from III - Dendritic cells and adaptive immune responses to bacteria
Published online by Cambridge University Press: 12 August 2009
INTRODUCTION
Immunity to a bacterial pathogen requires the generation of bacteria-specific T cells with appropriate effector function. Eliciting T cells during infection requires internalization of the bacteria and processing of bacterial proteins to generate peptides for presentation on major histocompatibility complex (MHC) class I (MHC-I) and/or MHC class II (MHC-II) molecules, depending on the pathogen. As not all host cells have the capacity to phagocytose bacteria, and not all bacterial pathogens have the capacity to actively invade non-phagocytic cells, phagocytic antigen presenting cells, macrophages and immature dendritic cells (DCs), are the key players in generating adaptive immunity to bacteria.
Both macrophages and immature dendritic cells can present antigens from the bacteria they internalize on their own MHC-I and MHC-II molecules and thus carry out so-called direct presentation of bacterial antigens (Sundquist et al., 2004; Harding et al., 2003). Direct presentation of bacterial antigens on MHC-II is the expected outcome following phagocytosis of bacteria and is the event necessary to elicit CD4+ T cells. However, both macrophages and DCs can also present antigens from internalized bacteria on MHC-I, molecules most renowned for their presentation of peptides derived from endogenously synthesized proteins (Rock and Goldberg, 1999), and generate CD8+ T cells (Sundquist et al., 2004; Harding et al., 2003).
Given the capacity of both macrophages and DCs to directly present bacterial antigens on MHC-I and MHC-II, these cells in principle could initiate adaptive immunity during primary infection. However, it is only DCs that have this ability (Banchereau and Steinman, 1998).
To save this book to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.