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PubMed2005

Rotational state-resolved reaction cross section in the reactions of state-selected CH with NO and with O2.

A pure and highly intense state-selected pulsed supersonic CH(X (2)Pi) radical beam source was developed by use of the C((1)D)+H(2) reaction with the combination of the state selection and purification by an electrostatic hexapole field. Under the beam-cell condition, the elementary reactions of CH+NO and CH+O(2) were studied by using this state-selected CH beam. NH(A (3)Pi) [and NCO(A (2)Sigma(+))] formations and OH(A (2)Sigma(+)) formation were directly identified in the elementary reaction of CH+NO and CH+O(2), respectively. For the CH+NO reaction, the relative branching ratio sigma(NCO*)sigma(NH) of NCO(A (2)Sigma(+)) formation to NH(A (3)Pi) formation was determined to be 0.35+/-0.15. The state-selected reaction cross sections were determined for each rotational state of CH. In the CH+NO reaction, a remarkable rotational state dependence of the reactive cross section was revealed, while the CH+O(2) reaction showed little rotational state dependence.

Journal Article↗
PubMed2004

Cross-reaction of SARS-CoV antigen with autoantibodies in autoimmune diseases.

To investigate the significance of the SARS-associated coronavirus (SARS-CoV) antibody, detected by ELISA and indirect immunofluorescence assays (IFA) for the SARS-CoV Vero E6 cell lysates, in non-SARS subjects, 114 serum samples from healthy controls and 104 serum specimens from autoimmune disease patients were collected. The results of ELISA showed that among 114 sera from healthy controls, 4 (3.5%) were positive of SARS-CoV-IgG antibody and 114 (100%) were all negative of SARS-CoV-IgM antibody; the specificity of SARS-CoV-IgG antibody for SARS patients was 96.5%, but the specificity of both SARS-CoV-IgG and -IgM antibodies for SARS patients was 100%. In 58 cases with SLE, positive rates of SARS-CoV-IgG and -IgM antibodies were 32.8% (19/58) and 8.6% (5/58), respectively, in which 11 cases (19%) were positive of both SARS-CoV-IgG and -IgM antibodies; in 10 cases with SS, positive rate of both SARS-CoV-IgG and -IgM antibodies was 10% (1/10); in 16 cases with MCTD, positive rate of SARS-CoV-IgG was 37.5% (6/16), positive rate of both SARS-CoV-IgG and -IgM antibodies was 6.3% (1/16); in 20 cases with RA, one case was positive (5%) of SARS-CoV-IgG. However, of all samples with positive SARS-CoV-IgG and -IgM antibodies for autoimmune diseases and healthy controls, SARS-CoV RNA and antibodies were all negative by RT-PCR and IFA. All sera for negative or positive ELISA results were also negative or positive results using ELISA with Vero E6 cells lysates. These studies showed that SARS-CoV Vero E6 cell lysates for the ELISA to detect SARS-CoV antibodies could lead to the false-positive reactions or cross-reactions of SARS-CoV antibodies in non-SARS diseases and healthy controls, and the false-positive reactions or cross-reactions were related to Vero E6 cell lysates and autoantibodies in non-SARS population.

Animals↗
PubMed1975

Titres and cross reactions of commercial antisera for the capsular typing of Klebsiella species.

Ninety commercially supplied sera for the capsular typing of Klebsiella species were tested in a full chequerboard against 72 type strains. Only four of 144 homologous reactions could not be detected. Of the 6336 possible heterologous reactions, 91 actual cross reactions were found. All positive reactions were titrated and working dilutions deduced. This provides essential information for the successful typing of unknown strains with these sera.

Antibodies, Bacterial↗
PubMed1989

[Detection of Chlamydia trachomatis antigen for diagnosis of respiratory infection I. Cross reaction with bacteriae consisting normal flora respiratory tract].

