Development of antibody-secreting cells and antigen-specific T cells in cervical lymph nodes after intranasal immunization

Abstract

Intranasal (i.n.) immunization with bacterial protein antigens coupled to cholera toxin B subunit (CTB) effectively induces mucosal, especially salivary immunoglobulin A (IgA), and nonmucosal antibody responses in mice. To examine the regional distribution of antigen-specific B and T cells after i.n. immunization, antibody-secreting cells and antigen-responsive T cells in cervical lymph nodes (CLN) were compared with those found after intraoral or subcutaneous (in the neck) administration of the same antigen and with T cells found in mesenteric lymph nodes (MLN) and spleen after intragastric immunization. The i.n. immunization induced predominantly IgA antibody-secreting cells in salivary glands and IgA and IgG antibody-secreting cells in the superficial and central CLN; these responses were quantitatively enhanced if the antigen was coupled to CTB. Intraoral immunization also induced IgA and IgG antibody-secreting cells in the superficial and central CLN, but only if intact cholera toxin was included as an adjuvant. In contrast, subcutaneous (neck) immunization induced IgG antibody-secreting cells mainly in the draining facial lymph nodes. CLN cell populations resembled those of MLN, except that CLN lymphocytes had higher proportions of T cells and lower proportions of B cells and a slightly higher CD4 ؉ /CD8 ؉ ratio among T cells than the MLN lymphocytes did. T cells that proliferated in response to antigen in vitro were found especially in central CLN 2 days after i.n. immunization and persisted for up to 6 months, whereas after intragastric immunization, responsive T cells were not found in the MLN for up to 14 days. After culture with antigen in vitro, T cells from the superficial CLN of i.n. immunized mice secreted both gamma interferon and interleukin-4. Therefore, after i.n. immunization, superficial and central CLN represent sites of regional lymphocyte development, and the central CLN in particular appear to be sites where memory T cells persist.

Nasal Lymphoid Tissue (NALT) as a Mucosal Immune Inductive Site

“…immunized mice, but not that of unimmunized mice [12], indicating that B cell activation and IgA isotype switching may have occurred in NALT before cell emigration. Strong IgA ASC responses were also detected in the draining lymph nodes of NALT [16]. In this study, we showed that these responses in NALT were related at several time points to those in SG after i.n.…”

“…Further work has shown that memory T cells could reside in NALT and also in the draining cervical lymph nodes for at least several months [12,16]. Such long lasting immunity may be desirable to prevent colonization of the nasal cavities, for example with pneumococci [5].…”

Induction and recall of immune memory by mucosal immunization with a non‐toxic recombinant enterotoxin‐based chimeric protein

“…Similar results have also been reported using AgI/II and purified CTB conjugated proteins. 45 Booster immunization did not further enhance splenic responses, which instead declined after three booster immunizations. This may have been a result of the development of regulatory cells that would suppress such responses to AgI/II 46 and may indicate the development of 'split' tolerance.…”

“…boosting, a modest increase in AgI/II-specific proliferation was found in cells from the CLNs that drain the nasal mucosa, but not in the NALT or a remote lymph node such as the ILN. Thus, it appears that recall of mucosal memory responses depends upon a pool of memory cells that are not immediately available at the inductive sites but must be recruited from more central lymphoid organs such as the spleen or possibly the deeper CLNs as suggested by Wu et al 45,47 With respect to the properties of the antigen chosen for study, extensive experience has shown that AgI/II is a potent immunogen; 48 this may influence the ability of CT or CTB to serve as an adjuvant or as a coupled delivery system for its SBR segment. Moreover, AgI/II is prone to induce T helper type 2 (Th2) responses in mice, such that attempts to use it in a model of delayed-type hypersensitivity that might be amenable to tolerization by mucosal immunization were unsuccessful (M. W. Russell, unpublished observations).…”

Long-term systemic and mucosal antibody responses measured in BALB/c mice following intranasal challenge with viable enterotoxigenicEscherichia coli

“…Research by Wu and coworkers (Wu et al, 1996(Wu et al, , 1997a has shown that nasal-associated lymphoid tissue (NALT) of intranasal immunized, but not naive, mice contains antigen-specific IgA antibody secreting cells (ASC), indicating that B-cell activation and IgA isotype switching occurs in NALT, with NALT serving as an inductive site for antigenspecific IgA ASC that migrate to distant mucosal effector sites following intranasal immunization. Further research by Wu et al (1996Wu et al ( , 1997aWu et al ( , 1997b has shown that memory T-cells reside in NALT for extended periods, acting in the prevention of the colonization of the nasal cavities. The presence of NALT in the upper respiratory tract, along with the ability to disseminate antigen-specific IgA ASC to distant mucosal effector sites, highlights the importance of NALT in respiratory and oral immunity, and in intranasal immunization (Kuper et al, 1992;Wu et al, 1996Wu et al, , 1997a.…”