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A Toivanen

Publications and source records attributed to A Toivanen.

At least 127 records · Page 7Linked to original sources
PubMed1987

Monoclonal antibodies reacting selectively with core and O-polysaccharide of Yersinia enterocolitica O:3 lipopolysaccharide.

In order to obtain specific tools for studying the alterations of the immunochemical structure of Yersinia enterocolitica lipopolysaccharide in various conditions, we have produced monoclonal antibodies reacting with core and O-polysaccharide chains of Yersinia enterocolitica O:3 LPS. Immunizations were made with whole bacterial cells and outer membrane preparation, respectively. Monoclonal antibody 2B5 reacted in enzyme immunoassay with purified core-lipid A complex, and its binding was not inhibited by Polymyxin B, suggesting that the target determinant is in the outer core. 2B5 recognized 100% of all tested Y. enterocolitica O:3 strains (n = 152) and reacted to some extent also with many other gram-negative bacteria. In immunoblotting with 2B5, a band corresponding to core-lipid A complex was visualized both with Y. enterocolitica, Brucella abortus and Haemophilus influenzae. In immunofluorescence assay, the only positive reaction was seen with Y. enterocolitica. Monoclonal antibody A6 reacted in enzyme immunoassay with purified O-polysaccharide chains, recognized 100% of tested Y. enterocolitica O:3 strains, and showed no cross-reactions with other bacteria. A typical ladder pattern was not seen in the immunoblotting analysis with A6. This suggests that the O-chain of Y. enterocolitica O:3 may be different from those in other gram-negative bacteria. These two antibodies will make it possible to study the structural variations of Yersinia enterocolitica LPS more precisely than described before, because of their fine specificity against important immunogenic components of LPS. They will also be useful in serology measuring the immune response against the target determinants of these antibodies.

Antibodies, Monoclonal↗
PubMed1987

Immunoblotting analysis of human IgM, IgG and IgA response to chromosomally coded antigens of Yersinia enterocolitica 0:3.

Human antibody response after Yersinia enterocolitica infection was studied by immunoblotting sequentially collected sera against a whole-cell homogenate of Y. enterocolitica serotype 0:3, grown under conditions restrictive for the plasmid. The antibodies observed were directed against a multitude of chromosomally coded antigens, and a considerable individual heterogeneity was found in the reactions of individual sera. The early (0-2 months) and late (greater than or equal to 11 months) responses were directed against the same antigenic determinants. Antibodies against different bacterial epitopes decreased evenly with time, indicating that several, if not all, antigenic epitopes of the bacteria are responsible for the prolonged antibody production. IgM responses by most patients declined within a few months but were surprisingly strong in some even one year after onset of the infection. IgG antibodies showed a strong reaction against a region corresponding to lipid A and core of the bacterial LPS, whereas IgM and IgA recognized this region less often. No other significant differences between IgM, IgG and IgA responses were observed. Immunoblotting of sera from patients with post-infection complications (arthritis, iritis, erythema nodosum) did not reveal any additional or specifically involved antigens. Altogether, these findings suggest that Yersiniae causing the original infection may hide in some of the patients for prolonged periods.

Antibodies, Bacterial↗
PubMed1987

Association of persisting IgA response with yersinia triggered reactive arthritis: a study on 104 patients.

Twelve to 16 months after Yersinia enterocolitica O:3 enteritis 33 (85%) of the 39 patients who developed reactive arthritis as a postinfection complication had IgA class and 28 (72%) had IgG class anti-yersinia antibodies. In contrast, 7 (32%) of the 22 patients who did not develop arthritis were positive in the IgA test and 11 (50%) positive in the IgG test. The results were about the same when the material was divided into cases with diagnosis of yersiniosis verified by stool culture or by serology. These results confirm the value of enzyme linked immunosorbent assay (ELISA) in the diagnosis of yersiniosis, particularly in cases with postinfection complications when the stool isolations remain negative.

Adult↗
PubMed1987

Circulating yersinia specific immune complexes after acute yersiniosis: a follow up study of patients with and without reactive arthritis.

