Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “KASP”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

49 records · Page 3Linked to original sources
PubMed1991

Idiotypic characterisation of monoclonal antibodies with restricted epitope specificity for retinal S-antigen.

This paper describes the idiotypic specificities of eight murine monoclonal antibodies directed to three independent epitopes on retinal S-antigen. The antigenic sites recognised by these monoclonal antibodies have previously been localised to a small region near the C-terminal of bovine S-antigen. Xenogeneic, site-related anti-idiotypes prepared against each of the monoclonal antibodies recognised common idiotypes only amongst those monoclonal antibodies which reacted with the same epitope on S-antigen. Two of the three idiotypes were detected in the sera of BALB/c mice but not in two strains of rat immunised with xenogeneic S-antigen and none could be detected in the sera of patients with anti-photoreceptor autoantibodies. Our results demonstrate that the idiotypes of murine monoclonal antibodies to retinal S-antigen exhibit restricted epitope specificity but are species-restricted and imply that the S-antigen lacks a dominant antigenic epitope.

Antibodies, Monoclonal↗
PubMed1992

Passive administration of antibody against retinal S-antigen induces electroretinographic supernormality.

Electroretinographic supernormality, affecting both the a- and b-waves of the electroretinogram (ERG), occurs consistently before the onset of experimental autoimmune uveoretinitis (EAU) in rabbits and rats. To investigate the possible role of antibody to S-antigen (S-ab) in this phenomenon, affinity-purified polyclonal rat S-ab was injected intravenously into normal rats and administered to isolated rat eyecup preparations by bolus perfusion. In both situations, ERG supernormality was observed. The effect in vivo peaked 90 min after injection, and ERG changes in vitro were observed within 15 sec. The ERG response in vivo and in vitro was dose dependent and was abolished in vivo by pretreatment with cyproheptadine (a serotonin antagonist). The ERG was not affected in either system by a control rat antibody (antiovalbumin) or by murine monoclonal or rabbit polyclonal antibodies to S-antigen. The induction of ERG supernormality in vivo and in vitro by homologous S-ab indicates the operation of species-specific mechanisms both involving and bypassing the blood-retinal barrier and highlights a significant role for humoral autoimmunity in the pathogenesis of S-antigen-induced EAU in the rat.

Animals↗
PubMed1988

Analysis of antigenic determinants of retinal S-antigen with monoclonal antibodies.

Eight murine monoclonal antibodies to retinal S-antigen were found to recognize three antigenic clusters in competitive binding experiments. Variable patterns of immunohistochemical staining of retinal sections supported the competitive binding studies. Monoclonal antibodies to two of these three antigenic clusters on S-antigen reacted by Western immunoblotting with both intact S-antigen and two cyanogen bromide cleaved peptide fragments of bovine S-antigen. The binding of the monoclonal antibodies was localized to epitopes contained on two peptide fragments of 26,000 and 18,000 molecular weight. The same peptide fragments also react with polyclonal rat or rabbit antisera to bovine S-antigen. Monoclonal antibodies to the third antigenic cluster did not react with either intact or fragmented S-antigen in immunoblotting studies.

Animals↗
PubMed1989

Morphometric analysis of T lymphocyte compartmentation in experimental autoimmune uveoretinitis.

Experimental autoimmune uveoretinitis (EAU) in the Lewis rat is characterized by extensive infiltration of inflammatory cells into all compartments of the eye, only some of which become irreversibly damaged. The apparent differences in the pathogenic impact of inflammatory cells within different ocular compartments may suggest that different mechanisms underlie cellular infiltration and selective tissue destruction. In order to investigate the importance of T lymphocyte infiltration, we carried out a precise topographical and temporal analysis of T cell infiltration into five compartments of the eye using an improved method for the fixation of ocular tissue. Our study showed that T cell infiltration began in the ciliary body and was most numerous and sustained in this area during EAU. The peak of T cell infiltration into the retina was comparatively delayed and was of lesser magnitude. Analysis of T cell subsets revealed a tendency for the helper phenotype to predominant during the course of disease in all ocular compartments except the retina where both helper and cytotoxic/suppressor T cells were equally represented at the height of inflammation. We suggest that the pathogenetic impact of autoreactive lymphocytes in EAU depends on the accessibility of relevant tissue antigen and on local microenvironmental features of lymphocytic traffic within different ocular compartments.

