Correlation of Tissue Distribution, Developmental Phenotype, and Intestinal Homing Receptor Expression of Antigen-Specific B Cells During the Murine Anti-Rotavirus Immune Response

Abstract

The intestinal homing receptor, α4β7, helps target lymphocytes to Peyer’s patches (PP) and intestinal lamina propria (ILP). We have previously shown that protective immunity to rotavirus (RV), an intestinal pathogen, resides in memory B cells expressing α4β7. In this study, using a novel FACS assay, we have directly studied the phenotype of B cells that express surface RV-specific Ig during the in vivo RV immune response. During primary infection, RV-specific B cells first appear as large IgD−B220lowα4β7− and α4β7+ cells (presumptive extrafollicular, Ab-secreting B cells), and then as large and small IgD−B220highα4β7− cells (presumptive germinal center B cells). The appearance of B cells with the phenotype of large IgD−B220lowα4β7+ cells in PP and most notably in mesenteric lymph nodes coincides with the emergence of RV-specific Ab-secreting cells (ASC) in the ILP. Thus, these B lymphocytes are good candidates for the migratory population giving rise to the RV-specific ASC in the ILP. RV-specific long-term memory B cells preferentially accumulate in PP and express α4β7. Nine months after infection most RV-specific IgA ASC are found in PP and ILP and at lower frequency in bone marrow and spleen. This study is the first to follow changes in tissue-specific homing receptor expression during Ag-specific B cell development in response to a natural host, tissue-specific pathogen. These results show that α4β7 is tightly regulated during the Ag-specific B cell response to RV and is expressed concurrently with the specific migration of memory and effector B cells to intestinal tissues.

Distribution and phenotype of murine rotavirus-specific B cells induced by intranasal immunization with 2/6 virus-like particles

“…immunization with 2/6-VLP, we used an FCM assay as previously described [15], based on the binding of labeled RV-Ag (GFP-VLP) to B cells that express RV-specific surface Ig. B cells are identified with fluorochrome-labeled mAb directed against a B cell marker (B220) and IgD (to distinguish Ag-activated from naive B cells).…”

“…Three types of RV-specific B220 + cells were identified as illustrated in Fig. 2 [15,17,18]. We also analyzed large B220 -cells to not exclude plasmablasts.…”

“…In this study, we used fluorescent virus-like particles (GFP-2/6-VLP) in a flow cytometry (FCM) assay described by Youngman et al [15] to trace RV-specific B cells in the different respiratory lymphoid tissues (NALT and cervical lymph nodes, CLN) of BALB/c mice immunized i.n. with 2/6-VLP in the presence of LT-R192G, a non-toxic mutant of Escherichia coli heat labile toxin [16].…”

CNS viral infection diverts homing of antibody‐secreting cells from lymphoid organs to the CNS

“…Stable levels of anti-viral serum Ab suggest ASC in the BM as a primary source throughout persistence. However, virus-specific ASC were preferentially retained within the CNS and were barely detectable in BM throughout persistent infection of the CNS by JHMV, in contrast to preferential accumulation in BM observed for heterologous peripheral infections [2,[31][32][33]. High levels of virus-induced CXCL9 and CXCL10 mRNA within the CNS implicate CXCR3 ligands as mediators of ASC recruitment.…”

“…However, in contrast to systemic infections, in which a decline in splenic ASC numbers is counterbalanced by an increase in BM ASC, few ASC ever appear in the BM following JHMV infection. Preferential CNS retention, concomitant with poor BM accumulation, appears unique compared to localized infections of lung or intestinal tract [31,33] and may reflect the primary role of intrathecal Ab in controlling viral persistence [13, 15, 16]. A prominent intrathecal Ab response to JHMV infection is supported by increased CFS to serum ratios of virus-specific antibodies in rats and mice [36].…”