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Dendritic cells pulsed with intact Streptococcus pneumoniae elicit both protein- and polysaccharide-specific immunoglobulin isotype responses in vivo through distinct mechanisms.

Colino J, Shen Y, Snapper CM - J. Exp. Med. (2002)

Bottom Line: Immature bone marrow-derived myeloid dendritic cells (BMDCs) are induced to undergo phenotypic maturation and secretion of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-12, and IL-10 when pulsed in vitro with intact Streptococcus pneumoniae.After transfer to naive mice, pulsed BMDCs induce immunoglobulin (Ig) isotype responses specific for both protein and polysaccharide pneumococcal antigens, having in common the requirement for viable BMDCs, T cells, and B7-dependent costimulation in the recipient mice.Whereas primary Ig isotype responses to bacterial proteins uniformly require BMDC expression of major histocompatibility complex class II, CD40, and B7, and the secretion of IL-6, but not IL-12, similar requirements for antipolysaccharide Ig responses were only observed for the IgG1 isotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.

ABSTRACT
Immature bone marrow-derived myeloid dendritic cells (BMDCs) are induced to undergo phenotypic maturation and secretion of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-12, and IL-10 when pulsed in vitro with intact Streptococcus pneumoniae. After transfer to naive mice, pulsed BMDCs induce immunoglobulin (Ig) isotype responses specific for both protein and polysaccharide pneumococcal antigens, having in common the requirement for viable BMDCs, T cells, and B7-dependent costimulation in the recipient mice. Whereas primary Ig isotype responses to bacterial proteins uniformly require BMDC expression of major histocompatibility complex class II, CD40, and B7, and the secretion of IL-6, but not IL-12, similar requirements for antipolysaccharide Ig responses were only observed for the IgG1 isotype.

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Phagocyted bacteria are not the immunogen by themselves. Groups of five C57BL/6 mice were injected intravenously with either 106 viable BMDCs pulsed with S. pneumoniae type 14 (live BMDCs) or pulsed BMDCs after three cycles of freeze-thaw (freeze-thaw BMDCs). Serum samples were collected at day 14 and serum titers of antigen specific Ig isotypes were determined by ELISA. The data show the arithmetic mean ± SEM of the individual titers.
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fig4: Phagocyted bacteria are not the immunogen by themselves. Groups of five C57BL/6 mice were injected intravenously with either 106 viable BMDCs pulsed with S. pneumoniae type 14 (live BMDCs) or pulsed BMDCs after three cycles of freeze-thaw (freeze-thaw BMDCs). Serum samples were collected at day 14 and serum titers of antigen specific Ig isotypes were determined by ELISA. The data show the arithmetic mean ± SEM of the individual titers.

Mentions: We next wished to determine whether pulsed DCs played an active role in initiating in vivo Ig responses, or perhaps were serving as nonspecific and passive carriers of antigen. Thus, BMDCs were first pulsed with S. pneumoniae type 14, then the excess of bacteria was washed and immediately fixed in formaldehyde before transfer into naive mice. As shown in Fig. 3 , BMDCs viability was critical for both anti-PspA and antipolysaccharide Ig responses. Similar results were obtained when BMDCs were pulsed with the nonencapsulated R36A strain, then fixed in ethanol before transfer (data not shown). The Ig induction was specific for BMDCs since viable thymocytes incubated with bacteria also failed to induce detectable antigen-specific Ig responses (Fig. 3), ruling out the possibility that carry-over of free bacteria was responsible for the observed Ig responses in vivo. Moreover, immunization with BMDCs which were first pulsed with S. pneumoniae, then freeze-thawed immediately before injection, did not induce detectable antiprotein- or antipolysaccharide-specific Ig responses (Fig. 4) . These data strongly suggest that internalized bacteria, in the absence of viable BMDCs, were not immunogenic by themselves. Collectively, these data demonstrate an active role for pulsed BMDCs in mediating both protein- and polysaccharide-specific Ig responses in vivo.


