Interaction characteristics of RAW264.7 macrophages with Streptococcus suis serotype 2 at different multiplicities of infection
Year: 2026
Type: article
Abstract: Streptococcus suis serotype 2 (SS2) is a highly pathogenic zoonotic agent responsible for severe systemic infections in both humans and pigs. Its pathogenesis is closely associated with host immune dysregulation, which is further aggravated by high bacterial load in the infected host. We hypothesized that the multiplicity of infection (MOI) plays an important role in SS2 evasion of macrophage-mediated immunity by modulating macrophage function. RAW264.7 cells were infected with the SS2 strain ZY05719 at gradient MOIs, and their defensive capacity against SS2 was systematically assessed. At low MOIs, RAW264.7 cells efficiently phagocytosed SS2 and exhibited potent bactericidal activity. In contrast, when the MOI reached 20 or higher, SS2 markedly impaired the phagocytic and bactericidal capacities of RAW264.7 cells, inhibited ROS production and pro-inflammatory cytokine transcription, and even induced apoptosis, ultimately promoting the intracellular survival of SS2. Taken together, this study provides a novel insight into the role of MOI as a critical determinant in the interplay between SS2 and macrophages.
Source: The Microbe
Institution: Shandong Agricultural University
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,150
OpenAlex ID: W7166577530