of human breast cancer cells to cyclophosphamide and ifosfamide by transfer of a liver cytochrome P450 gene.

The cancer chemotherapeutic agent cyclophosphamide (CPA) and its isomer ifosfamide (IFA) are alkylating agent prodrugs that require metabolism by liver cytochrome P450 (P450) enzymes for antitumor activity. The therapeutic effectiveness of these oxazaphosphorines is limited by the hematopoietic, renal, and cardiac toxicity that accompanies the systemic distribution of liver-derived activated drug metabolites. Transfer of a liver cytochrome P450 gene, CYP2B1, into human breast MCF-7 cancer cells is presently shown to greatly sensitize these cells to oxazaphosphorine toxicity as a consequence of the acquired capacity for intratumoral CPA and IFA activation. Thus, CPA and IFA were highly cytotoxic to MCF-7 cells following stable transfection of CYP2B1 but exhibited no toxicity to parental tumor cells or to a beta-galactosidase-expressing MCF-7 transfectant. This cytotoxicity could be appreciably blocked by the CYP2B1 inhibitor metyrapone. Cell cycle analysis revealed that CPA arrested the CYP2B1-expressing cells, but not CYP2B1-negative cells, at G(2)-M phase. A strong bystander cytotoxicity effect that does not require direct cell-cell contact was mediated by CYP2B1-expressing MCF-7 cells on non-CYP2B1 cells. Intratumoral CYP2B1 expression conferred a distinct therapeutic advantage when treating MCF-7 tumors grown in nude mice with CPA, as revealed by a 15-20-fold greater in vivo cytotoxicity, determined by tumor excision/colony formation assay, and by the substantially enhanced antitumor activity, monitored by tumor growth delay, for CYP2B1-e xpressing MCF-7 tumors as compared to CYP2B1-negative control tumors. These enhanced therapeutic effects were obtained without any apparent increase in host toxicity. To evaluate the extent to which a CPA/P450 gene therapy strategy may be generally applicable to other tumor cell types, a replication-defective recombinant adenovirus carrying the CYP2B1 gene driven by the cytomegalovirus (CMV) promotor ad.CMV-2B1 was constructed and used to infect a panel of human tumor cell lines. Ad.CMV-2B1 infection rendered each of the cell lines highly sensitive to CPA and IFA cytotoxicity, with substantial chemosensitization seen at multiplicities of infection as low as 10. The CPA/P450 prodrug activation system may thus serve as a useful paradigm for further development of novel cancer gene therapy strategies that utilize drug susceptibility genes to significantly potentiate the antitumor activity of conventional cancer chemotherapeutic agents.

Adenoviridae↗
PubMed1996

Serologic responses of cattle and other animals infected with Neospora caninum.

OBJECTIVE: To examine cross-reactivity among Neospora caninum and closely-related apicomplexans. DESIGN: Sera from animals were examined for antibody production to N caninum and cross-reactivity to Toxoplasma gondii. ANIMALS: Cattle were experimentally infected with 3 tissue cyst-forming protozoan parasites N caninum, T gondii, and Sarcocystis sp, and calves were monospecifically inoculated with the intestinal coccidia, Eimeria bovis and Cryptosporidium parvum. Similar studies were done in laboratory rabbits inoculated with N caninum, T gondii, Hammondia hammondi, and Sarcocystis sp. Additionally, sera were obtained from ewes, lambs, goats, sows, cats, rats, and mice inoculated with N caninum tachyzoites. PROCEDURE: The indirect fluorescent antibody (IFA) and ELISA antibody tests (cattle only) were used to examine reactivity to N caninum; the modified direct agglutination, Sabin-Feldman dye, and IFA tests were used to evaluate reactivity to T gondii. RESULTS: Serologic cross-reactivity among N caninum, T gondii, and Sarcocystis sp was none or minimal by the IFA test. There was some reactivity to N caninum by the use of ELISA in cattle inoculated with Sarcocystis sp. CONCLUSIONS: The IFA test for N caninum was specific for the diagnosis of neosporosis in animals.

Animals↗
PubMed1996

[Comparative study on serological diagnosis of entamoebiasis histolytica].

