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Biomedical subjects

Jesper Reinholdt

Publications and source records attributed to Jesper Reinholdt.

5 recordsLinked to original sources
PubMed2005

Immunoglobulin levels and phagocytes in the cervical mucus plug at term of pregnancy.

BACKGROUND: To characterize the potential for adaptive immune protection in cervical mucus plugs with respect to immunoglobulin isotypes and effector cells (phagocytes). METHODS: Thirty-one cervical mucus plugs were collected from healthy women in labor at term. The cervical mucus plugs were allocated either to analysis of immunoglobulins by enzyme-linked immunosorbent assay (ELISA), gel chromatography and Western blotting (n = 20) or to microscopical, including immunocytochemical, analyses. The levels of immunoglobulin in the plugs were compared to the levels in 10 samples of ovulatory cervical mucus from nonpregnant women. RESULTS: In the cervical mucus plugs, levels of immunoglobulin G (IgG) [median 3270 microg/mL (100-14 500)] and IgA [540 (22-2820)], but not IgM [30.5 (1.0-160)], were significantly elevated compared to cervical mucus from nonpregnant women (p < 0.02 for IgG and IgA). The IgG : IgA ratio in the plugs was also elevated (p < 0.02). The proportion of secretory immunoglobulin A (SIgA) relative to total IgA in the plugs ranged from 16 to 65% (n = 5). IgA and IgG were largely intact. Microscopically, the vagina-proximal part of the cervical mucus plugs contained bacteria and was rich in cells, mainly phagocytes. Conversely, the uterine part contained few cells. CONCLUSION: The high immunoglobulin levels in combination with the presence of phagocytes suggest a potential for adaptive immune defense in the cervical mucus plug, which, together with innate immune factors, may act as an immunological gatekeeper protecting the fetomaternal unit against infection from the vagina.

Blotting, Western↗
PubMed2005

Bet v 1-specific IgA increases during the pollen season but not after a single allergen challenge in children with birch pollen-induced intermittent allergic rhinitis.

Allergen-specific immunoglobulins of the Immunoglobulin A (IgA) type have been found in the nasal fluid of patients with allergic rhinitis. IgA may play a protective role, but there are also data which show that allergen-specific IgA can induce eosinophil degranulation. The aim of this study was to quantitate Bet v 1-specific IgA in relation to total IgA in the nasal fluid of children with birch pollen-induced intermittent allergic rhinitis and healthy controls, after allergen challenge and during the natural pollen season. Eosinophil cationic protein (ECP), Bet v 1-specific IgA and total IgA were analyzed in nasal fluids from 30 children with birch pollen-induced intermittent allergic rhinitis and 30 healthy controls. Samples were taken before the pollen season, after challenge with birch pollen and during the pollen season, before and after treatment with nasal steroids. During the pollen season, but not after nasal allergen challenge, Bet v 1-specific IgA increased in relation to total IgA in children with allergic rhinitis. No change was found in the healthy controls. The ratio of Bet v 1-specific IgA to total IgA increased from 0.1 x 10(-3) (median) to 0.5 x 10(-3) in the allergic children, p < 0.001. No change was seen after treatment with nasal steroids, although symptoms, ECP and eosinophils were reduced. In conclusion, allergen-specific IgA in relation to total IgA increases in nasal fluids during the pollen season in allergic children but not in healthy controls. These findings are compatible with the hypothesis that allergen-specific IgA plays a role in the allergic inflammation and further studies are needed to clarify the functional role of these allergen-specific antibodies.

Adolescent↗
PubMed2002

Isolation and detection of human IgA using a streptococcal IgA-binding peptide.

Bacterial proteins that bind to the Fc part of IgG have found widespread use in immunology. A similar protein suitable for the isolation and detection of human IgA has not been described. Here, we show that a 50-residue synthetic peptide, designated streptococcal IgA-binding peptide (Sap) and derived from a streptococcal M protein, can be used for single-step affinity purification of human IgA. High affinity binding of IgA required the presence in Sap of a C-terminal cysteine residue, not present in the intact M protein. Passage of human serum through a Sap column caused depletion of >99% of the IgA, and elution of the column allowed quantitative recovery of highly purified IgA, for which the proportions of the IgA1 and IgA2 subclasses were the same as in whole serum. Moreover, immobilized Sap could be used for single-step purification of secretory IgA of both subclasses from human saliva, with a recovery of approximately 45%. The Sap peptide could also be used to specifically detect IgA bound to Ag. Together, these data indicate that Sap is a versatile Fc-binding reagent that may open new possibilities for the characterization of human IgA.

Amino Acid Sequence↗
PubMed2002

The Clostridium ramosum IgA proteinase represents a novel type of metalloendopeptidase.

Clostridium ramosum is part of the normal flora in the human intestine. Some strains produce an IgA proteinase that specifically cleaves human IgA1 and the IgA2m(1) allotype. This prolylendopeptidase was purified from a broth culture supernatant, and N-terminal sequences of the native protein and tryptic fragments thereof were determined. A fragment of the iga gene encoding the IgA proteinase was isolated using degenerate primers in PCR, and the complete gene was obtained by inverse PCR. The identity of the iga gene was confirmed by heterologous expression in Escherichia coli. The deduced amino acid sequence indicated a signal peptide of 30 residues and a secreted proteinase of 133,828 Da. A typical Gram-positive cell wall anchor motif was identified in the C terminus. The presence of a putative zinc-binding motif His-Glu-Phe-Gly-His together with inhibition studies indicate that the proteinase belongs to the zinc-dependent metalloproteinases. However, the sequence of the C. ramosum IgA proteinase shows no overall similarity to other proteins except for significant identity around the zinc-binding motif with family M6 of metalloendopeptidases, and the unique sequence of the IgA proteinase in this area presumably establishes a new subfamily. The GC percentage of the iga gene is significantly higher than that for the entire genome of C. ramosum, suggesting that the gene was acquired recently in evolution.

Alanine↗