Differential accumulation of IgA ASC in sublingual vs. submaxillary salivary glands is directly correlated with the level of CCL28 expression. (40.4)

Abstract

Abstract Optimal function of the immune system is highly dependent on efficient homing and accumulation of leukocytes. The homing of leukocytes has been shown to be dependent on interactions between leukocyte expressed chemokine receptors and adhesion molecules, and tissue expressed chemokines and adhesion molecule ligands. The homing and accumulation of IgA antibody secreting B cells (ASC) to mucosal tissues is thought to be highly dependent upon leukocyte expressed chemokine receptors CCR9 and CCR10 interacting with the chemokines CCL25 and CCL28 respectively. CCL28 has been shown to be involved in the homing of IgA ASC to the gastrointestinal tract and the lactating mammary gland, but has not been demonstrated to play a role, in vivo, in the accumulation of IgA ASC to other mucosal tissues. CCL28 has been shown to be expressed in mouse salivary glands. Here we show that CCL28 is expressed at higher levels in mouse sublingual salivary glands than in submaxillary salivary glands. This higher level of expression in the sublingual gland correlates directly with greater numbers of IgA ASC in the sublingual gland compared with the submaxillary gland. These results demonstrate differential accumulation of IgA ASC into mouse salivary glands and suggest that this difference in lymphocyte accumulation is at least in part the result of differential expression of CCL28.