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Antigen-unspecific B cells and lymphoid dendritic cells both show extensive surface expression of processed antigen-major histocompatibility complex class II complexes after soluble protein exposure in vivo or in vitro.

Zhong G, Reis e Sousa C, Germain RN - J. Exp. Med. (1997)

Bottom Line: In striking contrast to conclusions drawn from indirect T cell activation studies, this direct method of TCR ligand analysis shows that i.v. administration of HEL protein results in nearly all B cells in lymphoid tissues having substantial levels of HEL 46-61-Ak complexes on their surface.Although the absolute number of displayed ligands is greater on such DC, the relative specific ligand expression compared to total MHC class II levels is similar or greater on B cells.The numerical advantage of the TCR ligand-bearing B cells may permit them to interact first or more often with naive antigen-specific T cells, contributing to the induction of high-dose T cell tolerance or immune deviation.

View Article: PubMed Central - PubMed

Affiliation: Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-1892, USA.

ABSTRACT
Intravenous (i.v.) injection of high amounts of soluble proteins often results in the induction of antigen-specific tolerance or deviation to helper rather than inflammatory T cell immunity. It has been proposed that this outcome may be due to antigen presentation to T cells by a large cohort of poorly costimulatory or IL-12-deficient resting B cells lacking specific immunoglobulin receptors for the protein. However, previous studies using T cell activation in vitro to assess antigen display have failed to support this idea, showing evidence of specific peptide-major histocompatibility complex (MHC) class II ligand only on purified dendritic cells (DC) or antigen-specific B cells isolated from protein injected mice. Here we reexamine this question using a recently derived monoclonal antibody specific for the T cell receptor (TCR) ligand formed by the association of the 46-61 determinant of hen egg lysozyme (HEL) and the mouse MHC class II molecule I-Ak. In striking contrast to conclusions drawn from indirect T cell activation studies, this direct method of TCR ligand analysis shows that i.v. administration of HEL protein results in nearly all B cells in lymphoid tissues having substantial levels of HEL 46-61-Ak complexes on their surface. DC readily isolated from spleen also display this TCR ligand on their surface. Although the absolute number of displayed ligands is greater on such DC, the relative specific ligand expression compared to total MHC class II levels is similar or greater on B cells. These results demonstrate that in the absence of activating stimuli, both lymphoid DC and antigen-unspecific B cells present to a similar extent class II-associated peptides derived from soluble proteins in extracellular fluid. The numerical advantage of the TCR ligand-bearing B cells may permit them to interact first or more often with naive antigen-specific T cells, contributing to the induction of high-dose T cell tolerance or immune deviation.

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B cells capture and present HEL injected i.v. independently  of receptor specificity. (A) B cell staining in the spleen is due to presentation of surface HEL 46-61–Ak complexes. Part of the spleen from each  animal used in the experiment summarized in Fig. 2 was dissociated into a  cell suspension and stained with C4H3. (B) HEL presentation by virtually  all B cells is also seen in lymph nodes. Superficial inguinal lymph nodes  from B10.BR mice injected with 8 mg BSA or HEL were dissociated  into a cell suspension and double stained with C4H3 and B220. Data for  splenic B cells from the same experiment are summarized in Table 1. Profiles in A represent total spleen cell staining and profiles in B represent the  C4H3 fluorescence of gated B220+ cells; BSA-injected mouse, thin line;  HEL-injected mouse, thick line.
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Figure 3: B cells capture and present HEL injected i.v. independently of receptor specificity. (A) B cell staining in the spleen is due to presentation of surface HEL 46-61–Ak complexes. Part of the spleen from each animal used in the experiment summarized in Fig. 2 was dissociated into a cell suspension and stained with C4H3. (B) HEL presentation by virtually all B cells is also seen in lymph nodes. Superficial inguinal lymph nodes from B10.BR mice injected with 8 mg BSA or HEL were dissociated into a cell suspension and double stained with C4H3 and B220. Data for splenic B cells from the same experiment are summarized in Table 1. Profiles in A represent total spleen cell staining and profiles in B represent the C4H3 fluorescence of gated B220+ cells; BSA-injected mouse, thin line; HEL-injected mouse, thick line.

Mentions: To confirm this result and to determine if these complexes were present at the cell surface, the remainder of the spleen from the same mice was analyzed by flow cytometry after staining with the same antibody. A distinct subpopulation of spleen cells from HEL-injected mice shows an increase in staining with C4H3 over the background seen on the same cell subpopulation from control mice (Fig. 3 A), consistent with the interpretation of the immunohistochemical data that essentially all B cells present processed HEL at the cell surface. A 1.5–20-fold increase in B cell staining with C4H3 (mean fluorescence) after i.v. injection of doses of 2–8 mg HEL was seen reproducibly in more than seven independent experiments and could be detected as early as 1–2 h after injection (data not shown). The same increase in staining could be seen in B cells isolated from other tissues, including lymph nodes (Fig. 3 B), blood, bone marrow, and Peyer's patches (data not shown). Thus, these results demonstrate that most antigen-unspecific B cells present peptides derived from protein antigens injected i.v.


