Definition of a Discontinuous Immunodominant Epitope of Intestinal Alkaline Phosphatase, an Autoantigen in Acute Bacterial Infections

Kolbus, Norbert; Beuche, Wolfgang; Felgenhauer, K.; Mäder, Michael

doi:10.1006/clin.1996.0127

Cited by 4 publications

(5 citation statements)

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“…A polyclonal activation of B cells as a mechanism driving IAPA production in patients seems less probable in the light of the above results, the more so since a homogeneous epitope pattern was found which was recognized by IAPA of all patients studied [10]. The data obtained by immunocytochemistry as well as by the T cell proliferation assay support the hypothesis that the anti-IAP autoimmune reaction is driven by the autoantigen itself, and depends on T-B cell interaction.…”

Section: Discussionsupporting

confidence: 54%

“…It is noteworthy that in these cases the identified B cell epitopes were continuous. However, the dominant IAP B cell epitope located within the CNBr 21 fragment is discontinuous [10]. The mean SI obtained by proliferation with the CNBr 21 fragment was not significantly different from that obtained with IAP using PBMC from IAPA-positive patients (cf.…”

Section: Discussionmentioning

confidence: 87%

“…The data obtained by immunocytochemistry as well as by the T cell proliferation assay support the hypothesis that the anti-IAP autoimmune reaction is driven by the autoantigen itself, and depends on T-B cell interaction. Additional experiments, partly outlined in the Introduction, have previously been conducted [1,2,10]. They also favour an antigen-driven mechanism for the generation of IAPA in bacterial infections.…”

Section: Discussionmentioning

confidence: 99%

“…Chemical cleavage of IAP and isolation of the IAP fragment CNBr 21 were performed as previously described [10]. SDS-PAGE and isoelectric focusing (IEF) were carried out according to Kolbus et al [2,10], protein quantification according to Reiber [11].…”

Section: Miscellaneousmentioning

confidence: 99%

“…We have previously shown that a discontinuous immunodominant B cell epitope is localized within an IAP fragment, comprising amino acids 334-462, which was designated CNBr 21 [10]. The CNBr 21 fragment was purified to homogeneity by high performance liquid chromatography (HPLC), using gel filtration chromatography (Fig.…”

Section: Localization Of a T Cell Epitopementioning

confidence: 99%

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Detection of T cells reactive to intestinal alkaline phosphatase, an autoantigen in acute bacterial infections, and discrimination between autoantigen-specific CD5+ and CD5− B cells

Kolbus

Fleischer

Mäder

et al. 1997

Clinical and Experimental Immunology

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SUMMARYAutoantibodies of the IgG isotype, specifically directed against intestinal alkaline phosphatase (IAP), occur transiently in the majority of sera from patients with acute bacterial infections. Sometimes they are observed in autoimmune diseases. Using a T cell proliferation assay, it was found that isolated peripheral blood mononuclear cells (PBMC) from IAP autoantibody (IAPA)-positive patients (n ¼ 18) responded significantly to IAP, whereas proliferation could not be induced in PBMC from healthy donors (n ¼ 11). Significant stimulation of PBMC from patients (n ¼ 11) was not obtained by use of transferrin, a common autoantigen in humans, indicating the specificity of stimulation of IAP-reactive T cells. Furthermore, T cell proliferation was observed when a highly purified IAP fragment (CNBr 21) spanning amino acids 334-462 of the primary structure of IAP was used as antigen. Thus, it was shown that an immunodominant T cell epitope resides within the CNBr 21 fragment which also contains a discontinuous B cell epitope as evaluated previously. Double immunocytochemical staining of T celldepleted PBMC with IAP and an anti-human CD5 antibody allowed the detection of CD5 þ B lymphocytes, which probably produce natural IAPA (nIAPA). These nIAPA-specific CD5 þ B cells occurred with approximately the same frequency among T cell-depleted PBMC from healthy donors and those from patients. In contrast, IAPA-producing CD5 ¹ B cells were found in B cell-enriched preparations from patients, but not in those from healthy individuals.

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Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 87%