We examined the cross reaction of Chlamydia trachomatis (C. trachomatis) by antigen detection method using EIA against the aerobic bacteria which colonize in the respiratory tract of children. Chlamydiazyme showed a cross reaction among 5 out of 7 species of Gram negative bacteria (= 71.4%) and Neisseria and Branhamella catarrhalis showed a cross reaction even in low concentrations of 1 X 10(3-4) CFU/ml. There were no Gram positive bacteria which showed cross reaction. IDEIA Mark III did not react to Gram negative bacteria even in high concentrations of 1 X 10(7-10) CFU/ml. One strain of coagulase positive staphylococcus (CPS) showed positive at a concentration of 1 X 10(8): however, other Gram positive bacteria including two other strains of CPS exhibited no cross reaction. The detectable concentration of C. trachomatis (D/UW 3 strain) using IDEIA Mark III was 1 X 10(3) IFU/ml. Low cross reaction rate and sensitivity suggest IDEIA Mark III is preferable for diagnosis of respiratory infection of C. trachomatis though further clinical studies are necessary.

Antigens, Bacterial↗
PubMed1994

Genuine and apparent cross-reaction of polyclonal antibodies to proteins and peptides.

Antiserum to a native protein may cross-react with the corresponding denatured protein or with peptides. The cross-reaction is either a genuine property of the antibodies or caused by antibodies produced against some unfolded protein contaminating the native protein used for immunization. Appropriate conformation-sensitive immunoassays must be employed to distinguish a genuine from an apparent cross-reaction. In the present study, we have analyzed critically the cross-reaction of rabbit antisera against proteins and peptides. We have distinguished between genuine and apparent cross-reaction with the help of the protein A antibody-capture ELISA, a new conformation-sensitive ELISA format. Three systems were analyzed: cross-reaction of antisera to native yeast and horse cytochrome c with unfolded apo-cytochrome c; cross-reaction of antisera to a coiled-coil leucine-zipper peptide with a homologous random-coil peptide obtained by introducing two proline residues into the leucine-zipper sequence; cross-reaction of antisera to two peptides that correspond to the N-terminal and an internal sequence of ferredoxin: NADP+ reductase (FNR), with the native enzyme. The reaction of the anti-(cytochrome c) sera was clearly due to antibodies produced against unfolded protein, it was an apparent and not a genuine cross-reaction. Furthermore, the apparently cross-reactive antibodies to horse cytochrome c did not discriminate against sequence-related proteins from dog, beef, rabbit and pigeon. In contrast, antibodies to the leucine-zipper peptide did cross-react in a genuine way with the homologous random-coil peptide, that is, the cross-reactive antibodies do not seem to have been produced against the unfolded form of the leucine-zipper peptide. Of the two anti-peptide sera the one against the unstructured and highly accessible N-terminal segment reacted strongly with the native protein. The second serum against a solvent-accessible turn-like sequence of FNR showed apparent cross-reactivity: antibodies recognizing the native protein were directed against a minor conformational isoform of the free peptide and did not react with the principal form(s) of the free peptide. The generation of cross-reactive antibodies depends on the conformational stability and integrity of the immunogen and on the molecular form of its application, i.e., free, polymerized or carrier-bound. The results clarify the different nature of cross-reactivity of antisera to proteins and peptides. This knowledge is crucial if antisera are to be used as conformation-specific probes.

Amino Acid Sequence↗
PubMed2004

Drug skin tests in cutaneous adverse drug reactions to pristinamycin: 29 cases with a study of cross-reactions between synergistins.

The present study was made to determine the value of drug skin tests in patients with cutaneous adverse drug reactions (CADRs) due to a synergistin (pristinamycin) and to determine the frequency of cross-reactions between synergistins. 29 patients were referred during the onset of the CADR due to pristinamycin: 18 with maculopapular rash, 9 erythrodermas, 1 angioedema and 1 Stevens-Johnson syndrome. They all had patch tests with pristinamycin and, in most cases, with other synergistins [virginiamycin and dalfopristin-quinupristin (DQ)], prick tests (10 cases) and intradermal tests (IDT) (5 cases). Skin tests with synergistins were positive in 27 cases, patch tests with pristinamycin in 20/29 cases (69%), prick tests with pristinamycin in 3/9 cases on immediate (1 case) or on delayed (2 cases) readings, and IDT with DQ in 4/5 cases. Cross-reactions between synergistins occurred in 9/22 with virginiamycin and in 7/8 cases with DQ. Skin tests with synergistins are useful in investigating CADR due to pristinamycin. Synergistins are composed of 2 chains (1 depsipeptide and 1 macrocyclic lactone) with many structural analogies between all synergistins. According to the chemical structures and our results, it seems advisable to avoid all synergistins in patients with CADR due to pristinamycin.

