Published in:
Open Access
01-12-2009 | Research article
Identification in milk of a serum amyloid A peptide chemoattractant for B lymphoblasts
Authors:
Berardo de Jesus Rodriguez, Claire Chevaleyre, Gwénaële Henry, Daniel Mollé, Isabelle Virlogeux-Payant, Mustapha Berri, François Boulay, Joëlle Léonil, François Meurens, Henri Salmon
Published in:
BMC Immunology
|
Issue 1/2009
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Abstract
Background
Normal mammary gland contains an extravascular population of B lymphoblasts, precursors of the immunoglobulin plasma cells that play a key role in the passive protection of neonates by secreting immunoglobulins to colostrum and milk. We investigated the presence of chemoattractants in the milk by analysing the chemoattractant activity of various fractions of this secretion. Milk chemoattractants are potentially involved in the recruitment of lymphocytes from the maternal bloodstream in lactating mammary glands.
Results
The dilution-related lymphoid cell chemoattraction of whey was associated with a < 10 kDa ultrafiltrate. Active fractions were purified by reverse-phase high performance liquid chromatography. Two peptides of 2.7 kDa (DMREANYKNSDKYFHARGNYDAA) and 1 kDa (RPPGLPDKY) were identified as fragments of the SAA protein family, tentatively identified as SAA2. Only the 2.7 kDa synthetic peptide displayed chemotactic activity, at two different optimal concentrations. At the lower concentration (3.7 nM), it attracted B-cell lymphoblasts, whereas at the higher (3.7 μM), it attracted B lymphocytes. Then, the SAA mRNA expression was analysed and we observed more SAA transcripts during lactation than gestation.
Conclusion
These data are consistent with the SAA23–45 fragment being involved in preplasma B-cell recruitment to the mammary gland and resultant benefit to the neonate.