Limits...
In vivo, multimodal imaging of B cell distribution and response to antibody immunotherapy in mice.

Thorek DL, Tsao PY, Arora V, Zhou L, Eisenberg RA, Tsourkas A - PLoS ONE (2010)

Bottom Line: Cellular imaging of the targeted population in vivo may provide significant insight towards effective therapy and a greater understanding of underlying disease mechanics.These data suggest that in vivo imaging can be used to follow B cell dynamics, but that the labeling method will need to be carefully chosen.SPIO labeling for tracking purposes, generally thought to be benign, appears to interfere with B cell functions and requires further examination.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT

Background: B cell depletion immunotherapy has been successfully employed to treat non-Hodgkin's lymphoma. In recent years, increasing attention has been directed towards also using B-cell depletion therapy as a treatment option in autoimmune disorders. However, it appears that the further development of these approaches will depend on a methodology to determine the relation of B-cell depletion to clinical response and how individual patients should be dosed. Thus far, patients have generally been followed by quantification of peripheral blood B cells, but it is not apparent that this measurement accurately reflects systemic B cell dynamics.

Methodology/principal findings: Cellular imaging of the targeted population in vivo may provide significant insight towards effective therapy and a greater understanding of underlying disease mechanics. Superparamagnetic iron oxide (SPIO) nanoparticles in concert with near infrared (NIR) fluorescent dyes were used to label and track primary C57BL/6 B cells. Following antibody mediated B cell depletion (anti-CD79), NIR-only labeled cells were expeditiously cleared from the circulation and spleen. Interestingly, B cells labeled with both SPIO and NIR were not depleted in the spleen.

Conclusions/significance: Whole body fluorescent tracking of B cells enabled noninvasive, longitudinal imaging of both the distribution and subsequent depletion of B lymphocytes in the spleen. Quantification of depletion revealed a greater than 40% decrease in splenic fluorescent signal-to-background ratio in antibody treated versus control mice. These data suggest that in vivo imaging can be used to follow B cell dynamics, but that the labeling method will need to be carefully chosen. SPIO labeling for tracking purposes, generally thought to be benign, appears to interfere with B cell functions and requires further examination.

Show MeSH

Related in: MedlinePlus

In vivo fluorescent imaging of contrast-labeled B cells prior to and following B cell depletion therapy.A, Representative whole animal fluorescence images of B cells loaded with SPIO and NIR815 (groups i and ii) or just NIR815 (groups iii and iv) following injection into C57BL/6 mice. Prior to injection (day 0), no signal was evident in the NIR channel. Signal accumulated within the spleen by 24 h after the cell injection. Immediately following imaging on day 1, animals were injected with either anti-CD79 antibodies or PBS. Anti-CD79 treatment led to a rapid (by day 3) loss is signal in mice injected with B cells labeled with NIR815 only. B, The abundance of B cells, labeled with SPIO and NIR815, in the spleen was quantified by measuring the spleen-to-muscle signal–to-background ratio (SBR). Quantification of fluorescence revealed only a gradual loss in SBR following treatment with PBS (group I, solid line) and anti-CD79 antibodies (group ii, dashed line). No statistical significance was observed between the two groups (p<0.05). C, NIR815-labeled B cells (i.e. no SPIO) were rapidly depleted following administration of anti-CD79 antibodies (group iv, dashed line) compared with PBS-treated controls (group iii, solid line). Statistical significance for individual time points is indicated with an asterisk (p<0.05).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2871797&req=5

pone-0010655-g003: In vivo fluorescent imaging of contrast-labeled B cells prior to and following B cell depletion therapy.A, Representative whole animal fluorescence images of B cells loaded with SPIO and NIR815 (groups i and ii) or just NIR815 (groups iii and iv) following injection into C57BL/6 mice. Prior to injection (day 0), no signal was evident in the NIR channel. Signal accumulated within the spleen by 24 h after the cell injection. Immediately following imaging on day 1, animals were injected with either anti-CD79 antibodies or PBS. Anti-CD79 treatment led to a rapid (by day 3) loss is signal in mice injected with B cells labeled with NIR815 only. B, The abundance of B cells, labeled with SPIO and NIR815, in the spleen was quantified by measuring the spleen-to-muscle signal–to-background ratio (SBR). Quantification of fluorescence revealed only a gradual loss in SBR following treatment with PBS (group I, solid line) and anti-CD79 antibodies (group ii, dashed line). No statistical significance was observed between the two groups (p<0.05). C, NIR815-labeled B cells (i.e. no SPIO) were rapidly depleted following administration of anti-CD79 antibodies (group iv, dashed line) compared with PBS-treated controls (group iii, solid line). Statistical significance for individual time points is indicated with an asterisk (p<0.05).

Mentions: In addition to MR imaging, it was possible to detect and monitor the trafficking and distribution of the introduced B cell population via NIR fluorescence imaging (Fig. 3A). Acquisitions of both Alexa 680 (i.e. fluorescent label on SPIO) and CellVue NIR815 (membrane dye) were obtained; however, there was insufficient signal from the Alexa 680 dye to be detected above the autofluorescence of living animals (not shown).


