Identification of a Secretory IgA Receptor on Breast-Milk Macrophages: Evidence for Specific Activation Via These Receptors

Robinson, G. A.; Volovitz, Benjamin; Passwell, J H

doi:10.1203/00006450-199105010-00004

Cited by 19 publications

(9 citation statements)

References 24 publications

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“…Recently a receptor for Fca (CD89) has been described on the surface of human neutrophils, eosinophils, monocytes and macrophages [27][28][29]. Studies on the molecular nature of the IgA receptor on human phagocytes have shown that it is distinct from the asialoglycoprotein or polymeric IgA receptors [30].…”

Section: Discussionmentioning

confidence: 99%

Colostral Mononuclear Phagocytes are Able to Kill Enteropathogenic Escherichia coli Opsonized with Colostral IgA

Honório-França¹,

Carvalho²,

Isaac³

et al. 1997

Scand J Immunol

123

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Honorio-França AC, Carvalho MPSM, Isaac L, Trabulsi LR, Carneiro-Sampaio MMS. Colostral Mononuclear Phagocytes are Able to Kill Enteropathogenic Escherichia coli Opsonized with Colostral IgA. Scand J Immunol 1997;46:59-66 Enteropathogenic Escherichia coli (EPEC) is the main aetiological agent of acute diarrhoea among low socioeconomic level infants in developing countries. Breast-feeding provides infant protection against acute gastrointestinal and respiratory infections; however, little is known about the protective role of colostral phagocytes in the gut of newborn infants. In the present investigation we studied the ability of human colostral MN phagocytes to kill EPEC as well as the interactions between these cells and colostral and serum opsonins. The authors observed that the microbicidal activity of colostrum MN phagocytes was dependent on previous EPEC opsonization with colostral supernatant or blood serum. A defatted colostrum supernatant pool presented opsonic activity for EPEC killing at levels equivalent to those of normal serum. IgA-depleted colostrum supernatant showed significantly lower opsonic activity, whereas purified IgA from the same colostrum pool was a potent opsonin which induced EPEC killing at levels equivalent to those of untreated colostrum. Colostral MN phagocytes are able to release superoxide anion when incubated with both EPEC opsonized with untreated colostrum and purified IgA. Purified IgA was also able to restore opsonic activity of IgA-depleted colostrum. A colostrum pool without C3 and IgG induced EPEC killing by colostral MN phagocytes at rates equivalent to those of untreated colostrum supernatant. Addition of an IgM MoAb (My43) anti-human Fca receptor resulted in a significant inhibition of EPEC killing when bacteria were opsonized with purified IgA, suggesting an interaction between IgA and FcaR. With respect to serum opsonins, we observed that IgG plus complement component C3 were necessary to induce EPEC killing by the colostrum MN phagocytes. Colostral phagocyte killing of enteropathogenic bacteria may represent an additional mechanism of breast-feeding protein against intestinal infections during the first week of life.

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Section: Discussionmentioning

confidence: 99%

Colostral Mononuclear Phagocytes are Able to Kill Enteropathogenic Escherichia coli Opsonized with Colostral IgA

Honório-França¹,

Carvalho²,

Isaac³

et al. 1997

Scand J Immunol

123

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“…Our results indicate that the majority of BMM express HLA-DR and the intensity of expression on BMM is significantly higher than PBM, simi lar to that described in tissue macrophages The interest in studying FcyR ligand ex pression on BMM was in relation to the role they may have in BMM activity in the nursing infants' GI tract. This is of particular impor tance since there is only indirect evidence of FcaR (receptor for IgA) expression on BMM [29], and recent reports indicate that secretory IgA, abundant in human milk, is an ineffec tive opsonin, and that in fact IgG, which is present in low concentrations (0.05 mg/ml), is responsible for 100% of the BM opsonic activ ity in vitro [30]. [7].…”

