ER-mediated latex beads phagocytosis and its influence in cross presentation of a soluble protein (2006)
- USP affiliated authors: BARCINSKI, MARCELLO ANDRE - ICB
- Unidades: ICB
- Subjects: PARASITOLOGIA
- Language: Inglês
- Abstract: Introduction and Objectives:MHC I molecules present peptides from intracellular proteins, whereas MHC II molecules present peptides from exogenous ones. Exogenous antigens can also be presented by MHC I through cross presentation. The Endoplasmic Reticulum (ER) mediated Phagocytosis provides a mechanism by which phagosomes could process and load exogenous antigens on MHC I molecules. We reasoned if the phagocytic load determine the ER membrane recruitment and consequently the ability to cross present an exogenous soluble antigen. Methods and Results:Cross presentation assays were performed with peritoneal macrophages (MØ) incubated with soluble ovalbumin (sOVA), beads (3.0mm) and OT-I cells. 3H-TdR incorporation was measured after a 3 day-culture. sOVA cross presentation was potentiated by the presence of latex beads. 1000 or 200 beads/MØ + sOVA were 2.4 and 1.75 fold more efficient in activating OT-I cells than sOVA only. Using confocal microscopy, ER membranes (calnexin+, TAP1+, and SEC61 +) were seen in phagosomes of MØ which had phagocytosed low or high numbers of beads (ranging from 1 to 6), suggesting that phagocytic load does not interfere with ER membrane usage.Surprisingly, the expression of Kb, CD80 and CD86 surface molecules did not change with the increase in the bead load and the amount of sOVA endocytosed is diminished (4.2 fold) at high bead/MØ ratios in comparison to the control (sOVA only). sOVA was displayed in citoplasmicvacuoles, but when MØ were incubated with sOVA and beads it seemed to occur an association between the sOVA containing endossome and the bead phagosomes. This is currently being studied by electron microscopy. Conclusion:ER molecules are present in phagosomes, regardless the number of phagosomes per cell. However, the higher the number of beads, the better the cross presentation of sOVA. These suggest a direct correlation between phagocytic rate and cross presentation apparently not set by differential ER use. Our data shows a possible mechanism by which beads promote the significative increase in cross presentation of a soluble antigen, allowing the antigen entry in a competent phagosome.
- Título do periódico: Abstracts
- Conference title: Meeting of the Brazilian Society for Immunology
ABNTBENJAMIN, A; SOUZA, N C C; SEABRA, S H; et al. ER-mediated latex beads phagocytosis and its influence in cross presentation of a soluble protein. Anais.. São Paulo: [s.n.], 2006.
APABenjamin, A., Souza, N. C. C., Seabra, S. H., Santiago, M. F., Barcinski, M. A., & Bonomo, A. (2006). ER-mediated latex beads phagocytosis and its influence in cross presentation of a soluble protein. In Abstracts. São Paulo.
NLMBenjamin A, Souza NCC, Seabra SH, Santiago MF, Barcinski MA, Bonomo A. ER-mediated latex beads phagocytosis and its influence in cross presentation of a soluble protein. Abstracts. 2006 ;
VancouverBenjamin A, Souza NCC, Seabra SH, Santiago MF, Barcinski MA, Bonomo A. ER-mediated latex beads phagocytosis and its influence in cross presentation of a soluble protein. Abstracts. 2006 ;
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