In vivo, multimodal imaging of B cell distribution and response to antibody immunotherapy in mice.

Thorek DL, Tsao PY, Arora V, Zhou L, Eisenberg RA, Tsourkas A - PLoS ONE (2010)

In vivo fluorescent imaging of contrast-labeled B cells prior to and following B cell depletion therapy.A, Representative whole animal fluorescence images of B cells loaded with SPIO and NIR815 (groups i and ii) or just NIR815 (groups iii and iv) following injection into C57BL/6 mice. Prior to injection (day 0), no signal was evident in the NIR channel. Signal accumulated within the spleen by 24 h after the cell injection. Immediately following imaging on day 1, animals were injected with either anti-CD79 antibodies or PBS. Anti-CD79 treatment led to a rapid (by day 3) loss is signal in mice injected with B cells labeled with NIR815 only. B, The abundance of B cells, labeled with SPIO and NIR815, in the spleen was quantified by measuring the spleen-to-muscle signal–to-background ratio (SBR). Quantification of fluorescence revealed only a gradual loss in SBR following treatment with PBS (group I, solid line) and anti-CD79 antibodies (group ii, dashed line). No statistical significance was observed between the two groups (p<0.05). C, NIR815-labeled B cells (i.e. no SPIO) were rapidly depleted following administration of anti-CD79 antibodies (group iv, dashed line) compared with PBS-treated controls (group iii, solid line). Statistical significance for individual time points is indicated with an asterisk (p<0.05).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2871797&req=5

pone-0010655-g003: In vivo fluorescent imaging of contrast-labeled B cells prior to and following B cell depletion therapy.A, Representative whole animal fluorescence images of B cells loaded with SPIO and NIR815 (groups i and ii) or just NIR815 (groups iii and iv) following injection into C57BL/6 mice. Prior to injection (day 0), no signal was evident in the NIR channel. Signal accumulated within the spleen by 24 h after the cell injection. Immediately following imaging on day 1, animals were injected with either anti-CD79 antibodies or PBS. Anti-CD79 treatment led to a rapid (by day 3) loss is signal in mice injected with B cells labeled with NIR815 only. B, The abundance of B cells, labeled with SPIO and NIR815, in the spleen was quantified by measuring the spleen-to-muscle signal–to-background ratio (SBR). Quantification of fluorescence revealed only a gradual loss in SBR following treatment with PBS (group I, solid line) and anti-CD79 antibodies (group ii, dashed line). No statistical significance was observed between the two groups (p<0.05). C, NIR815-labeled B cells (i.e. no SPIO) were rapidly depleted following administration of anti-CD79 antibodies (group iv, dashed line) compared with PBS-treated controls (group iii, solid line). Statistical significance for individual time points is indicated with an asterisk (p<0.05).
Mentions: In addition to MR imaging, it was possible to detect and monitor the trafficking and distribution of the introduced B cell population via NIR fluorescence imaging (Fig. 3A). Acquisitions of both Alexa 680 (i.e. fluorescent label on SPIO) and CellVue NIR815 (membrane dye) were obtained; however, there was insufficient signal from the Alexa 680 dye to be detected above the autofluorescence of living animals (not shown).

Bottom Line: Cellular imaging of the targeted population in vivo may provide significant insight towards effective therapy and a greater understanding of underlying disease mechanics.These data suggest that in vivo imaging can be used to follow B cell dynamics, but that the labeling method will need to be carefully chosen.SPIO labeling for tracking purposes, generally thought to be benign, appears to interfere with B cell functions and requires further examination.

View Article: PubMed Central - PubMed

Affiliation: Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.

ABSTRACT

Background: B cell depletion immunotherapy has been successfully employed to treat non-Hodgkin's lymphoma. In recent years, increasing attention has been directed towards also using B-cell depletion therapy as a treatment option in autoimmune disorders. However, it appears that the further development of these approaches will depend on a methodology to determine the relation of B-cell depletion to clinical response and how individual patients should be dosed. Thus far, patients have generally been followed by quantification of peripheral blood B cells, but it is not apparent that this measurement accurately reflects systemic B cell dynamics.

Methodology/principal findings: Cellular imaging of the targeted population in vivo may provide significant insight towards effective therapy and a greater understanding of underlying disease mechanics. Superparamagnetic iron oxide (SPIO) nanoparticles in concert with near infrared (NIR) fluorescent dyes were used to label and track primary C57BL/6 B cells. Following antibody mediated B cell depletion (anti-CD79), NIR-only labeled cells were expeditiously cleared from the circulation and spleen. Interestingly, B cells labeled with both SPIO and NIR were not depleted in the spleen.

Conclusions/significance: Whole body fluorescent tracking of B cells enabled noninvasive, longitudinal imaging of both the distribution and subsequent depletion of B lymphocytes in the spleen. Quantification of depletion revealed a greater than 40% decrease in splenic fluorescent signal-to-background ratio in antibody treated versus control mice. These data suggest that in vivo imaging can be used to follow B cell dynamics, but that the labeling method will need to be carefully chosen. SPIO labeling for tracking purposes, generally thought to be benign, appears to interfere with B cell functions and requires further examination.

Show MeSH
Related in: MedlinePlus