Adolescent↗
PubMedDate not supplied

Chemistry and immunochemistry of the pneumococcal polysaccharide vaccine with special reference to cross-reactions and immunologic factors.

This review summarizes data on the cross-reactions observed among the subtypes of Streptococcus pneumoniae. Types 6A and 6B; 19F, 19A, 19B, and 19C; 18F, 18A, 18B, and 18C; and 23F, 23A, and 23B were examined with use of radioimmunoassay for measurement of inhibition of binding; the cross-reactions are discussed in terms of the known chemical structures of the antigens involved. Cross-reactions observed with use of rabbit antisera proved to be an unreliable guide to the responses observed thus far in humans. Cross-reactions of pneumococcal capsular polysaccharide antigens with other bacterial antigens are mentioned. These cross-reactions are analyzed with the idea of maximizing the effectiveness of the pneumococcal vaccine. Immunologic factors that may determine the quality and/or quantity of the immune response to immunization are discussed. These factors include antigenic competition and influence of preimmunization levels of antibody. Antigenic competition, although not a major concern with the present vaccine, may determine the upper limit of the number of capsular types that can be present in a single vaccine. The preimmunization level of antibody may determine the specificity of the antibody produced after vaccination.

Animals↗
PubMed1984

[Cross reactions of HLA A and B antigens in 63 patients with rheumatoid arthritis].

Cross reactions are very frequently observed when HLA A and B antigens are determined by a routine lymphocytotoxicity method. Such cross reactions are probably due to biochemical structural similarities shared by several HLA antigens. In this work, we studied the cross reactions which occurred during HLA A and B typing of 63 patients with classical or definite rheumatoid arthritis (RA) according to the ARA criteria. No association was found between RA and any single HLA A or B antigen. In contrast, when cross reactions were taken into account, the B8 B14 cross reactant group frequency was increased in RA patients (34,9 p. cent) as compared to controls (20 p. cent, p less than 0,004) and was even more clearly elevated in the 42 seropositive RA patients (40,5 p. cent, p less than 0,002). No relation was found between HLA phenotype and Sjögren's syndrome even when cross reactions were considered. The B8 DR3 haplotype has been shown to be associated with drug intolerance . The B8 B14 cross reactant group was present in 22 out of our 63 RA patients, 16 of whom were B8+. Among the latter, 6 patients exhibited poor tolerance to gold salts and 6 other patients did not respond to gold therapy, suggesting that the B8 antigen could predict not only a poor tolerance but also a poor response to disease modifying drugs.

Arthritis, Rheumatoid↗
PubMed2006

Hypersensitivity reaction to mizolastine: study of cross reactions.

A 26-year-old male suffering from acute rhinitis took the first dose of Zolistan (mizolastine, 10 mg), orally, and 15 minutes later he developed intense generalized pruritus, cutaneous rash, oropharyngeal pruritus, edema on his face, difficulty in swallowing, and mild dyspnea. He was treated with methylprednisolone and epinephrine and improved within 30 minutes. The patient had not taken mizolastine before and he has avoided it since the reaction. Cutaneous tests with Zolistan and its excipients proved negative. Simple-blind oral challenge tests with the excipients and then with Zolistan were positive only with Zolistan. In order to confirm the absence of cross-reactivity between mizolastine and other benzimidazoles, we tested omeprazole, domperidone and mebendazole, all of which yielded negative results. To our knowledge, this is the second case of immediate hypersensitivity to mizolastine documented to date. In our case, the clinical history, physical examination and provocation tests allow us to establish the diagnosis of hypersensitivity to mizolastine and exclude the cross reactivity with other benzimidazole derivatives.

Acute Disease↗
PubMed1986

Cross-reactions in cell mediated immunity induced by atypical mycobacteria.

Cross-reactivity in the delayed hypersensitivity response to mycobacteria of different Runyon groups was tested in Swiss white mice immunised with live mycobacteria. All the strains tested gave cross-reactions and, generally, slow growers gave stronger cross-reactions with other slow growers than with rapid growers and vice versa. Sonicates of cross-reacting mycobacteria were also tested for their ability to generate activated macrophages in mice immunised with Mycobacterium avium. All the mycobacterial sonicates generated activated macrophages but a sonicate of Salmonella typhi did not. The sonicate of M. tuberculosis H37Rv also generated activated macrophages, which indicates that there might be protective cross-reactions between M. tuberculosis and atypical mycobacteria.

Animals↗