Biology subjects

Fry, L. M.

Publications and source records attributed to Fry, L. M..

4 recordsLinked to original sources

bioRxiv2024

Ability of mycobacterial pathogens to establish a persistent infection is lost by deletion of a single gene, rel, regulator of the stringent response

Studies in a mouse model revealed Mycobacterium tuberculosis (Mtb) with a deletion of rel, regulator of the stringent response, could not establish a persistent infection. Studies in cattle with a Mycobacterium. a. paratuberculosis rel deletion mutant revealed inability to establish a persistent infection was associated with development of CD8 cytotoxic T cells (CTL) that kill intracellular bacteria. Further comparative studies ex vivo with Mbv Calmette-Guerin (BCG) and a BCG rel deletion mutant revealed no clear difference in development of CTL in vitro. As reported, a study of the recall response was conducted with cattle vaccinated with either BCG or with BCGrel, to determine if information could be obtained that would show how gene products under control of rel interfere with the CTL response to mycobacterial pathogens in vivo. The study revealed the CTL response elicited by vaccination with BCG was impaired, in comparison with the response elicited by BCGrel. Comparative analysis of the recall response ex vivo revealed the functional impairment was not associated with the timing of appearance of the recall response, expression of IFN-{gamma}, TNF-, IL-17, or IL-22, or molecules that mediate intracellular killing. Further studies are needed to determine how CD8 CTL functional activity is modulated in vivo by gene products regulated by rel.

immunology↗

bioRxiv2023

Vaccination of cattle with a virus-vectored vaccine against a major membrane protein of Mycobacterium a. subsp. paratuberculosis elicits CD8 cytotoxic T cells that kill intracellular bacteria

Infection of cattle with Mycobacterium a. subsp. Paratuberculosis (Map), the causative agent of paratuberculosis, induces an immune response directed toward a 35 kD major membrane protein (MMP) of Map. CD8 cytotoxic T cells (CTL) are elicited when peripheral blood mononuclear cells from healthy cattle are incubated ex vivo with antigen-presenting cells (APC) primed with bacterial recombinant MMP. Ex vivo development of CTL was MHC-restricted and required the presence of both CD4 and CD8 T cells. The gene MAP2121c, encoding MMP, was modified to express a modified form of MMP (p35NN) in a mammalian cell line, also capable of eliciting an ex vivo CTL response. In the present study, the modified gene for p35NN was placed into a BoHV4 vector to determine the potential use of BoHV-4A{Delta}TK-p35NN as a peptide-based vaccine. Subcutaneous vaccination of healthy cattle with BoHV-4A{Delta}TK-p35NN elicited a CTL recall response, as detected ex vivo. Further studies are warranted to conduct a challenge study to determine if CD8 CTL elicited by vaccination with BoHV-4A{Delta}TK-p35NN prevents the establishment of a persistent infection by Map.

immunology↗

bioRxiv2021

Optimized Multicolour Immunofluorescence Panel for Cattle B Cell Phenotyping by an 8-Colour, 10-Parameter Panel

This 8-colour, 10-parameter panel has been optimised to distinguish between functionally distinct subsets of cattle B cells in both fresh and cryopreserved peripheral blood mononuclear cells (PBMCs). Existing characterised antibodies against cell surface molecules (immunoglobulin light chain (S-Ig(L)), CD20, CD21, CD40, CD71 and CD138) enabled the discrimination of 24 unique populations within the B cell population. This allows the identification of five putative functionally distinct B cell subsets critical to infection and vaccination responses; 1) naive B cells (BNaive), 2) regulatory B cells (BReg), 3) memory B cells (BMem), 4) plasmablasts (PB) and 5) plasma cells (PC). Although CD3 and CD8 can be included as an additional dump channel, it does not significantly improve the panels ability to separate "Classical" B cells. This panel will promote better characterisation and tracking of B cell responses in cattle as well as other bovid species as the reagents are likely to cross react.

immunology↗

bioRxiv2019

Cognate epitope recognition by bovine CD4 and CD8 T cells is essential for primary expansion of antigen-specific cytotoxic T-cells following ex vivo stimulation with a candidate Mycobacterium avium subsp. paratuberculosis peptide vaccine.

Studies in cattle show CD8 cytotoxic T cells (CTL), with the ability to kill intracellular bacteria, develop following stimulation of monocyte-depleted peripheral blood mononuclear cells (mdPBMC) with conventional dendritic cells (cDC) and monocyte-derived DC (MoDC) pulsed with MMP, a membrane protein from Mycobacterium avium subsp. paratuberculosis (Map) encoded by MAP2121c. CTL activity was diminished if CD4 T cells were depleted from mdPBMC before antigen (Ag) presentation by cDC and MoDC, suggesting simultaneous cognate recognition of MMP epitopes presented by MHC I and MHC II molecules might be essential for development of CTL activity. To clarify whether cognate recognition is essential for CTL development, studies were conducted with mdPBMC cultures in the presence of monoclonal antibodies (mAbs) specific for MHC class I and MHC class II molecules. The CTL response of mdPBMC to MMP-pulsed DC was completely blocked in the presence of mAbs to both MHC I and II molecules and also blocked in the presence of mAbs to either MHC I or MHC II. The results demonstrate CD4 T-cell help is essential for development of a primary CTL response to MMP, and indicate that cognate recognition is required for delivery of CD4 T-cell help during priming. Of importance, the findings provide support for the importance of CD4 and CD8 T-cell cognate antigen recognition in eliciting CTL responses to vaccines against intracellular pathogens. The methods described herein can be used to elucidate the intracellular interactions between lymphocytes and DC in humans and cattle.

immunology↗