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Outer periarteriolar lymphoid sheath arrest and subsequent differentiation of both naive and tolerant immunoglobulin transgenic B cells is determined by B cell receptor occupancy.

Cook MC, Basten A, Fazekas de St Groth B - J. Exp. Med. (1997)

Bottom Line: In addition, tolerant B cells were found to relocate from the follicles to the outer PALS of HEL/anti-HEL double Tg mice in which the concentration of soluble self-antigen had been increased by zinc feeding.Thus, subtle variations in antigen concentration resulted in dramatic changes in positioning of B cells within the spleen.A series of mixed bone marrow chimeras in which the effective antigen concentration was inversely related to the number of self-reactive B cells due to absorption of antigen by transgene-encoded membrane and secreted Ig, was used to confirm that alteration in B cell position previously attributed to changes in follicular composition could be explained on the basis of available antigen concentration, rather than the diversity of the repertoire.

View Article: PubMed Central - PubMed

Affiliation: Centenary Institute for Cancer Medicine and Cell Biology, Newtown, Sydney, New South Wales, Australia 2042.

ABSTRACT
T-dependent B cell responses in the spleen are initiated in the outer periarteriolar lymphoid sheath (PALS) and culminate in the generation of proliferative foci and germinal center reactions. By pulsing anti-hen egg lysozyme (HEL) immunoglobulin transgenic (IgTg) B cells with various concentrations of HEL in vitro before adoptive transfer into normal recipients, it was shown that a critical number of B cell receptors (BCRs) must be ligated for B cells to undergo arrest in the outer PALS. T cell help was manipulated independently of the BCR stimulus by incubating B cells expressing the appropriate major histocompatibility complex class II antigen with a peptide recognized by CD4(+) TCR Tg T cells. B cells which either failed to arrest in the outer PALS due to a subthreshold BCR stimulus, or arrested only transiently due to the brevity of the BCR stimulus, underwent an abortive response within the follicles when provided with T cell help. In contrast, naive B cells stimulated by a sustained, suprathreshold concentration of either foreign or self-antigen and given T cell help, proliferated in the outer PALS and then differentiated. Outer PALS arrest was not influenced by the nature of the B cells occupying the follicle, but appeared to be determined solely by the magnitude of BCR stimulation. Thus antigen-pulsed B cells arrested in the outer PALS in an identical manner irrespective of whether the follicles comprised a population of normal B cells with multiple specificities, a monoclonal naive population, or a monoclonal population of tolerant B cells. In addition, tolerant B cells were found to relocate from the follicles to the outer PALS of HEL/anti-HEL double Tg mice in which the concentration of soluble self-antigen had been increased by zinc feeding. Similarly, when anti-HEL Tg mice were crossed with a second HEL Tg strain expressing a higher concentration of soluble HEL, the tolerant anti-HEL Tg B cells were located constitutively in the outer PALS. Thus, subtle variations in antigen concentration resulted in dramatic changes in positioning of B cells within the spleen. A series of mixed bone marrow chimeras in which the effective antigen concentration was inversely related to the number of self-reactive B cells due to absorption of antigen by transgene-encoded membrane and secreted Ig, was used to confirm that alteration in B cell position previously attributed to changes in follicular composition could be explained on the basis of available antigen concentration, rather than the diversity of the repertoire.

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Outer PALS arrest of naive B cells is induced by BCR ligation with antigen. Fluorescent micrographs of frozen sections of spleen. HEL-binding B cells are stained green (fluorescein) and B220+ cells are stained red (Texas red). Non-Tg recipients of unstimulated IgTg B cells (A) and IgTg  B cells pulsed in vitro with 1 (B), 20 (C), and 100 ng/ml HEL (D). The follicle (F) and outer PALS (O) are indicated.
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Figure 1: Outer PALS arrest of naive B cells is induced by BCR ligation with antigen. Fluorescent micrographs of frozen sections of spleen. HEL-binding B cells are stained green (fluorescein) and B220+ cells are stained red (Texas red). Non-Tg recipients of unstimulated IgTg B cells (A) and IgTg B cells pulsed in vitro with 1 (B), 20 (C), and 100 ng/ml HEL (D). The follicle (F) and outer PALS (O) are indicated.

Mentions: The proposition that BCR ligation is the major determinant of outer PALS arrest was investigated using IgTg B cells expressing a high affinity anti-HEL receptor (1). Purified B cells obtained from the spleens of IgTg mice were pulsed with graded doses of soluble HEL in vitro and transferred into non-Tg syngeneic recipients (summarized in Table 1). In the absence of BCR ligation (Fig. 1 A), or after pulsing with 1 ng/ml of HEL (Fig. 1 B), the B cells migrated into the follicles unimpeded. A threshold for outer PALS arrest was observed at ∼20 ng/ml of HEL (Fig. 1 C), a concentration corresponding to occupation of ∼50% of surface Ig molecules on each B cell (24). When the B cells were pulsed with 100 ng/ml of HEL, which resulted in >95% receptor occupancy, there was near total arrest of B cells in the outer PALS for at least 24 h (Fig. 1 D). The crucial factor in determining the positioning of B cells at this site appeared to be the concentration of antigen rather than the duration of exposure to antigen in vitro, as similar results were obtained with B cells pulsed for 0.5, 4, and 12 h before transfer (not shown).


