Cell wall glycolipids from Corynebacterium pseudotuberculosis strains with different virulences differ in terms of composition and immune recognition

Abstract

Caseous lymphadenitis (CLA) is an infectious disease caused by Corynebacterium pseudotuberculosis in small ruminants and is characterized by the development of granulomas in the lymph nodes, spleen, liver, and lungs. Although little is known about the host-pathogen relationship of this bacterium, it was previously reported that the pathogen's lipids are important for its taxonomic classification and survival inside macrophages. However, there are no studies regarding the composition of these molecules. In this study, cell wall glycolipids from two C. pseudotuberculosis strains presenting different virulence profiles were purified and its composition was characterized. A difference was observed between the electrophoretic and chromatogram profiles for cell wall components from the two strains, mainly among molecules with low molecular weights. IgM from sheep with acute CLA recognized antigens with an estimated molecular weight of 11 kDa of the low-pathogenicity strain, while low-molecular weight antigens from the high-pathogenicity strain presented a lower recognition by these antibodies. Mass spectrometry analysis showed that the cell wall of the high-pathogenicity strain contained glycolipids with high amounts of unsaturated fatty acids and glycerophosphoinositols, which may contribute to the capacity of this strain to cause severe disease. In conclusion, it is indicated that cell wall non-protein antigens can play a key role in C. pseudotuberculosis virulence.

Avaliação de antígenos através do ensaio imunoenzimático ELISA ao longo de infecção experimental em caprinos com Corynebacterium pseudotuberculosis

“…O antígeno secretado BHI foi obtido da linhagem atenuada T1 de C. pseudotuberculosis (Carminati et al, 2003, com adaptações). Já o antígeno de membrana F3 foi produzido a partir da linhagem virulenta VD57 de C. pseudotuberculosis, de acordo com trabalho realizado por Rebouças et al (2020). Estas cepas fazem parte da Coleção de Culturas do Laboratório de Imunologia e Biologia Molecular do Instituto de Ciências da Saúde da Universidade Federal da Bahia (LABIMUNO-UFBA).…”

Comparative Characterization of Immune Response in Sheep with Caseous Lymphadenitis through Analysis of the Whole Blood Transcriptome

“…Sheep infected with Cp experience a slow progression of encapsulated pyogranulomas, which eventually lead to the formation of larger abscesses in superficial or visceral lymph nodes and organs, such as the lungs, liver, and kidneys [ 10 , 11 ]. The main factors contributing to the virulence of Cp are its cell wall lipids and exotoxin phospholipase D, which promote bacterial persistence and spread within the host and result in macrophage death and chronic inflammation [ 12 , 13 , 14 ]. Researchers are currently conducting genomic and proteomic studies to identify Cp ’s antigenic potential and pathogenicity islands involved in evading the host’s immune system.…”