The occurrence of immune complexes (ICs) containing Yersinia enterocolitica antigen and immunoglobulin was studied in 216 serum samples from 51 patients with recent yersiniosis at an early stage of the disease and during a follow up of two to 12 months. Twenty eight of the patients developed reactive arthritis, 23 recovered from the infection without any complications. An enzyme linked immunosorbent assay (ELISA) recently developed for detection of ICs containing yersinia antigen(s) and IgM, IgG, or IgA was applied. During the first two months after onset of the infection yersinia specific IgM complexes were demonstrated in higher concentrations in patients with arthritis than in those not developing this postinfection complication (p less than 0.02). The difference in the occurrence of IgM complexes between the two groups decreased with time. Yersinia specific IgA complexes were demonstrable in four patients with arthritis and in none of the non-arthritic patients. Yersinia specific IgG complexes were occasionally present in both patient groups. Altogether, more than eight months after onset of the infection yersinia specific ICs were detected in six arthritic and two non-arthritic patients, suggesting that in certain individuals yersiniae may hide after the initial infection for prolonged periods.

Acute Disease↗
PubMed1987

Yersinia specific immune complexes in the synovial fluid of patients with yersinia triggered reactive arthritis.

Yersinia specific immune complexes were demonstrated in the synovial fluid of three patients out of 12 with yersinia triggered reactive arthritis. They were not detectable in the synovial fluid of any of the 16 control patients, including nine with reactive arthritis triggered by factors other than yersiniae. Platelet reactive IgG was detectable in the synovial fluid of eight out of the 12 patients with yersinia triggered reactive arthritis and in three of the 16 control patients, all three having rheumatoid arthritis. An enzyme linked immunosorbent assay and a platelet 125I labelled staphylococcal protein A test were used to measure yersinia specific immune complexes and platelet reactive IgG respectively. The results obtained show for the first time the occurrence of bacterial antigens, derived from the causative strain, in the synovial fluid in yersinia triggered reactive arthritis.

Adolescent↗
PubMed1987

Yersiniosis as a gastrointestinal disease.

Anti-yersinia antibodies were assessed in sera from 630 patients admitted to a department of surgery for acute abdominal disease, using an enzyme-linked immunosorbent assay (ELISA). In 21 patients a high concentration of yersinia antibodies confirmed recent yersinia infection. Eight patients had an appendicectomy performed; in all patients with antibodies against Y. enterocolitica 9 or Y. pseudotuberculosis IA a true appendicitis was found at operation. Two patients with Y. enterocolitica 3 antibodies had acute terminal ileitis and mesenterial lymphadenitis. In 4 patients a diagnosis of acute pancreatitis was established; 2 of these had cholecystitis. Two further patients had cholecystitis without pancreatic affection. Two patients had colonic diverticulitis, 1 with perforation. The results demonstrate that yersinia infection may commonly give rise to a variety of acute abdominal inflammations, and stress the importance of serological and bacteriological diagnostic procedures.

Acute Disease↗
PubMed1987

Major histocompatibility complex and cell cooperation.

We have studied the role of major histocompatibility antigens on cell cooperation in the immune response of the chicken. In the 1970's, shortly after the initial discoveries in the mouse, we demonstrated that the T cell-B cell interaction is major histocompatibility complex (MHC)-dependent in the chicken and requires at least one haplotype identity between the collaborating cells. Later, by using MHC-congenic and MHC-recombinant lines, we demonstrated that the T-B cell interaction in antibody response is MHC-restricted, and more precisely, Class II MHC-antigen-restricted. Furthermore, we proved that T-B cell cooperation in splenic germinal center formation is likewise class II MHC antigen-restricted. Recently, we have focused our studies on MHC antigen identity requirements during antigen presentation by macrophages to T cells. In these studies, Class II antigens were found to serve as restriction elements in antigen recognition by T cells. Cytotoxic T cells of the chicken have been shown to be MHC-restricted in their function. Whether Class I or Class II MHC antigens serve as restriction molecules has not yet been determined. In conclusion, it is obvious that the function of the avian immune response is controlled by the polymorphic MHC gene products in the same way as that in the mammalian species.

Animals↗
PubMed1987

Failure to prevent cytomegalovirus infection by cytomegalovirus hyperimmune plasma: a randomized trial by the Nordic Bone Marrow Transplantation Group.

