Humans but not muroid rodents express group 1 CD1 molecules, CD1a, b, and c. Interestingly, group 1 CD1 molecules are closely tied to anti-mycobacterial immunity because they can present a variety of mycobacteria-derived lipid antigens and group 1 CD1-specific T cell responses are detected at higher frequencies in Mycobacterium tuberculosis (Mtb) infected individuals. However, due to the lack of a small animal model, there is no direct evidence of the protective capacity of group 1 CD1-restricted T cells. Therefore, my lab generated a transgenic mouse model (hCD1Tg) that harbored the human group 1 CD1 locus and supported the development of group 1 CD1-restricted T cells. Infection of hCD1Tg mice with Mtb generated group 1 CD1-restricted Mtb lipid antigen-specific T cell responses. In addition, adoptive transfer of group 1 CD1-restricted T cells conferred protection against infection. Taken together, these data indicate that group 1 CD1-restricted T cells play a role in adaptive immunity to Mtb and could serve as vaccine targets. This proposal seeks to further elucidate the role of group 1 CD1-restricted T cells in different stages of Mtb infection and evaluate whether group 1 CD1-restricted T cells play a role in immunity against other bacterial pathogens.
In aim 1, we will evaluate whether memory group 1 CD1-restricted T cells can be generated in secondary Mtb infection and determine the molecular and cellular events associated with the induction of memory group 1 CD1-restricted T cells. While group 1 CD1-restricted Mtb lipid antigen-specific T cells are present during early stages of Mtb infection, autoreactive group 1 CD1-restricted T cells expand at later stages in the lung of infected mice.
In aim 2, we will evaluate the surface phenotype, functional properties of these T cells and determine whether they play a protective role during Mtb infection. In addition, we will compare the activation requirements of autoreactive and Mtb lipid-specific group 1 CD1- restricted T cells during Mtb infection. The group 1 CD1-restricted microbial lipid antigens identified thus far are mainly of mycobacterial origin. There is relatively little known about the role group 1 CD1-restricted T cells play in immunity against other bacterial pathogens. We have selected Staphylococcus aureus (SA) because it is one of the most frequently isolated pathogens associated with nosocomial infections and SA contains several lipids that share common features with CD1-binding antigens.
In aim 3, we propose to assess the kinetics, expansion, and function of group 1 CD1-restricted T cells in the context of a systemic SA infection and identify the structure of stimulatory SA lipid antigens. Collectively, these studies will lead to a better understanding of how group 1 CD1-restricted T cells contribute to protective immunity against Mtb and SA and whether they can be targeted for the development of lipid antigen-based vaccines.
Group 1 CD1-restricted T cells are good targets for vaccine design because they respond to similar lipid antigens in most individuals. In this study, we propose to characterize group 1 CD1-restricted T cell responses during Mycobacterium tuberculosis (Mtb) and Staphylococcus aureus (SA) infection. Both Mtb and SA are bacterial pathogens of immense clinical relevance. However, there are no effective vaccines against these bacteria. Therefore, understanding of the contribution of group 1 CD-1 restricted T cells in immune protection or immune pathology during infections will facilitate the development of vaccine strategies that target these T cells.
|Bagchi, Sreya; Genardi, Samantha; Wang, Chyung-Ru (2018) Linking CD1-Restricted T Cells With Autoimmunity and Dyslipidemia: Lipid Levels Matter. Front Immunol 9:1616|
|Bagchi, Sreya; He, Ying; Zhang, Hong et al. (2017) CD1b-autoreactive T cells contribute to hyperlipidemia-induced skin inflammation in mice. J Clin Invest 127:2339-2352|
|Bian, Yao; Shang, Shaobin; Siddiqui, Sarah et al. (2017) MHC Ib molecule Qa-1 presents Mycobacterium tuberculosis peptide antigens to CD8+ T cells and contributes to protection against infection. PLoS Pathog 13:e1006384|
|Zhao, Jie; Siddiqui, Sarah; Shang, Shaobin et al. (2015) Mycolic acid-specific T cells protect against Mycobacterium tuberculosis infection in a humanized transgenic mouse model. Elife 4:|
|Siddiqui, Sarah; Visvabharathy, Lavanya; Wang, Chyung-Ru (2015) Role of Group 1 CD1-Restricted T Cells in Infectious Disease. Front Immunol 6:337|
|Weng, Xiufang; Liao, Chia-Min; Bagchi, Sreya et al. (2014) The adaptor protein SAP regulates type II NKT-cell development, cytokine production, and cytotoxicity against lymphoma. Eur J Immunol 44:3646-57|
|Bediako, Yaw; Bian, Yao; Zhang, Hong et al. (2012) SAP is required for the development of innate phenotype in H2-M3--restricted Cd8(+) T cells. J Immunol 189:4787-96|
|Cho, Hoonsik; Choi, Hak-Jong; Xu, Honglin et al. (2011) Nonconventional CD8+ T cell responses to Listeria infection in mice lacking MHC class Ia and H2-M3. J Immunol 186:489-98|
|Li, Sha; Choi, Hak-Jong; Felio, Kyrie et al. (2011) Autoreactive CD1b-restricted T cells: a new innate-like T-cell population that contributes to immunity against infection. Blood 118:3870-8|
|Felio, Kyrie; Nguyen, Hanh; Dascher, Christopher C et al. (2009) CD1-restricted adaptive immune responses to Mycobacteria in human group 1 CD1 transgenic mice. J Exp Med 206:2497-509|
Showing the most recent 10 out of 12 publications