Neonatal infection with a milk-borne virus is independent of β7 integrin- and L-selectin-expressing lymphocytes

Abstract

Mouse mammary tumor virus (MMTV) is acquired by neonates through milk and first infects lymphocytes in Peyer's patches. We show here that newborn mice lacking g 7 integrin or Lselectin were infected with MMTV at wild-type levels in both their lymphoid and mammary tissues. Superantigen-mediated activation and cognate T cell deletion were also unimpaired in both types of null mice. A large proportion of neonatal Peyer's patch lymphocytes in wildtype mice were g 7 and g 1 integrin low and both populations increased in response to MMTV infection. These results suggest that adhesion molecules other than g 7 integrin or L-selectin play a role in lymphocyte homing in the gut, peripheral lymph nodes and mammary gland in response to MMTV infection.

The Mammary Gland in Mucosal and Regional Immunity

“…In mice and in sows, MadCAM-1 is expressed in endothelial cells of MG during pregnancy and lactation (Bourges et al, 2008;Tanneau et al, 1999). However, an increase in α4β7 during lactation at a time when MAdCAM-1 levels are beginning to decline in both sows and mice suggests that additional factors might be involved (Czarneski et al, 2002;Tanneau et al, 1999). This was reminiscent of work by Czinn and Lamm, who in 1986 searched for chemoattractants in milk that might explain B cell recruitment of B cells from the MLN to the exclusion of cells from other peripheral LN.…”

Intestinal Immune System and Amplification of Mouse Mammary Tumor Virus

“…The bromodeoxyuridine incorporation assay and cell cycle analysis proved that cell division was not the cause of the B cells amplification ( Ardavin et al., 1997 ). However, neither β7 integrins nor L-selectin (CD62L) were indispensable for lymphocyte recruitment during MMTV infection ( Czarneski et al., 2002 ), suggesting that some other lymphocyte homing receptors may be involved in this process. The significance of B cell preactivation during MMTV infection is unclear.…”