The practicability of four diagnostic methods for entamoebiasis histolytica including micro-gel diffusion precipitin test (MGDP), indirect immunofluorescent antibody test (IFA), indirect hemagglutination test (IHA) and enzyme-linked immunosorbent assay (ELISA) was evaluated. The serological test methods were compared by using sera obtained from 30 entamoebiasis histolytica patients and 130 normal health individuals. The highest sensitivity was obtained with the method of ELISA, followed by IFA and IHA : the lowest was obtained with MGDP. On the contrary, the high specificity was obtained with IHA, IFA, MGDP : the lowest was obtained with ELISA. Intensity of the antibody titers in IHA was correlated well with that of IFA. In addition, we studied antibodies nonspecifically reactive to Entamoeba histolytica in sera from E. histolytica-negative individuals with high CRP patients with regard to the sensitivity and specificity. Among 101 sera examined, six showed false positive results of which five were the sera with extremely high CRP.

Animals↗
PubMed1998

Retroviral transfer of human cytochrome P450 genes for oxazaphosphorine-based cancer gene therapy.

Cyclophosphamide (CPA) and ifosfamide (IFA) are widely used anticancer prodrugs that are bioactivated in the liver by specific cytochrome P450 enzymes (CYPs). The therapeutic activity of these antitumor agents can be compromised by a low therapeutic index that is, in part, due to the systemic distribution of activated drug metabolites. Here, recombinant retroviruses were used to deliver six different CPA- or IFA-metabolizing human CYP genes to 9L gliosarcoma cells: 2B6, 2C8, 2C9, 2C18 (Met385 and Thr385 alleles), 2C19, and 3A4. Intratumoral cytochrome P450 expression conferred substantial sensitivity to CPA cytotoxicity, with the most dramatic effects seen with CYP2B6. Strong CPA chemosensitivity was also seen following transduction of CYP2C18-Met, despite a very low level of CYP protein expression (>60-fold lower than that of 2B6). In contrast to CPA, the cytotoxicity of IFA was greatest toward tumor cells transduced with CYP3A4, followed by CYPs 2B6 and 2C18-Met. A substantial further increase in chemosensitivity was achieved upon transduction of 2B6 or 2C18-Met-expressing tumor cells with P450 reductase, which provided for more efficient intratumoral prodrug activation and cytotoxicity at lower drug concentrations. With 2B6- plus P450 reductase-transduced tumor cells, CPA but not IFA conferred a strong cell contact-independent bystander cytotoxic effect on non-P450-expressing 9L cells. CPA treatment of tumors that were transduced with 2B6 or 2C18-Met together with P450 reductase and were grown s.c. in immunodeficient mice resulted in a large enhancement of the liver P450-dependent antitumor effect seen with control 9L tumors, with no apparent increase in host toxicity (growth delay of >25-50 days in P450-expressing tumors versus approximately 5-6 days without P450). CYP2B6 plus P450 reductase and CYP2C18-Met plus P450 reductase thus appear to be excellent gene combinations for use with CPA in P450/prodrug activation-based cancer gene therapy.

Animals↗
PubMed1998

Detection of Cryptosporidium oocysts and Giardia cysts in the tissues of eastern oysters (Crassostrea virginica) carrying principal oyster infectious diseases.

The potential cross-reactivity of the combined Cryptosporidium/Giardia direct immunofluorescence antibodies (IFA) of MERIFLUOR and HYDROFLUOR-COMBO tests was examined against tissues containing known developmental stages of 12 pathogens causing the principal infectious diseases in oysters. Spores of Haplosporidium nelsoni and Haplosporidium costale produced positive acid-fast stain (AFS) reactions similar in intensity to Cryptosporidium parvum oocysts. Hexamia nelsoni trophozoites produced positive IFA reactions in both IFA tests; however, the intensity of fluorescence was considerably lower and the fluorescein-staining pattern different than those of Giardia cysts. The applicability of AFS for screening oysters for Cryptosporidium oocysts is low, and positive identification of Cryptosporidium oocysts cannot be accomplished based on the AFS. Presumptive IFA identification of the Cryptosporidium oocysts or Giardia cysts in the oyster tissue should fulfill 3 criteria, i.e., bright-green fluorescence of the same intensity as C. parvum oocysts and Giardia cysts in the positive control, correct size and shape of the fluorescein-stained objects, and oocyst or cyst shell clearly visible.

Animals↗