Outer periarteriolar lymphoid sheath arrest and subsequent differentiation of both naive and tolerant immunoglobulin transgenic B cells is determined by B cell receptor occupancy.

Cook MC, Basten A, Fazekas de St Groth B - J. Exp. Med. (1997)

Outer PALS arrest of naive B cells is induced by BCR ligation with antigen. Fluorescent micrographs of frozen sections of spleen. HEL-binding B cells are stained green (fluorescein) and B220+ cells are stained red (Texas red). Non-Tg recipients of unstimulated IgTg B cells (A) and IgTg  B cells pulsed in vitro with 1 (B), 20 (C), and 100 ng/ml HEL (D). The follicle (F) and outer PALS (O) are indicated.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199013&req=5

Figure 1: Outer PALS arrest of naive B cells is induced by BCR ligation with antigen. Fluorescent micrographs of frozen sections of spleen. HEL-binding B cells are stained green (fluorescein) and B220+ cells are stained red (Texas red). Non-Tg recipients of unstimulated IgTg B cells (A) and IgTg B cells pulsed in vitro with 1 (B), 20 (C), and 100 ng/ml HEL (D). The follicle (F) and outer PALS (O) are indicated.
Mentions: The proposition that BCR ligation is the major determinant of outer PALS arrest was investigated using IgTg B cells expressing a high affinity anti-HEL receptor (1). Purified B cells obtained from the spleens of IgTg mice were pulsed with graded doses of soluble HEL in vitro and transferred into non-Tg syngeneic recipients (summarized in Table 1). In the absence of BCR ligation (Fig. 1 A), or after pulsing with 1 ng/ml of HEL (Fig. 1 B), the B cells migrated into the follicles unimpeded. A threshold for outer PALS arrest was observed at ∼20 ng/ml of HEL (Fig. 1 C), a concentration corresponding to occupation of ∼50% of surface Ig molecules on each B cell (24). When the B cells were pulsed with 100 ng/ml of HEL, which resulted in >95% receptor occupancy, there was near total arrest of B cells in the outer PALS for at least 24 h (Fig. 1 D). The crucial factor in determining the positioning of B cells at this site appeared to be the concentration of antigen rather than the duration of exposure to antigen in vitro, as similar results were obtained with B cells pulsed for 0.5, 4, and 12 h before transfer (not shown).

Bottom Line: In addition, tolerant B cells were found to relocate from the follicles to the outer PALS of HEL/anti-HEL double Tg mice in which the concentration of soluble self-antigen had been increased by zinc feeding.Thus, subtle variations in antigen concentration resulted in dramatic changes in positioning of B cells within the spleen.A series of mixed bone marrow chimeras in which the effective antigen concentration was inversely related to the number of self-reactive B cells due to absorption of antigen by transgene-encoded membrane and secreted Ig, was used to confirm that alteration in B cell position previously attributed to changes in follicular composition could be explained on the basis of available antigen concentration, rather than the diversity of the repertoire.

View Article: PubMed Central - PubMed

Affiliation: Centenary Institute for Cancer Medicine and Cell Biology, Newtown, Sydney, New South Wales, Australia 2042.

ABSTRACT
T-dependent B cell responses in the spleen are initiated in the outer periarteriolar lymphoid sheath (PALS) and culminate in the generation of proliferative foci and germinal center reactions. By pulsing anti-hen egg lysozyme (HEL) immunoglobulin transgenic (IgTg) B cells with various concentrations of HEL in vitro before adoptive transfer into normal recipients, it was shown that a critical number of B cell receptors (BCRs) must be ligated for B cells to undergo arrest in the outer PALS. T cell help was manipulated independently of the BCR stimulus by incubating B cells expressing the appropriate major histocompatibility complex class II antigen with a peptide recognized by CD4(+) TCR Tg T cells. B cells which either failed to arrest in the outer PALS due to a subthreshold BCR stimulus, or arrested only transiently due to the brevity of the BCR stimulus, underwent an abortive response within the follicles when provided with T cell help. In contrast, naive B cells stimulated by a sustained, suprathreshold concentration of either foreign or self-antigen and given T cell help, proliferated in the outer PALS and then differentiated. Outer PALS arrest was not influenced by the nature of the B cells occupying the follicle, but appeared to be determined solely by the magnitude of BCR stimulation. Thus antigen-pulsed B cells arrested in the outer PALS in an identical manner irrespective of whether the follicles comprised a population of normal B cells with multiple specificities, a monoclonal naive population, or a monoclonal population of tolerant B cells. In addition, tolerant B cells were found to relocate from the follicles to the outer PALS of HEL/anti-HEL double Tg mice in which the concentration of soluble self-antigen had been increased by zinc feeding. Similarly, when anti-HEL Tg mice were crossed with a second HEL Tg strain expressing a higher concentration of soluble HEL, the tolerant anti-HEL Tg B cells were located constitutively in the outer PALS. Thus, subtle variations in antigen concentration resulted in dramatic changes in positioning of B cells within the spleen. A series of mixed bone marrow chimeras in which the effective antigen concentration was inversely related to the number of self-reactive B cells due to absorption of antigen by transgene-encoded membrane and secreted Ig, was used to confirm that alteration in B cell position previously attributed to changes in follicular composition could be explained on the basis of available antigen concentration, rather than the diversity of the repertoire.

Show MeSH
Related in: MedlinePlus