Culture-attenuated pathogenic Leptospira lose the ability to survive to complement-mediated-killing due to lower expression of factor H binding proteins

• Published in: Microbes and infection Vol. 21; no. 8-9; pp. 377 - 385
• Main Authors: Moreno-Torres, Azaf, Malvido-Jiménez, Irving R., de la Peña-Moctezuma, Alejandro, Castillo Sánchez, Luz O., Fraga, Tatiana R., Barbosa, Angela S., Isaac, Lourdes, Sahagún-Ruiz, Alfredo
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01-10-2019
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Carrier Proteins - genetics; Carrier Proteins - metabolism; Complement evasion; Complement Factor H - metabolism; Factor H; Gene Expression Regulation, Bacterial; Humans; Immune Evasion - genetics; Leptospira; Leptospira - genetics; Leptospira - immunology; Leptospira - pathogenicity; Leptospira complement binding proteins; Leptospirosis - microbiology; Microbial Viability - genetics; Microbial Viability - immunology; Protein Binding; RNA, Messenger - genetics; Factor H; Leptospira complement binding proteins; Leptospira; Complement evasion
• ISSN: 1286-4579; 1769-714X
• DOI: 10.1016/j.micinf.2019.03.001

Several pathogens including Gram-negative bacteria hijack complement regulators to escape host's innate response. Pathogenic Leptospira species bind Factor H, C4b binding protein and vitronectin from the complement system. We evaluated the ability of low passage (LP) and culture-attenuated (CA) pathogenic strains of Leptospira, to bind Factor H. We used LOCaS46 (Leptospira interrogans sv Canicola), LOVe30 (L. interrogans sv Icterohaemorrhagiae) and MOCA45 (L. santarosai sv Tarassovi), and ten high passage strains of Leptospira [used in the microscopic agglutination test (MAT)]. Afterwards, we assessed their survival in normal human serum (NHS). Interestingly, the ability in binding Factor H was higher for LOCaS46 and LOVe30 LP strains, than for the respective CA strains suggesting that the ability of evading the alternative complement pathway is lost after culture attenuation. Accordingly, the level of mRNA expression of the Factor H binding proteins, LigA, LigB and Lsa23 was higher in these LP strains than in the corresponding CA strains. Unexpectedly, no difference in Factor H binding and surviving was observed between LP and CA MOCA45 strains. The high passage MAT-reference strains showed variation in Factor H binding ability, but, in most cases, the ability for capturing Factor H by Leptospira strains correlated with their survival in NHS.