Modulation of IgG effector functions by a monovalent fragment of staphylococcal protein A

Gheţie, Victor; Moţa, Gabriela; Dobre-Gheţie, Maria-Ana; Laky, Mariana; Olinescu, A; Dima, S.; Moraru, I; Sjöquist, John

doi:10.1016/0161-5890(86)90135-5

Cited by 6 publications

(3 citation statements)

References 31 publications

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“…This was accomplished with SpA, which several investigators have used to effectively inhibit ADCC (31)(32)(33). In control experiments, another wellstudied ADCC mediated lysis of targets was used, i.e., lysis of CRBC with rabbit anti-CRBC antibody.…”

Section: Methodsmentioning

confidence: 99%

Use of anti-HLA antibodies to mask major histocompatibility complex gene products on tumor cells can enhance susceptibility of these cells to lysis by natural killer cells.

Lobo

Spencer²

1989

J. Clin. Invest.

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Section: Methodsmentioning

confidence: 99%

Use of anti-HLA antibodies to mask major histocompatibility complex gene products on tumor cells can enhance susceptibility of these cells to lysis by natural killer cells.

Lobo

Spencer²

1989

J. Clin. Invest.

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“…Recently, a fragment of protein A has become commercially available which is monovalent with regard to its binding to IgG molecules (6). It was hypothesized that if sections immunolabeled with primary antibody and protein A-gold were then exposed to normal serum and subsequently to the protein A fragment, this might then serve to saturate IgG and then protein A binding sites on the first antibody-protein A-gold complex.…”

Section: Cytochem 40:435441 1992)mentioning

confidence: 99%

A novel methodology for double protein A-gold immunolabeling utilizing the monovalent fragment of protein A.

Thorpe

1992

J Histochem Cytochem.

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A method for sequential protein A-gold immunolabeling is described whereby the binding of second gold probe to the first antibody-protein A-gold complex is reduced to acceptably minimal levels. Immunolabeling of thin sections of embedded pituitary tissue was used as a model system. After an initial immunolabeling for prolactin, sections were incubated in normal serum (rabbit) followed by a monovalent fragment of protein A. These latter two incubations reduced artifactual second gold probe label over prolactin-labeled secretory granules to minimal levels (much less than 1 particle per granule) when sections were subsequently immunolabeled with normal serum. The combination of normal serum and protein A fragment incubations saturates IgG and protein A binding sites on the first antibody-gold probe complex. The latter is thereafter unable to bind further IgG (and thus gold probe) because of the monovalent nature of the protein A fragment. It is suggested that this methodology may be extended to multiple immunolabeling procedures for electron microscopy. In addition, when used before single labeling this method may be an effective way to minimize nonspecific IgG binding in cases where the tissue or antibody under study may be a problem.

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“…Microbial IBPs are produced by protozoa, viruses, and both gram-positive and gram-negative bacteria (13) and play important physiological roles (14). In particular, protein A (SpA) from Staphylococcus aureus can modify opsonization, phagocytosis, complement consumption (15,16), Ab-dependent cell-mediated cytotoxicity (17), and mitogenesis (18). Molecular properties of SpA are well documented.…”

mentioning

confidence: 99%

Presentation of Antigen in Immune Complexes Is Boosted by Soluble Bacterial Immunoglobulin Binding Proteins

Léonetti

Galon

Thaï

et al. 1999

The Journal of Experimental Medicine

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SummaryUsing a snake toxin as a proteic antigen (Ag), two murine toxin-specific monoclonal antibodies (mAbs), splenocytes, and two murine Ag-specific T cell hybridomas, we showed that soluble protein A (SpA) from Staphylococcus aureus and protein G from Streptococcus subspecies, two Ig binding proteins (IBPs), not only abolish the capacity of the mAbs to decrease Ag presentation but also increase Ag presentation 20-100-fold. Five lines of evidence suggest that this phenomenon results from binding of an IBP-Ab-Ag complex to B cells possessing IBP receptors. First, we showed that SpA is likely to boost presentation of a free mAb, suggesting that the IBP-boosted presentation of an Ag in an immune complex results from the binding of IBP to the mAb. Second, FACS ® analyses showed that an Ag-Ab complex is preferentially targeted by SpA to a subpopulation of splenocytes mainly composed of B cells. Third, SpA-dependent boosted presentation of an Ag-Ab complex is further enhanced when splenocytes are enriched in cells containing SpA receptors. Fourth, the boosting effect largely diminishes when splenocytes are depleted of cells containing SpA receptors. Fifth, the boosting effect occurs only when IBP simultaneously contains a Fab and an Fc binding site. Altogether, our data suggest that soluble IBPs can bridge immune complexes to APCs containing IBP receptors, raising the possibility that during an infection process by bacteria secreting these IBPs, Ag-specific T cells may activate IBP receptor-containing B cells by a mechanism of intermolecular help, thus leading to a nonspecific immune response.

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Modulation of IgG effector functions by a monovalent fragment of staphylococcal protein A

Cited by 6 publications

References 31 publications

Use of anti-HLA antibodies to mask major histocompatibility complex gene products on tumor cells can enhance susceptibility of these cells to lysis by natural killer cells.

Use of anti-HLA antibodies to mask major histocompatibility complex gene products on tumor cells can enhance susceptibility of these cells to lysis by natural killer cells.

A novel methodology for double protein A-gold immunolabeling utilizing the monovalent fragment of protein A.

Presentation of Antigen in Immune Complexes Is Boosted by Soluble Bacterial Immunoglobulin Binding Proteins

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