Distribution and phenotype of rotavirus-specific B cells induced during the antigen-driven primary response to 2/6 virus-like particles administered by the intrarectal and the intranasal routes.
J Leukoc Biol 2007;
82:821-8. [PMID:
17652448 DOI:
10.1189/jlb.0307173]
[Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Selection of mucosal sites is an important step in mucosal vaccine development. The intrarectal (IR) route represents an alternative to the oral route of immunization; nevertheless, immune responses induced by this route are not well defined. Here, we studied the early primary B cell response (induction, homing, and phenotype) induced by IR immunization with rotavirus (RV)-2/6 virus-like particles (VLP). Using flow cytometry, we traced RV-specific B cells in different lymphoid tissues and analyzed the expression of alpha4beta7 and CCR9, which are important receptors for homing to the gut, as well as CD5, a marker expressed by B1-a cells, which are a major source of natural antibodies. We observed a massive, specific B cell response in rectal follicles, lumbar, and mesenteric lymph nodes but not in Peyer's patches or cervical lymph nodes. A minority of cells expressed alpha4beta7, suggesting a probable lack of migration to the gut, whereas CCR9 and CD5 were expressed by 30-50% and 30-75% of specific B cells, respectively. Then, we compared the intranasal route of immunization and observed similar B cell frequency and phenotype but in respiratory lymphoid tissues. These results confirm the high compartmentalization of B cell responses within the mucosal system. They show that CCR9 expression, conversely to alpha4beta7, is not restricted to B cells induced in the gut. Finally, an important part of the RV-specific B cell response induced at the mucosal level during the primary response to VLP is most likely a result of B1-a cells.
Collapse