Section: Discussionmentioning

confidence: 99%

Mononuclear Phagocytic Cells in Human Milk: HLA-DR and FcγR Ligand Expression

Rivas¹,

El-Mohandes²,

Katona³

1994

Neonatology

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The study of the cellular immune components of human milk is essential in the understanding of the role human milk may play in protecting the nursing infant against infection. We have investigated some phenotypic characteristics of breast milk macrophages (BMM) and have compared them to the characteristics of adult peripheral blood monocytes (PBM) by using dual parameter flow microfluorometry. Most BMM expressed the monocyte/macrophage markers Leu-M3 and Leu-M5. The latter marker was present in high density (bright) on BMM, but the density of expression of Leu-M3 was higher on PBM than on BMM [median fluorescence intensity (MFI) 409 ± 105 versus 203 ± 106, p = 0.02]. The percentage of BMM (98 ± 2) that expressed the HLA-DR antigen did not differ significantly from PBM, but the density of expression was higher on BMM (MFI 318 ± 56 versus 264 ± 41, p = 0.03). The HLA-DR expression of BMM was further enhanced after incubation with interferon-γ for 36 h; however, receptor for interleukin-2 could not be induced on BMM by this treatment. The expression of the three classes of FcγR was lower on BMM than on PBM, in percentage (FcγRI 56 ± 23 versus 79 ± 17%, p = 0.02), density of expression (FcγRIII MFI 71 ± 20 versus 153 ± 73, p = 0.002), or both (FcγRII 74 ± 22% versus 94 ± 12%, p = 0.02, and MFI 115 ± 53 versus 202 ± 59, p = 0.003). These findings help to define the BMM as a Leu-M3+ (dull), HLA-DR ± (bright), phenotypically mature macrophage with a specifically low expression of the FcγR ligands. These cell surface characteristics could be ontogenic in nature, or could reflect pregnancy-induced down-regulation of the maternal immune system.

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“…Bacterial killing at this pH was~70% that of milk macrophages maintained at pH 7, arguing for the resiliency of the cells at lower gastric pH as the young infant matures and is able to acidify stomach content. The binding of secretory immunoglobulin A (sIgA) to human milk macrophages specifically and the activation of those macrophages via this route has clinical relevance and likely represents a cellular signaling mechanism that enhances the infant's own immune system [151]. Further support of milk macrophage bioactivity comes from in vitro studies in our laboratory where milk macrophages isolated from whole human milk were capable of TGFα and TGFβ 2 secretion [81,152].…”

Section: The Cellular Compartment Of Human Milk: Its Physiologic Relementioning

confidence: 99%

Host Factors in Amniotic Fluid and Breast Milk that Contribute to Gut Maturation

Wagner

Taylor

Johnson

2007

Clinic Rev Allerg Immunol

150

103

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The gut represents a complex organ system with regional differences, which reflect selective digestive and absorptive functions that change constantly in response to bodily requirements and the outside milieu. As a barrier to the external environment, gut epithelium must be renewed rapidly and repeatedly. Growth and renewal of gut epithelial cells is dependent on controlled cell stimulation and proliferation by a number of signaling processes and agents, including gut peptides-both endogenous and exogenous sources. This cascade of events begins during fetal development; with the ingestion of amniotic fluid, this process is enhanced and continued during infancy and early childhood through the ingestion of human milk. Events influenced by amniotic fluid during fetal development and those influenced by human milk that unfold after birth and early childhood to render the gut mature are presented.

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Identification of a Secretory IgA Receptor on Breast-Milk Macrophages: Evidence for Specific Activation Via These Receptors

Cited by 19 publications

References 24 publications

Colostral Mononuclear Phagocytes are Able to Kill Enteropathogenic Escherichia coli Opsonized with Colostral IgA

Colostral Mononuclear Phagocytes are Able to Kill Enteropathogenic Escherichia coli Opsonized with Colostral IgA

Mononuclear Phagocytic Cells in Human Milk: HLA-DR and FcγR Ligand Expression

Host Factors in Amniotic Fluid and Breast Milk that Contribute to Gut Maturation

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