Antigen-unspecific B cells and lymphoid dendritic cells both show extensive surface expression of processed antigen-major histocompatibility complex class II complexes after soluble protein exposure in vivo or in vitro.

Zhong G, Reis e Sousa C, Germain RN - J. Exp. Med. (1997)

B cells capture and present HEL injected i.v. independently  of receptor specificity. (A) B cell staining in the spleen is due to presentation of surface HEL 46-61–Ak complexes. Part of the spleen from each  animal used in the experiment summarized in Fig. 2 was dissociated into a  cell suspension and stained with C4H3. (B) HEL presentation by virtually  all B cells is also seen in lymph nodes. Superficial inguinal lymph nodes  from B10.BR mice injected with 8 mg BSA or HEL were dissociated  into a cell suspension and double stained with C4H3 and B220. Data for  splenic B cells from the same experiment are summarized in Table 1. Profiles in A represent total spleen cell staining and profiles in B represent the  C4H3 fluorescence of gated B220+ cells; BSA-injected mouse, thin line;  HEL-injected mouse, thick line.
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Related In: Results  -  Collection

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Figure 3: B cells capture and present HEL injected i.v. independently of receptor specificity. (A) B cell staining in the spleen is due to presentation of surface HEL 46-61–Ak complexes. Part of the spleen from each animal used in the experiment summarized in Fig. 2 was dissociated into a cell suspension and stained with C4H3. (B) HEL presentation by virtually all B cells is also seen in lymph nodes. Superficial inguinal lymph nodes from B10.BR mice injected with 8 mg BSA or HEL were dissociated into a cell suspension and double stained with C4H3 and B220. Data for splenic B cells from the same experiment are summarized in Table 1. Profiles in A represent total spleen cell staining and profiles in B represent the C4H3 fluorescence of gated B220+ cells; BSA-injected mouse, thin line; HEL-injected mouse, thick line.
Mentions: To confirm this result and to determine if these complexes were present at the cell surface, the remainder of the spleen from the same mice was analyzed by flow cytometry after staining with the same antibody. A distinct subpopulation of spleen cells from HEL-injected mice shows an increase in staining with C4H3 over the background seen on the same cell subpopulation from control mice (Fig. 3 A), consistent with the interpretation of the immunohistochemical data that essentially all B cells present processed HEL at the cell surface. A 1.5–20-fold increase in B cell staining with C4H3 (mean fluorescence) after i.v. injection of doses of 2–8 mg HEL was seen reproducibly in more than seven independent experiments and could be detected as early as 1–2 h after injection (data not shown). The same increase in staining could be seen in B cells isolated from other tissues, including lymph nodes (Fig. 3 B), blood, bone marrow, and Peyer's patches (data not shown). Thus, these results demonstrate that most antigen-unspecific B cells present peptides derived from protein antigens injected i.v.

Bottom Line: In striking contrast to conclusions drawn from indirect T cell activation studies, this direct method of TCR ligand analysis shows that i.v. administration of HEL protein results in nearly all B cells in lymphoid tissues having substantial levels of HEL 46-61-Ak complexes on their surface.Although the absolute number of displayed ligands is greater on such DC, the relative specific ligand expression compared to total MHC class II levels is similar or greater on B cells.The numerical advantage of the TCR ligand-bearing B cells may permit them to interact first or more often with naive antigen-specific T cells, contributing to the induction of high-dose T cell tolerance or immune deviation.

View Article: PubMed Central - PubMed

Affiliation: Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-1892, USA.

ABSTRACT
Intravenous (i.v.) injection of high amounts of soluble proteins often results in the induction of antigen-specific tolerance or deviation to helper rather than inflammatory T cell immunity. It has been proposed that this outcome may be due to antigen presentation to T cells by a large cohort of poorly costimulatory or IL-12-deficient resting B cells lacking specific immunoglobulin receptors for the protein. However, previous studies using T cell activation in vitro to assess antigen display have failed to support this idea, showing evidence of specific peptide-major histocompatibility complex (MHC) class II ligand only on purified dendritic cells (DC) or antigen-specific B cells isolated from protein injected mice. Here we reexamine this question using a recently derived monoclonal antibody specific for the T cell receptor (TCR) ligand formed by the association of the 46-61 determinant of hen egg lysozyme (HEL) and the mouse MHC class II molecule I-Ak. In striking contrast to conclusions drawn from indirect T cell activation studies, this direct method of TCR ligand analysis shows that i.v. administration of HEL protein results in nearly all B cells in lymphoid tissues having substantial levels of HEL 46-61-Ak complexes on their surface. DC readily isolated from spleen also display this TCR ligand on their surface. Although the absolute number of displayed ligands is greater on such DC, the relative specific ligand expression compared to total MHC class II levels is similar or greater on B cells. These results demonstrate that in the absence of activating stimuli, both lymphoid DC and antigen-unspecific B cells present to a similar extent class II-associated peptides derived from soluble proteins in extracellular fluid. The numerical advantage of the TCR ligand-bearing B cells may permit them to interact first or more often with naive antigen-specific T cells, contributing to the induction of high-dose T cell tolerance or immune deviation.

Show MeSH
Related in: MedlinePlus