Macropinocytosis is responsible for the uptake of pathogenic and non-pathogenic mycobacteria by B lymphocytes (Raji cells)

BMC Microbiology

Research Article

Hilda Villegas-Castrejón¹  Alma Delia Hernández-Pérez¹  Angel Caamal-Ley²  Julieta Luna-Herrera²  Jorge Ismael Castañeda-Sánchez²  Ethel García-Latorre²  Ana Rosa Muñóz-Duarte²  Blanca Estela García-Pérez²  Juan José De la Cruz-López² 

[1] Electron Microscopy Laboratory, Instituto Nacional de Rehabilitación, Av. México-Xochimilco No. 289, Col. El Arenal de Guadalupe, Tlalpan, México, D.F, México;Immunology Department, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala s/n, Z.P. 11340, México, D.F, México;

关键词: Macropinocytosis;    B lymphocytes;    Raji cells;    Mycobacterium smegmatis;    Mycobacterium tuberculosis;    Salmonella typhimurium;    Cytoskeleton;   

DOI  :  10.1186/1471-2180-12-246

 received in 2012-01-27, accepted in 2012-10-12,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe classical roles of B cells include the production of antibodies and cytokines and the generation of immunological memory, these being key factors in the adaptive immune response. However, their role in innate immunity is currently being recognised. Traditionally, B cells have been considered non-phagocytic cells; therefore, the uptake of bacteria by B cells is not extensively documented. In this study, we analysed some of the features of non-specific bacterial uptake by B lymphocytes from the Raji cell line. In our model, B cells were infected with Mycobacterium tuberculosis (MTB), Mycobacterium smegmatis (MSM), and Salmonella typhimurium (ST).ResultsOur observations revealed that the Raji B cells were readily infected by the three bacteria that were studied. All of the infections induced changes in the cellular membrane during bacterial internalisation. M. smegmatis and S. typhimurium were able to induce important membrane changes that were characterised by abundant filopodia and lamellipodia formation. These membrane changes were driven by actin cytoskeletal rearrangements. The intracellular growth of these bacteria was also controlled by B cells. M. tuberculosis infection also induced actin rearrangement-driven membrane changes; however, the B cells were not able to control this infection. The phorbol 12-myristate 13-acetate (PMA) treatment of B cells induced filopodia and lamellipodia formation, the production of spacious vacuoles (macropinosomes), and the fluid-phase uptake that is characteristic of macropinocytosis. S. typhimurium infection induced the highest fluid-phase uptake, although both mycobacteria also induced fluid uptake. A macropinocytosis inhibitor such as amiloride was used and abolished the bacterial uptake and the fluid-phase uptake that is triggered during the bacterial infection.ConclusionsRaji B cells can internalise S. typhimurium and mycobacteria through an active process, such as macropinocytosis, although the resolution of the infection depends on factors that are inherent in the virulence of each pathogen.

【 授权许可】

Unknown   
© García-Pérez et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.