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Monoclonal antibody-directed targeting of fluorescent polystyrene microspheres to Peyer's patch M cells
J Pappo1, T H Ermak, H J Steger
1Cell Biology and Aging Section, Veterans Administration Medical Center, San Francisco, CA 94121.
Abstract:
The ability to deliver particulates to Peyer's patch M cells for uptake into gut-associated lymphoid tissue was examined by administering simultaneously fluorescent green and red polystyrene microspheres into NZW rabbit intestinal loops containing Peyer's patches. Whereas green and red microspheres were taken up by M cells at equivalent concentrations (120 +/- 17 versus 125 +/- 18/mm length of dome), particles conjugated to the anti-M-cell monoclonal antibody 5B11 (IgM, kappa) were internalized by M cells 3-3.5 times more efficiently than conjugates displaying IgM of unrelated specificity (TEPC 183) or native particles of the reciprocal colour inoculated into the same loop at a comparable load. The microspheres formed a concentration gradient from lumen to subepithelial dome, and localized on M-cell apical membranes, M-cell pockets, and subepithelial domes. The transport rate across M cells of 5B11 or TEPC 183 conjugates was similar to that of untreated microspheres. These observations show that intestinal uptake into Peyer's patches can be upregulated by targeting M-cell luminal membrane structures.
Insights
Targeting Peyer's patch M cells with specific antibodies significantly enhances particle uptake into gut-associated lymphoid tissue. This antibody-mediated delivery offers a promising strategy for improving intestinal immune system targeting.
Area of Science:
- Immunology
- Gastroenterology
- Biotechnology
Background:
- Peyer's patches are crucial inductive sites for gut-associated lymphoid tissue (GALT).
- M cells within Peyer's patches facilitate antigen sampling from the intestinal lumen.
- Efficient delivery of particulates to M cells is key for mucosal immune responses.
Purpose of the Study:
- To investigate methods for enhancing the delivery of particulates to Peyer's patch M cells.
- To evaluate the efficacy of antibody-targeted delivery for M cell uptake.
- To understand the transport dynamics of targeted and non-targeted particles across M cells.
Main Methods:
- Administration of fluorescently labeled polystyrene microspheres into rabbit intestinal loops containing Peyer's patches.
- Simultaneous inoculation of green and red microspheres to compare uptake.
- Conjugation of microspheres to anti-M-cell monoclonal antibody (5B11) or irrelevant antibody (TEPC 183).
- Quantification of microsphere uptake by M cells and analysis of their distribution.
Main Results:
- M cells exhibited equivalent uptake of non-targeted green and red microspheres.
- Antibody-conjugated microspheres (5B11) were internalized 3-3.5 times more efficiently than controls.
- Microspheres localized to M-cell apical membranes, pockets, and subepithelial domes.
- Transport rate across M cells was similar for targeted and non-targeted microspheres.
Conclusions:
- Targeting luminal membrane structures of M cells with specific antibodies upregulates intestinal uptake into Peyer's patches.
- Antibody-mediated delivery offers a strategy to enhance the efficiency of particulate transport to GALT.
- This approach holds potential for improving oral vaccine delivery and therapeutic agent targeting.