Animals↗
PubMed1989

Precipitation of experimental autoallergic uveoretinitis by cyclosporin A withdrawal: an experimental model of uveitis relapse.

This study set out to determine whether withdrawal of cyclosporin A (CyA) in Lewis rats sensitized to retinal S antigen would precipitate experimental autoallergic uveoretinitis (EAU), and whether challenge of such animals with S antigen or an unrelated stimulus would accelerate EAU onset after drug withdrawal. Rats were sensitized with 50 micrograms S antigen in Freund's complete adjuvant (FCA) and EAU onset was suppressed by 18 days of treatment with CyA at doses ranging from 3 to 10 mg/kg daily. Without challenge, seven out of 11 animals developed EAU with a median onset of 78 days. This was reduced to 68 days in rats challenged on day 32 with FCA alone, to 48 days with 10 micrograms S antigen in FCA, and to 41 days with 50 micrograms S antigen in FCA. The incidence, onset and severity of anterior uveitis and extent of photoreceptor destruction were related to both CyA dose and nature of challenge. The extent of photoreceptor destruction ran parallel with severity of anterior uveitis; and delayed-type hypersensitivity reactivity on day 43 was related to both severity of anterior uveitis (P less than 0.001) and photoreceptor damage (P less than 0.002). At the highest dose, CyA also delayed the appearance of antibody to S antigen; however, subsequent antibody levels were unrelated to EAU severity or to nature of challenge. The results indicate that CyA-induced suppression of the immunological response to S antigen can recover spontaneously after drug withdrawal, that challenge with either S antigen or FCA alone can accelerate the subsequent onset of EAU, and that these phenomena may provide a basis for investigating mechanisms underlying relapse of human uveoretinitis.

Animals↗
PubMed1977

Streptococcal cross-reacting antigen and the bundle of His.

Five sera raised in rabbits against three strains of Streptococcus pyogenes (grown in semi-synthetic media) were shown by immunofluorescence to have antibodies reacting with both myocardial and conducting fibres. The pattern of staining on the conducting fibres was different to that on myocardial fibres and suggested the presence of larger amounts of cross-reacting antigen. Most work was done on ox heart, but the results were confirmed on human heart and rabbit heart. Absorption studies, carried out with three sera on ox heart only, showed that absorption with the homologous organism abolished in parallel the staining of both types of fibre. Absorption with heterologous organisms was less effective indicating the existence of more than one cardiac cross-reacting antigen. Absorption with myocardium, suggested that the conducting fibres contained streptococcal cross-reacting antigens additional to those found in the contractile fibres.

Animals↗
PubMed1977

The role of the plasmalogen in the cross-reaction between group A streptococcus and human myocardium.

Ethanol-soluble mycardial material which reacts with anti-streptococcal sera in a number of immunological tests has been isolated and identified as ethanolamine plasmalogen. The reactions of cardiac plasmalogen with antistreptococcal sera was specific and could be inhibited by streptococcus-derived materials. Guinea-pigs sensitized to streptococci gave positive skin reactions when challenged with myocardial plasmalogen. The pattern of the immunofluorescent staining given by antiplasmalogen sera was very much like that given by antistreptococcal sera. Nevertheless, the plasmalogen failed to compete for tissue-bound myocardial antigens when tried as an inhibitor of the immunofluorescent staining of myocardium either by antistreptococcal sera or by antiplasmalogen sera. A hypothesis of the role of the plasmalogen in the formation of complexes between streptococci and myocardium-derived material in the initiation of autoimmune processes is presented.

Antibodies, Bacterial↗
PubMed1987

Antigenicity and uveitogenicity of partially purified peptides of a retinal autoantigen, S-antigen.

S-antigen, a potent retinal autoantigen involved in human inflammatory eye disease, has been chemically digested with cyanogen bromide to generate various peptide fragments. Cleavage of bovine S-antigen at methionyl residues generates seven major polypeptide fragments of apparent molecular weight 26,000, 22,000, 19,000, 18,000, 12,500, 8000 and 3000, respectively. Immunoblotting following SDS-polyacrylamide gel electrophoresis either with monoclonal antibodies known to be directed to two separate antigenic determinants on S-antigen or with various polyclonal antisera identified two peptide fragments of 26,000 and 18,000 MW. The extreme insolubility of the larger peptide fragments in aqueous or organic buffers makes the purification of the polypeptides by biochemical procedures difficult. However partial purification of the remaining soluble peptides by gel filtration in urea containing buffers made it possible to ascertain that the 18,000 MW peptide is an important constituent that carries a uveitogenic determinant of this autoantigen.