Bone marrow transplantation recipients who were cytomegalovirus (CMV) seropositive and/or had a CMV seropositive donor were randomized for treatment with CMV hyperimmune plasma (n = 27) or no treatment at all (n = 27). The CMV hyperimmune plasma had neutralization titers greater than 250 and enzyme-linked immunosorbent assay titers greater than 18,000. Plasma (200 mg/kg body weight) was given on four occasions (during 2 days) from day 3 to day 76 after transplantation. Patient characteristics were similar in the two groups. After transplantation, the median CMV titers increased with greater than 100% in the group receiving the CMV plasma and decreased to less than 50% in the controls (p less than 0.01). Asymptomatic CMV infections occurred in 26% of the patients in the plasma group and 33% of the controls. The frequency of patients with symptomatic CMV infections was also the same in the two groups (51% vs 33%). Three patients each in the two groups developed CMV-associated interstitial pneumonitis. Patient survival and causes of death were similar in the two groups. To conclude, no beneficial effect of CMV hyperimmune plasma was seen in patients at high risk of developing CMV infections.

Antibodies, Viral↗
PubMed1987

Virulence-plasmid is associated with the inhibition of opsonization in Yersinia enterocolitica and Yersinia pseudotuberculosis.

Plasmid-cured variants of virulent strains of Yersinia enterocolitica and Y. pseudotuberculosis were obtained by selection after growth in calcium-deficient medium. To obtain antigen preparations consisting of whole bacteria the original plasmid-containing strains and the plasmid-cured variants were grown in conditions favouring expression of the temperature-inducible outer membrane proteins of Yersinia (YOP) (37 degrees C, calcium-deficient culture medium). The presence or absence of the YOP on the bacteria was verified by immunoblotting. Opsonophagocytosis of YOP-negative Yersinia preparations (YOP-) was compared to that of YOP-containing ones (YOP+) in human polymorphonuclear leukocyte (PMN) chemiluminescence (CL) assay. The attachment of complement C3b on the surface of the bacteria after opsonization with normal human serum was determined by using a fluorescent anti-C3c-antibody and flow cytometry. YOP+ bacteria resisted opsonization in the absence of specific antibodies, as indicated by diminished C3b-fixation on bacteria and weaker CL response. This implies that virulence-plasmid-coded structures provide Y. enterocolitica and Y. pseudotuberculosis with an ability to avoid complement-mediated opsonization and phagocytosis.

Bacterial Outer Membrane Proteins↗
PubMed1986

Detection of circulating Yersinia-immunoglobulin complexes by enzyme immunoassay (EIA).

An enzyme immunoassay (EIA) was developed for the detection of Yersinia-immunoglobulin complexes of known Ig class. Immune complexes (ICs) were attached to polystyrene microtiter plates by rabbit anti-human immunoglobulins, and the existence of Yersinia enterocolitica O:3 antigens was demonstrated using Fab fragments of alkaline phosphatase (AP)-conjugated antibody against the same serotype. Simultaneous binding of Yersinia antigens and immunoglobulins was a prerequisite for the detection of ICs. The method will be valuable for research into the immunopathogenetic mechanisms leading to reactive arthritis after Yersinia infection.

Animals↗
PubMed1986

Acute anterior uveitis and conjunctivitis following Yersinia infection in children.

We studied characteristics of ocular inflammation associated with yersinia infection in six children, three boys and three girls, ranging in age between 4 and 14 years. Four patients developed acute anterior uveitis with aqueous flare and cells, small keratic precipitates, cells in the vitreous, and occasionally with fibrinous exudates, posterior synechiae and macular edema. The uveitis was unilateral in two patients and bilateral in two. In three 10- to 14-year-old patients the uveitis resolved during corticosteroid treatment in 3 to 8 (mean 6) weeks. In a 4-year-old girl with positive antinuclear antibody titers bilateral uveitis lasted for 17 weeks. Two uveitis patients had recurrent episodes. Two patients had mucopurulent bilateral mild conjunctivitis which resolved in 3 to 5 days. All patients had symptoms of reactive arthritis and one had sacroiliitis. All tested patients were HLA-B27 positive. Our results indicate that in HLA-B27 positive children, especially after the age of 10 years, yersinia infection may occasionally trigger reactive iritis or conjunctivitis which often occur together with other HLA-B27 associated rheumatic diseases.

Acute Disease↗
PubMed1986

Restriction map of virulence plasmid in Yersinia enterocolitica O:3.

Restriction map of the 72-kb virulence plasmid isolated from Yersinia enterocolitica O:3 was generated using EcoRI, BamHI, HindIII, and XbaI restriction enzymes. The mapping was done after cloning all of the 13 BamHI fragments of the plasmid in Escherichia coli. In addition, the restriction enzyme analysis revealed two types of virulence plasmids (types I and II) in Y. enterocolitica O:3. No functional differences between the strains bearing type I or type II plasmid were observed.

Arthritis, Infectious↗