Biology subjects

Aguilar, M. S.

Publications and source records attributed to Aguilar, M. S..

3 recordsLinked to original sources

bioRxiv2023

Vaccination with mycobacterial lipid loaded nanoparticle leads to lipid antigen persistence and memory differentiation of antigen-specific T cells

Mycobacterium tuberculosis (Mtb) infection elicits both protein and lipid antigen-specific T cell responses. However, the incorporation of lipid antigens into subunit vaccine strategies and formulations has been underexplored, and the characteristics of vaccine-induced Mtb lipid-specific memory T cells have remained elusive. Mycolic acid (MA), a major lipid component of the Mtb cell wall, is presented by human CD1b molecules to unconventional T cell subsets. These MA-specific CD1b-restricted T cells have been detected in the blood and disease sites of Mtb-infected individuals, suggesting that MA is a promising lipid antigen for incorporation into multicomponent subunit vaccines. In this study, we utilized the enhanced stability of bicontinuous nanospheres (BCN) to efficiently encapsulate MA for in vivo delivery to MA-specific T cells, both alone and in combination with an immunodominant Mtb protein antigen (Ag85B). Pulmonary administration of MA-loaded BCN (MA-BCN) elicited MA-specific T cell responses in humanized CD1 transgenic mice. Simultaneous delivery of MA and Ag85B within BCN activated both MA- and Ag85B-specific T cells. Notably, pulmonary vaccination with MA-Ag85B-BCN resulted in the persistence of MA, but not Ag85B, within alveolar macrophages in the lung. Vaccination of MA-BCN through intravenous or subcutaneous route, or with attenuated Mtb likewise reproduced MA persistence. Moreover, MA-specific T cells in MA-BCN-vaccinated mice differentiated into a T follicular helper-like phenotype. Overall, the BCN platform allows for the dual encapsulation and in vivo activation of lipid and protein antigen-specific T cells and leads to persistent lipid depots that could offer long-lasting immune responses.

immunology↗

bioRxiv2022

MR1-restricted T cell clonotypes are associated with 'resistance' to M.tuberculosis infection

T cells are required for a protective immune response against the human adapted pathogen Mycobacterium tuberculosis (M.tb). We recently described a cohort of Ugandan household contacts of tuberculosis cases that appear to resist M.tb infection (RSTRs) and showed that these individuals harbor IFN-{gamma} independent T cell responses to M.tb-specific peptide antigens. However, T cells also recognize non-protein antigens via antigen presenting systems that are independent of genetic background, leading to their designation as donor-unrestricted T (DURT) cells. We used combinatorial tetramer staining and multi-parameter flow cytometry to comprehensively characterize the association between DURTs and resistance to M.tb infection. We did not observe a difference in peripheral blood frequencies of invariant natural killer T (iNKT) cells, germline encoded mycolyl-reactive (GEM) T cells, or {gamma}{delta} T cells between RSTRs and matched controls with latent M.tb infection (LTBIs). However, we did observe a 1.65-fold increase in frequency of circulating MR1-restricted T (MR1T) cells among RSTRs in comparison with LTBI (p=0.03). Multi-modal single cell RNA-sequencing of 18,251 MR1T cells sorted from a subset of donors revealed 5150 clonotypes that expressed a common transcriptional program, the majority of which were private. Deep sequencing of the TCR- repertoire revealed several DURT clonotypes that were expanded among RSTRs, including at least two MR1T clonotypes. Taken together, our data reveal unexpected donor-specific diversity in the TCR repertoire of human MR1T cells as well as associations between MR1 clonotypes and resistance to M.tb infection.

immunology↗

bioRxiv2020

CD4 and CD8 co-receptors modulate functional avidity of CD1b-restricted T cells.

CD4 and CD8 co-receptors define distinct lineages of T cells restricted by major histocompatibility complex (MHC) Class II and I molecules, respectively. Co-receptors interact with the T cell receptor (TCR) at the surface of MHC-restricted T cells to facilitate antigen recognition, thymic selection, and functional differentiation. T cells also recognize lipid antigens presented by CD1 molecules, but the role that CD4 and CD8 play in lipid antigen recognition is unknown. We studied the effect of CD4 and CD8 on the avidity, activation, and function of T cells specific for two CD1b-presented mycobacterial lipid antigens, glucose monomycolate (GMM) and diacylated sulfoglycolipids (SGL). In a human cohort study using SGL-loaded CD1b tetramers, we discovered a hierarchy among SGL-specific T cells in which T cells expressing the CD4 or CD8 co-receptor stain with a higher tetramer mean fluorescence intensity (MFI) than CD4-CD8- T cells. To determine the role of the TCR co-receptor in lipid antigen recognition, we exogenously expressed GMM and SGL-specific TCRs in Jurkat or polyclonal T cells and quantified tetramer staining and activation thresholds. Transduced CD4+ primary T cells bound the lipid-loaded CD1b tetramer with a higher MFI than CD8+ primary T cells, and transduced CD8+ Jurkat cells bound the SGL-CD1b tetramer with higher MFI than CD4-CD8- Jurkat cells. The presence of either co-receptor also decreased the threshold for IFN-{gamma} secretion. Further, co-receptor expression increased surface expression of CD3{varepsilon}, suggesting a mechanism for increased tetramer binding and activation. Finally, we used single-cell sequencing to define the TCR repertoire and ex vivo functional profiles of SGL-specific T cells from individuals with M.tb disease. We found that CD8+ T cells specific for SGL express canonical markers associated with cytotoxic T lymphocytes, while CD4+ T cells could be classified as T regulatory or T follicular helper cells. Among SGL-specific T cells, only those expressing the CD4 co-receptor also expressed Ki67, suggesting that they were actively proliferating at the time of sample collection. Together, these data reveal that expression of CD4 and CD8 co-receptor modulates TCR avidity for lipid antigen, leading to functional diversity and differences in in vivo proliferation during M.tb disease.

immunology↗