Animals↗
PubMed1987

Immunoaffinity purification of S-antigen using monoclonal antibodies to different antigenic sites.

Retinal S-antigen (S-ag) was purified by monoclonal antibody (MoAb) immunoaffinity chromatography from soluble protein extracts of bovine and human retina. Purification of S-ag was readily achieved by affinity chromatography using four different MoAb-Sepharose 4B columns. The four antibody columns gave different recoveries with material of comparable enrichment with greater than 95% purity as judged by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The use of two different MoAbs covalently bound to Sepharose 4B and known to be directed to disparate, spacially distant epitopes on S-ag led to at least a twofold increase in recovery, with the aforementioned purity. Immunoaffinity purified S-ag retained its serological and uveitogenic properties. The high recovery of S-ag associated with this one-step procedure is preferable to conventional preparatory techniques, and enables high antigen recovery when tissue availability is limited (eg human retina).

Antibodies, Monoclonal↗
PubMed1985

Cyclosporin A in the treatment of posterior uveitis.

Cyclosporin A was used in nine patients with severe refractory posterior uveitis. Four patients had Behcet's disease, one had sarcoidosis, one had HLA B27 related arthritis and uveitis and three had idiopathic retinal vasculitis. The drug had beneficial ocular effects in all patients in the early stages of treatment with an improvement in the visual acuity and reduction in the severity of inflammation. The relapse rate and need for additional steroids were reduced in all patients. However, renal function deteriorated in seven patients to such an extent that the dose of Cyclosporin A had to be reduced with consequent relapse of uveitis.

Adult↗
PubMed1985

Autoimmune mechanisms in inflammatory eye disease.

This paper summarises the principal immunopathological mechanisms which may underlie ocular inflammation and draws attention to how autoimmune reactions may be regulated by idiotypic networks of the immune system. The study of autoimmunity in inflammatory eye disease is illustrated by our current investigations of retinal vasculitis in man and of experimental autoimmune uveoretinitis in rodents where three lines of evidence indicate that immune complex formation may be a compensatory host response to the development of antiretinal autoimmunity. In discussing immunological implications of these results we suggest that retinal inflammation in antiretinal autoimmunity is limited by a protective anti-idiotypic antibody response and that retinal disease arises when this compensatory response is improperly balanced. The clinical implications of this reasoning include the identification of patients at risk of relapse of ocular disease and the development of therapeutic methods for restoring an imbalanced anti-idiotypic autoimmune response towards normality.

Animals↗
PubMed1981

Autoimmunity and circulating immune complexes in retinal vasculitis.

This paper presents the results of a point-prevalence study of circulating autoantibodies and immune complexes in 44 patients with isolated retinal vasculitis (RV alone), 38 patients with retinal vasculitis accompanied by systemic inflammatory disease (RV + SID), and 33 patients with a similar range of systemic inflammatory disease but without eye involvement (SID alone). In isolated retinal vasculitis, antiretinal antibodies, non-retinal antibodies, and circulating immune complexes each showed a prevalence of about 50 per cent, but there was an inverse relationship between marked antiretinal autoimmunity and the occurrence of circulating immune complexes. In SID alone, antiretinal antibodies (ret-AB) were of lower prevalence (about 20 per cent) and occurred only in patients who had circulating immune complexes (CIC). Patients with RV + SID fell into two principal categories: (a) ret-AB with CIC, and (b) ret-AB without CIC. In isolated retinal vasculitis, the occurrence of high levels of retinal autoimmunity in the absence of circulating immune complexes was associated with the more severe retinal disease, while in those RV + SID patients who did not express autoimmunity, the more severe retinal disease was associated with the presence of circulating immune complexes. It is suggested that the formation of circulating autoimmune complexes, possibly of an idiotypic: anti-idiotypic character, may be a 'risk' mechanism for limiting retinal-specific autoimmunity, and that certain patients with severe retinal vasculitis may undercompensate or overcompensate in this way.

Antigen-Antibody Complex↗