Dendritic cells pulsed with intact Streptococcus pneumoniae elicit both protein- and polysaccharide-specific immunoglobulin isotype responses in vivo through distinct mechanisms.

Colino J, Shen Y, Snapper CM - J. Exp. Med. (2002)

Phagocyted bacteria are not the immunogen by themselves. Groups of five C57BL/6 mice were injected intravenously with either 106 viable BMDCs pulsed with S. pneumoniae type 14 (live BMDCs) or pulsed BMDCs after three cycles of freeze-thaw (freeze-thaw BMDCs). Serum samples were collected at day 14 and serum titers of antigen specific Ig isotypes were determined by ELISA. The data show the arithmetic mean ± SEM of the individual titers.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2196017&req=5

fig4: Phagocyted bacteria are not the immunogen by themselves. Groups of five C57BL/6 mice were injected intravenously with either 106 viable BMDCs pulsed with S. pneumoniae type 14 (live BMDCs) or pulsed BMDCs after three cycles of freeze-thaw (freeze-thaw BMDCs). Serum samples were collected at day 14 and serum titers of antigen specific Ig isotypes were determined by ELISA. The data show the arithmetic mean ± SEM of the individual titers.
Mentions: We next wished to determine whether pulsed DCs played an active role in initiating in vivo Ig responses, or perhaps were serving as nonspecific and passive carriers of antigen. Thus, BMDCs were first pulsed with S. pneumoniae type 14, then the excess of bacteria was washed and immediately fixed in formaldehyde before transfer into naive mice. As shown in Fig. 3 , BMDCs viability was critical for both anti-PspA and antipolysaccharide Ig responses. Similar results were obtained when BMDCs were pulsed with the nonencapsulated R36A strain, then fixed in ethanol before transfer (data not shown). The Ig induction was specific for BMDCs since viable thymocytes incubated with bacteria also failed to induce detectable antigen-specific Ig responses (Fig. 3), ruling out the possibility that carry-over of free bacteria was responsible for the observed Ig responses in vivo. Moreover, immunization with BMDCs which were first pulsed with S. pneumoniae, then freeze-thawed immediately before injection, did not induce detectable antiprotein- or antipolysaccharide-specific Ig responses (Fig. 4) . These data strongly suggest that internalized bacteria, in the absence of viable BMDCs, were not immunogenic by themselves. Collectively, these data demonstrate an active role for pulsed BMDCs in mediating both protein- and polysaccharide-specific Ig responses in vivo.

Bottom Line: Immature bone marrow-derived myeloid dendritic cells (BMDCs) are induced to undergo phenotypic maturation and secretion of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-12, and IL-10 when pulsed in vitro with intact Streptococcus pneumoniae.After transfer to naive mice, pulsed BMDCs induce immunoglobulin (Ig) isotype responses specific for both protein and polysaccharide pneumococcal antigens, having in common the requirement for viable BMDCs, T cells, and B7-dependent costimulation in the recipient mice.Whereas primary Ig isotype responses to bacterial proteins uniformly require BMDC expression of major histocompatibility complex class II, CD40, and B7, and the secretion of IL-6, but not IL-12, similar requirements for antipolysaccharide Ig responses were only observed for the IgG1 isotype.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.

ABSTRACT
Immature bone marrow-derived myeloid dendritic cells (BMDCs) are induced to undergo phenotypic maturation and secretion of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-12, and IL-10 when pulsed in vitro with intact Streptococcus pneumoniae. After transfer to naive mice, pulsed BMDCs induce immunoglobulin (Ig) isotype responses specific for both protein and polysaccharide pneumococcal antigens, having in common the requirement for viable BMDCs, T cells, and B7-dependent costimulation in the recipient mice. Whereas primary Ig isotype responses to bacterial proteins uniformly require BMDC expression of major histocompatibility complex class II, CD40, and B7, and the secretion of IL-6, but not IL-12, similar requirements for antipolysaccharide Ig responses were only observed for the IgG1 isotype.

Show MeSH
Related in: MedlinePlus