Secretion of respiratory syncytial virus inhibitors and antibody in human milk throughout lactation

Abstract

Neutralising inhibitors to respiratory syncytial (RS) virus have been demonstrated in the whey of most samples of human milk tested. Although high titres were secreted in colostra of some mothers (1/10-1/2,560; median 1/40) inhibitor levels in milk collected after the first week of lactation were uniformly low (median 1/10). High neutralising titres correlated with high colostral levels of specific antiviral IgA but, unlike neutralising activity, IgA antiviral antibody persisted in the milk of only four of 18 mothers. Similarly, antiviral IgG and IgM antibodies were not generally detected after the first post-partum week. Differences in antibody secretion among mothers did not correlate with differences in total protein or total immunoglobulin secretion, and appeared to reflect maternal immune status. In one mother a marked rise in specific antiviral IgA and IgG secretions during the second and third months of lactation suggested a response to virus infection. The relevance of maternal immunity and colostral and milk antiviral antibody to protection of breast-fed babies from RS-virus bronchiolitis is discussed.

Respiratory syncytial virus infection results in airway hyperresponsiveness and enhanced airway sensitization to allergen.

“…Controls were sham infected with PBS or UV-inactivated RSV (equivalent of 10 5 PFU) in the same way. Efficacy of this infection procedure was regularly tested by qualitative plaque-forming assays (20). Briefly, on day 4 postinfection mice were killed, the lungs were removed, homogenized, and centrifuged, and the supernatant was added to Hep 2 cell cultures.…”

Analysis of the local and systemic immune responses induced in BALB/c mice by experimental respiratory syncytial virus infection

“…as well as in lung homogenates was achieved by virus plaque assay performed as described previously (Toms et al, 1980).…”

Effect of compounds with antibacterial activities in human milk on respiratory syncytial virus and cytomegalovirus in vitro

“…Human milk contains not only specific secretory IgA to viruses, but also various other factors that can inhibit viruses, including the infant pathogenic virus, respiratory syncytial virus (RSV) [ 1,2]. These inhibitors of RSV, some of which still remain to be identified, can be of small [2] or large, (>400000) mol. wt [1].…”